bearings and oil flow

grumpyvette

Administrator
Staff member
Bearings and oil flow

viewtopic.php?f=53&t=88

http://www.babcox.com/editorial/us/us90126.htm

http://www.insightservices.net/testoil/ ... cation.htm

http://www.thirskauto.net/BearingPics.html

http://micapeak.com/info/oiled.html

http://www.unofficialbmw.com/all/misc/all_oilfaq.html

http://www.fd3s.net/oil_pressure.html

http://www.aa1car.com/library/us1097.htm
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keep in mind both engine oil temps and trans fluid temps seldom reach operational temps,fluid
and stabilize , for semi consistent data,in under 12-15 minutes of drive time,temps have a huge effect on lubricant viscosity and durability. .
in my opinion , and experience and from lots of G.M. engine, race testing.
theres no need for oil pressure to exceed about 65 psi,
it takes power to spin the oil pump against that extra resistance, it induces extra wear on the distributor and cam gears,
and it does nothing to reduce bearing wear or increase cooling on the bearing surfaces, he should open some bearing clearances marginally
(maybe an extra half thousandth on the mains) to increase oil flow volume reaching the main bearings, and use a lower resistance oil pump bye-pass spring.
extra oil flow volume cooling the bearings and valve train will do more for durability than oil pressure exceeding 65-70 psi
http://engineparts.com/it_crankinstall.asp

http://engineparts.com/it_bearinginstall.asp

http://engineparts.com/techbulletins/CL77-1-205R.pdf

http://www.micapeak.com/info/oiled.html

http://www.nordicgroup.us/oil.htm

http://www.carbibles.com/engineoil_bible.html

http://data.melling.com/Select/small_block_chevy.php

http://data.melling.com/Select/big_block_chevy.php

http://www.thirskauto.net/Engine_Thrust_Bearings.html

http://www.engineparts.com/motorhead/te ... stall.html

http://www.babcox.com/editorial/ar/ar20128.htm

http://www.babcox.com/editorial/cm/cm99828.htm

http://www.thirskauto.net/Engine_Thrust_Bearings.html

http://www.diabolicalperformance.com/clearances.html

http://www.babcox.com/editorial/ar/ar10180.htm

http://data.melling.com/TECH.php

http://www.babcox.com/editorial/ar/eb110127.htm

http://theoildrop.server101.com/forums/ubbthreads.php

http://minimopar.knizefamily.net/oilfilterstudy.html
Id also point out that, if you properly set up an engine's oil system, open the oil drain holes and use the proper oil pan, windage screen and crank scraper, its virtually impossible , in a well designed engine to run the engine "long enough to pump all the oil upstairs."
as with a properly designed baffled oil pan, with a carefully fitted and clearanced windage screen and crank scraper, the oil pump simply reaches a flow rate pumping oil out of about 100 or so potential lubricant flow leakage points
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http://garage.grumpysperformance.com/index.php?threads/whats-a-windage-tray-do.64/
thats a very common question but the answers no!
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ALL THAT OIL FILTER BYE-PASS VALVE DOES IS ROUTE OIL FLOW PAST THE OIL FILTER
IF IT BECOMES SO CLOGGED WITH TRASH THAT THERES
A 10 PSI DIFFERENCE IN THE RESISTANCE TO OIL FLOW THROUGH THE FILTER
VS AROUND IT INTO THE BLOCKS OIL PASSAGES, oil enters the area over the oil filter in the block and is forced into the outer holes in the oil filter perimeter down through the case and filter element and up through the central hollow screw retention stud into the blocks oil passages, if the resistance too flow is too great the oil filter bye-pass valve routes oil around the filter directly from oil pump to the blocks oil passages.
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pressure is a measure of RESISTANCE to oil flow, if the pumps providing flow and yes that needs to be verified,
( because if the oil pump pick-up is less than a 1/4" off the oil pan floor flow is potentially restricted)
if your getting oil flow from the oil pump and no back pressure Id suggest checking the flow control valves, bearing clearances and oil passage plugs at the ends of the lifter gallery passages, any major open to flow oil passage results in very low oil pressure readings
http://garage.grumpysperformance.co...ark-v-bbc-engine-oil-system-differences.4576/

https://www.chevydiy.com/oil-lubrication-systems-guide-big-block-chevy-engines/
https://paceperformance.com/i-51345...ich-adapter-for-external-oil-cooler-only.html

http://garage.grumpysperformance.com/index.php?threads/basic-info-on-your-v8-lube-system.52/
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Big Block Chevrolet Gen V and Gen VI Oiling SystemSolving the mystery of the Gen V and Gen VI Priority Main Oiling system
Priority Main Oiling System
The Generation V and VI big block Chevrolet blocks feature a priority main oiling system where the main oil supply passage is located adjacent to the camshaft tunnel. Drilled passages which intersect this large oil tunnel carry oil directly to the main bearings. If you are facing the front of the block with the engine in the upright position, this main oil supply tunnel is located in the 2 o’clock position just below the right hand lifter oil supply line.

Oil Cooler Plumbing
Located along the oil pan rail just ahead of the oil filter pad are two drilled and tapped (3/8” NPT) oil passages for routing oil to an external oil cooler. The hole located closest to the oil filter pad (#2) is for the outgoing supply line to the oil cooler. The front passage (#1), which is farthest from the filter pad, is the return line from the oil cooler.

Careful examination reveals that these two passages intersect the same return line that feeds oil back to the main oil tunnel. This requires that a special fitting be used in the #2 supply line to prevent oil from short circuiting the oil cooler.

Part number SD1540 provides the necessary diverter basket to prevent the supply oil from entering the return line before going to the oil cooler. This fitting has a dash 10AN thread to allow the use of aftermarket components to plumb your external oil cooler. The front passage #1 will require a 3/8” NPT by dash 10AN adapter (#FCM2185), which is available from Scoggin-Dickey.

Understanding By-pass Valve Locations
Factory assembled 454, 502 engines and short blocks have two by-pass valves installed in the block. These factory installed by-pass valves (#25013759) will open at an 11 psi pressure differential. One by-pass valve is installed in the center hole on the oil filter pad (#4). This hole is the oil return passage from the oil filter. The second by-pass valve is installed in the adjacent hole (#3). The egg shaped hole (#5) is the high pressure oil supply passage from the oil pump.

For all racing application that will NOT use an oil cooler but will maintain the stock oil filter location, you must remove the center by-pass valve in location #4. Removing this valve eliminates three redundant right runs in the oil system. However, if you leave this by-pass in place the oil system will still function as it was intended, but a loss of oil pressure can result from the four right angle turns required for oil to return to the main oil tunnel.

If you intend to use a remote oil filter, a high pressure by-pass valve part number 25161284 must be installed in position #3. This valve will open at a 30 psi pressure differential. A plug will be installed in position #4 to prevent oil flow thru this passage. Oil should be returned to the block in the 3/8” hole located just able the oil filter pad. An oil filter block off plate kit (#SD3891) can be purchased from Scoggin-Dickey for Gen V and VI blocks to plumb your external oil filter.

If you intend to maintain the stock filter location and will use the factory provided oil cooler passages to install your oil cooler, then you must install two high pressure by-pass valves (#25161284). One will be installed in location #3 and the second in location #4.
MORE USEFUL INFO
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yes the oil flows around the mounting stud,from oil pump to main cap to reach the engine oil passages, thru the oil filter
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BIG-BLOCK-CHEVY-4-BOLT-%20REAR%20MAIN-CAP.jpg

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failure to use the correct oil pump,mounting stud, bolt or nut or carefully check clearances when mounting an oil pump can cause problems
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ONE RATHER COMMON MISTAKE IS USING THE WRONG OIL PUMP STUD OR BOLT TO MOUNT THE OIL PUMP AS IF EITHER EXTENDS THRU THE REAR MAIN CAP IT CAN AND WILL BIND ON THE BEARING AND LOCK OR RESTRICT, SMOOTH ROTATION
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http://garage.grumpysperformance.co...-friction-and-pumping-losses.8966/#post-31978

heres a cooler several guys I know use.
https://www.jegs.com/i/Derale/259/15900/10002/-1

you will rather obviously need to carefully and accurately,
measure the location you want to install any fluid cooler and its fluid line connections, you should seriously consider a AN#8 line size as minimum

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you can easily run the trans fluid or oil cooler without the thermostat controlled feed/return lines,
a cooler with AN#8 or 1/2" line size preferred
many guys that do that have a toggle switch that shuts the fan on the auxiliary oil cooler off until the fluid comes up to operational temps.
will a thermostat valve on the auxiliary cooling lines help maintain a stable fluid or oil temp,
and speed up the time it takes for the engine and transmission fluids to come up to operational temps? hell yes
,but theres millions of guys that have run a cooler without one.
on the down side, both engines and transmissions tend to last longer when the lubrication fluids are both stable and consistently in the ideal range.



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http://shop.perma-cool.com/1073-Oil-The ... s-1073.htm


heres a cooler several guys I know use.

https://www.jegs.com/i/Derale/259/15900/10002/-1

you will rather obviously need to carefully and accurately,
measure the location you want to install any fluid cooler and its fluid line connections, you should seriously consider a AN#8 line size as minimum

oilpassb.JPG

theres zero doubt an accusump oil feed is a good insurance policy to maintain oil pressure at the bearings, but simply having a 7-8 quart baffled oil pan,properly clearanced, windage screen and crank scraper will insure the oil pressure remains consistent , mostly due to the fact that theres always going to be enough oil over the oil pump pick-up, simply because theres really no room to pack most of the available oil volume in the upper engine ,plus the fact that hot oil flows well.
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OIL PRESSURE read on the oil pressure gauge is a MEASURE of RESISTANCE to oil flow, you can REDUCE the pressure the gauge reads by either increasing the engine clearances or REDUCING the oil viscosity (thickness) so it flows thru the clearances faster with less resistance.(OR INSTALLING A SLIGHTLY WEAKER OIL PUMP BYE_PASS SPRING,that limits the pump pressure before it allows some oil to re-circulate back through the bye-pass valve ,from the high pressure back to the low pressure side of the pump impellers, but only the max pressure you reach is limited by the bye-pass spring,in your oil pressure bye pass circuit and its that spring resistance determines the point where the bye-pass circuit, opens and limits max oil pressure, but the bye-pass circuit has zero to do with anything else, if its functioning correctly,
there are many oil leakage points(100) in a standard Chevy engine.
16 lifter to push rod points
16 push rod to rocker arm points
32 lifter bores 16 x 2 ends
10 main bearing edges
9 cam bearing edges
16 rod bearing edges
2 distributor shaft leaks
1 distributor shaft to shim above the cam gear(some engines that have an oil pressure feed distributor shaft bearing.)
once oil exits the bearings or valve train it flows mostly by gravity back to the oil pan sump, but a properly designed windage screen and crank scraper correctly clearanced allows the spinning crank/rotating assembly to act like a directional pump that drags the vast majority of the oil flow back to the sump, by design.
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A simple modification to the upper thrust bearing may be beneficial in some engines. Install the upper thrust bearing in the block to determine which thrust face is toward the rear of the engine. Using a small, fine tooth, flat file, increase the amount of chamfer to approximately .040" (1 mm) on the inside diameter edge of the bearing parting line. Carefully file at the centrally located oil groove and stroke the file at an angle toward the rear thrust face only, as shown in the illustration below. It is very important not to contact the bearing surface with the end of the file. The resulting enlarged ID chamfer will allow pressurized engine oil from the pre-existing groove to reach the loaded thrust face. This additional source of oiling will reach the loaded thrust face without passing through the bearing clearance first (direct oiling). Since there may be a load against the rear thrust face, oil flow should be restricted by that load and there should not be a noticeable loss of oil pressure. This modification is not a guaranteed "cure-all". However, the modification should help if all other conditions, such as surface finish, alignment, cleanliness and loading are within required limits.
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Preference on assembly lube?

50% marvel mystery oil

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and 50% crane moly lube, or the paste moly, the mix of moly paste and M.M.O. is generally applied liberally with the paint brush, in multiple applications to surfaces like cam gears, timing chains, lifters, rockers, and cam lobes, to provide an extra layer of lubrication protection on initial engine start up.
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what Ive used for decades
but this works

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I have used J&B WELD EPOXY on a large magnet
https://www.zoro.com/value-brand-ring-magnet-98-lb-pull-10e797/i/G4187224/
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on the base of an aluminum 1/2 cup measuring cup I purchased at a yard sale for 25 cents to mix up the mixture, the magnet allows me to stick the cup to the block oil pan rail or engine stand where its handy too get at, and I simply brush on the mix with a 1" paint brush, with synthetic bristles that won,t shed
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OH! slide it off the block don,t try to just pull it off , its going to be much less messy that way trust me!
when your done , wipe it clean and stick it inside the lid of your tool box , after placing it in a ziploc bag to prevent it from picking up trash while in storage

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shopping

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http://garage.grumpysperformance.com/index.php?threads/whats-a-windage-tray-do.64/

http://garage.grumpysperformance.com/index.php?threads/oil-system-mods-that-help.2187/

http://garage.grumpysperformance.com/index.php?threads/basic-info-on-your-v8-lube-system.52/
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from chevy high performance mag

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yes Ive seen several cases where guys failed to install the oil pump pick-up at the proper minimum 3/8"-to-1/2" off the oil pan floor clearance,
the result is the pump is starved for oil intake flow.
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http://garage.grumpysperformance.co...m-sure-your-convinced-its-the-oil-pump.11085/

http://garage.grumpysperformance.co...m-oil-pump-installed-now-no-oil-pressure.525/

http://garage.grumpysperformance.com/index.php?threads/bbc-oil-pump-in-a-sbc.2598/

ChevyOilingPlug.jpg

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with the engine up to operational temp.of between about 180f-210f
and using an oil viscosity that maintains at least 15-20 psi at hot idle in traffic,
your engine should maintain a MINIMUM of 10 psi per 1000rpm and max out pressure at about 4500-5500rpm at 60psi or higher
remember the thicker the oil the harder it is to force thru the clearances in the engine, and pressure is how you measure the RESISTANCE to oil flow, but you should use an oil viscosity that at least maintains that 15-20 psi at idle

one factor thats frequently over looked is that many bearing manufacturers don,t seem to have placed the bearing oil feed holes in bearing shells so they exactly match the oil feed passages in the engine blocks
example heres a common minor mis-match on the bearing shell/oil passage alignment
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but Ive seen some where over 1/3-to-1/2 the oil feed hole was blocked due to misalignment, thats usually easily cured, by drilling a shallow increased diameter recess in the blocks oil passage to open it to match the bearing or opening up the bearing feed hole, but which ever route you take be sure to carefully clean and deburr both
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increasing the groove, from 180 deg to 270 deg, lowers bearing support, increases oil flow rates and tends to increase wear

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As you'll see in Figure 1, below two different types of grooved upper main bearing shells

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the oil groove terminates before it gets to the bearing parting line. This style of main bearing has accounted for a 15 percent or more increase in hot idle oil pressure. So if you're looking to eliminate some of those unexplained low oil pressure gremlins contact your bearing manufacturer and ask about this style bearing and availability for the engine applications that you are building.

keep in mind only the upper main bearing shell should have an oil groove, having a 360 degree oil groove lowers the bearing ability to handle high rpm loads

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THESE BEARING PICTURED ABOVE, LOOK GREAT BUT HAVE LOWER LOAD CAPACITY
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a 180 degree bearing has only the upper in the block grooved to improve oil flow,a 270 degree has the oil feed groove extend further 45 degrees on each lower bearing shell

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MAIN BEARINGS WITH 360 degree oil grooves
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these CLEVITE (H) SERIES, ABOVE MAY NOT LOOK AS GOOD BUT HAVE HIGHER LOAD CAPACITY AND BEVELED EDGES FOR THE CRANK FILLETS, or ROUNDED CORNERS ON THE JOURNALS THAT INCREASE STRENGTH LIKE ON THE CRANK BELOW
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Introduction:
The main bearing oil groove is required for the sole purpose of supplying oil to the
connecting rod big end bearing. At one time it was common to have a full 360° groove on the
main bearing to provide an uninterrupted supply of oil to the big end by means of a single
drilling from the main journal. This was achieved by having identical upper and lower bearing
shells.
As bearing loads increased this design proved unsustainable as the oil film thickness, on
which every crankshaft bearing relies, became insufficient for reliable main bearing
operation. The solution was to increase the bearing area on the more heavily loaded lowerhalf
bearing by reducing the extent of the groove to around 230° or even 180° in order to
provide a single bearing land of greater width. Any increase in bearing width enables a
higher oil film pressure to be sustained as the distance from the centre of the bearing to the
edges, which cannot sustain an oil pressure, is increased. This in effect allows the
generation of a thicker oil film with which to separate the shaft and bearing shell.
The reduced oil groove extent would sometimes be compensated by a cross-drilling on the
main journal in an attempt to maintain an uninterrupted supply of oil to the big end bearing.
However, in many cases it was found that the big end could cope very well with the
subsequent intermittent oil flow offered by a single drilling from a 180° groove.
Nowadays, with the use of computer simulation and engine testing the optimum extent of the
groove may be determined. It is not now just a case of allowing the big end to survive but
that the efficiency of the bearing system can actually be improved by due attention to the
groove geometry. This is because the big end bearing, like any hydrodynamic lubricated
bearing, will use as much oil as it needs to generate an oil film for any given operating
condition. Any less than this amount risks disrupting the oil film and ultimately starving the
bearing of oil, but equally, feeding excessive oil to the bearing simply results in additional
leakage, and reduced efficiency. Therefore, the oil groove, like many other features on a
bearing shell, can be optimised.

read thru these links

http://vandervell.co.uk/images/slidesho ... forman.pdf

http://www.stealth316.com/misc/clevite- ... ooving.pdf
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TB 2051 2/10/2000
Influence of Grooving on Main Bearing Performance
Various forms of main bearing grooving have been used over the years. We are
frequently asked what difference grooving makes.
First, it’s essential to understand that bearings depend on a film of oil to keep them
separated from the shaft surface. This oil film is developed by shaft rotation. As the shaft
rotates it pulls oil into the loaded area of the bearing and rides up on this film much like a
tire hydroplaning on wet pavement. Grooving in a bearing acts like tread in a tire to break
up the oil film. While you want your tires to grip the road, you don’t want your bearings
to grip the shaft.
The primary reason for having any grooving in a main bearing is to provide oil to the
connecting rods. Without rod bearings to feed, a simple oil hole would be sufficient to
lubricate a main bearing. Many early engines used full grooved bearings and some even
used multiple grooves. As engine and bearing technology developed, bearing grooving
was removed from modern lower main bearings. The result is in a thicker film of oil for
the shaft to ride on. This provides a greater safety margin and improved bearing life.
Upper main shells, which see lower loads than the lowers, have retained a groove to
supply the connecting rods with oil.
In an effort to develop the best possible main bearing designs for High Performance
engines, we’ve investigated the effects of main bearing grooving on bearing performance.
The graphs on the next page illustrate that a simple 180
°
groove in the upper main shell is
still the best overall design.
While a slightly shorter groove of 140
°
provides a marginal gain, most of the benefit is to
the upper shell, which doesn’t need improvement. On the other hand, extending the
groove into the lower half, even as little as 20
°
at each parting line (220
°
in total), takes
away from upper bearing performance without providing any benefit to the lower half.
It’s also interesting to note that as groove length increases so do Horsepower Loss and
Peak Oil Film Pressure which is transmitted directly to the bearing

from what I've read pressure over 65 psi at W.O.T.
or over 20PSI at idle for a sbc or BBC adds no benefit.
some ford engines are designed to work with up to 100 psi of oil pressure at peak rpms
added oil flow rate volume helps cool and lubricate to a greater extent than added pressure


yeah the linked info holds a great deal more info
http://garage.grumpysperformance.com/index.php?threads/testing-a-chevy-oil-pump.6479/#post-87726

http://garage.grumpysperformance.com/index.php?threads/oil-system-mods-that-help.2187/

http://garage.grumpysperformance.co...l-pumps-pressure-bye-pass-circuit-works.3536/

http://garage.grumpysperformance.com/index.php?threads/installing-an-oil-pump-pick-up-tube.1800/

http://garage.grumpysperformance.com/index.php?threads/bearings-and-oil-flow.150/

http://garage.grumpysperformance.com/index.php?threads/shimming-an-oil-pump-relief-spring.16240/

http://garage.grumpysperformance.com/index.php?threads/basic-info-on-your-v8-lube-system.52/
 
Last edited by a moderator:

grumpyvette

Administrator
Staff member
http://www.daymotorsports.com/product/1 ... NG-SPACERS
KING BEARING SPACERS
Part Number Description Price Qty Add
EB-MB5224AM Chevy 350 to 400 Spacer $49.99

http://www.speedwaymotors.com/MAIN-BEAR ... K,533.html

400 sbc block/350 crank main bearing spacers

theres also TRW MS3110P is the part number for a main bearing set to put a standard pre 1968 small journal (283, 265, sj327) crank into a medium journal (350) block

http://www.chevyhiperformance.com/techa ... index.html

IT should be obvious that you'll need to pre-prime the blocks oil passages and adjust the rockers so oil flows from the rockers with the engine being pre-primed with a priming tool being used BEFORE trying to start any engine with a new cam to insure oil flow begins instantly on the engines start-up,you WON,T get oil to all lifters equally unless the engines crank & cam are spinning,(so during testing spin the engine slowly with a breaker bar or ratchet), because the oil passages feeding the lifters aligns differently at different lifts,your oil leak at the distributor base is normal, but the clearances and flow may be excessive, with a priming tool, some are not nearly to spec. ID measure the diam. of the oil pump primer and then measure the distributor base, Id bet the distributor base is larger and fits better, which reduces the potential for leakage.
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those bottom two bands form a wall on the oil passage, some guys cut a rounded grove and install an O-RING so the upper band seals too the block, you don,t want to do that to the lower band simply because that's the oil flow source to the distributor /cam gear
20 psi is about normal for your typical 3/8 drill,max pressure is not nearly as important as checking flow, and for leaks where there should not be leaks, with an engine primer tool,Ive brazed a socket to the top of my oil pump primer and use the 1/2" drive air ratchet to drive it, it won,t heat up and burn up like a electric drill will.
don,t get alarmed if you get zero pressure or flow for a few seconds,(the oil filter and passages need to fill first) that's one reason WHY your pre-priming, to get oil flow to the bearings instantly on start up , you don,t want them running without oil flow if you can prevent it even for 20 seconds
the difference between a stock capacity BBC and high volume SBC oil pump is minimal,
in the power needed to drive either one, you can use either, oil pump,
Ive used several standard volume bbc oil pumps in SBC engines but the stock z28 SBC oil pump works very well.
neither pump will require anywhere close to 10 hp,the tests Ive seen show closer to 2hp at peak rpms for either oil pump.
significantly less with normal .002-.003 clearances and hot 10w30 oil.
you certainly do not need a high volume BBC oil pump on a SBC engine
obviously bearing clearances, oil viscosity , oil temperature,and the other lube system mods will effect the power required to spin any pump,

heres a calculator, if you put in the typical 6 gallons a minute at 65 psi you get less than 1/4 hp required
http://www.wallaceracing.com/oil-pump-hp-calc.php

http://www.badasscars.com/index.cfm/page/ptype=product/product_id=91/prd91.htm

http://www.wallaceracing.com/oil-pump-hp-calc.php

http://www.badasscars.com/index.cfm/page/ptype=product/product_id=91/prd91.htm

Are high volume oil pumps OK to run on the street?


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We get asked this one from time to time, and the answer is, it depends on the engine. First off; why do you think you need to run a high volume oil pump? The reason performance and race engines use them is because the clearances are upwards of twice the amount as a stock engine. Those voids flow oil out much quicker so they need more volume to stay filled with oil.

A typical stock engine has about .001" - .0015" of rod and main bearing clearances. When you get into more serious engines you will find rod clearances as much as .002" or more, and crank clearances upwards of .0025" - .003" or more. This is also why in the older days, race and performance engines used to run much thicker oils to help "take-up" all of that space. It was common to see straight 40wt and 50wt race oils in engines back in the day. Now days, with much better oils, we tend to run tighter clearances and much thinner oils. We've learned that thinner oil gets to where it needs to go much quicker and with less effort than thicker oils. Larger clearances on serious performance and race engines drain-out quicker so you need a pump that'll push more oil volume into them to keep those larger clearances full. Stock or mild performance engines don't really require that much oil flow because the clearances are much less and therefore "flow" oil much less.

You can't pump oil where it doesn't want to go. In other words, unless your crank and rod clearances are a lot more than a stock engine, then oil simply isn't going to flow and all you are going to do is make a lot of oil "pressure" but not much additional "flow". There's a HUGE difference between "pressure" and "flow". Contrary to what most guys believe, pressure is actually the negative result of flow. If you had full flow, you would have very little oil pressure. What happens when you eat a rod or main bearing? Your .001" - .003" clearance got chewed-up and is now .020" - .030", or basically ten times more than it is supposed to have, so now you have a huge amount of clearance that oil is just POURING out of. It's like slicing into an artery in your body, blood openly flowing out drops your blood pressure.

Other than the noise of a knocking rod or a squeaking "spun" main bearing, how can you tell when you have a bad bearing problem? The pressure reading on your oil pressure gauge drops WAY down. This is because you've opened-up that clearance way too far and now oil is just pouring out that huge space, which causes the pressure to drop way down. So, you increased the flow, and as a result, decreased the pressure.

Pressure can basically be looked at as "effort". How much effort is the pump going through to push that oil. The thicker the oil, the more the effort, and... the tighter the clearances, the more the effort to push oil into those tight spaces. Just because there is effort there (higher oil pressure) doesn't mean more oil is actually flowing. This again is especially true with thicker oils and why thicker oils create more oil pressure. Let me put this is terms even a kid can understand. Go to the local fast food joint and buy 2 drinks. One soft drink and one milk shake. Take a sip through the straw of the soft drink, now take a sip from the milk shake. It's a hell of a lot harder to sip that thick milk shake up through that straw than it is to sip-up that watery soft drink, right? Oil pumps and oil thicknesses are no different. You increased your effort to sip that milk shake and yet got much less of it into your mouth than you did the soft drink. That's exactly the same thing with oil pressure and oil flow vs. clearances and oil thicknesses, vs. oil volumes and pressures. if you want more milkshake with less effort, get a bigger diameter straw, which is like opening-up clearances on your engine, OR wait until the milkshake gets a bit warmer and thins down a bit. This is exactly like oil pressure dropping when your engine warms-up. It's because the cold, thick oil is requiring more effort (pressure) to push it into those clearances, but when it warms-up and gets thinner, it requires even less pressure, yet your FLOW increased. People seem to think this is such a complicated subject, but it really isn't at all.



Another thing is that higher volume oil pumps put much higher loads on the gears that are driving them, meaning the distributor and cam gears. Chevy engines can handle the higher loads of high volume oil pumps just fine, where most Ford's have troubles. Why? Chevy's use a much larger gear than a Ford does, in fact, it's about twice the size, which means it's about twice as strong. The distributor gear is what takes the load of spinning the oil pump. The more volume you pump through an engine, the more load gets put on that gear.



Ford gears tend to get eaten-up because they just aren't big or strong enough to take the load that a high volume pump puts on it. Once you eat-up a distributor gear it is pretty much disaster for the cam gear as well. If you wipe either one out, count on having to replace the cam shaft! This doesn't even get into all of that metal going through the engine, which doesn't help things like bearings and such.


prdp_578.JPG

We tend to use stock oil pumps on Ford's and high volume pumps on "performance" Chevy's where the clearances were opened-up a bit. On race prepped Ford engines that we run high volume pumps on, we use aluminum-bronze gears and just keep a close eye on them for premature wear because they WILL wear out in a short amount of time. In fact, that's what aluminum-bronze gears are designed to do... wear-out instead of the expensive cam wearing out on you. Technology has advanced a little these days with the invention of composite gears. They aren't made out of metal, they're made out of a material that is kind of like carbon fiber and are practically indestructible. The cool thing is they are compatible with all types of cams, from cast iron to billet steel, where before... if you didn't have the right type of gear on your distributor to match the type of cam you had, you were looking at disaster in a short amount of time.

When the 5.0L engines came-out with steel roller cams, they also went to steel distributor gears which are much stronger than the older cast iron gears, but they are still about half the size of a GM gear, so it is still about half the strength, which means you still have to be careful if you want to run a high volume pump. A lot of guys get away with it, but that's just it... they're "getting away with it". In other words, we still see a lot of guys NOT get away with it and then they have a serious and expensive problem to deal with. Going back to everything I explained above, did they really even NEED a high volume pump in the first place? Most likely not. If they wanted more flow, they should have probably just ran a thinner oil which would have increased the flow and not put undue loads on the cam and distributor gears.


Now, some people will say to run a stock pump because it won't rob as much power from the engine as compared to a high volume pump, but they install the "high pressure" spring in it to make more pressure. In some cases, pressure makes volume, but again, volume = load. If you ever forget to hook-up your oil pressure gauge line and you fire the engine up, you are going to have a LOT of oil coming out of that tiny little 1/8" line because of the pressure behind it. If there was very little pressure, not much oil would come out. Like I said; pressure makes volume IF there is a means for flow. But again, pressure increases load.

Some people say that a high volume oil pump will pump all of the oil to the top of the motor and basically empty out the oil pan before it can all drain back again. On some engines, such as Oldsmobiles where oil drain back through the heads is a common problem because of the long - small diameter drain back holes, so in cases like that this "could" have some slight truth to it, but 98% of the time, it has no basis. First off; high volume oil pumps only pump about 15% to 20% more oil than a stock pump does. So that would mean that your stock pump is only 15% - 20% away from sucking your oil pan dry. That's highly unlikely. Again, running thicker oils means draining back through long, skinny holes in some of the heads out there (such as Oldsmobiles) MIGHT be an issue because just like that thick milkshake I mentioned earlier, if you turned both the soft drink and the milk shake cups upside down, which one will pour through the straw better than the other? It would probably take (literally) a minute or two for the thick milkshake to even start to dribble out of the straw under gravity conditions, where by that time, the entire soft drink cup would be completely empty. Thicker oils and small drain back holes in heads would have similar results, but in most cases, most engines have plenty of oil drain back holes and areas, so it isn't a problem most of the time.

In a nutshell, 95% of all engines out there, whether stock or mild performance (under 550 HP or so) will do just fine with standard oil pumps, especially if a little thinner oil is used and if the clearances that aren't too loose.
 
Last edited by a moderator:

grumpyvette

Administrator
Staff member
IF your having excessive oil heat problems with an engine, my
first suggestion swap to a decent synthetic oil in the 10w30 range or at least the thinnest viscosity that maintains 20 psi at hot idle temps, as SYNTHETICS don,t generally start breaking down until about 280F PLUS while mineral base oils tend to start degrading after repeated 250F use, and the thinner the oil the faster it circulates thru the clearances, and the faster heats absorbed and transferred out off the hotter components
and Id need to know more about the complete engine parts list, clearances, etc. but Id sure want to verify the fuel/air ratio is at about 12.6:1 not alot leaner and your ignition timing was carefully checked to not be a couple degrees advanced from ideal., and that your running a 7-8 quart oil pan, heres the oil cooler I use and I had to install a thermal switch or it OVER COOLED my engine oil in FLORIDA where average outside air temps closer to 90F
oil does most of an engines real cooling and the cooling system allows heat absorbed by the oil and transferred to the block to be transferred to the coolant and removed, but a significant percentage of that heat can be removed if an efficient oil cooler is installed, that maintains a significantly lower average oil temp while the engines under stress., think about it a second. the HOT PARTS like rings, valves, cams, lifters, bearing surfaces and valve springs and pistons get cooled mostly by oil splash or pressurized oil flow not direct coolant contact

my oil pan looks similar to this
http://canton.carshopinc.com/product_in ... 88bb985ecf
Canton Oil Pans
11-120 and 11-120T Oil Pans
11-120.jpg


but I extended the sump forward with 14 ga steel and a tig welder to add 4 inches extra to the sump to get 10 qt capacity

http://www.summitracing.com/parts/PRM-1 ... mage=large


prm-12318.jpg


But I was always under the impression that Chevys liked thicker mineral oils, and I should avoid synthetics? Not true then?

NOT TRUE, TRY THE THINNER SYNTHETIC OIL, as LONG AS YOU HAVE A MINIMUM of 20 PSI at hot idle your fine!
IVE run a MIX of 90%/ synthetic 10% mineral oil in my race cars for many years

usually 1 qt MARVEL MYSTERY OIL, 9 qts MOBILE 1 10w30 synthetic

http://www.marvelmysteryoil.com/

https://www.mobiloil.com/USA-English/Mo ... /Oils.aspx


obviously these won,t fit all chevy applications but if you have the room for the longer, spin on filters

The "longer high capacity oil filter" Purolator is L40084.

"longer high capacity oil filter" N.A.P.A: # 1794

"longer high capacity oil filter" ACDelco: PF932


keeping the oil cool basically comes down to having the oil flow thru both the engine and the cooler but having the surface area of the cooler large enough and the number of passes thru the cooler ,allow the oil to transfer most of the heats its absorbed in the engine back out into the air flowing thru the cooler,before its routed back to the engine,and that generally requires ducting cool air into the cooler and placing it where the flows not restricted, on my corvette I removed the rear spare tire, and built a mount that allowed a good deal of clearance and no significant engine heat, with it working all the time I had problems getting the heat over 220 f and it mostly stayed at or near 200f,theres basically about 3 qts in the upper engine and oil passages at any time , absorbing heat so having a similar volume in the cooler, releasing heat during the same time makes sense, and having a similar amount in the baffled oil pan sump and filter sure helps,naturally if you have the oil routed to spend more time with the majority of the oil being heated and less of the oils times spent cooling average temperatures rise rapidly
 

grumpyvette

Administrator
Staff member
theres some confusion as to the correct oil pan size and dip stick markings,, ILL try to keep this simple, basically the oil pan should never be less than a 5 qt capacity in a performance application, and as long as clearances under the car permit a 6-7-8 or larger capacity baffled oil pan with a windage screen is preferred, some guys will suggest restricting oil flow return routes to the sump by installing lifter valley breather tubes, but a decent cranl scraper and windage screen on a high capacity baffled oil pan reduces windage losses significantly, and that oil cools the pistons, rings and cam and lifters so reducing its ability to cool and lube those components by restricting flow is not a great idea

theres about 2-3 quarts of oil in a running engine thats not sitting in the sump, around the oil pump that lowers the oil pan oil level a good deal, normal 5 qt oil pans still have 2-3 qts around the pickup, but that lowers the oil level in the oil pan in most cases about 2-3 inches while the engine runs, so most dip sticks measure the correct oil level as about 2" up on the crank counter weights, because once the engines spinning that puts the oil level below the windage screen or at least below the spinning crank.
DIP STICKS are NOT always correctly marked,you should be able to research your oil pans intended capacity, Id suggest running NO LESS than a 5qt capacity oil pan and a baffled 6-7-8 qt is vastly preferable if your not sure add 5 qts to an empty oil pan and start the engine for a minute to fill the oil filter and oil passages, then look at where the oil level is in relation to the indicator band on the dip stick so you know what the minimum level should be, if its significantly lower than the dipstick marks, add the required oil level the pans rated for and pay attention to the dipstick.
just remember oil levels drop several inches once the engines running and as the rpms increase the level tends to drop slightly more, your very unlikely to (PUMP THE PAN DRY) like you commonly hear as a MYTH with the high volume oil pumps, because hot oil with a well designed oil pan and windage tray drains back into the sump quickly and the vast majority of the oil never makes it to the upper engine as its leaking from rod, man and cam bearings and lifter bores and gets swept back into the sump.
now it should be obvious that to use a high volume oil pump you need a MATCHING high capacity baffled oil pan and windage screen to CONTROL the extra oil flow rates, and the bearing, and other engine clearances and oil drain holes in the block should be designed to use the extra oil flow.
its not that difficult to remove the oil pan, replace the gasket with a new one piece synthetic one and cure that leak,
most guys can do that in a single afternoon with the car up on 4 12 ton jack stands rather easily.
be aware that the crank counter weights rotated to the correct location makes removing the oil pan a bit easier.
it might be a great opportunity to swap to a higher capacity baffled oil pan.
obviously youll want to carefully research the correct oil pan for your engine and chassis before purchasing one

https://www.summitracing.com/parts/ctr-15-240/overview/make/chevrolet/model/corvette
7" deep

https://www.cantonracingproducts.com/cgi-bin/commerce.cgi?preadd=action&key=11-102
6.5" deep


https://www.carid.com/moroso/oil-pa...MIraOQn-602QIVBJ7ACh2mTwt4EAQYAyABEgJZWfD_BwE


7" deep

theres lots of 8" and 8.25" deep corvette oil pans but they don,t last too long with speed bumps and raised manhole cover rims

http://www.substech.com/dokuwiki/do...e_design_for_high_performance_engine_bearings

https://www.summitracing.com/parts/...MIytnIx-y02QIVHrjACh35mQ-OEAQYASABEgJnZvD_BwE

http://garage.grumpysperformance.co...etic-oil-cause-leaky-gaskets.2725/#post-13817

http://garage.grumpysperformance.com/index.php?threads/under-car-safety.26/page-4#post-69999

http://garage.grumpysperformance.co...-pan-gasket-still-small-leak.3084/#post-11971
viewtopic.php?f=54&t=64

viewtopic.php?f=54&t=525

viewtopic.php?f=54&t=615
 
Last edited by a moderator:

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
http://kingracebearings.com/wp-cont...-oil-groove-for-high-performance-bearings.pdf

http://www.powerperformancenews.com/tech-articles/bearing-need-know-buy-next-set-engine-bearings/

http://www.superchevy.com/how-to/engines-drivetrain/0707ch-main-bearing-clearance/

http://www.enginebuildermag.com/2016/10/pera-parties-in-toronto-makes-plans-for-florida/

http://garage.grumpysperformance.com/index.php?threads/oil-system-mods-that-help.2187/
as a general rule as your engine oil viscosity is reduced the effort required to pump the oil thru clearances is lower and the pressure reading on the gauge drops, thats not necessarily an indication of lower bearing protection, as thats generally a function of oil quality and its formula, and basic components used, in its design, and generally its increased flow rate increases bearing cooling, a good quality 10w30 should ideally provide 20-22 psi at 800rpm idle (anything over 15-17 psi at 800rpm is fine) and 60-65psi by 5000rpm which is all you can use
keep in mind fluids like oil, are not compressible the resistance to flow increases as the pump is turned simply because the oil flow exiting the oil pump is flowing through the bearing clearances thus the oil flow exiting the oil pump is being restricted, if the engine was rotating the restriction too oil flow is reduced.
if the oil pumps pressure relief valve opens as designed max resistance is limited to the pump producing flow rates that will build until resistance to that flow volume reaches about 60 psi, when the pressure relief valve opens re-ce-recirculating additional oil flow back to the low pressure side of the oil pump.

http://garage.grumpysperformance.com/index.php?threads/bearing-clearances.2726/page-2#post-75256

http://garage.grumpysperformance.com/index.php?threads/bearings-and-oil-flow.150/#post-68205

http://garage.grumpysperformance.co...l-pumps-pressure-bye-pass-circuit-works.3536/

at times having a long small diameter light that you can stick through the blocks oil passages to check the oil feed to the bearings passage alignment helps

STE10150A.jpg


https://www.tooltopia.com/steelman-...MI4s7coYzY2AIV3I2zCh3U6AFUEAQYAiABEgI0PfD_BwE




viscosityvstemperature400.gif

oilvis1.jpg



clearanceload.jpg



clearanceflow.jpg



clearancetemp.jpg

shop carefully cam bearing tools sell for $40-$300 plus and almost identical tools car vary in price by over $120, and be awre all cam bearings in a single block may be different sizes based on the location, so pay attention as you remove them as to the oil feed hole location(S), how they are indexed or clocked and the outside diameter and be aware in many cases the bearing is beveled on one side to aid installation
LIL-18000a.jpg

12cal.jpg

heres some info from napa
http://knowhow.napaonline.com/know-notes-measure-engine-bearing-clearance/
bearing_clearance_feature.jpg

KNOW-HOW NOTES: HOW TO MEASURE ENGINE BEARING CLEARANCE


When rebuilding an engine, there is nothing more critical than getting the bearing clearance correct. Every engine has its own bearing clearance specs, but the measuring procedure does not change. There are two main methods used for checking bearing clearance – Plastigage® or gauges.

Plastigage®
Plastigage® has its place, as it serves a purpose for backing up and verifying your bearing clearances. Plastigage® is a special plastic that expands a specific amount when squeezed. Sold in sleeves of threads for specific thickness ranges, Plastigage® works really well in situations where the components are not being completely removed, such as in-engine bearing replacement, and other non-automotive uses. Originally put on sale in 1948, Plastigage® is fairly accurate and the method of choice for many DIY enthusiasts.

IMG_7335a.jpg

Plastigage® is quite useful, so don’t automatically throw it out. It is a good way of verifying your measurements.
crankse.jpg

In reality, the right way to check bearing clearances is with the proper tools. In order to check the clearances for rod and main bearings, you need a set of micrometers and a dial-bore gauge. These are readily available at budget prices, but if you are going to use them a lot, better quality tools are advised.

Micrometer
This looks like a horseshoe with a round handle attached to one leg. Micrometers typically only adjust 1”, so you need multiple sizes to get the job done. A 1-6” set usually has the sizes you need for most jobs.

IMG_6558a.jpg

This a complete micrometer set that will cover just about anything you could need for automotive work.

Dial-Bore Gauge
This tool uses a dial indicator on a post with a small wheeled measuring apparatus. These are adjustable through graduated post extenders that increase the diameter of the measurement circle.

IMG_6564a.jpg

The dial bore gauge measures the inside of round holes, such as the bearing journals.



IMG_6565a.jpg

This one tool can measure 2″ up to 6″ diameter holes.

Both tools are needed in order to check the interior and exterior dimensions of the crankshaft, rods and engine block journals, as well as the thickness of the bearings themselves. Making all of this happen can be tricky, so here are a few tips to help you work through the process.

Using a micrometer means following a couple of rules. The key to a micrometer is not to tighten it too much. There are two knobs – a large knob and then a smaller one. The smaller knob clicks when the micrometer is in contract with the part. DO NOT use the larger knob to tighten the mic onto the part as this can damage the tool.

Reading a micrometer can be confusing, they are graduated differently than rulers. The inside barrel is marked in .100” (large) and .025” (small) notations. Once you reach those marks, the scale on the thimble (large rotating knob) comes into play to get the finite measurements. The thimble is scaled in .001 divisions from .000 up to .025”.

IMG_6562a.jpg

The hash marks are how you read micrometers. It takes some practice, and unless you use them daily, you will forget over time. Just be patient.

Outer Diameter Measurements
These are fairly simple, just choose the micrometer that covers the range needed and measure. It is a good idea to check the part in three different locations, staying away from the oiling holes as they can throw off the measurements due to the chamfers.

Measuring Bearings
Even though bearings are flat enough, they cannot be accurately measured with calipers, instead you need a micrometer. There are special micrometers available for measuring round inside surfaces, but you don’t have to have one of those. Instead, you can use the shaft of a drill bit (good quality, and use the smooth part, not the fluted section). Place the drill bit on the inside curve, and then measure the bearing. Subtract the thickness of the drill bit (measure, don’t assume), and you will have the thickness of the bearing.

IMG_6571a.jpg

An tube mic is useful for measuring bearings and over inside-curved pieces. In a pinch, you can use a drill bit or pushrod and an outside mic.



IMG_6576a.jpg

This is how bearings are measured. DO NOT use calipers, you can easily scratch the babbit material and ruin the bearing, plus they are just not accurate enough.

Using A Dial-Bore Gauge
Setting up a dial-bore gauge requires using a micrometer. You need the base measurement of the bore, rough is enough. Set the gauge to just over the diameter, using the correct extensions. Set the micrometer to the bore size you need, then place the gauge between inside the mic and rock the gauge back and forth, and side to side. Note the minimum reading, and zero the gauge to that reading.

crop-1a.jpg

Setting the dial bore gauge uses both the bore gauge and a micrometer. Make sure the measuring ends are square inside the micrometer’s anvils (not as shown)

Inside Diameter Measurements
With the dial-bore gauge set to the correct size, place the gauge inside the journal or rod end and rock the gauge back and forth and side to side, just like the setup process. Note the smallest diameter, that is the size of the journal. Just like the outside measurements, take the reading in three different places. One note – the bore must be as it would be in use, so torque the caps to their correct specs and they need to be clean, no oil at all.

IMG_5607a.jpg

Place the gauge inside the journal and move it slowly till you find the largest measurement. Take readings in three places.

if your serious about building engines as a hobby or even as a part time side business,
you'll be forced to either buy or borrow some decent quality precision measuring micrometers,
simply due to the need to check clearances accurately

http://www.globalindustrial.com/p/t...mpaignId=T9F&gclid=CL3al-3ZqNECFVU6gQodqAQF-g (ABOUT $250 a set)
micss1a.jpg


http://www.mscdirect.com/product/details/06400865
(ABOUT $415 a set)
micss3a.jpg



http://www.mscdirect.com/product/details/57480832?cid=ppc-google-Returning+-+Measuring+&+Inspecting+-+PLA_s2ymmR5OE&cid=PLA-Google-PLA+-+Test___164124957330_c_S&mkwid=s2ymmR5OE&cid=PLA-Google-PLA+-+Test|dc&pcrid=164124957330&gclid=CLPzkdLaqNECFYw8gQodiR0LNg
(ABOUT $877 a set)
micss2a.jpg

dial bore gauges are about useless without a set of accurate mics, in the sizes of the bore diameter your checking as you use a dial bore gauge to measure consistency in a given bore size and basically how consistent or "ROUND" a bearing is but you use the mics to verify dimensions.
in my opinion you,ll also be smart to cross check ,bearing clearances with plasti-guage


dialborega.png

http://www.tooltopia.com/fowler-72-646-300.aspx
BEARv02.jpg
BEARv09.jpg
BEARv11.jpg

plastig1.JPG

https://www.carshopinc.com/product_info.php/products_id/49347/SPG1-12

71DiMRV8kgL._SX522_.jpg


plastig2.png

yes I use both micrometers and snap gauges and cross check with plasti-gauge
and yes when you compare the crushed width of the plasti-gauge youll find it rarely falls as an exact match to the bar chart tape that is packaged with it so you can judge clearance based on crush width
http://garage.grumpysperformance.com/index.php?threads/bearing-clearances.2726/
plas1v.jpg

plas2v.jpg

BEARv13.jpg

micrometerset.jpg



pistondie.png

video




 
Last edited:

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member



https://www.harborfreight.com/engine-brush-kit-20-pc-63732.html

GM Small Block Performance Pumps
10550

High volume performance upgrade for M-55HV.
25% increase in volume over stock oil pump.
The 10550 housing and cover are CNC machined and phosphate coated.
The lower pressure spring is included to reduce pressure if desired.
Includes intermediate shaft with steel guide. Uses 5/8” press in screen.





10551

High volume performance upgrade for M155HV.
25% increase in volume over stock oil pump.
The 10551 housing and cover are CNC machined and phosphate coated.
The lower pressure spring is included to reduce pressure if desired.
Includes intermediate shaft with steel guide. Uses 3/4” press in screen.





10552

High volume performance oil pump.
10% increase in volume over stock oil pump.
The 10552 is manufactured with the drive and idler shafts extended to allow for additional support in the cover eliminating dynamic shaft deflection at increased RPM levels.
The cover is doweled to the pump housing to assure alignment of the shaft bores.
Screw in plug retains relief valve spring instead of pin.
Relief hole in cover uses screw in plug instead of pressed cup plug.
All bolts are self locking socket heads, with the wrench supplied.
The housing and cover are CNC machined and phosphate coated.
Includes intermediate shaft with steel guide. Uses both 3/4” bolt on or press in screen.
The lower pressure spring is included to reduce pressure if desired.
Patent No. 5,810,571.

10552C (Anti-Cavitation)

10552CHigh volume performance oil pump.
10% increase in volume over stock oil pump.
Same as the 10552 with the addition of grooves machined in the body and cover. The grooves reduce cavitation effects in high RPM applications.
Includes intermediate shaft with steel guide.
Uses both 3/4” bolt on or press in screen.
Using this oil pump will reduce pressure at idle.
The 10552C uses the high pressure spring only.
Racing Applications Only.
Patent No. 5,810,571.

10553

10553High pressure performance upgrade for M-55 & M-55A.
Standard volume oil pump.
The 10553 housing and cover are CNC machined and phosphate coated.
Manufactured with pink spring installed for higher pressure (M-55A).
To change pump to lower pressure (M-55) install the supplied yellow spring.
Includes intermediate shaft with steel guide.
The 10553 uses a 5/8” press in screen.



10554

Performance upgrade for M155. Standard volume oil pump.
The 10554 housing and cover are CNC machined and manganese phosphate coated.
Manufactured with pink spring installed for higher pressure.
To change pump to lower pressure install the supplied yellow spring.
Includes intermediate shaft with steel guide.
The 10554 uses a 3/4” press in screen.



10555

High Volume performance upgrade for the 10550 oil pump.
25% increase in volume over stock oil pump.
The 10555 is manufactured with the drive and idler shafts extended to allow for additional support in the cover eliminating dynamic shaft deflection at increased RPM levels.
The cover is doweled to the pump housing to assure alignment of the shaft bores.
Screw in plug retains relief valve spring instead of pin.
Relief hole in cover uses screw in plug instead of pressed cup plug.
All bolts are self locking socket heads, with the wrench supplied.
The housing and cover are CNC machined and manganese phosphate coated.
Includes intermediate shaft with steel guide.
Uses both 3/4” bolt on or press in screen.
The lower pressure spring is included to reduce pressure if desired.
Patent No. 5,810,571


10555C (Anti-Cavitation)

High volume performance upgrade for the 10550 oil pump.
25% increase in volume over stock oil pump.
Same as the 10555 with the addition of grooves machined in the body and cover. The grooves reduce cavitation effects in high RPM applications.
Includes intermediate shaft with steel guide.
Uses both 3/4” bolt on or press in screen.
Using this oil pump will reduce pressure at idle.
The 10555C uses the high pressure spring only.
Racing Applications Only.
Patent No. 5,810,571



10990

High volume performance upgrade for the M-99HV-S.
Increase in volume of 25% over stock oil pump.
The 10990 is a Big Block style oil pump made to fit the Small Block applications.
The drive and idler shafts have been extended to allow for additional support in the cover. Additional support eliminates dynamic shaft deflection at increased RPM levels.
The cover is doweled to the pump housing to assure alignment of the shaft bores.
The relief valve has a screw-in plug instead of a pin.
The housing and cover are CNC machined and phosphate coated.
An additional spring, the original stock replacement is supplied which will reduce bypass pressure if needed.
Includes intermediate shaft with steel guide.
Uses 3/4” press in screen.
Patent No. 5,810,571.


10990C (Anti-Cavitation)

High volume performance upgrade for the M-99HV-S.
Increase in volume of 25% over stock oil pump.
The same as the 10990 except with the addition of grooves machined in the housing and cover. The grooves reduce cavitation effects in high RPM applications.
Using this oil pump will reduce pressure at idle.
Includes intermediate shaft with steel guide.
Uses 3/4” press in screen.
Racing applications only.
Patent No. 5,810,571.




GM B.B. Performance Pumps



10770

High volume performance upgrade for M-77HV.
25% increase in volume over stock pump.
The housing and cover are CNC machined and phosphate coated.
The lower pressure spring is included to reduce pressure if desired.
Includes intermediate shaft with steel guide.
Uses 3/4” press in screen.



10774

10774Standard volume performance upgrade for M-77.
The housing and cover are CNC machined and phosphate coated.
The lower pressure spring is included to reduce pressure if desired.
Includes intermediate shaft with steel guide.
Uses 3/4” press in screen.




10778

High volume performance upgrade for the 10770.
Increase in volume of 25% over stock oil pump.
The drive shaft has been manufactured from chrome-moly steel.
The drive and idler shafts have been extended to allow for additional support in the cover. Additional support eliminates dynamic shaft deflection at increased RPM levels.
The cover is doweled to the pump housing to assure alignment of the shaft bores.
The relief valve has a screw-in plug instead of a pin.
The housing and cover are CNC machined and phosphate coated.
An additional spring, the original stock replacement is supplied which will reduce bypass pressure if needed.
Includes intermediate shaft with steel guide.
Uses 3/4” press in screen.
Patent No. 5,810,571.


10778C (Anti-Cavitation)

High volume performance upgrade for the 10770.
Increase in volume of 25% over stock oil pump.
The same as the 10778 except with the addition of grooves machined in the housing and cover. The grooves reduce cavitation effects in high RPM applications.
Using this oil pump will reduce pressure at idle.
Includes intermediate shaft with steel guide.
Uses 3/4” press in screen.
Racing applications only.
Patent No. 5,810,571



RELATED INFO

viewtopic.php?f=54&t=6479&p=20555&hilit=testing+pump#p20555

viewtopic.php?f=54&t=2598

http://garage.grumpysperformance.com/index.php?threads/bearing-clearances.2726/page-2#post-75256

viewtopic.php?f=54&t=8735&p=30834&hilit=test+pump#p30834
http://garage.grumpysperformance.com/index.php?threads/thrust-bearing-wear.619/#post-37676
both G.M. engineering and smokey yunick working for NASCAR and G.M. ENGINEERING,
did extensive testing on engine longevity, and bearing durability in relation to oil pressure
there was no measurable improvement in bearing protection once oil pressure reached 70 psi.
there was an improvement if the volume of oil flow was increased but not pressure,
pressure is simply a measurement of RESISTANCE to flow.
look at these charts, the sweet spot in bearing clearance vs load falls in the 2-2.5 thousanths of an inch range



clearanceload.jpg



clearanceflow.jpg



clearancetemp.jpg

rlcf1.jpg

rlcf2.jpg

rlcf3.jpg

trashinbearing5.jpg



keep in mind all that metallic trash, cycles through the oil pump BEFORE it reaches the oil filter
if you just assume that the machine shop must have cleaned the parts they worked on carefully...
giphy.gif

IF you find metallic glitter in your oil during any oil change that metal came, from someplace,and things are likely to get worse over time, if the engines still driven, ,if you pull it down for a close detailed inspection NOW, you might find its fairly cheap and easy to repair,
COMPARED, too what it will be inevitably if you continue to drive it in its current condition,
as all that metallic trash in the oil WILL constantly continue to do ever more DAMAGE
shop carefully the exact same set of mics from the same company can cost $270-$900 depending on where you buy the set
https://www.greatgages.com/products...MIyYigxdnA1QIVU2p-Ch1Z7wX8EAQYASABEgLrvvD_BwE



read through these links, the time spent will be well worth the effort anf knowledge gained should help
http://garage.grumpysperformance.com/index.php?threads/metal-in-oil.10875/#post-47688

http://garage.grumpysperformance.co...ilter-you-sellect-does-make-a-differance.117/

http://garage.grumpysperformance.com/index.php?threads/oil-filters.11189/

http://garage.grumpysperformance.co...g-up-oil-feed-holes-in-bearings-shells.10750/


http://garage.grumpysperformance.co...oil-passages-and-improved-oil-flow-mods.3834/

http://garage.grumpysperformance.co...k-after-a-cam-lobe-rod-or-bearings-fail.2919/

http://garage.grumpysperformance.co...g-up-oil-feed-holes-in-bearings-shells.10750/

http://garage.grumpysperformance.com/index.php?threads/oil-system-mods-that-help.2187/


moroso sells plug kits
plugkit.jpg

pluginstall.jpg

drillplug.jpg

frontgroove.JPG

be sure only one oil passage plugs drilled, generally only the pass side oil passage plug with a single .025-.030 hole, many guys use a 1/32" drill bit because its easy to locate, I prefer the smaller #72 drill
IMAG0096pl.jpg

passplug.png


oilpasblc.jpg



http://buydrillbits.com/products/hss/gp2.php?c=AIR

blockdrill.png

http://www.victornet.com/subdepartments/HS-Long-Drills/1180.html


btw I got asked how I apply the 50%/50%
mix of MARVEL MYSTERY OIL AND CRANE MOLY ASSEMBLY LUBE TO BEARINGS
I generally spray crank journals and bearing surfaces with moly spray first , then paint on the mix linked below.
molysp2.JPG


Preference on assembly lube?

50% marvel mystery oil
marvel.jpg

and 50% crane moly lubes
crn-99004.jpg

what Ive used for decades
but this works
permassembly.jpg

I have used J&B WELD EPOXY on a large magnet
https://www.zoro.com/value-brand-ring-magnet-98-lb-pull-10e797/i/G4187224/
Z_o3v-kcpEx-.JPG


on the base of an aluminum 1/2 cup measuring cup I purchased at a yard sale for 25 cents to mix up the mixture, the magnet allows me to stick the cup to the block oil pan rail or engine stand where its handy too get at, and I simply brush on the mix with a 1" paint brush, with synthetic bristles that won,t shed


OH! slide it off the block don,t try to just pull it off , its going to be much less messy that way trust me!
when your done , wipe it clean and stick it inside the lid of your tool box , after placing it in a ziploc bag to prevent it from picking up trash while in storage
1aae7f99-2e0a-4629-aae6-e646e15a8533_1000.jpg


shopping


READ LINKS AND ALL SUB LINKS

http://garage.grumpysperformance.co...tion-of-crank-durring-short-blk-assembly.852/

https://www.motor.com/magazinepdfs/082010_09.pdf

http://www.atraonline.com/gears/2005/2005-01/2005_01_064.pdf

http://www.4secondsflat.com/Thrust_bearing_failures.html
Crankshaft Thrust Bearing Failure - Causes & Remedies
For years both transmission and engine rebuilders have struggled at times to determine the cause of crankshaft thrust bearing failures. In most instances, all of the facts concerning the situation are not revealed at the onset of the failure. This has led to each party blaming the other for the failure based only on hearsay or what some "expert" has termed the "cause". Some of those explanations have led to an argument, that ends up in litigation while the truth lingers uncovered in the background. This document is a group effort of combined information compiled by the Automotive Transmission Rebuilders Association (ATRA), the Automotive Engine Rebuilders Association (AERA), the Production Engine Rebuliders Association (PERA), the Automotive Service Association (ASA) and bearing manufacturers. This group of industry experts has assembled the following information to consider and offers solutions that may prevent a similar thrust bearing failure.

Background:
Although thrust bearings run on a thin film of oil, just like radial journal (connecting rod and main) bearings, they cannot support nearly as much load. While radial bearings can carry loads measured in thousandsof pounds per square inch of projected bearing area, thrust bearings can only support loads of a few hundred pounds per square inch. Radial journal bearings develop their higher load capacity from the way the curved surfaces of the bearing and journal meet to form a wedge. Shaft rotation pulls oil into this wedge shaped area of the clearance space to create an oil film which actually supports the shaft. Thrust bearings typically consist of two flat mating surfaces with no natural wedge shape in the clearance space to promote the formation of an oil film to supportthe load.

Conventional thrust bearings are made by incorporating flanges, at the ends of a radial journal bearing. This provides ease in assembly and has been used successfully for many years. Either teardrop or through grooves on the flange, face andwedge shaped ramps at each parting line allow oil to enter between the shaft and bearing surfaces. However, the surface of the shaft, as well as the vast majority of bearing surfaces, are flat. This flatness makes it more difficult to create and maintain an oil film. As an example; if two gauge blocks have a thin film of oil on them, and are pressed together with a twisting action, the blocks will stick together. This is similar to what happens when a thrust load is applied to the end of a crankshaft and oil squeezes out from between the shaft and bearing surfaces. If that load is excessive, the oil film collapses and the surfaces want to stick together resulting in a wiping action and bearing failure. For this reason, many heavy-duty diesel engines use separate thrust washers with a contoured face to enable them to support higher thrust loads. These thrust washers either have multiple tapered ramps and relatively small flat pads, or they have curved surfaces that follow a sine-wave contour around their circumference.

Recent developments:

In the past few years some new automotive engine designs include the use of contoured thrust bearings to enable them to carry higher thrust loads imposed by some of the newer automatic transmissions. Because it’s not practical to incorporate contoured faces on one piece flanged thrust bearings, these new engine designs use either separate thrust washers or a flanged bearing whichis a three piece assembly.

Cause of failure:

Aside from the obvious causes, such as dirt contamination and misassembly, there are only three common factors which generally cause thrust bearing failures. They are:




      • Poor crankshaft surface finish
      • Misalignment
      • Overloading
Surface finish:

Crankshaft thrust faces are difficult to grind because they are done using the side of the grinding wheel. Grinding marks left on the crankshaft face produce a visual swirl or sunburst pattern with scratches - sometimes crisscrossing - one another in a cross-hatch pattern similar to hone marks on a cylinder wall. If these grinding marks are not completely removed by polishing, they will remove the oil film from the surface of the thrust bearing much like multiple windshield wiper blades. A properly finished crankshaft thrust face should only have very fine polishing marks that go around the thrust surface in a circumferential pattern.

Alignment:

The grinding wheel side face must be dressed periodically to provide a clean, sharp cutting surface. A grinding wheel that does not cut cleanly may create hot spots on the work piece leading to a wavy, out-of-flat surface. The side of the wheel must also be dressed at exactly 90° to its outside diameter, to produce a thrust face that is square to the axis of the main bearing journal. The crankshaft grinding wheel must be fed into the thrust face very slowly and also allowed to "spark out" completely. The machinist should be very careful to only remove minimal stock for a "clean-up" of the crankshaft surface.

In most instances a remanufactured crankshaft does not require grinding of the thrust face(s), so the grinding wheel will not even contact them. Oversize thrust bearings do exist. Some main bearing sets are supplied only with an additional thickness thrust bearing. In most of those instances, additional stock removal from the crankshaft thrust face surface may be required. Crankshaft end float should be calculated and determined before grinding additional material from the thrust face.

Crankshaft grinding wheels are not specifically designed for use of the wheel side for metal removal. Grinding crankshaft thrust faces requires detailed attention during the procedure and repeated wheel dressings may be required. Maintaining sufficient coolant between the grinding wheel and thrust surface must be attained to prevent stone loading and "burn" spots on the thrust surface. All thrust surface grinding should end in a complete "spark out" before the grinding wheel is moved away from the area being ground. Following the above procedures with care should also maintain a thrust surface that is 90° to the crankshaft centerline.

When assembling thrust bearings:





      • Tighten main cap bolts to approximately 10 to 15 ft.lb. to seat bearings, then loosen.
      • Tap main cap toward rear of engine with a soft faced hammer.
      • Tighten main cap bolts, finger tight.
      • Using a bar, force the crankshaft as far forward in the block as possible to align the bearing rear thrust faces.
      • While holding shaft in forward position, tighten main cap bolts to 10 to 15 ft.lbs.
      • Complete tightening main cap bolts to specifications in 2 or 3 equal steps.
The above procedure should align the bearing thrust faces with the crankshaft to maximize the amount of bearing area in contact for load carrying.

Loading:

A number of factors may contribute to wear and overloading of a thrust bearing, such as:

1. Poor crankshaft surface finish.

2. Poor crankshaft surface geometry.

3. External overloading due to.

a) Excessive Torque converter pressure.

b) Improper throw out bearing adjustment.

c) Riding the clutch pedal.

d) Excessive rearward crankshaft load pressure due to a malfunctioning front mounted accessory drive.

Note: There are other, commonly-thought issues such as torque converter ballooning, the wrong flexplate bolts, the wrong torque converter, the pump gears being installed backward or the torque converter not installed completely. Although all of these problems will cause undo force on the crankshaft thrust surface, it will also cause the same undo force on the pump gears since all of these problems result in the pump gear pressing on the crankshaft via the torque converter. The result is serious pump damage, in a very short period of time (within minutes or hours).

Diagnosing the problem:

By the time a thrust bearing failure becomes evident, the partshave usually been so severely damaged that there is little if any evidence of the cause. The bearing is generally worn into the steel backing which has severely worn the crankshaft thrust face as well. So how do you tell what happened? Start by looking for the most obvious internal sources.

Engine related problems:





      • Is there evidence of distress anywhere else in the engine that would indicate a lubrication problem or foreign particle contamination?
      • Were the correct bearing shells installed, and were they installed correctly?
      • If the thrust bearing is in an end position, was the adjacent oil seal correctly installed? An incorrectly installed rope seal can cause sufficient heat to disrupt bearing lubrication.
      • Examine the front thrust face on the crankshaft for surface finish and geometry. This may give an indication of the original quality of the failed face.
Once you are satisfied that all potential internal sources have been eliminated, ask about potential external sources of either over loading or misalignment.

Transmission related problems:





      • Did the engine have a prior thrust bearing failure?
      • What external parts were replaced?
      • Were there any performance modifications made to the transmission?
      • Was an additional cooler for the transmission installed?
      • Was the correct flexplate used? At installation there should be a minimum of 1/16" (1/8" preferred, 3/16" maximum) clearance between the flex plate and converter to allow for converter expansion.
      • Was the transmission property aligned to the engine?
      • Were all dowel pins in place?
      • Was the transmission-to-cooler pressure checked and found to be excessive? If the return line has very low pressure compared to the transmission-to-cooler pressure line, check for a restricted cooler or cooler lines.
      • If a manual transmission was installed, was the throw out bearing properly adjusted?
      • What condition was the throw out bearing in? A properly adjusted throw out bearing that is worn or overheated may indicate the operator was "Riding The Clutch".
How does the torque converter exert force on the crankshaft?

There are many theories on this subject, ranging from converter ballooning to spline lock. Most of these theories have little real bases and rely little on fact. The force on the crankshaft from the torque converter is simple. It is the same principle as a servo piston or any other hydraulic component: Pressure, multiplied by area, equals force. The pressure part is easy; it’s simply the internal torque converter pressure. The area is a little trickier. The area that is part of this equation is the difference between the area of the front half of the converter and the rear half. The oil pressure does exert a force that tries to expand the converter like a balloon (which is why converter ballooning is probably often blamed), however, it is the fact that the front of the converter has more surface area than the rear (the converter neck is open) that causes the forward force on the crankshaft. This difference in area is equal to the area consumed by the inside of the converter neck. The most common scenario is the THM 400 used behind a big-block Chevy. General Motors claims that this engine is designed to sustain a force of 210 pounds on the crank shaft. The inside diameter of the converter hub can vary from 1.5 inches up to 1.64 inches. The area of the inside of the hub can then vary from 1.77 square inches to 2.11 inches. 210 pound of force, divided by these two figures offers an internal torque converter pressure of 119 psi to 100 psi, respectively. That is to say, that depending on the inside diameter of the hub, it takes between 100 to 119 psi of internal converter pressure to achieve a forward thrust of 210 pounds. The best place to measure this pressure is the out-going cooler line at the transmission because it is the closest point to the internal converter pressure available. The pressure gauge must be "teed" in so as to allow the cooler circuit to flow. Normal cooler line pressure will range from 50 psi to 80 psi , under a load in drive.

Causes for excessive torque converter pressure:

There are two main causes for excessive torque converter pressure: restrictions in the cooler circuit and modifications or malfunctions that result in high line pressure. One step for combating restrictions in the cooler circuit is to run larger cooler lines. Another, is to install any additional cooler in parallel as opposed to in series. This will increase cooler flow considerably. An additional benefit to running the cooler in parallel is that it reduces the risk of over cooling the oil in the winter time—especially in areas where it snows. The in-parallel cooler may freeze up under very cold conditions, however, the cooler tank in the radiator will still flow freely. Modifications that can result in higher than normal converter pressure include using an overly-heavy pressure regulator spring, or excessive cross-drilling into the cooler charge circuit. Control problems such as a missing vacuum line or stuck modulator valve can also cause high pressure.

What will help thrust bearings survive? When a problem application is encountered, every effort should be made to find the cause of distress and correctit before completing repairs, or you risk a repeat failure.

A simple modification to the upper thrust bearing may be beneficial in some engines. Install the upper thrust bearing in the block to determine which thrust face is toward the rear of the engine. Using a small, fine tooth, flat file, increase the amount of chamfer to approximately .040" (1 mm) on the inside diameter edge of the bearing parting line. Carefully file at the centrally located oil groove and stroke the file at an angle toward the rear thrust face only, as shown in the illustration below. It is very important not to contact the bearing surface with the end of the file. The resulting enlarged ID chamfer will allow pressurized engine oil from the pre-existing groove to reach the loaded thrust face. This additional source of oiling will reach the loaded thrust face without passing through the bearing clearance first (direct oiling). Since there may be a load against the rear thrust face, oil flow should be restricted by that load and there should not be a noticeable loss of oil pressure. This modification is not a guaranteed "cure-all". However, the modification should help if all other conditions, such as surface finish, alignment, cleanliness and loading are within required limits.

bearing1.jpg

Other External Problems. Aside from the items already mentioned, there is another external problem that should be considered. Inadequate electrical grounds have been known to exacerbate thrust surface wear. Excessive current in the vehicle drive train can damage the thrust surface. It affects the thrust bearing as though the thrust surface on the crankshaft is not finished properly finished (too rough). Excessive voltage in the drive train can be checked very easily. With the negative lead of a DVOM connected to the negative post of the vehicle battery and the positive lead on the transmission, there should be no more than .01 volts registering on the meter while the starter is turning over the engine. For an accurate test, the starter must operate for a minimum of four seconds without the engine starting. It is suggested to disable the ignition system before attempting this test. If the voltage reading observed is found to be excessive, add and/or replace negative ground straps from the engine to the vehicle frame and transmission to frame until the observed voltage is .01 volts or less. Note: Some systems may show a reading of .03volts momentarily but yet not exhibit a problem. For added assurance, it is a good idea to enhance the drive train grounding with larger battery cables or additional ground straps.

A special thank you goes out to Dennis Madden of ATRA, Dave Hagen of AERA, Ed Anderson of ASA, Roy Berndt of PERA and John Havel of AE Clevite for their contributions to this article.

The AERA Technical Committee

March 1998 - TB 1465R
http://garage.grumpysperformance.com/index.php?threads/basic-info-on-your-v8-lube-system.52/

http://garage.grumpysperformance.com/index.php?threads/oil-system-mods-that-help.2187/

http://garage.grumpysperformance.com/index.php?threads/cam-bearing-install-tools-install-info.1479/

http://garage.grumpysperformance.com/index.php?threads/installing-an-oil-pump-pick-up-tube.1800/

http://garage.grumpysperformance.com/index.php?threads/bearings-and-oil-flow.150/

http://garage.grumpysperformance.co...oil-passages-and-improved-oil-flow-mods.3834/

http://garage.grumpysperformance.com/index.php?threads/testing-a-chevy-oil-pump.6479/
 
Last edited:

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
the average outside temperatures where you drive should have some influence on your choices in oil used,
here in florida as an example
most of the year we see 70F-90F
remember when chevy builds a car/truck and makes suggestions,
they don,t know if it gets sold in northern Wisconsin , Alaska,
or Miami or Dallas
selecting a 10w30 or 5w30 works ok here in mid fla
oilvis1.jpg

at these temps, oil is already easy flowing at engine start-up

http://garage.grumpysperformance.com/index.php?threads/viscosity-centistoke.15612/#post-93303

http://garage.grumpysperformance.com/index.php?threads/which-oil-what-viscosity.1334/

http://garage.grumpysperformance.com/index.php?threads/bearings-and-oil-flow.150/

use plenty of moly based assembly lube:like:




drt-70000009_sn_xl.jpg

ISK-RL-1_RW.jpg

man-40199_xl.jpg


mor-35000_hh_xl.jpg
 
Last edited:

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
When I got my 265 back from the machine shop the camshaft would not go all the way in. The machine shop installed a common 2 inch freeze plug instead of the correct 2 1/64” shallow rear cam plug. The back of the camshaft was hitting the freeze plug! The thrust surface on the cam sprocket is supposed to ride against the machined surface at the front of the block to correctly position the camshaft. I knocked out the incorrect freeze plug and test fit the camshaft with the sprocket installed. It’s a good thing I checked because I found that they had also installed the cam bearing almost ¼ inch too far back. The back oil hole in the cam bearing was completely blocked of by the camshaft. If I had installed the engine as the machine shop had built it there would have been zero oil supply to the lifters.

Just lining up the rear cam bearing holes to the block is not good enough on a 265. The bearing must also line up with the rear journal of the camshaft to ensure that both holes line up with the machined slot in the camshaft. The best way to check the position of the rear cam bearing is to test fit the bearing on the camshaft before you install it in the block. After you install the cam bearings, bolt the cam sprocket on the camshaft and test fit the camshaft into the block. The back edge of the camshaft should be flush with the back edge of the rear cam bearing. The point here is don’t trust the machine shop to correctly install the rear cam bearing in your 265. Have the machine shop leave the cam plug out so you can check the rear cam bearing position yourself.

cam-bearing-002.jpg


cam-bearing-009.jpg


cam-bearing-007.jpg


Cam_Bearings-021.jpg


After you are sure the rear cam bearing is installed correctly it’s time to install the rear cam plug. Do not use a 2 inch freeze plug! The 265 uses a rear cam plug which is slightly smaller in diameter than the cam plug used in a 1958 and up engines. 265 V8’s use a 2 1/64 inch shallow cam plug, while 1958 and up engines use a 2 3/32 inch cam plug. There is a machined step in the newer engines that prevent driving the plug to deep. There is no step machined into the block on a 55-57 engine, so care must be taken not to drive the plug to deep. The 1956 Shop Manual says the cam plug should be “installed flush to 1/32” deep to maintain a level surface on the rear of the cylinder block”. Here is my original cam plug and the correct replacement.

cam-bearing-012.jpg

All small block Chevy engines were produced with an annular groove under the rear cam bearing regardless of what year they are. This groove supplies oil to the two lifter galleries. The difference in the 55-56 engines is in how the oil is supplied to the groove. On 1955 and 1956 265’s full oil pressure from the main oil galley passed through a drilled passage to feed a small hole in the rear cam bearing. As the camshaft rotated the machined slot in the rear cam journal would uncover the hole allowing oil to flow (via the machined slot) out a second hole in the cam bearing that was located over the annular groove. This setup supplied "pulsed" oil to the annular groove which supplies reduced pressure to the lifter galleries.

Starting in 1957 the drilled passage from the main oil gallery was redesigned to connect directly to the annular groove. With this change the annular groove and the lifter galleries have full oil pressure. The rear cam bearing on 57 and up engines only needs one oil hole to lubricate the rear cam journal from high pressure oil in the annular groove, and there is no longer a need for the machined slot on the rear cam journal.

A popular modification on 55-56 265 blocks is to grind an oil passage in the block connecting the drilled oil feed passage to the annular groove. This way the 265’s will oil just like the other SBC’s, and there is no longer a need to use a camshaft with a machined slot. If you do this modification you should use a 1957 and up "window" distributor because the higher oil pressure in the lifter galleries may be too much for the 1955-56 distributor which may cause it to leak oil.

Here is a 265 and a newer 327 with the rear cam bearings removed. Note the different location of the drilled oil supply passage from the main oil gallery on these two engines.






If you convert the 265 to full pressure oiling you may have problems with your 55-56 distributor filling with oil. The lower bushing on these early distributors was fed low pressure "pulsed" oil from the RH lifter gallery. After the oil lubricates the lower distributor bushing it drains out via a hole above the bushing and then spills down the flat on the side of the distributor housing. That is what the "flat" on a 55-56 distributor is for, to let the oil from the distributor drain out. If you convert to full pressure oiling you could overcome the capacity of the drain hole, sending oil up the shaft, past the upper bushing, into the top of the distributor where it will cause all kinds of problems. A worn lower distributor bushing, combined with a high pressure-high volume oil pump, will make the problem worse. In 1957 Chevrolet redesigned the distributor to splash oiling from the drive gear so oil pressure in the lifter galley won’t have any affect on the distributor.


1957 and up distributors will work just fine in any 265. Even an HEI distributor will work in both stock and modified 265’s. If you are going to use the early 265 distributor you should not modify the block for full pressure oiling.









Steve

.
 
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