Yves said:
yes thats a rather common sensor to fail in a 20 plus year old corvette.
https://www.howacarworks.com/accessories/how-an-oil-pressure-guage-works
the gauge circuit works by reading OHMS resistance.
Basically a bad sender that is open would make the gauge peg.
When there is no oil pressure it is grounded.
Which is why unplugging it may have made no difference
some early c4 vettes have the gauge and oil pressure switch on an adapter near the distributor base into the block,
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.
MORE USEFUL INFO
yes the oil flows around the mounting stud,from oil pump to main cap to reach the engine oil passages, thru the oil filter
failure to use the correct oil pump,mounting stud, bolt or nut or carefully check clearances when mounting an oil pump can cause problems
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
http://garage.grumpysperformance.co...-friction-and-pumping-losses.8966/#post-31978
broken , or improperly installed oil pump pick-ups can cause several major oil pressure issues
ITS always a good idea to verify the oil pan floor to oil pump pick-up clearance and to braze the pick-up to the oil pump, to reduce the potential for it to come loose.
yes you can MIG ,TIG or TORCH WELD the pick-up but I found BRAZING works the best and is less likely to warp or crack the pump or pick-up
"how in hell do those twisty, safety wire pliers work?"
well a video should be helpful here! Id also point out that you can buy the wire in several diameters and the thicker sizes are far more difficult to use, home depot sells the 22 gauge and 18 gauge, the 22-24 gauge is what youll use far more commonly, as its much easier to use,both stainless (PREFERED) and galvanized are used, and will work on 95% of the applications on a car your likely to use.
using anti-seize paste on bolt or stud threads helps prevent future problems
using safety wire pliers
pressure drops with remote coolers or filter mounts are almost always the result of using hydraulic lines AND hydraulic line connections with too small an INTERNAL cross sectional area, anything less than AN#8 is bound to be restrictive and AN#10 is far better, and much less likely to cause issues with pressure drops, obviously the adapters and fittings used for fluid transmission must also have at least AN# 8 OR PREFERABLY AN#10 CONNECTIONS , if you run 3/8" OR an#6 LINES YOUR BOUND TO FIND IT DROPS RETURN LINE PRESSURE
you should NEVER shim an oil pumps pressure relief spring as it may prevent the piston it holds from moving down its bore far enough to allow it to open the bay-pass passage, that allows the pressure on the high pressure side of the oil pump from bleeding off back into the intakes side of the oil pump
Many pressure relief springs have one end larger than the other end,the spring always mounts with the larger end facing away from the bypass piston, if installed reversed the piston can,t move far enough to completely open the bypass circuit passage and pressures skyrocket, under some conditions
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,if your engine shows more than about 70 psi, you 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
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.
the idea that you can 'pump the pan dry" with a high volume oil pump, in a properly set up chevy engine has been proven false dozens of times, thats a myth that myth been repeated for decades and the reason its gained its supposed verification as fact is simply that guys install a high voluum oil pump in the same engine that they just removed a stock oil pump from and find that they reve the engine and the oil pressure starts to go up then tops out or even drops off , the instant and wrong conclusion drawn is that the high voluum oil pump sucked the oil pan dry, but what really happened in almost every case was a bit simpler.
high volume oil pumps have a longer body that moves the oil pump pick-up closer to the oil pan floor and if the clearance is not checked and corrected to maintain the required 3/8"-1/2" minimum clearance it severely restricts the flow into the oil pump and pressure drops of as a result of the restriction on the intake side of the oil pump pick-up.
your typical small block oil pump has a 4 bolt cover, a 5/8" pick-up tube diameter and the pick-up presses into the cover , it has the smaller 7 tooth gears, and because the pick-up tube presses into the cover swapping from a standard to a high volume pump, with its longer impeller and hoseing casting, tends to move the pick-up about 1/4" closer to the oil pan floor
http://www.mellingselectperformance.com ... -Oil-Pumps
BTW HERES AN IMPORTANT TIP, IF YOUR INSTALLING A REMOTE OIL COOLER, IT is really common for guys to use lines that are far too small, that restrict flow oil flow or select a transmission or oil cooler that has to small of internal passages, shop carefully you want a MINIMUM of 1/2, or AN8 line size and 5/8" or AN10 is BETTER.
many guys don,t realize that adding an oil and/or a transmission fluid cooler, with its own fan and radiator that allows those liquids to be cooled separately, to your engine and drive train, significantly reduces the heat load on the radiator, and generally allows the engine temps to decline noticeably. in fact just adding a high volume oil pan and a transmission cooler can drop your engine coolant temps 20F-30F in many cases
a rather common issue with adding oil coolers, is that many of the coolers available can significantly restrict fluid flow because of the small restrictive internal cross section of the internal tubing, AN #6 and 3/8" tube coolers can be quite restrictive, the AN#8 are better but DUAL AN#8 coolers and AN#10 lines generally work the best, and there's also frequently limited space to position a cooler in the outside cool air flow mandating a powered fans.
the solution to both issues can and frequently does require use of two different oil coolers but placed in series this can further increase flow restrictions, the solution is in use of larger internal cross sectional area,transfer lines and mounting the twin coolers in parallel thus doubling the effective cross sectional area reducing the flow restriction the cooler potentially could produce if used in series
you need to think of oil flow as needing to be a constantly circulating and unrestricted fluid flow path, similar to the chain on a bike, the oil needs to circulate and any restriction too the oil circulating freely both too the bearings under pressure or freely draining back too the sump,can and will cause problems.
youve selected a decent oil pan design, and while I prefer a different windage screen design yours should function.
it should be pointed out that a block must be carefully cleaned of casting flash and loose crud smoothed and the oil return holes opened up to allow efficient oil drain back,before you start. the oil pump pick -up clearance to the oil pan floor MUST be in the 3/8" minimum-1/2" max range and this is often over looked , assumed to be correct,and not measured, or the oil pan or pump pick-up gets damaged
I had similar issues when I installed my oil cooler with the AN#6 lines that came in the mounting kit from SUMMIT RACING, swapping to AN #8 lines at first which helped a great deal but once I swapped to AN#10 lines those cured the issue, and yes I mounted my oil cooler where the spare tire normally mounts , so its a good distance from the engine.
keep in mind the old "WEAK LINK IN THE CHAIN" CONCEPT
if you install 5/8" inside diameter hydraulic lines and try to feed the oil flow thru a 3/8" inside diameter oil cooler the oil cooler tubes are a huge restriction so obviously the cooler needs to be upgraded or a second similar cooler run in parallel, not in series should be used to effectively reduce the flow restriction
obviously some testing here is called for, too locate and isolate the source of your problem, but the first hint , is your statement that the use of spring oilers, which increase upper rpm and upper engine oil flow rates, necessitating a increased oil drain back rate to match, and use of a remote oil filter , oil cooler and accusump are installed, all of these add -ons and the oil flow lines and adapters and fittings potentially restrict oil flow rates as the rpms and oil flow rates increase, thus your statement that use of a thinner faster flowing oil reduced the problem, or restriction, makes perfect sense.
Ive seen similar issues in a couple cases and the problem was resolved with an increase in internal line cross sectional areas and carefully matched AN#10 fittings, rather than the commonly used an #6 or even #8 lines which especially if the wrong fittings are used can be very restrictive , and routing the oil flow lines, so the accusump had a totally different oil port on the block,access point and was not in series with the other accessories.
The rather obvious test procedure would be too move the accusump to a separate port on the block if its not mounted that way already, and too temporarily swap out the current oil line that goes from the engine too the accessories that are not mandatory, like the remote oil filters during the test,like the oil cooler for a couple feet of hydraulic hose section of AN#10, run the engine, if the problems cured plumb in the rest and retest, but be aware that the AN fittings internal passage cross sectional area not the AN#10 hydraulic hose alone will effect your results so its very possible that your current oil cooler, oil filter adapter , or the adapters or fittings used ate the choke point.
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