the sources of or factors effecting ENGINE HEAT!

[grumpyvette]

Id bet serious money that if I asked a hundred guys why an engine gets hot durring its opperation I get almost 95% plus of the answers that stated it was due to the burning of the compressed fuel/air combustion in the cylinders , and the exhaust gases exiting the cylinder after on the exhaust stroke,and maybe 10% might mention friction, but it would be very rare to get the valve train, rings, pistons and bearings mentioned, as a significant source of heat.
while Im sure that most of those reading this will be rather amazed to find that only about 60%-65% of the heat orriginates in the combustion chamber and exhaust and that about 35%-40%of the heat is due to friction and valve springs flexing, etc. now if you have not seen it it might be rather surprising to know that valve springs will run well over 500 degrees (F) within 5 minutes at 6000rpm if they are not cooled with a constant bath of oil spray dribbling and spraying over them and that valves, lifters, and rockers , and other valve train and piston skirts, rings,bearings, basically all moving components bathed in oil generate some heat,those components,generate a significant percentage of an engines total heat due to friction.
One factor in cooling an engine thats often overlooked is that a large capacity, baffled oil pan with a 7-8 quart capacity and a carefully planed, designed & installed windage tray with a high volume oil pump can be used to bathe, absorb and transfer heat away from the hotter components like rings, wrist pins piston skirts, and valve train components and transfer that heat to the oil pan, block, valve covers etc, where air flowing past its surface, or coolant rushing thru internal passages in the block, can draw off some of that absorbed and transferred heat, and that a decent oil cooler with its own electric fan can significantly reduce the heat load the coolant in the radiator needs to deal with. even something as simple as using taller valve covers with their larger surface area, or a longer oil filter will tend to radiate more heat and drop oil temps slightly.
then theres the ignition timing, compression ratio and clearances, all effect the engines heat levels, retard the ignition timing from its ideal setting and the exhaust temps tend to rise significantly while the spark plugs and combustion chamber temps drop off noticeably, advance the timing ,from its ideal setting and the exhaust temps tend to drop off significantly while the spark plugs and combustion chamber temps spike upward noticeable,and detonation, pre-ignition is frequently the result.
if you run the fuel air ratio, for the ideal low emission results at about a 14.7 :1 ratio exhaust temps and piston temps tend to run almost 100 degrees hotter than they will at the ideal 12.5-12.7:1 ratio used to produce max torque, simply because there a lower combustion temp and the extra liquid fuel tends to absorb some heat and slow the burn slightly.
Id also mention a surprisingly high percentage of guys who rarely check coolant levels ,oil levels or serpentine belt condition, until problems occur.
one other factor often over looked is the anti-freeze concentration, your going to ideally use a 50% water 50% antifreeze mix that balances cooling efficiency with corrosion resistance, if you run strait water electrolysis is very likely, almost certainly going to cause major problems, but if you run strait anti-freeze youll run 15-20 degrees hotter as strait anti-freeze does not transfer heat as effectively

Here's a list of a few things which can cause an overheating problem.

Thermostat not opening fully,
Dirty Cooling System heavy dirt deposits in engine,
Radiator clogged (internal/external), excessive Tube repair/closure,
Hoses deteriorating inside/collapsing, blocking flow,
Improper Coolant Mix,
Captured Air in Engine,low coolant level
Combustion Gas Leak into Cooling System,
low oil level
engine vacuum leaks
defective or wrong water pump design
Excessive over-bore of engine,
Engine Timing set excessively in advance,
Fuel Mixture too lean,
Bad Water Pump,
too small a radiator
restrictive exhaust
inadequate electrical fans
Belt slipping,
Air Flow blocked in frontal Air Ram, (forward of Radiator)
Incorrect information from temperature sensor/gauge,
Shroud missing/improperly set to fan position,
Bad Thematic Clutch for Fan,
Heater bypassed with hose loop,
Excessive temperature contribution from Automatic Transmission, via Radiator Capsule,
Bad Radiator Cap, if there is any loss of Coolant.
improper ring end gap
improper bearing clearances
you'll be amazed at the info contained in these post links

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viewtopic.php?f=4&t=1337&p=2921&hilit=infrared#p2921

 

[grumpyvette]

Re: the sources of ENGINE HEAT!

if the cars got an automatic trans the transmission might be putting out more heat as its aged, especially if the trans fluids not been changed in a few years, and that can put significant loads on a radiator, especially with a high stall converter.
a radiator doesn,t need to leak, look rusted or have the cooling fins stuffed full of trash to be , not working correctly,there's rows of internal tubing that tends to get coated with crud over time,from the block rusting or the anti-freeze deteriorating, that crud needs to be flushed out every few years or radiator efficiency drops off, and the anti-freeze replaced,the water pump can also loose its efficiency over time.
and fan belts can get loose and slip,get the fuel/air mix ratio or the ignition timing off a bit and youll see increased heat, run low on oil or run crap quality oil or low on trans fluid and heat goes up
radiators vary in quality and cost but a cheap aluminum stock replacement costs about $200
theres several different factors that may be causing the car engine temp to run on the warm side.
locating the source of the heat lets you deal with the problem more effectively
if the carbs running lean (vacuum leaks, the wrong ignition advance curve)or the exhaust is restricted the engine tends to run hotter.
not using the correct duct work or fan is suspect on an older car, the pumps flow rate, a restriction in the radiator, a hose, a bad pump or t-stat, a bad head gasket,Ive seen partly clogged original radiators, defective water pumps and even automatic transmissions that used connections in the radiator to cool trans fluid that was running hotter than ideal cause that
if your running an auto trans and not running a separate trans cooler that can be a problem if the original radiators still in use as efficiency drops with age
adding a new high capacity aluminum radiator is a good idea if its the original radiator,you can also add a large pusher fan to the front of the radiator. and keep in mind a large baffled oil pan and a separate oil cooler can be used that can dissipate a great deal of engine heat. btw 220F coolant temps with the air conditioner on in Florida while on the high end of the temp range should be considered almost normal below 45mph and not all that rare in an older vette


http://forum.grumpysperformance.com/viewtopic.php?f=57&t=149

http://forum.grumpysperformance.com/viewtopic.php?f=57&t=755

http://forum.grumpysperformance.com/viewtopic.php?f=57&t=176

http://www.genesisautoparts.com/all_aluminum_radiator-chevrolet-corvette-1986-5dot7l_v8_350.htm

http://forum.grumpysperformance.com/viewtopic.php?f=57&t=853

Id also point out that 220F is nothing to get crazy over with a car sitting still, the radiator could obviously use more air flow and a more effective fan and duct work will help, your generally not going to have any problems if that 220F-230F in coolant temps is rarely exceeded, especially if it drops rapidly once your moving the car, before I added a transmission cooler my corvette almost always ran at 195f-210f coolant temps and oil temps in the 210f-235f range under hard driving and easily jumped up a few degrees in traffic.
adding an oil cooler also keeps the engine temps top low for too long so I only run the trans cooler now
but ID point out that almost all the hotter components in an engine are cooled by OIL FLOW and the OIL after its absorbed most of the heat transfers some of that heat to the coolant as it flows back to the sump, so an OIL COOLER and a 7-8 quart BAFFLED OIL PAN will go a long way to LOWERING the ENGINES total temperatures, the radiator needs to deal with, its not at all unusual to drop engine temperatures by 20 degrees with a 7-8 qt baffled oil pan and an oil cooler added to the engines oil system
ID also suggest drilling 8 1/8" holes in the T-STAT flange so any trapped air will circulate and exit the system and you ALWAYS have at least minimal coolant flow
use a good 7-8 quart baffled oil pan

http://forum.grumpysperformance.com/viewtopic.php?f=54&t=296

http://forum.grumpysperformance.com/viewtopic.php?f=57&t=149&p=183#p183

OIL COOLER
Perma-Cool 12318 $195.95

http://store.summitracing.com/partdetail.asp?autofilter=1&part=PRM-12318&N=700+115&autoview=sku

Perma-Cool 13311 $169.95

OIL AND TRANS FLUID COOLER

lets look at a few points


finding the source of the heat will generally allow you to figure out a way to reduce the heat,if you can reduce the heat theres a lower load on the cooling system.
the first rather obvious source is the engine tune, if your ignition timing or your fuel/air ratio is off the ideal ranges heat increases, generally youll want the fuel/air ratio to be between about 12.7:1 and 14:1 for decent power production, and anything leaner than 14.7:1 generally increases heat, in the exhaust, mild detonation increases engine heat quickly, vacuum leaks tend to increase engine heat.
reading the spark plugs and use of an INFRARED TEMP GUN for tuning helps, it allows you to isolate the hotter areas and get a good idea as to the source, of problems. In most cases it also allows you to track the heat as its routed thru the cooling system and spot restrictions,
any restriction of coolant flow such as a restrictive T-stat,restrictive hoses, or less than efficient water pump will reduce the cooling systems potential, so check out those issues.

viewtopic.php?f=4&t=1337&p=2921&hilit=+infrared#p2921

ok first the HEAT generated is the direct result of BOTH the amount of fuel/air burnt PER minute and the engines internal FRICTION, both contribute a significant amount of heat.
cooling is the process of EFFICIENTLY TRANSFERRING the engine heat, produced by friction, from the OIL, that absorbs the heat and that transports the heat from the valve train, rotating assembly and bearings to the block, and from the block to the coolant where, that heat dissipated to the air flowing thru the radiator, from its surface fins & tubes where its again transferred to the air, and dispersed.

MORE INFO
viewtopic.php?f=57&t=853

to reduce heat theres several routes you can go,
you can reduce friction thru the use of the better synthetic oils
you can speed the heat transfer rates thru the use of thinner viscosity oil that flows thru the clearances faster
you can add a large oil cooler with a electric fan , and a baffled high capacity oil pan,as the combo will dissipate heat directly to the air ,lower the heat loads transferee to the coolant and radiator.
you can increase the size of the radiator, or its surface area thru use of larger tubes and more fins.
you can increase the air flowing thru it with larger fans or more efficient duct work
you can change the coolant type, or composition, and use additives like water wetter that increases the heat transfer rates by lowering surface tension, and you can add a high volume water pump.

CURES

as a general rule if the engines tuned correctly, and has the correct clearances and theres no mechanical issues, (you'll want to verify that carefully)
Obviously the cure is to have your system set up so the coolant in the radiator and the oil in the engine dissipate heat to the outside air at a far faster rate than the engine can add heat to those fluids
Generally the larger the surface area of the radiator and the higher is fluid capacity, the longer the coolant flowing thru it has to transfer heat, to the outside air, the larger the fans flow capacity and the tighter and more effective the duct work is around the fan, or fans the more air can be forced thru the radiator fins to absorb heat. id point out that a pusher fan in front and a puller fan behind the radiator will usually help, and a fairly cheap source of pusher electric fans is salvage yards(fords like taurus use them alot)
youll want to either add a large efficient oil cooler with a powered fan, and try to maintain, your oil temps at a steady 215F-220F range(as oil does far more of the actual engine cooling than most people will ever believe)
or add EITHER or BOTH a larger radiator or use more effective duct work and fans to force far more air over the radiator fins, to aid heat transfer rates

in a few cases a T-stat is restricting flow, and simple mods tend to have amazing results, since its free and easily done IVE always suggested drilling 6-8 1/8" holes in the T-stat flange area and in some cases it has produced remarkable reductions in average coolant temp ranges

viewtopic.php?f=57&t=348

BTW one frequently overlooked factor is your alternator size,in amps and wiring the alternator correctly, if your running a 70amp-100 amp stock alternator and using electric fans to cool the engine,its not going to provide the power required to spin the fans nearly fast enough to cool the engine like a better 200 amp alternator can

Im using a fairly large TRANS fluid COOLER , and I can,t imagine a 3/8"-1/2" line being a problem if its correctly plumbed into the system,naturally youll want check valves so it won,t drain and have large volumes of compressed air vs oil at start-up and Id point out that there are thermostatically controlled valves that limit the flow thru the cooler too maintain a minimum oil or trans fluid temperature and up till recently I had a dual oil/trans fluid cooler installed
and youll want to have the OIL cooler set up so all the oil does not route thru the cooler all the time, but only when its over a set temperature.oil coolers are not as simple as a radiator, if correctly installed but they are a huge advantage on transmission and engine durability in some cases
If I had a quality oil/trans fluid cooler with 1/2" lines I would install it without a second thought!
a large capacity baffled oil pan hanging under a car used at higher speeds,will effectively cool oil a good deal more effectively than many people would suspect

COMMENTS? QUESTIONS?

The latest I found is this:
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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. Happy oiling!

Here's the one from GM:

Excerpt from Speed Reading written by Wade Hajek of GM Performance Parts :
"Gen V and Gen VI big-block crate engines come with two oil pressure bypass valves installed in the engine blocks. Both of these valves are rated at 11 psi pressure differential. One valve is for the oil filter and the other is for the production oil cooler. If you install an aftermarket oil cooler or remote oil filter that attaches to the oil filter pad on the engine block, you should be aware that you need to change the oil filter bypass valve in the engine block. The aftermarket oil lines add resistance which will cause the bypass valve to bypass the aftermarket oil cooler and/or oil filter all the time. Obviously, if the cooler and filter are bypassed the oil will be dirty and hot. Your engine could run hotter and could be damaged by dirt in the oil. If you choose to use an aftermarket cooler or remote oil filter that attaches to the pad, you should change the bypass valve to one with a higher differential pressure rating. A good choice would be GM# 25161284 which is rated at 30 psi. Remove the valve that is closest to the crankshaft and replace it with the new valve. Press the new valve into the engine block and stake it in three places. You should note that the bypass valves don't need to be changed if you use a production oil cooler which uses the production holes in the engine block and you don't use a remote oil filter. Also, if you use an adapter that just angles the filter for clearance you don't need to change the bypass valves."