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For the M30 engine, at what level of desired performance are oil cooled pistons required? I've seen them mentioned now and again but don't know much about when they SHOULD be used or when they MUST be used.

-Greg in Ypsi, MI
86 E24 turbo (Dinan)
89 E32 735iA

Todd doesn't use them in his car, and that car makes 389 rwhp and over 400 ft-lb rwtq. If the car is in good tune, they're a "nice to have" kind of thing. They will extend the service life of the engine, and may reduce the chances of predetonation, but they aren't necessary most of the time in our cars.

I think they are a "should" have thing. Alpina and Hartge install them on their NA engines too. Almost all race engines be it FI or NA have them. How can you argue with the experts?

Todd is planning one building a engine from the ground up for turbo and guess what, it will have oil jets.

If you are (re)buiding an engine, they are cheap enough to install.

If you are (re)buiding an engine, they are cheap enough to install.

Easy to install, eh? Do tell. I would appreciate hearing about the installation.

I have Corky Bell's book. Is there another publication out there that would describe builing up an engine in general? A web link to some fella's site who has done this? Is it a matter of tapping into an oil channel in the block and installing nozzles?

I have much to learn.

gkrea1 wrote:

If you are (re)buiding an engine, they are cheap enough to install.

Easy to install, eh? Do tell. I would appreciate hearing about the installation.

He said cheap, not easy! The squirters themselves aren't expensive, but installing them is not "easy" unless you have access to a Bridgeport-style milling machine -- see this thread for how Sweeney did his. I am contemplating fabricating a jig to do the same, but it hasn't gotten past the conceptual stage.

Great link. Thank you.

Todd isn't too far away in Ohio. I guess someday I'll haul my block down there and see if he's built a jig. Or if a local machine shop has his setup instructions filed away (with his blessing, of course).

Duke M535ti wrote:I think they are a "should" have thing. Alpina and Hartge install them on their NA engines too. Almost all race engines be it FI or NA have them. How can you argue with the experts?

Todd is planning one building a engine from the ground up for turbo and guess what, it will have oil jets.

i would hazard a guess here and say, the more you're on the gas then the more you need cooling for the pistons.

in the rotary world, this is the same as rotor face temps, when they get too hot, power drops in a non turbo, and the turbos pre-ignite/detonate/blow up.

the factory has squirters to spray oil at the rotors, but at some point, you need bigger ones, but its mostly used in road racing cars, as those are the ones that are full throttle the most...

i would think piston engines are similar, but they are wierd so i dunno...

mike

gkrea1 wrote:For the M30 engine, at what level of desired performance are oil cooled pistons required? I've seen them mentioned now and again but don't know much about when they SHOULD be used or when they MUST be used.

-Greg in Ypsi, MI
86 E24 turbo (Dinan)
89 E32 735iA

"The system delivers pressurized oil to continuously lubricate and cool the pistons, which reduces friction and noise and ensures durability for the engine’s higher power levels" - Pontiac News January 1st, 2006

For a given power level, I believe oil cooling the piston will result in one or more of the following: 1) marginally lower octane fuel may be used without resultant combustion knock (preignition), 2) Improved part-load efficiency, 3) more spark advance, and 4) lower exhaust gas temperatures. Depending on other factors, it will also reduce the likelihood of pressure spikes in the combustion chamber caused by combustion knock which can cause damage to the piston, cylinder head and cylinder-head gasket.

Oil cooled pistons “SHOULD be used” in a high performance engine and “MUST be used” when you wish an engine to survive and other measures to reduce or eliminate thermal overload prove insufficient.

Remember the intended use of this car, Autobahn at 130mph for extended periods of time. The oil squirters can help alot then. In 65mph levels, not so important.

RussC