Oil temp or piston/jug/cylinder heat cooling the bigger issue with large Type 4 engines? Options

[Tdskip]

Hi guys - now that I know that I have a 2.7l engine I removed from the turbo car I've been wondering about what presents the bigger challenge in keeping the engine healthy - keeping oil temps down or keeping the piston/jug/heads cool enough.

I had been thinking oil temps but after trying to read everything I could come across it appears that air flow over the top end of the engine becomes the harder thing to properly manage.

This car had (still has actually) a 914/6 style front oil cooler but would this big of a big bore also require airflow mods?

Thanks

[Bleyseng]

Hi guys - now that I know that I have a 2.7l engine I removed from the turbo car I've been wondering about what presents the bigger challenge in keeping the engine healthy - keeping oil temps down or keeping the piston/jug/heads cool enough.

I had been thinking oil temps but after trying to read everything I could come across it appears that air flow over the top end of the engine becomes the harder thing to properly manage.

This car had (still has actually) a 914/6 style front oil cooler but would this big of a big bore also require airflow mods?

Thanks

I think Raby attacked this problem of keeping the heads cool by cam mods. He added extra duration to the exhaust valve opening so hot gases escaped out the exhaust so the heads didn't have to absorb as much. Another trick now is to have the combustion chamber thermal coated so the heat doesn't soak in to the head. I would still think a external oil cooler is in order for that engine.

[Tdskip]

Thanks @Bleyseng .

Will be interesting to see if the cam in this thing has an altered profile. I didn't know Jake did that, thanks for the tip.

Edit: related question, is the reason that stock 911 engines don't have an issue with this is that the displacement is spread over 6 rather than 4 cylinders and thus the thermal load is better distributed?

[mepstein]

Thanks @Bleyseng .

Will be interesting to see if the cam in this thing has an altered profile. I didn't know Jake did that, thanks for the tip.

Edit: related question, is the reason that stock 911 engines don't have an issue with this is that the displacement is spread over 6 rather than 4 cylinders and thus the thermal load is better distributed?

Probably, as well as a big engine driven fan & large capacity dry sump oil system.

[Tdskip]

@mepstein - thanks for the response and hope you are doing well. Not sure if the shop is still open, hope customers are being reasonable.

It would seem that keeping the oil cool should be manageable, and when I did run this engine (minus boost) on the highway it managed it's temperature OK. The oil temp and CHT readings were all comfortably within normal.

Wonder what air flow mods, out side of the vertical set up, could be done?

[stownsen914]

Aircooled motors depend heavily on oil cooling. If the oil runs hot, your top end will suffer too. I don't have experience with big type 4's, but have heard that oil temp management is a challenge, even with a good size front cooler. Personally I'd want to see temps not too much over 200 degrees. Dry sumping is a big improvement and helps a lot in both oil supply and temp management.

[Tdskip]

Thanks for the response, just joined another Engine build forum and will share discussion and suggestion from there.