Cooling RPM, Oil temp Vs RPM Options

[DavidSweden]

I have got my engine back together and running after 2 dropped valve seats.
I am keen to keep the heads cool, I think I read something on this forum about keeping the engine revs about 3500 to provide adequate cooling even if this means driving in 4th gear to keep the revs up.

What to members advise?

[Big Len]

Elliot - I know far less than you, but I had this conversation with Porschef last week, so let me ask you -

If the car is set up stock...Air/fuel mixture, timing, fan and belt in good shape, no deep air dams, using the correct grade oil, correct temp. plugs, etc, etc. Shouldn't the car be able to handle that kind of load? Wouldn't the factory have tested the cooling system under extreme conditions when the car was developed? If one factory spec is off, wouldn't that contribute to overheating?

I just don't see a reason to keep high revs unless under the most adverse conditions.
Is that correct?

[era vulgaris]

Elliot - I know far less than you, but I had this conversation with Porschef last week, so let me ask you -

If the car is set up stock...Air/fuel mixture, timing, fan and belt in good shape, no deep air dams, using the correct grade oil, correct temp. plugs, etc, etc. Shouldn't the car be able to handle that kind of load? Wouldn't the factory have tested the cooling system under extreme conditions when the car was developed? If one factory spec is off, wouldn't that contribute to overheating?

I just don't see a reason to keep high revs unless under the most adverse conditions.
Is that correct?

You're thinking like a water-cooled driver. Air-cooled engines are designed to run between 3K and 4K rpm for cruising. They're just different than water-cooled engines. Get used to it. Really, GET USED TO IT!!!!

Also, here's a quote from the late and very great Cap'n:

3500 RPM is cruising speed, NOT where you should be shifting. I recommend 4000-4500 as a shift point, and NEVER load the engine under 2500 RPM. Too many 356s, I guess, where cranks break under low RPM loading. As for 5th gear, I recommend cruising in 4th anytime you're under 60 MPH. Keeps the fan speed up, allows you to jump on the gas when necessary. 5th is an overdrive gear, meant for sustained high speeds on freeways and such.

The Cap'n