Big Four, External oil cooler required? Options

[saigon71]

To the collective world knowledge database...

What is the largest size type IV that can built and used safely as a street car without adding an external oil cooler?

Thanks!

[Mark Henry]

Yes and no, because I've built both with no over heat issues.
Do not use over 96mm P&C's without Nickies. Any bigger is automatically a misconfigured engine in my book.
That's a pretty basic rule, why Porsche when to an all aluminum cylinder as their engines got bigger.

Adding an oil cooler not really going to help a misconfigured engine, maybe a bit but it's a bandaid solution.
Also maybe you need one in socal, etc., but I'm taking into account the OP's location.

[r_towle]

Yes and no, because I've built both with no over heat issues.
Do not use over 96mm P&C's without Nickies. Any bigger is automatically a misconfigured engine in my book.
That's a pretty basic rule, why Porsche when to an all aluminum cylinder as their engines got bigger.

Adding an oil cooler not really going to help a misconfigured engine, maybe a bit but it's a bandaid solution.
Also maybe you need one in socal, etc., but I'm taking into account the OP's location.

Now that LN makes nickies, it's a new possibility if you have the money.
For many years, something like 30 years, building 103mm cast iron cylinders was the norm and a typical configuration.

With cast iron cylinders, you really do need a front cooler.
With the nickies, it may help, but I have no experience with the nickies....

I do not consider using cast iron cylinders a mis configured motor or design.....it's just a cheaper way to go that has been proven to last by many builders, many motors etc.
I agree to disagree with Mark on that statement.

Rich