The Ford Barn

Ol' Ron · 03-27-2012, 08:17 AM

The stock flathead does not have an efeective filter. Using a detergent oil keeps the grit,dirt and other unwanted stuff in suspension so the filter can remove it. A good 10-30 non detergent oill would be best, in my opinion. I also believe that a newly rebuilt engine should be run hard and not spend much time running without a load. After a few 100 miles you can drain this and use what ever oil you see fit for your application. I recommend 10-30 as this is what the Ford factory specs. I feel 20-50 is best used in old warnout engines to keep the oil pressure up.

03-27-2012, 08:17 AM	#11
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,985	Re: flathead oil The stock flathead does not have an efeective filter. Using a detergent oil keeps the grit,dirt and other unwanted stuff in suspension so the filter can remove it. A good 10-30 non detergent oill would be best, in my opinion. I also believe that a newly rebuilt engine should be run hard and not spend much time running without a load. After a few 100 miles you can drain this and use what ever oil you see fit for your application. I recommend 10-30 as this is what the Ford factory specs. I feel 20-50 is best used in old warnout engines to keep the oil pressure up.