The Ford Barn

Ol' Ron · 11-27-2018, 08:47 AM

I wrote that book back in the late 80's, after spending most of my building time on racing engines. Published in 1992. Over the past 25 years, I've learned allot about engine building, you can't stay stagment in a field like this. The vast majority of these engines are now used in street applications. However, the bearing load factors have increased by larger displacements and compression ratios. What most people don't realize is the fact that tight bearing clearances create heat with high viscosity oils. Stock clearances of .001/.002 must have a thinner grade oil to prevent this. Today, Main bearing clearances are much tighter in performance engines, I try to get .0025 +/- .0002. Rod clearance depending on he type rod and bearing and following the manufactures recommend numbers . We also have to consider the advances made in the quality of the oil available today. Modern auto engines are small in displacement yet produce a great deal of power, and last hundreds of thousands of miles using a lubricant that runs like water at 200 F. I hope some of the new builders will look into this, there is no reason why these engines can't giver reliable service for 100,000 miles or more.

11-27-2018, 08:47 AM	#7
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,985	Re: Bearing clearance I wrote that book back in the late 80's, after spending most of my building time on racing engines. Published in 1992. Over the past 25 years, I've learned allot about engine building, you can't stay stagment in a field like this. The vast majority of these engines are now used in street applications. However, the bearing load factors have increased by larger displacements and compression ratios. What most people don't realize is the fact that tight bearing clearances create heat with high viscosity oils. Stock clearances of .001/.002 must have a thinner grade oil to prevent this. Today, Main bearing clearances are much tighter in performance engines, I try to get .0025 +/- .0002. Rod clearance depending on he type rod and bearing and following the manufactures recommend numbers . We also have to consider the advances made in the quality of the oil available today. Modern auto engines are small in displacement yet produce a great deal of power, and last hundreds of thousands of miles using a lubricant that runs like water at 200 F. I hope some of the new builders will look into this, there is no reason why these engines can't giver reliable service for 100,000 miles or more.