The Ford Barn - View Single Post - The Terry Burtz 5 main bearing engine blocks are back on track.

Terry Burtz, Calif · 05-27-2021, 02:23 PM

There has been some discussion on another forum regarding the choice of rear main seal and should the garter spring be removed.

The seal that we used in the Engineering Evaluation Engine was a National 415035 with the garter spring removed and we had no leaks.

National 415035 and 37939 seals both have an outside diameter of 5.004 inches and are a press-fit into the 4.999 inch housing bore of the "New Model A Engine".

The National 37939 seal has a lip made from Teflon and it does not have a garter spring.

The National 37939 seal is used in Detroit Diesel 6V53 engines as a rear main seal.

The Detroit Diesel part number is 8926902.

The seal and redi-sleeve is $20.01 at the following website (store.reliableindustries.com) under their part number A-8926902.

The redi-sleeve is used to repair a groove worn in the shaft and is not needed in the "New Model A Engine".

05-27-2021, 02:23 PM	#340
Terry Burtz, Calif Senior Member Join Date: May 2010 Location: Campbell,CA, USA Posts: 319	Re: The Terry Burtz 5 main bearing engine blocks are back on track. There has been some discussion on another forum regarding the choice of rear main seal and should the garter spring be removed. The seal that we used in the Engineering Evaluation Engine was a National 415035 with the garter spring removed and we had no leaks. National 415035 and 37939 seals both have an outside diameter of 5.004 inches and are a press-fit into the 4.999 inch housing bore of the "New Model A Engine". The National 37939 seal has a lip made from Teflon and it does not have a garter spring. The National 37939 seal is used in Detroit Diesel 6V53 engines as a rear main seal. The Detroit Diesel part number is 8926902. The seal and redi-sleeve is $20.01 at the following website (store.reliableindustries.com) under their part number A-8926902. The redi-sleeve is used to repair a groove worn in the shaft and is not needed in the "New Model A Engine".