The Ford Barn - View Single Post - Rear Main Leak

CT Jack · 04-17-2019, 04:26 PM

I had a similar excessive oil leak experience immediately after my engine was completely rebuilt. As I was going throught he break in period it looked as thought the area around the rear main was leaking badly. Notice I didn't say main seal because the Model A doesn't have one. After removal of the engine and returning to the rebuilder, the engine was disassembled and rechecked for possible causes for the excessive leaking. The problem was directly related to a large clearance (.020") between the bell housing and the back of the block. As has been mentioned in several threads the rear of the cam that rides in the block does not have a seal. Any gap between the bell housing and the block will allow oil to leak by. The bell housing mounting face was blanchard ground and reinstalled. No more oil leaks.
This might be the cause of your oil leak.

04-17-2019, 04:26 PM	#17
CT Jack Senior Member Join Date: May 2010 Location: Hebron, CT Posts: 432	Re: Rear Main Leak – Bear with me I had a similar excessive oil leak experience immediately after my engine was completely rebuilt. As I was going throught he break in period it looked as thought the area around the rear main was leaking badly. Notice I didn't say main seal because the Model A doesn't have one. After removal of the engine and returning to the rebuilder, the engine was disassembled and rechecked for possible causes for the excessive leaking. The problem was directly related to a large clearance (.020") between the bell housing and the back of the block. As has been mentioned in several threads the rear of the cam that rides in the block does not have a seal. Any gap between the bell housing and the block will allow oil to leak by. The bell housing mounting face was blanchard ground and reinstalled. No more oil leaks. This might be the cause of your oil leak.