cronic rear main oil leak!! help!!!

[vintagemotors60]

Help! I have a 200 six in my 1974 bronco. I have rebuilt the motor from the bottom up. its has a ford six cam with a big valved late 250 head,header and webber. Its runs great!
Heres my problem. I have replaced the rear main and pan gasket 3 times! I have had the engine out twice. I can not stop it from leaking.
the last time I took the motor out i sealed the flywheel bolts and put in a NOS ford two piece seal. It now seems to only leak when the engine is not running. I am getting oil into the bell housing.
I know that the valve cover on these motors leak and I have put a new cover on it and put rags aroung it to make sure its not coming from there.
The crank has not ever been turned on the rear main seal. It still has the little groves in the seal area on the crank. I have not been able to find anything on the this tech page to help me!

I had the same problem before I rebuilt the engine. but this is a differnt block . the crank is same.

what am I doing wrong?

 

[wsa111]

This is from a previous post, & it seals to perfection. Bill

Hope this helps, install the rear main seal with the ends at 10:00 o'clock on one side & 4:00 o'clock on the other side. Then put a small daub of sealer which you need to purchase at a toyota or lexus dealership. Its called FIPG. Put a small daub at the butting surfaces of the neoprene rear main oil seal. Before you put the rear main bearing cap in place place a very small bead of this sealer at the outer edge or lip where the rear main bearing cap contacts the block. Also place a very small bead from the seal to the outer edge where the main cap sits to the outer edge or where the cap contacts the block. Don't forget to place sealer on the flywheel or flexplate bolts to the crankshaft.
Using this procedure i have never had a rear main oil seal leak or even seep. This applies to fords & chevrolets, big block or small block with the 2 piece rear main seals. Bill

 

[vintagemotors60]

i did almost all that you just described eccept turning the seal to the 2 and 4 clock position. i used case sealer Yamaha bond on the bolts. i used RTV on the endgap of the seal.
the first time i even glued the main seal in the grove so it wouldnt turn and it was worse becuase the RTV wouldnt let the seal seat against the crank.
Any ideas what turning the seal to the 2 and 4 position does? the motor had the same problem with the old rope seal.

 

[vintagemotors60]

sorry i ment 10 and 4 position

 

[wallaka]

Makes it so the gap in the seal doesn't coincide with the gap in the bearing cap.

 

[63comet]

I have the same problem with my 250, I replaced the rear main twice and the last 2 times I installed them exactly as Bill stated with the ends at 10 and 4. I finally found out it was the oil pan not fitting right against the rear main and allowing the rear seal of the oil pan to leak. I discovered this one day when I parked on a steep incline and when I returned several hours later, oil was running out and puddling up on the ground. Make sure when you pull and replace the pan seal, that it seats right and use RTV black silicone all over the gasket.