Thread: 390 hemerage

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My favorite hauler is a 1976 Ford F150 Super Cab that I bought from the original owner about 5 years ago. After blowing up the tierd 360 that was in it origanlly I found a 4bbl 390 engine out of a 68 Gallaxy and had it rebuilt and balanced. The motor runs great but after it warms up it leaks oil out of the back of the motor some where under the bell housing. This isn't just a little drip. In fact for a couple of minutes after you shut it off it runs a small stream of oil out on the ground. We had a lot of problems lining things up when we went back in with the motor and I am woundering if it is posible that I knocked the rear main seal out of it or could it be something else?

i would say that your rear main seal is bad, pretty much the easiest way to fix that is to pull the motor. i would deff. say that it is the rear main

Get a flash light and a mechanic's mirror. Duplicate the problem and crawl under when it's doing the same thing and peer up into the block area. Cam plug or lifter galley plug is what it sounds like. A small stream is usually not present after shut off from the main seal. Maybe some dripping from residue but the stream action sounds like upper area such as cam plug and lifter galley plugs.

The back seal on the intake is bad for leaking on FE's, but yours keeps leaking after shutdown, so that should rule it out. It does sound like a rear seal, or the welch plug behind the cam.

yah i didnt think of the cam plug and the lifter galley plugs and yah those rear seals on the intake could deff. be the problem i should have thought of that before man im getting slow now that school out and i have graduated, i guess now i can stop thinking

Degrease it and wash. After it's dry enough, dupicate and verify the source. You'll find it.

I'm quit sure it isn't the manifold. the oil is coming out of the fly wheel cover underneath so I am pretty sure it is coming from the back of the motor behind the fly wheel. My cousin (a very compotent machinest) built and balanced the motor for me and I'm pretty sure he said he taped and threaded plugs in these holes in the back but I wasn't quite sure what he was talking about. Could these be the plugs you guys are talking about.

Those are the ones. It's not uncommon for the cam plug to leak even with careful installation. The tool used could have dinged the plug or it was not securely seated, etc. Take a look as I described. That stream you described is awfully suspicious.

Sounds like the rear main seal to me. If a plug was leaking it would do it right at start up not just when its warmed up. Pull the pan to check it. The seal could be installed backward or the crankshaft could have a groove in it at the seal causing the leak. Not too common on the old motors like the FE but not out of the question. Good luck