replace 340 rear main seal

[coupe32]

I replaced my 340 engine in my streetrod a few months ago with another fresh rebuilt 340. The one I removed had only 13K miles on it an ran great however the rear main seal was leaking slightly. By leaking maybe a new drop of oil found on the garage floor every week. I'm probably going to sell this 340 engine but I thought I would change the rear main seal while it is on the stand.
Is this an easy fix? Will I have to drop the crank to do it? Any tips I need to know? I'm pretty sure it is the rear main seal. The pan gaskets have been replaced a couple of times already. The engine never used any oil but the drop of oil every once in a while was annoying and the bottom of the flywheel cover always had that small drop of oil hanging from it.

[dodger1]

My 1980 FSM details how it's done, and I would assume the 340 procedure would be the same as the 318. The 360 is slightly different. (No 340's in 1980) If you don't have access to the right FSM (340 included) I can scan and pm or e-mail you the info from mine.

[coupe32]

Thanks for the info. That would be great if you want to email it to me. My email address is coupe32@wowway.com

[dodger1]

Done. Hope it helps.

[aarracer]

coupe32

You may wish to first check that your drips are not coming from a weeping rear intake manifold gasket, distributor seal or oil pressure sending unit?

[Stoga]

Good point aarracer! Nothing is much more of a drag than finding out you fixed the wrong thing or not enough things!

[coupe32]

Everything else looks dry. I think it is the rear main seal. dodger1 emailed me info on changing the seal. Thanks

[dodger1]

Good point about the rear intake seal especially. The corners can be squished and the sealant squeezed out. However, since it's on the stand this should be easy to inspect, unlike when it's in the car.

[John Kunkel]

For a "drop of oil every once in a while" I wouldn't mess with it, a botched seal change could leave it leaking worse than that.

[coupe32]

John, That is exactly why I never fixed it. I sure didn't want to make the problem worse. I was planning on selling this engine and I could just wipe off the drip and let it go and not say anything but that woudn't be honest.
It really does only drip about once a week but whoever is buying it might not believe that it only drips once a week if I tell them that. If I have the time I will eventually try to do the fix. Thanks