340 rear main oil seal installed?

[DART340H]

How is the rear main oil seal installed? Any picture, diagram, or drawings will be helpful. I thought i may of had a cracked block but the guys at the machine shop say it probably a rear main seal put in backwards. Thanks for the help. Dart340h.

 

[70rr-brian]

Never done one on a small block only big block. But the seals are directional. (assuming you are using a neoprene (non-rope version)) That is to say they have a taper in one direction. That taper needs to be installed pointed towards the front of the motor not the rear. The idea being that once oil pressure/gases builds up inside the block the seal is then compressed around the crank.

I know there are a million people who love the neoprene and never had issues with them but then there are a million who prefer the rope style. Since they stopped making rope seal with asbestos they have lost some of their effectiveness. Hell Mopar had a service bulletin with procedures for changing the rope seals to neoprene for warranty issues way back in the day. (Big blocks I know, not certain about small blocks) But if your crank is factory with the knurling still on it I would stick with rope even being less effective today than in yesteryear. Of course getting a rope seal in without dropping the crank a bit can sometimes prove to be difficult which is why I think a lot of people just throw the neoprene in... Its a lot easier.

But sometimes its not even the seal itself that is leaking but rather incorrect installation of the side seals or poor RTV sealing use that is ultimately to blame.

On big blocks these can be installed with the engine in the car. Drop steering centerlink, remove oil pan and remove rear main seal retainer. I will let someone more knowledgable about small block confirm if this can be done similarly in your case.

Depends on what seal you buy there may or may not be a procedure included with it.

 

[DART340H]

Ok thanks 70rr-brian. Thats what i had thought too just wanted a 2nd opinion. Thats the way i had it in there but still had a leak.maybe not a good enough sealer was used.