E-Bodies.org Cuda Challenger Forum

Technical Shop => Engine, Transmission & Rear End => Topic started by: soccernut43 on June 13, 2020, 01:09:48 PM

Title: Correct position of rear crankshaft seal 340 engine
Post by: soccernut43 on June 13, 2020, 01:09:48 PM
Can anybody tell me the correct way this rear crankshaft seal is installed?  It's a 340 block.

Directions say "INSTALL SEAL HALVES. The large sealing lip must be positioned toward the front of the engine."

Then it goes on about a plastic installation guide or shoehorn aid which i think is if you,re installing with the crankshaft in the engine.

The large sealing lip looks to me to be the front lip of the seal with the smaller lip on the other side.

I found a picture of a rear seal installed on the "A Body" sight but I swear according to the directions I'm reading theirs is installed backwards.

Thanks!  I know all the answers I just forget the questions lol

Title: Re: Correct position of rear crankshaft seal 340 engine
Post by: Mrbill426 on June 13, 2020, 02:19:51 PM
The thicker lip goes (points) towards the crankcase.  The idea is to direct oil back away from the seal.



Quote from: soccernut43 on June 13, 2020, 01:09:48 PM
Can anybody tell me the correct way this rear crankshaft seal is installed?  It's a 340 block.

Directions say "INSTALL SEAL HALVES. The large sealing lip must be positioned toward the front of the engine."

Then it goes on about a plastic installation guide or shoehorn aid which i think is if you,re installing with the crankshaft in the engine.

The large sealing lip looks to me to be the front lip of the seal with the smaller lip on the other side.

I found a picture of a rear seal installed on the "A Body" sight but I swear according to the directions I'm reading theirs is installed backwards.

Thanks!  I know all the answers I just forget the questions lol
Title: Re: Correct position of rear crankshaft seal 340 engine
Post by: soccernut43 on June 13, 2020, 03:13:18 PM
So this is correct?  This follows the directions that are on the bag.

This is what I get for looking at a picture on the A-Body forum lol.
Title: Re: Correct position of rear crankshaft seal 340 engine
Post by: Mrbill426 on June 13, 2020, 03:42:08 PM
Looks backwards from here.

Quote from: soccernut43 on June 13, 2020, 03:13:18 PM
So this is correct?  This follows the directions that are on the bag.

This is what I get for looking at a picture on the A-Body forum lol.
Title: Re: Correct position of rear crankshaft seal 340 engine
Post by: Mrbill426 on June 13, 2020, 03:46:24 PM
Fairly good picture showing the thicker of seal on the crankcase side' edge pointing towards the crankcase.


Quote from: soccernut43 on June 13, 2020, 03:13:18 PM
So this is correct?  This follows the directions that are on the bag.

This is what I get for looking at a picture on the A-Body forum lol.
Title: Re: Correct position of rear crankshaft seal 340 engine
Post by: Mrbill426 on June 13, 2020, 03:49:18 PM
Another shot
Title: Re: Correct position of rear crankshaft seal 340 engine
Post by: soccernut43 on June 13, 2020, 04:15:49 PM
Thank you.  It was according to your pictures.  The installation you show makes more sense.  Thanks for taking the time to replay.  Appreciate it.  Plus thanks for the pics.
Title: Re: Correct position of rear crankshaft seal 340 engine
Post by: Chryco Psycho on June 13, 2020, 08:32:57 PM
Bill has it right , the sharp lip always points inward towards the oil , the ramp side is outside , small block seals usually have a have a part of the seal going outward across the cap to seal the cap to the block also .
Title: Re: Correct position of rear crankshaft seal 340 engine
Post by: soccernut43 on June 14, 2020, 10:41:48 AM
If you're talking about the seal half that is in the rear main cap, yes, there are "wings" that go inside the cap.  You add a little bit of high temp RTV to the cap mating surface then torque down and then trim the remaining "wing" sticking out from the main cap.

Thanks for all the awesome responses guys.
Title: Re: Correct position of rear crankshaft seal 340 engine
Post by: MOPAR MITCH on June 15, 2020, 11:56:58 AM
Soccernut - your picture shows it incorrectly installed.   Those slashed angled ridges (helix lines) are supposed to be on the outside of the engine... intended the pump oil back into the engine.   The way you show it installed will actually pump oil OUT of the engine.

I'm a former gasket engineer with a major company... this question always was coming into our tech line.
Title: Re: Correct position of rear crankshaft seal 340 engine
Post by: soccernut43 on June 15, 2020, 06:04:39 PM
 Thank you. I did switch it to match the two photos I was sent by another member. Appreciate it.