Changing Seal on L20B

[difrangia]

I've searched around in the forum and can't find the info I need. This is pertinent to my 1978 620 pickup with L20B engine.

 

We will be replacing the clutch/pressure plate/,throw-out bearing, & tailshaft seal in the next week or so. The flywheel will be off for a refaceing.

 

While the trany is out, we will replace the engine rear main seal if not too difficult a task.

 

Question is: 

 

Is this seal accessible from the back of the engine very easily with the transmission out?

 

In looking at the replacement seal, I'm assuming that the crank is not flanged like the earlier E & J series engines?

 

If replaceable with the engine assembled and installed, will the adapter plate between the engine & trany need to come off?

 

Any other issues that I might anticipate in doing this operation?

 

 

Thanks in advance for information.

steve

[datzenmike]

The flywheel will have to come off to get at the rear seal, the engine plate sandwiched between the transmission and engine now will fall off. Drive a wood screw(s) into the old seal and pull it out.

 

 

 

Lube the crankshaft side lips on the seal so it doesn't start up and run dry. Place a suitable size block of wood over the seal, line it up evenly and nudge into place with a heavy hammer or sledge tap. Once flush, switch to something like the 3/8 extension and go round and round. tapping it gently in until fully seated.

[Stoffregen Motorsports]

Try not to push the new seal in too far. It will bottom out on the main cap, but it's original home is flush with the back of the block.

 

Use Gasgacinch on the perimeter of the seal to help it slide in and adhere once it dries.

[banzai510(hainz)]

rockauto has a sale on 620 parts now

get new t/o collar and bearing together

[racerx]

Theres also tons of manual downloaded in general discussion

[difrangia]

Thanks, Rats. 

 

I didn't know how the back of the crank is configured and if the adapter plate is held on with bolts in addition to the transmission plates. Only Datsun engine that I've been into is E1. The E1 has a flanged crankshaft where the flywheel mounts and has a graphite rope seal. Also there are 4-6 bolts besides the transmission bolts that secure the adapter plate to the block. 

 

I've had an Exedy clutch,PP,throwout bearing kit and the output and engine seals for a while. I'm actually paying a friend and local import mechanic to do the install.  He has the lift and jacks and I'm tied up on a Honey-doo project for another month or so. Putting together a greenhouse before winter for the patio/pool plants and to do some early gardening start-up stuff next Spring.

 

Thanks again.

Steve