JoJo
Well-Known Member
When installing the rear main seal (block side), does it fit all the way into the groove before installing crankshaft or will it rest on the two extended ends? Also, will those ends flatten easily as the rear main is torqued?
318 Rear Main Seal
- Thread starter JoJo
- Start date
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MRL Performance
Well-Known Member
The rear main seal 1/2 with the "wings" goes in the cap, not the block. There should be grooves in the cap for the "wings"
JoJo
Well-Known Member
Thanks. I seen it when I flipped the cap over to clean it... The light bulb came on, lol.
340sFastback
Well-Known Member
You will want to put a thin film of RTV sealant between cap and block or it will leak.
JoJo
Well-Known Member
I put a dollop on both side between the cap and block. Just may pull it off and reapply the sealant to be on the safe side.
One other thing I learned is that they say to nip off the wings, and rotate the seal about 3/8" of an inch so that in the cap it is sticking out a bit on one side and in a bit on another side. Do the same for in the block. Then reinstall the wings. Make sure to put RTV where there are any joints/seals. Easiest way to explain it is think of hardwood flooring, you never lay 2 pieces side by side with the joints beside each other, this is due to "weakening". Same goes for the seal if you dont rotate them, you have the seam from the seal as well as the seam from the cap to the block in exactly the same spot. Good luck!
BillGrissom
Well-Known Member
I wonder about using RTV. I recall instructions to use a few drops of "anerobic sealant" between the metal surfaces. Maybe that was for my later Mopars (2.2 or 2.4L), or maybe my 383. Anyway, the same principles should apply since the same issue of sealing steel-steel. Not sure we had RTV in the 60's or maybe anerobic sealant is newer. We want a thin sealant that provides tight metal-metal contact so the bearing is well supported, but seals oil leaks long-term.
Rotating the seal so the split halves don't align with the bearing mount's sounds like a good idea. I didn't in my 273 because I followed the TSM, but that is the instructions for the big block and slant as I recall (no wings). If anyone is doing this to just fix a rear seal leak, they should know that you can do this fairly easily in the car with the crankshaft in place.
Rotating the seal so the split halves don't align with the bearing mount's sounds like a good idea. I didn't in my 273 because I followed the TSM, but that is the instructions for the big block and slant as I recall (no wings). If anyone is doing this to just fix a rear seal leak, they should know that you can do this fairly easily in the car with the crankshaft in place.
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