Is my oil pump output compressible seal the wrong size

DennisMo

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Jun 6, 2023
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Hello all from Vancouver!

I opened my timing cover to fix a leak and am replacing the oil pump output rubber seal that seals between the pump and the outer timing cover case by compression.
The outer diameter of the small oil pump output pipe is .260 inches. The inner diameter of the new compressible seal is .200 inches.
I can put the seal onto the output pipe by stretching it, but it is quite a stretch. Using (my rarely used) high school math, the stretch increase of the new seal along its inner circumference is from .062 inches to .082 inches which is about 33% stretch

I wonder whether the seal inner diameter might be wrong and whether the seal may split one day ...
If anyone has a new seal in their inventory and could measure the inner diameter I would be grateful

Looking forward to your comments with thanks

Dennis
 
Weird, the seal can be a loose fit on the pump, it doesn't need to be tight at all! But then again, I haven't seen a new one since about 1980.
 
DennisMo said:
Hello all from Vancouver!

I opened my timing cover to fix a leak and am replacing the oil pump output rubber seal that seals between the pump and the outer timing cover case by compression.
The outer diameter of the small oil pump output pipe is .260 inches. The inner diameter of the new compressible seal is .200 inches.
I can put the seal onto the output pipe by stretching it, but it is quite a stretch. Using (my rarely used) high school math, the stretch increase of the new seal along its inner circumference is from .062 inches to .082 inches which is about 33% stretch

I wonder whether the seal inner diameter might be wrong and whether the seal may split one day ...
If anyone has a new seal in their inventory and could measure the inner diameter I would be grateful

Looking forward to your comments with thanks

Dennis
Click to expand...
Assuming the original pump and the part the seal goes one is original:

Should be: https://andover-norton.co.uk/en/sho...ming-cover-oil-pump-oil-pressure-relief-valve

Not: https://andover-norton.co.uk/en/shop-details/16729/oil-pump-seal-mk3
 
I just measured one of my new seals. I can slide a 13/64 drill snuggly into the hole (.203”). You might check if the pipe on the pump is correct. It is a push in fit….maybe in backward?
 
The little output stub that comes out of the pump (to the timing cover) is the same outside diameter on both sides at .260 inches
Thanks
Dennis
 
DennisMo said:
The old one that came off it is now .260 hole diameter (It was likely less that than when installed)
The one I got in a complete seal kit for the engine is .200 hole diameter
Dennis
Click to expand...
Please see the two pictures in my post #5. You may have a MKIII gasket set!
 
Also, confirm if you have a mkIII timing cover installed, as they are sometimes retrofit to mkII engines b/c they have anti wet sump check valve and timing chain tension check opening. It would ththen need the mkIII oil seal, not the mkII seal.
 
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