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MG MGB Technical - Crankshaft End Diameter

Anyone got a stock crankshaft handy? I'd like to know what the diameter is on the rear end where the rear main seal rides. My 18V engine was leaking quite a bit of oil before I replaced the main seal last week. That was a small part of the operation to replace the clutch and transmission, so I didn't really think about it much at the time, but now I wonder if the replacement seal fit correctly. I expect the ribbed surface of a seal to lie flat against the surface of the shaft. But the new seal (and the old one) did not fit that tight. So the ribbed surface was visible when the seal was installed and the rear plate attached to the engine. The seal did make contact and therefore sealed the gap, but it seemed to have a very light grip on the shaft. Is this normal? If I had a measurement for the shaft diameter, I could assure myself that the shaft hadn't been turned down at some point. Thanks. -G.
Glenn G

Outer diameter of rear crank for oil seal is 3.5" Three and one half inches. I have on several occasions ground up to -.0005 to reduce the worn groove without problems with oil leakage. Alternatively try to fit new seal a bit proud to avoid seal dropping into groove.
jim soutar

ANother way to fix the groove problem is the use a speedi sleeve, which is a very thin stainless sleeve that fits over a shaft before fitting a new seal. I got mine from the local bearing shop.

One tip, if using a sleeve, is to wrap tape around the edge, to protect the seal when fitting, otherwise you might nick the seal.

Herb
Herb Adler

Thanks, guys. I just measured the ID of the old seal, and it is close enough to 3.5" that I can believe the crank is standard. I did not notice a groove on it when I replaced the engine back plate and seal. Just wanted some assurance that the seal was correct. Of course, the true test will be the condition of the garage floor in the weeks to come. -G.
Glenn G

Glenn-
Just in case it leaks (with a groove already there it probably will), SKF produces a Speedi-Sleeve for the rear end of the crankshaft (SKF Part # 520-515). Darn good product.
Stephen Strange

If unsure about the rear hub condition; install a speedi-sleeve to assure that there will be no oil leakage: Also use the Sherpa rear (Black) oil seal; it has a tigher fit.

http://www.jbr17llc.com/skf-99346.html
Rich Boris

This thread was discussed between 14/04/2012 and 15/04/2012

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