View single post by Judson Manning
 Posted: 07-30-2006 01:54 am
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Judson Manning



Joined: 03-14-2005
Location: Atlanta, Georgia USA
Posts: 406
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Steve,

The post 1973 907 equipped JHs (aka MkII & JH5) have a removable rear housing and lip-type rear oil seal easily changed (realatively speaking).  Among other things,  the earlier versions of the 907 have the rope-type seal.

The bad news is that the rope-seal is in two pieces embedded in the upper & lower halves of the block.  The only way to remove/replace each piece is to split the block and remove the crankshaft.

Yes, you read that correctly, the entire bottom half of the engine has to be disassembled just to get to that damn seal.  This sets off a cascading series of events (i.e. "while you are at it") that concludes with a (nearly) complete engine rebuild.

One possibility is that your engine has developed a lot of crankcase pressure due to excessive blow-by from gummed-up piston rings.  The rope-seal may not be 'bad' just not able to handle the pressure.

If you suspect your piston rings are gummed-up, try flushing the oil several times using 5W20 and a commercially available crankcase cleaning product.  No guarantees, but pretty simple compared to pulling the engine.

Judson