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Bearing Clearances

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Marc W

Well-Known Member
Joined
Mar 31, 2017
Messages
1,234
Location
Colorado
I have been trying to diagnose the cause of the oil leaking past the front hub seal on my 2180 VW. It has the Force 1 prop hub. I pulled the hub again to check it. I turned a tapered mandrel on the lathe to fit the hub taper. I was then able to measure the runout on the bearing surfaces and seal surfaces. The bearing surfaces are probably fine. I measured TIR(total indicated runout) of less than .001". However the hub wasn't finished completely in the seal area. There is a .005 " step on one side of the hub right where the front seal rides. That may well be why the front seal is not sealing. I can probably machine the step down and install a Speedi-Sleeve there for the sealing surface.

I also tried to measure the runout on the end of the crankshaft. There seems to be a lot of slop in the #4 bearing. I can easily push the nose of the crank back and forth .004" and with moderate pressure move it .005". This engine only has about 90 hours on it so I would expect the main bearings to be tighter than that. I don't know VW's so maybe this is fine. What do you experienced VW builders think?
 
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