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Old 01-17-2021, 11:52 AM
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avrojockey avrojockey is offline
Join Date: Aug 2019
Location: Appleton, WI
Posts: 347

Originally Posted by lr172 View Post
Through stud is supposed to be a tight slip fit fit with the case bore. Most shops, like Divco, won't let the case out with bolts that do not meet that spec. This type of fit should not allow any significant oil passage. Further, o-rings are used inside the case surrounding these studs to avoid exactly this problem. How many hours on this engine? Loctite on the threads of the nut will do nothing. Would need to remove the jug and put some kind of sealant where the bolts leaves the case, if it is actually coming out via clearance at the stud.

If it truly is coming from the through studs, I would be worried about significant case fretting or a case crack at the webbing. Either way, it needs a professional examination.
About 1300 on a field overhaul that was thorough and extensively documented. almost 700 since topped with new ECI jugs....engine is running very good with clean oil so I would hate to jump to any conclusions.

Wouldn't fretting show up in oil analysis? Screen and filter have been clean, and AL is 5 ppm which is the universal average. Also, wouldn't fretting cause seeping at case split? I don't think anything is coming from there...either on top or bottom. Or, is it fretting between the through bolt and case?
Tim Holmes
Appleton, WI
RV-9A N904DC
2019-2021 Dues Paid

Last edited by avrojockey : 01-17-2021 at 12:16 PM.
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