1941 Matchless G3L - Oil Leak Between Crankcases

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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phenry
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Joined: Mon Jun 04, 2018 7:22 pm
Location: Tamil Nadu INDIA

1941 Matchless G3L - Oil Leak Between Crankcases

Post by phenry »

Hello,

Before 6 months I dismantled the crankcases for a complete rebuild. Though I took utmost care to put them back together, I can see oil leaking between the crankcases. Not much but enough to keep me worrying. Is there any remedy for this as I do not want to separate the cases again. Please let me know if you have any advice for me.

Regards
PHenry
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Rob Harknett
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Re: 1941 Matchless G3L - Oil Leak Between Crankcases

Post by Rob Harknett »

http://archives.jampot.dk/technical/Spe ... y_1941.pdf
Crank case halves were machined to match when they left the factory. After a long time has passed, perhaps they needed to be re matched.
The above link may give some clues. It would not however, have considered rebuilding an engine after some 75 years have passed, since cases were matched.
Dixter
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Location: Seattle area, WA USA

Re: 1941 Matchless G3L - Oil Leak Between Crankcases

Post by Dixter »

Hi PHenry, I feel your pain. We've all been there. If you have a weep, “Leakage great enough to form drops, but not enough to cause drops to drip from the item being checked/inspected.” AND, if the repair is not likely to be easily seen, a tidy solution I've used is a smear of silver colored silicon gasket goo, over the area where the weep occurs.

Permatex and others make this product.

I use this stuff sparingly, and never to seal engine cases. Little bits of silicone gasket goo can break off, and the lubricating oil will carry the bits into unwanted places like the oil jets in your AMC engine. For crank cases I favor anaerobic gasket makers like Loctite 513, Permatex 51813 which fill gaps to 0.015”, or Wellseal.

But, please, do not tell anyone I told you this trade secret. It's not very elegant. I've too many rivet counters tracking me already. And burn this message after reading.

Ciao, DC
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