"My Mummert valley cover is leaking oil.
I have been snugging the bolts after runs and am at the point that I have to ask: Since I can’t use a torque wrench, how tight can I go? Or have I gone to tight already, I’m up to applying moderate force using a 1/2” box wrench."
So the problem is the cap screws are continually backing out?
You are going to have to beg, borrow or steal a proper torque wrench. I would imagine MUMMERT has a suggested torque value for an aluminum cover so as not to stress the aluminum component and possibly use longer cap screws (per MUMMERT).
Are you using a cork gasket or neoprene?
Once you each suggested torque value -
https://www.loctiteproducts.com/products/central-pdp.html/loctite-threadlocker-blue/SAP_0201OHL029W4.html
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