My engine came in bits with a lot of new stainless steel studs. A lot of the original steel ones were missing to I used these for the cylinder base and sump plate.
Earlier this week I was check tightening the sump after some running. I do the nuts up just over finger tight.
One nut just kept turning, this was at a very low torque. So I took the stud out and it came out with all the ally thread very neatly.
(A 1/4BSW helicoil is on its way)
I cut a slightly oversize steel stud as a stop gap.
But its got me thinking, I also drive a Land Rover and have had problems with SS fastening in the ally (Birmabright) bodywork. The galvanic potential between stainless and ally is significantly greater than between zinc plated steel and ally and its noticeable that the body does not corrode around the zinc plated bolts but does around the stainless ones.
I'm now wondering whether the stainless studs are attacking the ally crankcase and I should swap the SS out for plain steel?
In a marine environment stainless in ally is a high risk combination with the ally corroding.
