We are rebuilding a little cat vblock for school. We’re putting one of the heads back on today. There’s a 5 step torquing procedure in the book. So we’re on step 1, on the 4th bolt in the pattern, and something (not the torque wrench) pops. It is the threads in the bolt hole in the block. Came out very prettily: the first 4 threads in one piece nicely with the bolt.
So we go hunting, and find 3 more holes that already have suffered the same fate and have not been repaired. So we’re getting the repair kit ordered. Ok, what caused it?
I have an idea: The book says use moly-coat on the bolts. I didn’t like the look of the “moly” we have in the shop, and there was still some left on the bolts, so I didn’t apply any more. The can doesn’t say “moly” or “molibdinum” anywhere on it, but it looks like moly-coat and it is for the same purpose. What I didn’t like was that it had separated into the silver paste and a thin yellow oil. When I mixed it up it still seamed too thin and lubricious to me. So my idea is that the last group to work on this thing used this “moly-coat” or what-ever-it-is on the bolts and, because it was too lubricious, they got it over-torqued.
Whatcha reckon, guys?