When I was torquing up the head bolts there was a crack and bolt nearly sheared.


I hadn't reached the required torque, in fact I was tightening to 15nm to make sure my torque wrench was working. The holes had been cleaned out. What surprised me was how easily the bolt came out!

What do you think,- dodgy bolts?

I am going to tap the hole, what thread size is it? I know about cutting grooves in an old bolt but I have a tap & die set so might as well use it.

its not unheard of to get faulty bolts 7/16 unc thread size ,the fact bolt came out easily means threads in hole okay but faulty bolt,if bolt had been tight in thread and so hard to get out thread in block suspect

Thanks for quick reply. I'll get back to it now.

Cheap bolts from eBay heard of a few duff sets out there I have now gone down the arp stud kit to at least get some coman torque tightening!
I had i happen when using gen dealer ones once