How many degrees can you go past recommended last 90 degree turn before they break? Reason I ask is I went an extra 45 degrees due to using the first random directions I googled. To later find they were wrong. So I went torque to 22 ft/lbs 90 , 90 then 45 degrees which is maybe 1/8th of a turn. Think it is ok ? Or should new bolts be installed ? Thanks

 

I'd replace it. They're inexpensive compared to having to do it all over again if it blows out the headgaskets or worse.

 

Agreed. You already pushed them beyond TTY. They're ready to pop. I wouldn't trust them beyond a few heat/cool cycles. I'd say you're lucky they didn't pop yet.

 

1/8 th of a turn isnt much to go past. I honestly cant see it making a difference. I turned a head bolt on a junk motor i have 3 complete turns past tight before it broke today.

 

Are you sure you wanna take a chance with stock bolts? There have been a few who've broken GM head bolts before getting to their angle.

 

There has to be a margin of error , because not every bolt will be the same in every engine. But now im nervous and will be replacing them. Its not my engine doing it for someone else. I have arp studs in my engine.

 

I'd throw them away and get ARP bolts at least. Screw GM TTY.

 

Not my car , my car has arp's .