Torque-to-yield explained

[twobjshelbys]

https://www.jalopnik.com/2069042/what-are-torque-to-yield-bolts-why-automakers-use-them/

[Alloy Dave]

I dealt with TTY at Cummins...we were using those on head bolts back in the late '80s. We actually had a tool you could put on the head of the bolt with a little oil, and measure the actual distance the bolt was stretching in tenths of a millimeter lol...very expensive tool. Ours were torque plus angle. On one of our engines, the head bolts had to be torqued to 325 foot pounds...and there were 36 bolts. We'd use two guys...one would move the socket around based on the pattern, the other guy would do the tightening. We'd plan that for 10 AM so by noon you'd be done and could rest over lunch.

[twobjshelbys]

Some bolts on the Ford GT were labeled one use but had a torque pattern that was not torque plus angle but torque to x-LB-FT then torque to y-LB-FT y>x. I don't remember for sure but I think you torqued all to x then backed off to loose then retorqued to y. I think it was the supercharger bolts but also the transaxle half shaft bolts which were torx to boot