Head bolt angle/torque question.
02-26-2019, 04:50 PM
#1
12 Second Club
Thread Starter
Head bolt angle/torque question. Ok, I screwed up; please don't torch me. I am installing heads on a '98 ls1, and all was going well until the furthest rearward bolt on the upper row. I torqued everything to 22 foot pounds, marked the bolt heads horizontally with a sharpie in conjunction with using an angle guage. Long story short, the marking on the rear most bolt was weak, and I lost track with the angle guage, etc. Now what? Is there a torque value that will approximate 22 ft. Lbs. +90' + 50'? Do I just go to 70 foot pounds and hope for the best? Am i the first idiot this has happened to?
02-26-2019, 05:16 PM
#2
TECH Enthusiast
No, you're not the first idiot, and won't be the last. It's happened to me, and usually it's on the most difficult bolt, just as you mentioned.
I've never been a fan of TTY fasteners, for this reason, and because they are supposedly not reusable.
I started in this trade in the mid '90s, back when most engines still used a simple 3-step torque procedure. What I liked about that procedure (and what I was taught) was that after the final pass with the highest torque spec, RE-DO all of the bolts (head, main, intake manifold, whatever) in the appropriate pattern until they don't move anymore; trust me, there were always a few that would tighten up a little more the second or third time.
With TTY bolts, it seems like there is always at least one that doesn't feel right, and turns a little too easy for my tastes. If I had a torque specification, I would know if it was tight enough, but that's just not how these bolts work.
TL;DR : I don't like TTY bolts, but I have to work with them anyway.
But in answer to your question, here's what I've done in the past: Set your torque wrench up for a lower torque than you know what the final will be, like say 60 lb/fts. Try torquing a few of the bolts that YOU KNOW were done properly. They shouldn't move.
Now turn up the torque 5 lb/ft and repeat. Do this until they just barely move.
Then go with that spec on the bolt in question.
At this point, I usually just torque all of them in the appropriate pattern at whatever torque spec it settled on.
I'm sure some people are going to come on here and **** all over my idea, but it's worked for me.
One last thing: You're using 22 lb/ft + 90 degrees, then 50 degrees?
What kind of bolts are you using? Typically, it's 22 lbs, then 90, 90.
I've never been a fan of TTY fasteners, for this reason, and because they are supposedly not reusable.
I started in this trade in the mid '90s, back when most engines still used a simple 3-step torque procedure. What I liked about that procedure (and what I was taught) was that after the final pass with the highest torque spec, RE-DO all of the bolts (head, main, intake manifold, whatever) in the appropriate pattern until they don't move anymore; trust me, there were always a few that would tighten up a little more the second or third time.
With TTY bolts, it seems like there is always at least one that doesn't feel right, and turns a little too easy for my tastes. If I had a torque specification, I would know if it was tight enough, but that's just not how these bolts work.
TL;DR : I don't like TTY bolts, but I have to work with them anyway.
But in answer to your question, here's what I've done in the past: Set your torque wrench up for a lower torque than you know what the final will be, like say 60 lb/fts. Try torquing a few of the bolts that YOU KNOW were done properly. They shouldn't move.
Now turn up the torque 5 lb/ft and repeat. Do this until they just barely move.
Then go with that spec on the bolt in question.
At this point, I usually just torque all of them in the appropriate pattern at whatever torque spec it settled on.
I'm sure some people are going to come on here and **** all over my idea, but it's worked for me.
One last thing: You're using 22 lb/ft + 90 degrees, then 50 degrees?
What kind of bolts are you using? Typically, it's 22 lbs, then 90, 90.
02-26-2019, 05:40 PM
#3
Tq it back to 22 ft lbs and continue the tq sequence. That bolt is the last in the sequence and will be fine if you do all steps in one shot on it.. You tq from the inside out to push the gasket outward as the head clamps. Once you reach the last bolt everything is squished and in it's final place so just go ahead and do the whole sequence on that bolt. Then move on to the small bolts up by the intake.
I'm a tech and have been for 20 years, I wouldn't recommend this if I didn't have full faith in it or if I wouldn't do it on my own car.
I'm a tech and have been for 20 years, I wouldn't recommend this if I didn't have full faith in it or if I wouldn't do it on my own car.
02-26-2019, 05:47 PM
#4
For even length head bolts.
22 ft lb
90 degrees
70 degrees
For unequal length it's
22 ft lb
90 degrees
90 degrees on the long bolts 50 on the short (which is one of the ones in question by OP)
For all the final is 22 ft lb on the little bolts by the intake
22 ft lb
90 degrees
70 degrees
For unequal length it's
22 ft lb
90 degrees
90 degrees on the long bolts 50 on the short (which is one of the ones in question by OP)
For all the final is 22 ft lb on the little bolts by the intake
02-26-2019, 06:52 PM
#5
12 Second Club
Thread Starter
Thanks guys, I toyed with the idea of taking it back to 22 lbs. I have already "reverse torqued it in accordance with the other short bolt. I appreciate the responses, I always like to run this stuff past the experts!! Cheers.
