Replace Head Studs?
08-16-2011, 09:27 PM
#181
Former Sponsor
Thread Starter
Thanks for your input Greg,
I found that when backing them off 90 deg and re-torquing them, that after a couple times they did not turn further and gain degrees turned indicating that the gasket was at full compression.
Brendan,
I agree, I took two days to do the last motor I did.
I found that when backing them off 90 deg and re-torquing them, that after a couple times they did not turn further and gain degrees turned indicating that the gasket was at full compression.
Brendan,
I agree, I took two days to do the last motor I did.
08-16-2011, 10:08 PM
#182
Rennlist Member
So does the wait a day, back off and re torque (by angle) apply to the 32v cars as well? Or is this just a stud question. I'll be putting my engine together this weekend and want to know if is should just do the 20nm then 90, 90 or should I back off after the last 90 a day later and re torque to the 90 again? Manual doesn't say this.
08-17-2011, 02:58 AM
#184
Nordschleife Master
Jeffrey,
No, you cannot retorque by angle without backing them all the way off and starting again.
So when using the bolts I would use the factory angle method. Or convert to studs (Simard??), and do something similar.
No, you cannot retorque by angle without backing them all the way off and starting again.
So when using the bolts I would use the factory angle method. Or convert to studs (Simard??), and do something similar.
08-17-2011, 04:07 AM
#185
Former Sponsor
Thread Starter
I love this!
This is what Rennlist should be about. People helping people with these cars we love.
Not everyone has every answer...not everyone is always going to be correct in how they do things.
Colin stepped up here, shared his method for everyone to see. Makes total sense and solves almost any problems anyone could be having with studs.
That's classy!
This is what Rennlist should be about. People helping people with these cars we love.
Not everyone has every answer...not everyone is always going to be correct in how they do things.
Colin stepped up here, shared his method for everyone to see. Makes total sense and solves almost any problems anyone could be having with studs.
That's classy!
06-12-2012, 11:38 PM
#186
HELI-COIL
I would say studs everytime, irrespective of wether they are designed to yield or not and wether they are replaced every time or not.
For one reason. Studs are screwed into the block with no load on them. Bolts are screwed into the block with load on them. There is lots of chance that the bolt threads could gall against the alu threads in the block while being tightened and damage the threads in the block = mucho problemo.
For one reason. Studs are screwed into the block with no load on them. Bolts are screwed into the block with load on them. There is lots of chance that the bolt threads could gall against the alu threads in the block while being tightened and damage the threads in the block = mucho problemo.
06-12-2012, 11:48 PM
#187
Former Sponsor
Thread Starter
And I'm told that there is a particular BMW model that requires inserts if the head is ever removed. I don't work on these cars, so I'm not familiar with the model that is involved, but this is very common knowledge, in the BMW crowd.
10-08-2012, 11:39 AM
#190
Nordschleife Master
Not the studs themselves. It's the way they're installed.
Studs can be run all the way into the holes. Good to back them off a bit so the tips aren't touching, though.
Tightening bolts wears on the threads in the block. Those can get heli-coils but it's work. The Al has to hold the strain eventually and a stud doesn't work better with a helicoil.
With the studs sticking out you can also get better torque results as the cleanliness and lube condition is much easier to control.
Studs can be run all the way into the holes. Good to back them off a bit so the tips aren't touching, though.
Tightening bolts wears on the threads in the block. Those can get heli-coils but it's work. The Al has to hold the strain eventually and a stud doesn't work better with a helicoil.
With the studs sticking out you can also get better torque results as the cleanliness and lube condition is much easier to control.
10-08-2012, 01:11 PM
#191
But the stated problem with certain studs is that they do not stretch to placement. The stock ones do I guess, but with the 89 heads you are relegated to bolts as the only studs are aftermarket.
02-18-2016, 01:25 PM
#193
Team Owner
I just put my 85 Euro 16V back together and used the suggested way by Colin it worked out well
first the 20NM then 2 X 90 degrees.
I waited a few hours then 1/4 turn loose,
then torqued to 67 ft lbs ,
all of the nuts went back to the original 2nd 90 mark that I made with a marker
first the 20NM then 2 X 90 degrees.
I waited a few hours then 1/4 turn loose,
then torqued to 67 ft lbs ,
all of the nuts went back to the original 2nd 90 mark that I made with a marker
02-18-2016, 01:46 PM
#194
Rennlist Member
I just put my 85 Euro 16V back together and used the suggested way by Colin it worked out well
first the 20NM then 2 X 90 degrees.
I waited a few hours then 1/4 turn loose,
then torqued to 67 ft lbs ,
all of the nuts went back to the original 2nd 90 mark that I made with a marker
first the 20NM then 2 X 90 degrees.
I waited a few hours then 1/4 turn loose,
then torqued to 67 ft lbs ,
all of the nuts went back to the original 2nd 90 mark that I made with a marker
As i mentioned a few years ago on this thread, Bill and I did the angle torque method and with the cometic gaskets, the resulting torque was almost hand tight (exaggeration) when it settled in. we re -did it and verified the re-angle torquing method actually had near 80ft-lbs of torque the second time around... engine has been running for 8 years now and no issues, so i guess that worked.
i still am puzzled with the angle torque method.. seems if you dont have new hardware, that final value is going to be way off.
I guess the hybrid method that Colin found makes more sense, as you end up at the same torques and you get there in a safe way too.
02-18-2016, 01:57 PM
#195
Rennlist Member
IIRC...studs are better...
Because the stud threads go into the block relaxed..which is important..
As you tighten the nut..the stud distributes force better along more threads, but the nut...is more efficient because only about 6 threads of a bolt or a nut when torque is allied to it, do anything.
Past 6 threads, there is almost no grip at all.
A long bolt as you tighten it, grips no more than the nut.
Read that in an engineering book a long time ago...
Because the stud threads go into the block relaxed..which is important..
As you tighten the nut..the stud distributes force better along more threads, but the nut...is more efficient because only about 6 threads of a bolt or a nut when torque is allied to it, do anything.
Past 6 threads, there is almost no grip at all.
A long bolt as you tighten it, grips no more than the nut.
Read that in an engineering book a long time ago...