just replaced the head gasket on my grubee and the bolts are 14mm and i was wondering what is the torque inches on that? i went off some of al.fishermans posts and it says 120 to 175 on 8mm i did 150. but sense these are bigger i want to make sure it is right.
head bolt torque?
- Thread starter noble b
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The head studs are either 6mm or 8mm. That is the diameter of the stud, not the wrench size of the nut. Either way, the 150 should do you good. A 14mm nut on a 6mm stud is not common. A 14mm nut is common on am 8mm stud though.
Fabian
Well-Known Member
Don't be so hard on yourself noble_b
It would instantly make you feel better to have seen some of the obvious mistakes i have made along the way with regards to re-engineering a motor bicycle.
It would instantly make you feel better to have seen some of the obvious mistakes i have made along the way with regards to re-engineering a motor bicycle.
Al.Fisherman
Active Member
In my research, I found that with cast aluminum, the MAXIMUM torque (for 8mm threads) is 215 INCH INCH # (although I never go that high), and with 6mm threads is INCH 75#. In that case the first time I torque cylinder studs I use 120/50, second time I use slightly a little more torque, about 10% more. These are using Metric 8.8 (USS 5) grade hardware, not the cheap Chinese grade 3. To tell the difference in size of the cylinder studs, if the stud is the same as the engine mount studs they are 6mm, if larger they are 8mm. AS mentioned, don't go by the wrench used on the nuts. So with the 150 INCH # that you used, that's just fine, if they are 8mm. With all that said...I have gone as high as 175 INCH # on 8mm, with NO problem.
Chookawatts
New Member
I built a 400 chev a few years ago with cast iron block and heads and the torque settings in the chev are 65lbs, 120 seems a bit high to me! oh well I can only crack the head my studs will never break that's for sure! I made them myself and they are the strongest part of the whole bike
BigBlue
Active Member
Chookawatts,
that's 120 inch pounds not 120 foot pounds. 120 inch pounds = 10 foot pounds
Chris
AKA: BigBlue
that's 120 inch pounds not 120 foot pounds. 120 inch pounds = 10 foot pounds
Chris
AKA: BigBlue
Chookawatts
New Member
Hi BigBlue
Now you tell me! My head is torqued down to 50ft lbs it must be like a hand grenade at the moment! I wondered with one of the spring washes peeled out like foil, and I had to replace it. Now my question is: if I loosen it off and re torque it to say 10 ft lbs is it going to leak?
Now you tell me! My head is torqued down to 50ft lbs it must be like a hand grenade at the moment! I wondered with one of the spring washes peeled out like foil, and I had to replace it. Now my question is: if I loosen it off and re torque it to say 10 ft lbs is it going to leak?
Fabian
Well-Known Member
50ft lbs
I'm surprised the head gasket hasn't been squashed paper thin.
I'm even more surprised that the head bolts haven't striped out of the cases.
I'm surprised the head gasket hasn't been squashed paper thin.
I'm even more surprised that the head bolts haven't striped out of the cases.
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