head bolts.

[Farmallken.]

Hi Guys.
Please help, I have two books, one is telling me 54 ft pounds and the other one is saying 110 ft pounds, plus I have a papper that said 75 ft pounds, this is for the head on a Farmall H tractor with 7/16 studs with nuts, please what is the right torque.Thanks for any help.
Ken.

 

[Earl - IL]

70 - 75 is the correct torque. This coming from my Federal-Mogul Engine Bearing manual.

 

[buickanddeere]

Why was this H taken apart?
A standard grade 5 7/16 bolt should be torqued to a max of 49ft lb. That gives a clamping force of 6777lbs per bolt. Assuming the threads are clean, dry, square and not stressed from decades of usage.
Ever hear tell of engines that blow up shortly after a rebuild or leak? Some of the best and cheapest engine insurance is new fasteners.
It's a safe bet that some tinkerer at some time had those bolts out and tightened them down "real good" without using a torque wrench.
If the bolts are grade 8 then 70lb ft & 9567lb clamping force.
This is assuming the threads don't get pulled out of the cast iron. This also assumes the block threads have been chased with a tap, threads cleaned out and the top thread de-burred.

 

[Roy Suomi]

I'll bet that higher torque is a misprint..It should have read; Tighten it up till it breaks off , then back it off half a turn..
Seriously, I ran into a torque problem on 6.9 diesel heads on a Ford F-350..One book said one torque , the other said a much higher torque..Turns out the lower munber was correct...

 

[Anonymous-0]

I always went 75. Just dont go torque em all at once,,,, then do no more,,,,, it takes a few times to get the gasket crushed to get the torques even at all the bolts. Get it close, fire it up and warm it up, then go back and do it again. Also, use copper coat sealer on the gasket, will help hold up a lot longer with less chance of blowing. (not that there is much to worry about) Chad