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MG MGA - Torque spec for head bolt

I had to reomove the number 11 nut to put the vacuum pipet bracket on and I can't find the torque spec for the head nuts in the workshop manual it just gives the order of tightening
Tysen

Follow-up question.

I've seen torque wrenches at Autozone for $19.99 and torque wrenches for 79.99 at sears.

I'm sure theres a qualitative difference; is it a necessary one?

what have you guys done in this regard? Cheapest or nicest you can afford.

Thanks again,

Tysen
Tysen

I've used the el cheapo version (Pep Boys) and it works fine, but have not checked the calibration. I did break the pawl on one by gross overloading (undoing FWD hub nut). Only buy the type that clicks when it reaches the load (as opposed to the type with a pointer and scale.
Art

Tysen - The $19.99 Autozone torque wrench is a good half in drive ratchet wrench with a long handle, but not something to be trusted for critical like torquing bolts in an engine. I don't think that I would even trust the $79 Sears torque wrench. For a torque wrench that is going to be used on an engine, I want one that I can send back to the manufacture periodically for calibration. The reason for this is that the michrometer adjust torque wrenches are notorious for going out of calibration (even the really expensive ones) and there is too much in an engine that is riding on a properly torqued fastener to trust to luck. I have a block out of a TD in the garage with the lower two inches of the crank case missing on hte right side due to an over torqued wrist pin pinch bolt that finally broke while I was cruising down the highway at 4200 RPM (not an unreasonably high engine speed for the XPAG engines). Once I had found out what had caused the problem, I toopk the next set of pistons into work and used a recently calibrated torque wrench used for work on submarines to torque those bolts - haven't had any more problems. Under torquing can cause just as much in the way of problems in that it will cause a bolt to flex more than it should and shorten its life from fatigue. If you want to use a cheap torque wrench, make it one of the old beam and pointer torque wrench, they don't go out of calibration like michrometer adjust wrenches do. Also, regardless of the torque wrench you use, use only in one direction. Don't loosen bolts with it and the calibration will last much longer. Cheers - Dave
David DuBois

Tysen

What are you doing attaching the vacuum bracket to a head stud? It goes on an exhaust manifold stud!

Steve
Steve Gyles

Steve,

Don't worry, I put the bracket on the exhaust stud as we've discussed.

But there's a second guide, where the tube wraps around the head, it is intended to go on the number 11 head bolt.

I think you can see the second one in clausager.
Tysen

Oooh. Looks like another bracket I don't have and never missed!

I must say I am surprised that such a bracket should be attached to a head stud. I thought these were normally kept clear of ancilliaries. I will look at Clausager with renewed interested tonight.

Steve
Steve Gyles

I recently snapped #2 head stud with one of those cheap torque wrenches. You get what you pay for.

Tysen, I would recommend you invest in a workshop manual which will have all of the info you are seeking. Invaluable for the $20 investment.

j
JohnB

Follow-up question:

I have the same bracket that Tysen is referring to for the vacuum pipe, and I aslo want to attach it to the #11 head bolt. Is there any risk of warping the head by removing and immediately reinstalling/retorquing just one stud bolt? I plan to do this while the engine is cold. Thanks.

M.D.
'57 Coupe
M. D.

Steve

We were in about this on another thread. There is a bracket for the flame trap which is supposed to go on the second exhaust manifold stud from the rear and what is called a P-Clip which goes on the head stud No.11. For the record - both "clips" came with a new vac pipe from Moss.

Had a snoop around a concours "A" last Saturday and sure enough the flame trap was poking up between the rear exhaust port and rear carby.

So get bending that pipe again...

Pete
Pete Tipping

This thread was discussed between 09/04/2006 and 11/04/2006

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This thread is from the archive. The Live MG MGA BBS is active now.