Author Topic: Cylinder Head Bolt Torque Settings  (Read 1391 times)

Offline Terryb

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Cylinder Head Bolt Torque Settings
« on: 17.12. 2016 11:55 »
Hi All,

Treating the Shooter to a Top End Refurb. Can any body recommend Torque Settings for tightening the Ali Head please? I've got the tightening sequence, but no torque figures. *conf*

Offline terryg

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Re: Cylinder Head Bolt Torque Settings
« Reply #1 on: 17.12. 2016 12:36 »
It may be less than you expect.  If I remember right it's around 27-32 lbf ft.  That's enough to tighten down a well annealed copper gasket - and that is the important bit.

Try the 'search' function.  I'm sure it's been raised a number of times in the past few years.

edit - the correct thick washers are also important, to spread the load effectively.

edit - searching on 'torque' and 'head' throws up one reply that says 32 lbf ft is already too much!

Now the experts can chime in!
Terry
'57 'SR', '59 SR, '63 RGS

Online Billybream

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Re: Cylinder Head Bolt Torque Settings
« Reply #2 on: 17.12. 2016 14:46 »
Hi Terry
You will struggle to find official data, I used BSA A65 information and it quoted for 5/16" head bolt 25 ft lbs and for 3/8"  26 ft lbs.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Online muskrat

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Re: Cylinder Head Bolt Torque Settings
« Reply #3 on: 17.12. 2016 20:38 »
G'day Terry.
I find 25 is enough for my low comp A7 (alloy head) but need 30 to seal up the 10.5:1 cafe.
As terryg said a well annealed copper gasket is a must.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline Rgs-Bill

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Re: Cylinder Head Bolt Torque Settings
« Reply #4 on: 17.12. 2016 21:59 »
  BILL, here, I was setting my alloy head 62 RGS at 34 pounds as per my Haynes manual.  I am running 9 to 1, and an old timer told me Haynes sucks, alloy heads can distort at that much torque, and head gasket can leak, which is exactly what happened to me, until I started torqueing at 26 to 27 lbs, never had a problem since.  Also exercise your torque wrench if it sits for 2 to 5 years in between uses, like mine does, it gets the lubricants around inside to where they should be.  I do about  20 click stops on my Ford van lug nuts before torqueing down my cylinder head, so torque wrench is accurately operating.  Now I do not know about Iron heads, I am guessing you could use 34 pounds, they would not distort as easily.  What say you Musky, you raced these, can the Iron heads be torqued to 34 pounds without leakage ?  I do not know  if  you need to do this, he also said get the bike up to operating temperature, and shut it off, let sit over night, and re-torque head, I had 3 that were light on second torqueing.  Not sure the second torqueing is a must, but that is the way I did it 10 years ago, no problems since.
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Although getting a bit tougher to do ! !

Online RichardL

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Re: Cylinder Head Bolt Torque Settings
« Reply #5 on: 17.12. 2016 22:11 »
Retorquing is a pretty big commitment, since the rocker box must come off. I check compression right after assembly, then again after riding for some time. So far this has led to one box-off for retorquing at 32 ft-lb. Can't say for sure head is perfectly flat, but I'll check it next time it's off.

Richard L.
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Offline Terryb

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Re: Cylinder Head Bolt Torque Settings
« Reply #6 on: 18.12. 2016 12:35 »
Hi Guy's,

Many thanks for the advice. You right about the Haynes Manual, I've found conflicting info on other bikes when looking. I new about the Annealing process being a must and I think I'll go for the 26-27 lbf ft for mine. Thanks Guy's

Terryb *smiley4*