Author Topic: Cylinder head bolts  (Read 675 times)

Offline TomL

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Cylinder head bolts
« on: 10.08. 2017 10:11 »
Hi all, A7 clutch sorted! Now burning oil on rh cylinder! Did comp test and both cylinders are at 80psi, around 100 with a little oil in there. Now stripping top end. Is there a sequence for undoing head bolts? It's iron head. Any advice for what to look out for will be appreciated.
Cheers, Tom.
'61 A7 essex

Offline duTch

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Re: Cylinder head bolts
« Reply #1 on: 10.08. 2017 10:21 »

 
Quote
......Is there a sequence for undoing head bolts?.......

 I would suggest a reversal of the tightening sequence, don't have that at hand but which by logic is progressive and radially/diametrically opposed maybe start in the centre and work out (just a wild guess based on above if I had to do it on the side of the road *smile*)
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline TomL

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Re: Cylinder head bolts
« Reply #2 on: 10.08. 2017 10:33 »
Thanks, Dutch, that's what I was thinking, just needed second opinion. Off with its head! ( and barrels ) tonight, see what horrors lurk inside!
Thanks again, Tom
'61 A7 essex

Offline jachenbach

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Re: Cylinder head bolts
« Reply #3 on: 21.08. 2017 00:27 »
If you haven't yet torn it down, I'd suggest a leakdown test. Much more informative than a compression check.

Online muskrat

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Re: Cylinder head bolts
« Reply #4 on: 21.08. 2017 10:05 »
G'day Tom.
80psi seems a lot low, even 100 isn't great. My low comp A7 is around 130 and my cafe is 180.
Are you holding the throttle wide open when kicking and for at least 6 compression strokes?
As JB suggests a leakdown test is better. Listed for a hiss at the carb (throttle open), exhaust and breather.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Offline TomL

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Re: Cylinder head bolts
« Reply #5 on: 21.08. 2017 13:18 »
Hi, It's all apart, rings have had it so new rings and a hone. Should get it back together this week. Thanks for the advice, jachenbach, but i pulled it apart before I had a chance to do a leak down test. Head looks good.  Hi muscrat, comp test was done properly and several times. Hopefully rings will fix it! I'll keep you posted. Cheers to everyone for all your helpful advice. Tom
'61 A7 essex

Offline TomL

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Re: Cylinder head bolts
« Reply #6 on: 13.09. 2017 08:48 »
Hi all, rings an a hone seem to have sorted it! Thank you for advice. I've done about 300 miles on it since and no problems. When should I re-torque the head? It's iron head and I did it up to 38 ft lbs.
cheers Tom
'61 A7 essex

Online ellis

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Re: Cylinder head bolts
« Reply #7 on: 13.09. 2017 12:43 »
Hi TomL,   If you have fitted a copper head gasket you shouldn't need to re torque the bolts. I check the torque of the 4 long bolts that carry the top steady brkts. If they are ok then I leave it alone and never had a problem with gasket leakage. Head bolts should be 30ft lbs. Any more and you do run the risk of stripping threads.   *smiley4*

ELLIS
 

Offline TomL

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Re: Cylinder head bolts
« Reply #8 on: 13.09. 2017 13:06 »
Thanks, Ellis, yes, copper gasket was used, and annealed. I'll leave them alone. Wasn't looking forward to rocker box shenanigans anyway! Next time it's apart I'll remember the 30 ft-lbs. just need to put a few more miles on it before winter 😄
Cheers again, Tom.
'61 A7 essex