Do I need to retension head studs?

[tilly]

I after some advice on the need to retension the head studs on my A10 following a rebuild. I’ve fitted a copper head gasket and used copper head gasket spray.  I was told to get the engine up to temperature and then to retension it once it has cooled down. Is this necessary?  It is a pain in the proverbial to remove the rocker box again, and don’t want to do so if I don’t need to.
While I’m asking questions, is the rockerbox meant to be so difficult to fit?  Mine is a very hard interference fit with the top of the valves when trying to lower it on. What’s the trick for fitting? It seems that I have to clear the exhaust valves first, but the use of studs rather than bolts to retain the rockerbox makes this difficult.
Any and all advice gratefully received!

[Swarfcut]

G'Day Tilly

        Far easier to remove the rear rocker box studs, lower the box on from the inlet side, down past the springs and push it forward to clear the exhaust springs. If it still fouls  the front studs may have to come out. Fit the pushrods, settle the box and then use your gynaecologist skills to re-insert the studs. Some ruffians use Whitworth hex head cap bolts, or even cut a screwdriver  slot in the stud.  I have seen boxes with indents cut to clear the springs, but this narrows the  seal area for the rocker cover gasket.

    I would be inclined to leave the head alone, get some miles in, see if it leaks.  If you gave it a good bit of tighten, sleep easy.

  Well done for getting it back together.

  Swarfy.



 

[muskrat]

G'day tilly.
If the copper gasket was annealed (read sot enough to mark with your thumb nail) and the copper spray it should be good to go. I only re-tension if the rockerbox leaks  .
The alloy head rockerbox's are even harder but I've never had to take the studs out bar the top rear tappet cover stud. It has flats on it to help removal. Sometimes it takes 15 minutes, sometimes hours!
Cheers

[Duncan R]

I have removed the head 3 times during ownership - never bothered re torqueing and have had no leaks. Never done it on my other bikes either. Maybe if the rocker box wasn't such a pain I would.


Good luck

[Greybeard]

For me; annealed copper gasket. 20ft/lbs first then back off and retorque to 35ft/lbs. I've never gone back in to retighten.

[Butch (cb)]

Well I learnt something there. I thought re-tightening after a few heat  cycles was a given.

[Greybeard]

The reliability of a once-only tightened head gasket probably has an inverse relationship to how hard the engine is worked. Mind you, if Musky doesn't retighten, that theory goes out of the window!

[A10 JWO]

I don't re tighten, if it was a two stroke I would cause it's easy.

[JulianS]

I always retighten after about 250 miles from replacing the head. Read it in the instruction book many many years ago and it has always worked for me. Usually find one or two bolts need just a little more torque.

[KiwiGF]

A compromise approach is to check the head bolts you can get at after a heat/cool cycles, if any of those have loosened off significantly take the rocker box off and check the rest.....I DID’NT have to the rocker box off mine  and it’s been fine.

[Butch (cb)]

I think ... When Roger did mine for me he used a heat gun to cycle it a couple of times and then re-tightened as required before putting the rocker box on at all.

[mugwump]

I believe a common place for these ( and Ariel ) heads to blow is btn cylinders and  down the p/rod tunnel, is probably caused by only the outer head bolts being re-tightened. I know its a pain having to remove the rocker box but worth it for peace of mind. 

[Klaus]

The reliability of a once-only tightened head gasket probably has an inverse relationship to how hard the engine is worked. Mind you, if Musky doesn't retighten, that theory goes out of the window!

I make my own coppergaskets, special for every barrel from 0,8mm copperplate.
A light grease with HTL Silicone, and I never retight any bolts over 4 yaers hard work with a racebike.

cheers Klaus

[Rgs-Bill]

For me; annealed copper gasket. 20ft/lbs first then back off and retorque to 35ft/lbs. I've never gone back in to retighten.

    Graybeard says to torque to 35 ft lbs, as does Haynes manual.  On alloy heads only torque to 26 max of 27 ft. lbs. so as not to distort the head, and cause leaks.  My 62 RGS I torque to 10-then 20-then 25-then 26-27 for final.  One heat cycle, with 2 foot box fan blowing across fins, then let it sit overnight, then remove R. Box  and you will find at least 2 that are too low in torque.  Usually in the middle where the push rods go down to the followers
    Could someone explain here how a heat gun could qualify as a heat  motor running heat cycle, do not see how it could heat evenly enough at same time, over the whole motor.
   When I was torqueing my alloy head to 35 ft. lbs. as per Haynes manual I kept getting leaks between cylinders, and push rod tube, since using 26 ft. lbs. have never had a problem, and the last time I  did it was 11 years ago.

[scotty]

Very interesting

I have to replace my A10 head gasket when I return from little Norway (still on board Norwegian ship)

What is and how do you do a heat cycle ?.....

Enquiring minds and all

S