Too Cold For The Nuts?

B Murr

Registered user
Joined
Nov 29, 2004
Messages
4,391
Reaction score
0
Location
Cork, Ireland
When doing valve clearances and torqueing cylinder head bolts, is there a temperature below which you shouldn't do this work. Just asking as its only 2 to 4 C thesedays and I was thinking of checking clearances and torqueing cylinder head bolts.

Only difference I can figure is that cold bolts will be shorter than warm ones and so will lose a bit of torque when back to mid teens type temps but I'd guess its negligible unless I was working at -20C.
 
I wouldn't think these temperatures here would have too much of an effect, if any. Personally, I've never bothered re-torquing heads unless the heads have been off in the recent past. Any time I've checked them, they have been fine so I gave up ! These are not high tech, high revving engines with ultra close tolerances. Others may have a different opinion on this but it works for me.
I do the valve clearances annually as part of the service interval.
 
Especially with the later 85 on engines do not go near those cylinder head nuts unless you are re torquing after 600 miles from fitting a new Head gasket after having a head off ***

Valve clearances should only need to be done at service If you are having to do them frequently there is something else going on !


Double check that they are screwed into the block the proper distance and that you don;t have loads of thread beyond the head nut!!! :eek:

35NM load spread over 12 threads is a helluva lot better than just over 6 or 8 threads :rob
 
on a clattery, mostly bolloxed old tractor :D I think you could use a house brick for a feeler gauge and it wouldn't make any difference at all :D
 
I wouldn't worry about the temperature effect, it will be negligible.

I wouldn't bother either about torquing the head bolts as a service item - only bother if you have had the heads/cylinders off.
 
I'll do the torquing as a once off since it's never been done since bike in my ownership, most likely done in service it had about 3000kms ago in 2004.
 
Given the number of studs that end up getting pulled out of the block I would just leave them unless the head gasket is actually leaking.
I once checked the valves on a Ariel Square Four and while a house brick wouldnt go in the entire set of feeler gauges would, especially on the rear exhausts.
It was around the time of the Suez crisis and petrol rationing so the PO had probably been running on paraffin, which didnt do the valves or seats much good.
It was a old scrapper with a cast iron head so it wasnt a huge job to remake the seats and the valves cut down from something cheap so 30/- bobs worth of scrap quickly became a 10 - quid bike.
I have only adjusted the valves once in the 170,000 km I have had my G/S, and they didnt really need doing, just a couiple of thou out.
I try to keep the revs below 5000 and use the best synth I can find, both probably help.
 
"It it ain't broke, leave well alone" !

Oh by the way, I found a very good match for the purple section of the seat. Now to hand it in and get it done.........
 
"It it ain't broke, leave well alone" !

Oh by the way, I found a very good match for the purple section of the seat. Now to hand it in and get it done.........

Thats great, perhaps you could let me know where you managed to find it. I dropped into Jim Savage in Bishopstownm a few weeks back and he thinks he will have something close but not 100% sure if a perfect match. I was going to put a big 3" wide section of purple into the corbyn but I'm thinking that just a band of piping behind riders butt and one behind passengers seat might do it. I find the corbin a bit too hard so will be softening it up a little with an extra 1/2" to 1" of height.
 
Funnily enough, I got the sample from Jim ! I took the sample home and offered it up to my own and it was an excellent match. Raspberry Crush is the colour I found.

27116139419_a751dd01f1_z.jpg
 
I'll do the torquing as a once off since it's never been done since bike in my ownership, most likely done in service it had about 3000kms ago in 2004.

The head bolts were torqued when engine was built and should never need doing again until the heads come off.

Regular torque testing risks over tightening the bolts and breaking one.
There is no benefit and plenty of risk.
 
Remember too that UON all torque values are given for clean, dry threads.
So if you re torque them without cleaning and drying all the threads you should reduce the torque by around 25 to 35%, and failure to do this is why so many studs get pulled out.
There is also the problem if you dont that the two bolts into the barells will be in a different condition to the studs inside the rocker box, so the same torque might give a different clamping force, which might make things worse than they are now!
 
I'll be leaving well alone, just checking valve clearances. Cheers everyone for steering me away from trouble.:thumb2
 
Our old power plant had a routine job to retorque equipment mounting bolts. Sensible enough - we had to to store ball bearing motors away from main buildings - floor vibration put flats on the rollers.
But after a few months we had a spate of broken mounting bolts. There were from 1” diameter so not exactly what we’d find on a bike.
Some fitters would rap the bolt heads with a hammer handle but when torque checks stopped we had no more broken studs/bolts and none shook loose.
 
Thats great, perhaps you could let me know where you managed to find it. I dropped into Jim Savage in Bishopstownm a few weeks back and he thinks he will have something close but not 100% sure if a perfect match. I was going to put a big 3" wide section of purple into the corbyn but I'm thinking that just a band of piping behind riders butt and one behind passengers seat might do it. I find the corbin a bit too hard so will be softening it up a little with an extra 1/2" to 1" of height.

Jim modified my Sargent for my F800GS recently.
Made a grand job of it too.
 


Back
Top Bottom