Club 80-90 Forums

Its important to realise thag the torque is not always going to give the right strain on the stud if not done right.

If you do up all nuts to say 30Nm, then do up one slowly to 50Nm until it clicks you hopefully have 50Nm
if you do the next one slowly but stop before the click you will often find it won't go further, torque wrench just clicks, the sticktion prevents it, so ask yourself is this second nut at 50Nm or not? and is the strain on ths stud the same as the previous one?

Because of sticktion you need to keep the nut moving between each stage, this is why I prefer multiple stages because its hard to keep if moving if you have to turn too much.

Threads should also be cleaned and degreased with meths internal threads of nuts tapped out and washed in meths, any grease or oil will reduce the friction and put more strain on the stud for a given torque.

if the nuts and threads are rusty there will be more friction giving less strain than is needed for a given torque.

And in both oily threads and rusty threads the danger I see is inconsistant strain of the bolts

Quick question - what are these green marks on the compression rings. It looks like the inner edge may be slightly asymmetrical, so maybe they're supposed to indicate which way round the rings go. But which is it - green mark to the barrel, or green mark to the head?

Come along folks - you're holding me up!

Well there's no mention of the green marks in the gasket kit (no literature at all), no mention in Haynes or Bentley, and I can't find anything by Googling (except the photo below, which seems to show one with green mark showing and one without).



And even with a magnifying glass I can't reliably see an asymmetry to either edge. So I really can't find evidence of a reason for the green marks.

I wondered that....then though if it were important I would have hard or read about it.

Not going for Hymolar AF on rings then ( as reccomended by Tencenflife)

itchyfeet wrote: Not going for Hymolar AF on rings then ( as reccomended by Tencenflife)

I certainly am.

Rings in - green mark to barrels for what it's worth. Hylomar AF brushed onto head and smeared onto both sides of rings:


Hylomar AF on barrels:


Water jacket seal on, Dirko-S both sides:


One head done - resting at 25Nm for a while.

Note the shiny new head nuts - I didn't have a full set of good used ones from the strip down, so I bought eight new ones (for those that show), and used the eight best used ones for under the rocker covers.

That's it - nuts all sealed and torqued down to 50Nm. Boy, it's along way from 40Nm to 50Nm.

Excellent work, I'm too mean to buy new nuts, or heads

is it me or do those inlet gasket faces have damage on them?

I noticed that in the photo too. It's just where the swirls from the machining change direction and catch the light differently.

If they are copper nuts you have they do not last I'm told.
Stainless nuts do.

Really? I think they're brass. Do brass nuts last (obviously they fall off in very cold weather - I know that )? But I do have a set of stainless studs with copper lock nuts that I was going to use instead. Maybe I'll use the stainless studs but keep the brass nuts.

Brass nut (like the ones on the exhaust studs in the earlier photo) on the left, copper lock nut on the right.



Except the copper nuts aren't copper after all. They must be copper plated steel.



When you say that copper nuts don't last, what happens to them. Is copper plated steel ok?

I have no idea why, but I always put the green mark towards the barrel, and at 12 o'clock. It's just pleasing to the eye.
As for the torquing technique, stiction is not so really a problem when the threads are clean, and the contact faces of the nuts are lubed with yellow gunk. The last stage should always be done in one smooth motion without stopping (and yes, it does take some nerve the first time!). The reason I revisit the nuts, and go round again in the prescribed order, is that the compression rings squash down as the head pulls down, leaving the first centre ones carrying less load than when first torqued. Going round twice, the nuts turn a little, click, and spring back due to the length of stud and the lubed face, so I'm pretty sure that they all carry virtually the same load at virtually the same torque.

Sent from my B1-830 using Tapatalk

CJH wrote:Brass nut (like the ones on the exhaust studs in the earlier photo) on the left, copper lock nut on the right.



Except the copper nuts aren't copper after all. They must be copper plated steel.



When you say that copper nuts don't last, what happens to them. Is copper plated steel ok?

The copper coated nuts in your pic are the same as the ones I used 2 years ago, had to undo them last week when changing the engine and they've corroded to the point where the metric socket was slipping and I had to use an imperial one. They came undon easy enough but bear in mind they hadn't been on for particularly long in my instance. Another 2 years and they maybe so corroded that mole grips would have to be used for removal. Gone the stainless route this time.

Interesting, thank you. So do you think it's just the copper layer that's corroded away? I would have thought that would be so thin that it wouldn't be enough to affect the fit of a socket. So maybe underneath they're just not very good steel?

Since I'd like to use the stainless studs I've bought, I don't want to use stainless nuts as well (to avoid galling), so I think I'll stick with the brass nuts.

never had gaulling with stainless at 20Nm ( or 30Nm), you have to tighten much more to get gaulling
been using stainless nuts on stainless exhaust on my WBX for 10 years and its been on and off a few times....easily.

Too many armchair engineers out there who haven't actually tried what they are commenting on.