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Head nut torque with solid copper gasket
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Glenn Crawford



Joined: 06 Dec 2007
Posts: 68
Location: Dorset, SW England

PostPosted: Mon Sep 22, 2008 8:56 pm    Post subject: Head nut torque with solid copper gasket Reply with quote

I've a pre-war car in my workshop (it's a Riley Nine) which has come in to have its head torqued down. Trouble is, it's been fitted with a solid copper, rather than a copper-asbestos, head gasket, and I feel that I need to take this into account when tightening the head. It has twelve 3/8" BSF studs holding the head down.

First part of question: who would like to offer a correct torque figure for this setup? And is that less than, same as, or greater than the torque for the copper-asbestos case?
Second part of question: with engine hot, or cold, and why?

All informed opinion welcome and appreciated!

Glenn Crawford
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peter scott



Joined: 18 Dec 2007
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PostPosted: Mon Sep 22, 2008 9:15 pm    Post subject: Reply with quote

Hi Glenn,

Is the gasket entirely flat or are there corrugated rings around the various aperatures?

Peter
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Glenn Crawford



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Location: Dorset, SW England

PostPosted: Mon Sep 22, 2008 10:20 pm    Post subject: Reply with quote

I didn't fit the gasket myself, but my understanding is that it's just a plain sheet of copper, and fairly thick - the bit which I can see along the side of the engine looks as if it's around 0.5mm / 0.020".
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Rick
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PostPosted: Mon Sep 22, 2008 10:35 pm    Post subject: Reply with quote

it may be worth asking the question to one of these companies that scratch-make rare head gaskets, perhaps make out you're after one to be made, and ask a few questions re torque settings and different types of gasket material Smile

Rick
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Phil - Nottingham



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PostPosted: Mon Sep 22, 2008 10:45 pm    Post subject: Reply with quote

Cast Iron engines with cast iron heads are always torqued down hot.

Those with any alloy head/block or both must be stone cold at least 24 hours.

Cannot help with torque settings though - eveness is more crucial I would say but quite tight using a normal length spanner (92?) hand held and use this to set the torque wrench.

This assumes unstretched and not too oily bolts
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peter scott



Joined: 18 Dec 2007
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PostPosted: Mon Sep 22, 2008 11:13 pm    Post subject: Reply with quote

For what it's worth the Riley RMs (i.e. post war) are as follows:

for the 1.5's torque figure is 540in.-lb [6.21 m.-kg.]
for the 2.5's torque figure is 900in.-lbs. [10.35 m.-kgs.]

The friend who supplied this info will tell me whether they used plain copper
sheet tomorrow.

Peter
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Last edited by peter scott on Tue Sep 23, 2008 11:23 am; edited 1 time in total
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Uncle Joe
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PostPosted: Tue Sep 23, 2008 7:35 am    Post subject: Reply with quote

Sorry to disagree here, but there are quite a few cast iron block/head engines that must be torqued cold. My Chrysler and Ford V8's are two examples...
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Ray the rocker



Joined: 01 Aug 2008
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Location: south wales

PostPosted: Tue Sep 23, 2008 9:59 am    Post subject: torque head settings Reply with quote

I agree with uj,on most engine rebuilds especially cast head /blocks,torque settings are made at room temperature making sure you sytematically start in the centre and work outwards.
After an initial road test,the head is retightened and tappets adjusted to suit when engine is at running temperature.This applies to O.H.V. engines with side valve considerably easier---as there are no tappets to adjust.

Cheers----Ray the Rocker.
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peter scott



Joined: 18 Dec 2007
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PostPosted: Tue Sep 23, 2008 11:20 am    Post subject: Reply with quote

The post war cars use a thin copper asbestos gasket but in the absence or any other info I would use the same torque setting as the RM 1.5 litre namely 45 lb-ft. The absolute value, assuming you are not stretching or pulling the studs out of the block, is probably less important than having them all tightened evenly.

If you use a jointing compound I can highly recommend Hylomar. Until I discovered Hylomar I had always used Hermetite.

As others have said, re-check after the car has been run.

Peter
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Glenn Crawford



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PostPosted: Tue Sep 23, 2008 12:35 pm    Post subject: Reply with quote

Thanks one and all. I don't see a definitive answer in there! Someone has told me (regarding the hot/cold question) that because cast-iron expands at a faster rate than the H.T. steel studs, torquing should be done cold - so that the head clamps more tightly as the cast iron warms up. But I haven't been able to check the science behind this idea.

Just to conclude: my investigations this morning have proved that the head gasket is still leaking despite the higher torque (I dare not go more, the studs may rip out from the block - it happens on Riley RMs, which are essentially a pre-war engine developed from the Riley Nine). So it's head off time.

Your comments on jointing compounds are noted, but I hate the idea of using it on a head joint! - Glenn
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peter scott



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PostPosted: Tue Sep 23, 2008 12:43 pm    Post subject: Reply with quote

Hi Glenn,

You won't regret using Hylomar and it will certainly solve any water or oil leakage issues. It is much more effective at high pressures than other compounds I've tried. I have no connection with the company. I just love their product. I have have used it on three different cylinder heads now without any problems.

Peter

p.s. All three of the above were with a single thin copper sheet gasket although admittedly of the Corrujoint variety.
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PAUL BEAUMONT



Joined: 27 Nov 2007
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Location: Barnsley S. Yorks

PostPosted: Tue Sep 23, 2008 1:26 pm    Post subject: Reply with quote

I have to agree with Peter about Hylomar - with one exception. It does not like modern petrol, so do not use it on fuel systems. It generates little blue balls that are sure to block something!
I do tend to agree with Glenn though on the head gasket. I would prefer it without sealant ( a little grease maybe) I suggest that if it is not sealing under reasonable torque then a skim is needed.
Someone once told me that if you use a solid copper gasket it needs to be annealed first to make it soft as copper work hardens when you butcher it like making a gasket from sheet. Thoughts anyone?
PAUL
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Uncle Joe
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PostPosted: Tue Sep 23, 2008 4:29 pm    Post subject: Reply with quote

Yes, copper gaskets should be annealed before being reused.

I've always found Hylomar to be good with aluminium, but I do know that it shouldnt be used with some modern fuels/lubricants. The one that I have used for a while now though is Permatex 300. Copes with anything that it comes into contact with....
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pigtin



Joined: 23 Nov 2007
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PostPosted: Tue Sep 23, 2008 5:45 pm    Post subject: Reply with quote

I seem to recall having to anneal copper head gaskets and I can confirm that Hylomar is brilliant.
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wrinx



Joined: 22 Jun 2008
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Location: Derbyshire

PostPosted: Tue Sep 23, 2008 11:36 pm    Post subject: Reply with quote

Is Hylomar just for use with copper head gaskets, as opposed to other materials?

Not sure if anyone recalls my thread about HG problems...but I think it may reoccurring!

wrinx
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