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Cylinder head gasket re annealing?
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Miken



Joined: 24 Dec 2012
Posts: 379

PostPosted: Thu Aug 13, 2020 7:56 pm    Post subject: Reply with quote

[quote="Glenn Crawford"
The feller says it makes a huge difference, adding 50% to the clamping force, which I am happy to believe, but what do other forum users think about this practice? I thought that cylinder head nuts are fitted and torqued-down dry.[/quote]


I wasn't sure either, so when I fitted the head on my A40 Devon A coup!e of Weeks ago I rang up Gosnays Engineering (Who have done work for me in the past) "Ooh, we used to do loads of them back in the 50/60's"
And he told me apply, " a bit of engine oil on the threads"
Which is what I did.
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MVPeters



Joined: 28 Aug 2008
Posts: 755
Location: Northern MA, USA

PostPosted: Thu Aug 13, 2020 9:02 pm    Post subject: Reply with quote

I was always taught, mostly by my grandfather, fount of all wisdom & knowledge, that no fasteners should be assembled 'dry'.
So a light cleaning of nuts & bolts, followed by a drop of 3-in-1 was his, & now mine, rule.
I'm not sure if torque wrenches or Loctite existed then, so 'tight' & 'very tight' were the guidelines.
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ukdave2002



Joined: 23 Nov 2007
Posts: 3653
Location: South Cheshire

PostPosted: Thu Aug 13, 2020 10:27 pm    Post subject: Reply with quote

MVPeters wrote:
I was always taught, mostly by my grandfather, fount of all wisdom & knowledge, that no fasteners should be assembled 'dry'.
So a light cleaning of nuts & bolts, followed by a drop of 3-in-1 was his, & now mine, rule.
I'm not sure if torque wrenches or Loctite existed then, so 'tight' & 'very tight' were the guidelines.

Torque wrench settings are quoted normally dry.
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petelang



Joined: 21 May 2009
Posts: 310
Location: Nottingham

PostPosted: Thu Aug 13, 2020 11:25 pm    Post subject: Reply with quote

I'm no expert but good engineers have told me, under no circumstances to oil the thread section on head studs. However it may be he means to lubricate the non threaded part to allow the head to slide down onto the block properly.
But do also check the stud has thread below the top face or the nut, whilst achieving the torque, may not actually be clamping the head. In such case you may need a washer under the nut.
Peter
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Ray White



Joined: 02 Dec 2014
Posts: 4176
Location: Derby

PostPosted: Fri Aug 14, 2020 1:04 am    Post subject: Reply with quote

I would say if you prefer to lightly lubricate threads then fine...but please don't then rely on "dry" torque wrench figures - they differ considerably.!!
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Glenn Crawford



Joined: 06 Dec 2007
Posts: 73
Location: Dorset, SW England

PostPosted: Thu Aug 20, 2020 8:33 am    Post subject: Reply with quote

All points noted. I carried out a test to see whether enough torque was being applied by the head nuts (with oil) to squish the copper gasket even a little tiny bit - to give me confidence that it would seal - but it measured precisely the same after the test as before.
That being the case I have admitted defeat (which I hate to say!) and gone back to using a traditional gasket. I can't for the life of me understand how solid copper gaskets can ever work if they don't compress, but clearly they do, and they have a loyal following especially in the motorcycling world.
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Miken



Joined: 24 Dec 2012
Posts: 379

PostPosted: Thu Aug 20, 2020 5:15 pm    Post subject: Reply with quote

Glenn Crawford wrote:
I can't for the life of me understand how solid copper gaskets can ever work if they don't compress, but clearly they do, and they have a loyal following especially in the motorcycling world.


An advantage of solid copper head gaskets, especially in air cooled motorbike engines is that they allow heat from the head to transfer to the cylinder barrel which aids cooling by increasing the cooling area. Whereas a copper asbestos sandwich gasket tends to insulate the head from the cylinder and gives the exhaust valve a hard life.
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Nick57



Joined: 09 Dec 2013
Posts: 35
Location: Leicestershire

PostPosted: Thu Mar 11, 2021 6:48 pm    Post subject: Reply with quote

A bit late to the party on this, but this is what I used to do with our Aston that had a solid copper head gasket

I found a local foundry who would anneal the gasket and it would come back so soft you could almost mark it with a finger nail.

Prior to fitting it was sprayed both sides with Sperex copper gasket cement and then the head torqued down in the normal manner.

This cured the head gasket problem once and for all. I think it is down to getting the gasket fully annealed

Hope its useful to somebody
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Clactonguy



Joined: 20 Mar 2018
Posts: 77
Location: clacton on sea

PostPosted: Sat Mar 13, 2021 7:50 am    Post subject: gasket fails Reply with quote

I never reuse gaskets and here would ensure no warping had occurred as a non flat head or block will severely impact sealing. looking at pics ..it looks (possible illusion) like where the studs go into block we have cracks ? hopefully I am wrong. where we have series of fails it is important to ensure surfaces are flat and clean ( skimming ?) .studs may have stretched? we ought be using 12.7 type( high stress load) studding ideally. much liek we get 12.7 bolts and Allen head bolts that are stretch resistant and maintain torque loads on gaskets. we might want to think about applying a very thing layer of sealer to both sides of gasket ( stress 'thin' ) such as Mylomar as I seem to recall rolls Royce used this on some cylinder heads long time ago but I satnd to be corrected . 60nm is about 10 less than that used on my nissan micra all aluminium engine. new modern type gaskets are designed to be compressed in 2 stages . might be worth checking torques application second tiem after say 10 mins or so as gasket may have 'compressed' slightly thus lessening sealing effect. do also ensure correct torque sequence. rule of thumb is too start in middle and work out each way equally to 'flatten' any distortion and enable distribution of land on gasket eg do not tighten to full torque each bolt/stud but hand tighten always from centre working out. much like going in a spiral and then torquing to spec .again in 2 stages and recheck later. good luck.
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Churchill Johnson



Joined: 11 Jan 2011
Posts: 356
Location: Rayleigh Essex

PostPosted: Sat Mar 13, 2021 11:09 pm    Post subject: Reply with quote

To correct slightly the sealer Rolls- Royce developed is Hylomar it needs to be used on a surface that is completely oil free or it will roll into a ball rather than stick, i can vouch that it never sets as when in the motor trade i fitted a head gsk to a vauxhall and i used hylomar then found it was the wrong gsk, bore too small, so i hung it up, over a year later it was still sticky.
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