Head Saver Shim

[Ian Durrant]

The discussion on head gasket problems and what to look out for had me thinking.

If the so called "head saver shim" is simply bonded to the head with silicone sealant, why doesn't that blow all the time. Here we are talking about payen gaskets, head bolt torque and on another forum about using racing spec ARP bolts and studs, when apparently a coat of silicone would do the job.

Surely I am missing something, I know the payen gasket is designed to allow for the differential expansion rates of iron and aluminium, but stainless steel and aluminium have different co-efficients of expansion too but no gasket is used, just silicone.

[nib]

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Ian,I think the head saver shimsgoes on the block,gasket on that,then the head.

Mark

[Ian Durrant]

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Hi Mark,

That would make a bit more sense, but even then I can't see how it seals just using silicone.

http://cgi.ebay.co.uk/TRIUMPH-STAG-V8-HEAD-SAVER-SHIM-VKM-650_W0QQitemZ200284059401QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item2ea1dc3709

gaskets for classic says bond to the head.

I seem to remember Tony Harts one was similar.

It just seems odd to me, we have all this technology like payen multi layered steel gaskets, with surface coatings etc, then we just stick a sheet of stainless down with silicone.

[Giles]

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Rover V8s and the Daimler Turner V8s used to use a thin metal head gasket originally I think - but I can see what you mean

[MB]

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It doesn't say if you use a normal head gasket with it or if it is supplied with the "SILICONE TYPE SEALING COMPOUND". These would seem a preferred route but its doesn't quote how thick they are.

http://cgi.ebay.co.uk/Triumph-Stag-N...item56398a3c4c

[Giles]

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I think it says you gain 20thou - I suppose it depends how much and how often the heads have been skimmed but at least we have some options

[Dieter H. Marschall]

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Hello everybody,

If I understand correctly, these shims are sealed directly onto the heads with silicone, then come the normal (not the thick) Payen head gaskets, then the cylinder heads.

What sort of silicone might suitable here?

Who of you has ever tried to compensate the shimmed heads with that? I might be tempted to try them, as after shimming the heads my engine obviously has too much compression and has that ticking sound, when I accelerate hard.

Kind regards, Dieter.

[Dieter H. Marschall]

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Sorry, I misread: The shim should go on the head- not the block!

Kind regards, Dieter.

P.S.: Today is the first day this year where we get the feeling here that the sun is getting more powerful - despite the snow.

[Dieter H. Marschall]

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... one more: The seller recommends Stag Wellseal to be put in between head and shim. Do you think this product can resist the heat?

Kind regards, Dieter.

[nib]

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Dieter H. Marschall wrote:

... one more: The seller recommends Stag Wellseal to be put in between head and shim. Do you think this product can resist the heat?

Kind regards, Dieter.

Hi Dieter

Wellseal is used to put the saver shim on,I thought the saver shim went on the block,I know on some cars theyput the saver shim on thehead and then the gasket but I thought with the stag it was put on the block.

I would be very interested to know the definite answer to this one

Mark

[Dieter H. Marschall]

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Hello Mark,

in the eBay description the seller mentions that the shim goes on the head first.

My problems with that solution are:

a) Is Wellseal heatresistant enough? The producers says up to about 200°C, but heads get hotter I guess.

b) Is that shim with only 0.5 mm thickness really a solution to over-skimmed heads? That thickness is just a foil.

Kind regards, Dieter.

[nib]

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All will be revealed in a couple of weeks Dieter as my left hand head is being taken off as its a Mk2 head,it has a saver shim on it,its been stuck down with wellseal,ive had my Mk1 left hand re-conditioned and theres plenty of meat on it so I will remove the saver shim.

When I got my car back from the garage that done my head gaskets,the wellseal was oozing out of the side of the head near the timing chain end,apparently this is the norm when the saver shim has been fitted with wellseal and the cars reached normal temp according to the garage that carried out the work and to be fair my car has run perfect,the garage were also the ones who said they fitted the saver shim to the block as my mate questioned this, as when used on someother cars they are attached to the head.

Saver shims do work and when I pull the left hand off in a couple of weeks it should confirm the saver shim is attached to the block but it may be that various makes differ.

Mark

[Bob Heritage]

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I have posted on this before Re- MLS gaskets and savershims. A popular cure for knackered K Series engines like MGF etc. The machine shop I spoke to had to have a new planner installed to get the head in a mirror like finish. Don't think they do a MLS (multi layered steel ) for a Stag.

[nib]

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Bob Heritage wrote:

I have posted on this before Re- MLS gaskets and savershims. A popular cure for knackered K Series engines like MGF etc. The machine shop I spoke to had to have a new planner installed to get the head in a mirror like finish. Don't think they do a MLS (multi layered steel ) for a Stag.

That was the MGF savershimsthat my mate mentioned Bob,I think these are stuck to the head,hence my mates query in relation to the garage saying they stick them to the block.

Mark

[peteroz]

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Hi Dieter,

The Head shims you refer to have been successfully used by numerous Stag owners here in Australia for a number of years, in the past they have been manufactured from a variety of materials including Brass, Copper, Stainless Steel,but the ones currently in use are made from High Grade Aluminium, Laser cut.

Thickness is 2.03mm, a Triumph specialist in Perth Western Australia sources them locally and has been using them successfully on Stags and TR7's, two of our club members have only recently rebuilt engines using this method and to date there appear to be no drawbacks.

Good luck in your endeavors.

Peteroz