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The mkiv Supra Owners Club

skimmed head


baldy

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the head was skimmed on my supra back when the headgasket bailed out

 

 

they took 11 tho off ( i can only hope this was the only time its been done)

 

but whats the maximum it can be skimmed or is that onthe limit

 

cheers baldy

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I would have thought the place that skimmed the head would have been best able to tell you that, Si. As long as the skim doesn't intrude into the combustion chamber I suppose you would be alright, provided that you correct the compression ratio with a suitable thickness HG of course. Not ideal I know, but what else can you do when not replacing the head or spending ££££?

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hi jake

head was skimmed though jps

2mm head gasket now fitted,all has been good for 2 years but something not right at the mo,im hoping its the thermostat sticking part open and not the head gasket again

Hi mate.

Isn't 11 thou less than 0.3mm? Why such a thick HG?

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What did your search find? Who said 1.4mm?

 

I really don't know the correct answer, but how come HKS sell 1.2mm, 1.6mm and 2.0mm HGs? I can't imagine there's a lot of demand for a thinner than stock HG.

i havent got a clue but more than 1 trader agreed that they were 1.4mm. I dont suppose HKS makes a 1.4mm gasket as they are no better than the oem stock one. Not really sure why anyone would want a thinner one either

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HKS will sell a thinner one as it may be needed for certain engine builds. For one, people may be looking for higher CR - simple as that. Two, if the chambers (and/or the pistons) are modified and the head isn't skimmed enough to bring the CR back up then a thinner gasket will be needed to get back to the desired CR.

 

I don't know what size stock is though - have heard 1.2 and 1.4mm.

 

0.011" is just over 0.279mm

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Standard Spec's for the 2jzgte (From Aria)

http://specialists.supras-ireland.net/images/Aria2j.jpg

 

 

Just a quick question, but when they fitted the Gasket, was the Block face machined or cleaned? MLHG's need a finish of RA30 or better on the mating surfaces, if not they dont seal properly.

 

Marty

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I could chew better than Ra 30 with my gran's false teeth. I think you mean Rmax.

 

I've attached a surface finich spec for a Federal Mogul multi layer steel head gasket. I think if you took it to any run of the mill machine shop they would either:

 

a) Laugh in your face.

b) Say "yes, we can do that" and then just machine it as best they could to get you off their back.

c) Invite you to go elsewhere.

 

In any case, even if they could do it, you can't check for that kind of spec without specialist equipment, and how could you prove they had got it right or wrong? I think with aftermarket head skims you pays your money and takes your choice, but what you end up with won't be anywhere near as good as a stock finish.

 

Better than a warped head, though.

Gasket face.jpg

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Yup Digsy i did mean Rmax. As you know, Every headgasket has a different spec, and it always worth investigating how well a machine shop can do the work before choosing which headgasket to run with...

the most forgiving I have come across are the Cometic MLHG especially if used with Arps, then the HKS stopper types which have a coating like the other HKS gaskets but use a Stooper instead of a bead or grommet to help maintain surface seal. Choice of gasket is Defo something worth checking before getting work done IMHO

 

Marty

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Hi mate.

Isn't 11 thou less than 0.3mm? Why such a thick HG?

 

 

leon felt it was needed because its running 1.45 bar on stock turbos

 

please dont all start i know what your gona say

 

(that was set by him when he traded from home in the old days,although he tried to say he would not have done so,but i have a reciept to prove this)

 

its been running like this for years,so its stayin like it

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