Thickness of standard 4age gasket VS TRD

[Sam_Q]

I have a 0.8mm Gasket from trd that I am going to use in my 20V,

- does anyone know the compressed thickness of a standard gasket?

- does a trd 0.8mm compress more than 0.8mm?

thanks

[30psi 4agte]

I think .8 is the compressd thickness of the gasket.

If you have a set of verniers measure its thickness. Id say it will prob be close to 1mm uncompressed.

Sorry ....dont know std gasket thickness

[-GT-]

Ok, so stated thickness is under compression? I was going to post last night but it's only an 'i think', and it wasn't much help if it wasn't the compressed thickness, but here it is anyway: I THINK the standard gasket is stated at 1.4mm, so that might be useful if that's compressed thickness?

[Sam_Q]

hey guys can this be worked out? I know the standard compression ratio for a 20V, the swept volume and the head cc, so is this enough to use my maths on it? Not sure how the volume of the piston takes into account though

[oldcorollas]

a 1mm initial thickness normal gasket comrpesses to about 0.8mm... the thickness it comes out used is not far off the thickness in service.

you need to know the dish/dome of the pistons, and you need to know the clearance betweent he blocks deck and the top of the flat part of piston..

you can take that measurement, but it is not close enough really.. 10:1 for example coupel actually be 9.8 or 10.2.. there is only a few cc's in it... (like maybe 5cc per 1 compression... ie, for 1.3L K motors, 3cc is difference between 9:1 and 10:1.. so thats 0.3cc per point)

is the TRD gasket a normal squishy one? or a metal? or a graphite? metal and graphite will nto compress much and you can probably take it as 0.8 or 0.75
volume is 5.09cc per mm of gasket thickness
0.8mm = 4.07cc
0.7mm = 3.56cc..
thats 0.51 difference... so about 0.1CR difference depending on the gasket compressed thickness... not a big difference

[Mr Revhead]

the thickness when torqued to spec is 0.8mm on the TRD one.
and 1.2mm on the stock toyota one

[Sam_Q]

thanks heaps revhead, now I can finally work out the compression difference

the TRD gasket is a multilayer stainless one

[Mr Revhead]

should p/n 11115-ae001

no sweat

[Sam_Q]

yep thats the one, I have it next to my desk, its a 4 layer

[Mr Revhead]

if you want it thinner you can remove sheets

[Sam_Q]

I cant say I ever thought of that, I guess the two middle layers dont have any markings on them so in theory they could go. I would rather shave the head though.

I did some maths today and if I am not mistaken then adding this gasket to a stock silvertop will raise the compression from 10.5:1 to 10.98:1 so basicly almost the same as a blacktop.

[Mr Revhead]

you say how much for stock silver top compression?

[Sam_Q]

whoa thanks for the correction that was a typo

[terryo]

I can confirm the TRD gasket is 0.80mm when compressed. The stock gasket is 1.15mm.
I can also confirm it will probably ping like mad on local 98RON fuel when you fit this gasket AND machine the head and block faces to the correct finsh for the gasket.
The black-top engines have a different piston crown and different ECU maps, so you cant make direct comparisons. they however, have the same problem once their head and block have been faced.
I've thrown away several of these gaskets beacuse the engines cant hack it once the block and head have been faced.
if you ever get the chance to dyno test them and listen to the pinking, you'll also be worried.
I can post all the calculations if anyone is interested

[Sam_Q]

thanks for that Terryo, I will adjust all my calculations now