[Mk2] [Turbo] Head Gasket thickness?

[Deano2915]

Long story short, got my head skimmed, garage went bust, didn't inform me how much was skimmed.

The impression they left me with was it wasn't a great deal!

Questions

Any way to tell how much was taken off?
Which gasket to get?
What thickness?
And where from?

BTW - Rev 1 '91

[bobhatton]

You should aim for a piston to head clearance of 1mm or just less so do some mesurements and work it out.

[Danbob]

You can measure the height of the head from block face to rocker cover face. that was the best datum I could find.

Here is my data for your reference:

A skimmed Rev 3 head measured 119.22mm (Average of 5 measurements)

A bone stock untouched Rev 3 head measured 119.4mm (Average of 5 measurements)

The same bone stock Rev 3 head after I had it skimmed measured 119.318 (Average) 0.082mm removed

I have a never skimmed Rev 2 head in the garage I could measure in the new year if you're interested.

I don't have a big enough micrometer so these are only taken with a digital caliper.


As Bob stated, choose your headgasket thickness based on your piston to head clearance. Check your piston to block deck clearance at TDC, then go from there.

General consensus is tighter the Piston to head clearance the better, the trick is to make sure they never touch! It's up to the builder, but I personally decided not to go any tighter than 0.76mm, stock rev 3 clearance is a fraction over 1mm.

If you are using a stock bottom end, then your piston-Deck height is likely to be zero.

The skim is going to raise your compression slightly, Worst case at a skim of 0.1mm the increase will be less than 0.07:1

The argument is that it is better to retain a suitably tight piston to head clearance and raise compression slightly, than it would be to lose the clearance with a thicker gasket to maintain the same compression

[bobhatton]

As Bob stated, choose your headgasket thickness based on your piston to head clearance. Check your piston to block deck clearance at TDC, then go from there.

General consensus is tighter the Piston to head clearance the better, the trick is to make sure they never touch! It's up to the builder, but I personally decided not to go any tighter than 0.76mm, stock rev 3 clearance is a fraction over 1mm.

If you are using a stock bottom end, then your piston-Deck height is likely to be zero.

The skim is going to raise your compression slightly, Worst case at a skim of 0.1mm the increase will be less than 0.07:1

The argument is that it is better to retain a suitably tight piston to head clearance and raise compression slightly, than it would be to lose the clearance with a thicker gasket to maintain the same compression