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Posted

Hi,

 

I'm going to be using a cometic MLS Head Gasket (I need a specific thickness due to block & head machining to remove pitting) and would like your feedback on these gaskets as they are v.expensive!

 

The block and head will both be freshly machined surfaces, but the gasket specifies a surface finish of 50 microinches or finer.........how do I know if the faces have achieved this!!!!

 

Any advice will be greatly appreciated.

Guest Mr_Frosty
Posted (edited)

Hello,

I've just put a new head gasket in my pinto engined car. I paid about £31 pound for just the head gasket from Burton power. Bought a cheap head set from motor factors for all the other gaskets for about £15 and new bolts for about the same.

 

Mine has a stage 3 head and I had another 10 thou skimmed off the head after the head gasket blew. The new gasket made by Felpro was 47thou thick uncrushed. (The standard one on this engine is 40 thou thick I think.) The one from Burton has more metal around the cylinders than the cheap one.

 

All I did was explain to Burton what I had done and they suggested that one. Seemed very helpful.

Edited by Mr_Ftrosty
Posted

there are probably better ways but when I was an apprentice we used scratch test gauges, basically a book of machined squares about 1"x1" with different grade of finish which your run your nail across to compare.

might have just been something the lads made though!

 

Posted

Richard, what thickness of gasket do you need?

What compression ratio are you going for.

How much has been skimmed from block and head?

You can run 10.5 to 1 with cast pistons and get more bhp

  • Like 1
Posted

The machinist should be able to tell you approx what the finish is, they may have a set of the scratch gauges, yes they are available but not cheap. Where are you? any where near me? Or try the local tech they may have a tally surf or similar to measure it.

Posted

The number of jobs I have done on my car in blissful ignorance just keeps on growing!

 

I had a 60 thou taken off my head and put it back together with a cheap gasket from 'Gaskets for Classics' It has been OK so far (2 years)

 

 

If I were you I would fit the Cometic one with complete confidence

Posted

Hi everyone, thanks for your replies.

 

Basically, because of the pitting on the block face the machinist thinks that approx 20-30 thou needs to be machined to get the face back to a smooth face.

 

Currently, my pistons are about 10 thou above the block at TDC and I have a 40 thou gasket, therefore I envisage that the new gasket I'll need to return me back to the origanal CR will need to be 60-70 thou thick..............hense the multi-layer cometic gasket which Burton's have suggested (not suprising at £100 a go!)

 

Oh, and to make things more complicated, the block is bored out to 94.5mm, therefore standard-bore head gaskets (92mm) are no good.

 

As I said before, because I'm spending a lot on this gasket and they've specify a surface finish of 50 microinches, I want to make sur ethat the job is done correct.

  • 2 months later...
Posted

After ordering the gasket in November...............it has finally arrived along with the ARP stud kit!

 

I can finally get my head back on and see if my Megajolt works!!!!

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