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M20 Piston Skirt Clearance

guys
I am currently having the barrel of my M20 Bored to suit a 0,040" oversize piston when I reported to the machinist the recommended clearance on the Web Site of Between 0.004" and 0.006" he Thought this was A bit Wide and you Would hear the Piston Slap for Some Distance is this the correct clearance and where on the piston is it measured?
Regards

email (option): grumpy.moran@gmail.com

Re: M20 Piston Skirt Clearance

Hi Ron, Piston clearance is measured on the piston skirt at the front and rear of the piston (the thrust faces when the crank is rotating). .004"-.006" is the correct clearance and will run without problems.
I generally get them honed to the minimum figure and 'run in' carefully.
It is frequently the case that machine shops more familiar with modern engines think the clearances are excessive..and that includes the valve guides.
However, tighten them up at your peril...I have experimented and they don't like it!
My local engine shop man also can't get his head around a 4.9-1 compression ratio and is convinced it should be at least 8-1.. ...Ian

email (option): julie@wright52.plus.com

Re: M20 Piston Skirt Clearance

Well we all know how to fix the compression problem don't we??

Re: M20 Piston Skirt Clearance

Ian
Thankyou again for the QUALITY information the Machinist always does Qualty work but his Bread and Butter are Mainly Modern Watercooled Engines but we will educate hin as we Go as an aside without putting Pressure on how are the Early Patten Bash Plates Crankcase Shields What ever you like to call Them Coming
regards
Ron Moran

email (option): grumpy.moran@gmail.com

Re: M20 Piston Skirt Clearance

I've mailed you direct Ron...Ian

email (option): julie@wright52.plus.com

Re: M20 Piston Skirt Clearance and sumpplate

Hi Ian,

Can you also tell me when you think the sump-plates are availeble?

Cheers,

Leon

email (option): ljvbekkum@hotmail.com

Re: M20 Piston Skirt Clearance and sumpplate

can i have one as well please ian?

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