Piston indentification

Cribby

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Hi

I’ve just stripped the engine (1970 XS1) and the pistons are marked 952

Are these standard are over sized?

Thanks

Ant
AF35E8F3-5AD6-42EA-9C65-9622D23684D7.jpeg
 
Yes, that looks like a standard original piston. The size new would have been 74.952mm.
 
Not that I'm aware of. There should also be a 3 digit number stenciled on the sides of the cylinder sleeves where they hang out the bottom of the cylinder casting. That would indicate the bore sizes when they were new. This one was 75.010mm .....

CylinderSize3.jpg


Subtract one from the other and you should get a clearance in the .050-.055mm range. The question is, what are they now? You need to measure both parts and subtract their new sizes from each other to see if they are still within spec. I think the limit is .10mm or about .004".
 
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