My spare GX head has had something like .040 taken off of it. Unless you are running a really high lift .460ish I'd wouldn't worry about .010. Check the link below, its for Datsun Cherry / F10 but the motor portion of it is a great resource since they are A-Series powered.

http://www.datsuncherry.ch/PDF/Rennteile75.pdf

According to that Nissan factory service manual, #1 is not loose, it is within spec

FSM: Piston clearance to cylinder block: 0.0010-0.0018 (inch)

Quote:

Block was decked and GX head shaved for a total of about 10 thousandths. Should I be concerned with piston to valve clearance?

Correct Tom. All the pistons are slightly different in size based on what my machinist measured. So #1 piston will be a little loose. Doug gave me some specs from the 1981 Datsun shop manual (.0010-.0018)and all my pistons are within tolerance with #1 being on the upper end. Machine shop guy said to put the smallest piston in #4 cylinder since it usually runs the hottest. Not sure how accurate that statement is. Maybe I am overreacting based on some comments posted. Motor came out real clean and like the look after having it cleaned at the machine shop. Does it have to be painted or will it start showing surface rust? No harsh chemicals used because I preserved the cam bearings. Rings and gasket set have been ordered. Tri metal Clevite bearings received from ebay. I have had to pick all of this up from different sources. Its been a real challenge finding quality parts.

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I could be off here but if you add the clearances to the piston dimensions you get 2.994 for every cylinder. Wouldn't you just be moving the issue from one cylinder to the next?

I'd run it and not worry as only #1 is outside the tolerance and it a rely is. My poor tired A12 race motor had way more than that and it still pulled over 7000, the bores were so bad I had to got to 1mm oversize.

Tom

These motors are very forgiving of "bonus tolerance"
She'll be sweet as mate.

http://www.dprracing.com/scec.html just in case you need to coat skirts to get tolerances up

Ok thanks DD. I'll weigh and cc the pistons from both motors and come up with the best 4 pistons to get within tolerance. They appear to be the same. The motor I am working with is from a 1981 210 car. The other motor is from a 1982 210 car. Where can I find the piston-to-bore clearances in Tech Wiki?

It's OK to move pistons around, they should all four be the same

But from another A15, the pistons may differ. There were at least three different pistons designs used by A15. CC the dish to see if they are the same, then weight the piston to see if they are the same manufacture

After moving them around the engine should be re-balanced except if the pistons weigh exactly the same

Another option I have is using Pistons from another A15 block that I have to get within tolerance. Would it be ok to use Pistons from another motor?