Since the pistons at the rear of the zed, take an absolute pounding and are generally the ones to fail!

 

If you are doing a rebuild and can't afford forged jobs, might it be a good idea to reverse the order of the pistons, so that the ones that were under less strain are now taking the punishment?

Each cylinder has a different grade of piston. Having the wrong grade pistons could cause more problems than solutions. Also cylinder and rings wear down together, putting a piston in the wrong cylinder would mean the ring is not worn to the same shape even if its thousands of a mm.

Stu,

 

I was taking it that people would put in new rings and hone the block if you were rebuilding the engine!

 

Explain to me the different grade of piston for each cylinder?

Pistons and bores are measured and graded. i.e. the correct piston is selected to have the correct clearance in the bore.

 

Too much clearance and you get piston slap, too little and you will sieze piston up.

 

But in reality, the sizes we are talking are really miniscule........this is from a toolmaker who can work in microns (with the help of my Wire EDM machine)........... lol ;)

I realise that aftermarket pistons are graded, depending on the rebore!

 

But I can't see Nissan sitting down and measuring each piston for each bore at the factory?

I realise that aftermarket pistons are graded, depending on the rebore!

 

But I can't see Nissan sitting down and measuring each piston for each bore at the factory?

 

more info

 

1's are the smallest 3's the biggest more info here

 

http://www.courtesyparts.com/z32/oe_pistons-rings-rods.html

But unless the rearmost pistons have actually already suffered damage there is nothing to gain. If they came near to failure maybe there would be stress cracks, opened up ring grooves etc but you wouldnt want them anywhere near the engine if there was any doubt about their integrity. So while rearmost ones have the hardest life in terms of nearness to disaster unless they cross the fine line they have to still be as good as the rest.

 

If you had more ring groove wear on those I think you'd be back to new pistons anyway.

You live and learn!!!

very interesting stuff all the same