[240/260Z]

About two years ago, I brought my 260 and partially rebuilt engine from Texas to Las Vegas. While in San Antonio, I bought some Perfect Circle Piston Rings (.020). I just got to the point of inserting the rings in the bore for gauging the gap with my feeler gauge. All of the rings measure up except the oil ring. Even the two oil-ring spacers fit. The only way to get the oil rings (corrugated-looking ones) in the cylinder bores is to overlap each of them a bit. I know that rings can be filed or grinded a bit at a time, with care, but I am not sure whether or not this applies to the oil ring. I have never filed or grinded an oil ring, but it looks logical and simple enough (as long as the ends but-up evenly, smooth out each end and ensuring that both ends of each oil-ring but-up, without a gap, while it fully fits flush around the inside of the cylinder bore). Help, I need to get some work done while I am off of my real job for a few days. Thanks, Ernest

 

[JT240Z]

I've used the Perfect Circle Rings many times and never had to modify the oil ring gaps. How are you checking the ring gap on the oil ring? Check with the Perfect Circle sevice deptartment before you screw up a good set of rings. It's possible they packed the wrong oil rings for the set or your checking them wrong.

 

[mizhele]

i also used perfect cirlce rings on my 71 240z and they fit well "perfect" i'd check where you got them and besure you have the correct ones...good luck michele

 

[240/260Z]

After reading more in "How to Rebuild Your Nissan Datsun OHC Engine," I think I figured it out. It appears that the expander oil ring ends are to but-up while in the piston groove in order to press against the cylinder bore (with adequate tension), and the upper and lower spacers are to have a gap to avoid butting-up while in the smallest part of the bore. Thanks JT and Mizhele; I will make absolutely certain, even if I have to call Perfect Circle. I had already emailed two different entities within Perfect Circle and have not received a reply. I assume that the holiday season is slowing down things. Ernest