Piston End Gap Clearance

ratlee2
ratlee2 Expert Adviser
Forgive my ignorance as I am a rookie engine builder.  I know there are a lot of knowledgable people here, so I''ll ask my stupid questions now regarding the piston rings for my 262 rebore (new 3 ring pistons  and grant rings from Dale Cooper)

1. Piston ring intructions give the end gap clearance for the compression rings but make no mention oil control rings.  Do the rings above and below the expanded-spacer ring also get filed or installed as is since they are really thin?

2.  The intructions for The grant rings state to clock the expanded-spacer ring at the wrist pin and the ring above and below the expanded-spacer ring 1 to 2" to the left and right.  They make no mention of gap placement for the two compression rings.  Would the second ring get gapped 180 degrees from the oil control ring and the first ring back to the same wrist pin location?

Thanks,
Rich

Comments

  • Ol racer
    Ol racer Senior Contributor
    Rich,
     I like 3 ring pistons...The oil rings do not get gapped. I clock the Compression Rings left & right but avoid the 'recessad valve relieve area' (so a ring edge dont get caught while sliding thru ring compressor)
    .
     I also dunk the piston in oil before compressing then put pc neopreme hose on rod bolts so dont scratch crank installing.

    Be sure the small oil hole on rod is pointing toward cam lobes then oil shell & crank well. Ive always discard the rod pal nuts.
  • Geoff
    Geoff Senior Contributor
    It depends on what gap there is on the ring when inserted in the bore.  Too wide doesn't matter a hoot, but too little can cause scoring and seizing.   Around 9 to 12 thou is fine, but anything smaller you should file the ends.  As ol racer says, put the gaps on the side away from the valves.  Original Hudson  pinned rings of course had the gaps all in a line, and this didn't matter.  
  • ratlee2
    ratlee2 Expert Adviser

    Thanks guys.  I hadn't thought about the valve recess area.  I'll gap the compression rings at 180 degrees apart with one facing forward and one facing towards the back and the oil control rings on the wrist pin side away from the valve recess.

  • Uncle Josh
    Uncle Josh Senior Contributor
    If you're using pinned rings, it's easier to get the oil ring in using a hose clamp with the screw-holder ground so the whole thing lays flat on the block.  Then put a ring compressor on the other three.  Always hold the compressor against the pin when tightening so a ring doesn't rotate and get on the pin and snap the end off.  Can't do that with the compressor on all 4 rings since the oil ring is 1/3 off from the top ones.
  • ratlee2
    ratlee2 Expert Adviser
    I am only working with the 3 ring replacement pistons and the oil rings were the hardest part so far.  Once I got past the oil ring, the compression rings were easy enough.  I have 2 pistons left to install.  I will have to give the hose clamp a try.  Thanks for the tip uncle Josh.