Piston Ring Install Technique

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340sFastback

340sFastback

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A lot of people I talk to say they just walk the ring around the piston to get it into the groove. But a lot of books and online technical articles say to use a Ring Expander to put the rings onto the pistons. The reason for using the Ring Expander is its supposed to prevent twisting the ring. But the down side is you would be stretching the ring. I am leaning toward walking the ring around the piston to get them into the groove.
 
done it both ways...

the last engine last summer i walked them around...probably do it again this summer...
 
I walk 'em on. If I had my own machine shop I would have an expander to save the wear and tear on my hands.
 
On the same subject where do you guy like placing the gaps? I've heard a couple of different opinions. 180 degrees opposite the adjcent one and I've heard 120 degrees staggered. The only real agreement seems to be that the oil rings should have the gap at 10 o'clock and 2 o'clock as you lean over the fender.
 
MVRCorp said:
On the same subject where do you guy like placing the gaps? I've heard a couple of different opinions. 180 degrees opposite the adjcent one and I've heard 120 degrees staggered. The only real agreement seems to be that the oil rings should have the gap at 10 o'clock and 2 o'clock as you lean over the fender.
Click to expand...

The '69 FSM says to have the oil ring tensioner gap toward the front of the engine and the oil ring gaps at 10 and 2 o'clock positions when looking from the side of the engine like you said. It then states that the compression ring gaps "should be staggered so they don't line up with the oil ring gaps." I have read its not good to put the compression ring gaps toward the outside of the engine because this is the thrust side.

Technology has changed quite a bit since that manual was printed so I plan to look into this further.
 
I've spiraled them on before, but now I use a ring expander. Why? Because you don't want to have any distortion in the ring to prevent it from rotating in the groove. It's what keeps the grooves clean.

This also relates to the question about gaps. Just make sure they are staggered well. They will move in the groove as the engine runs, so whereever you line them up, the aren't going to stay there. You just want to keep them as far apart as possible. The theory is that if the all rotate at about the same speed, they won't ever line up, but worrying about exactly where the are located in relation to the thrust side really doesn't matter IMHO.
 
If the rings are filed square it should be no problem where the gaps end up. The heat of combustion actually closes the ring gaps and if heat is not kept under control the rings actually grow too much, getting bigger than the grooves and scoring the cylinders. Thats how most engines die and the most damage gets done.
 
MVRCorp said:
On the same subject where do you guy like placing the gaps? I've heard a couple of different opinions. 180 degrees opposite the adjcent one and I've heard 120 degrees staggered. The only real agreement seems to be that the oil rings should have the gap at 10 o'clock and 2 o'clock as you lean over the fender.
Click to expand...

Kick me to the "Jokes" forum if you must but thats :AM on the left bank and :pM on the right, right ? :bootysha:
 
A ring expander is about $8 at Advance or Autozone. It doesn't expand the ring enough to stress it. You are much more likely to damage the ring walking it on plus you will mark up the piston as you work it down to the groove it goes in.

Get a ring expander!
 
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