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piston ring gaps realigning

8.8K views 7 replies 7 participants last post by  sandman351  
#1 ·
Anyone got any getter ways to stagger piston ring end gaps and keep them from realining. I have 300 miles on a rebored motor and have found that most of my compression and oil ring gaps are now in line with each other. I did very carefully stagger the ring end gaps like Ford recomends. The compression rings faced towards the front of the engine 1 1/4 inches above and below the pin bore and the oil rings facing towards the rear 1 1/4 inches above and below the pin bore.

Blue Fastback
 
#2 ·
If someone has a way I would love to hear it. Every motor I have tore down has had the gaps lined up. From my race motors to my street motors, it never mattered, they all end with the gaps aligned.
 
#7 ·
I thought about using gappless rings but that still leaves the oil rings to realign themselves. It is just kind of disapointing to see ring gaps realigned after such a short time. I thought maybe someone had a better way to stagger the rings. I just got an email back from a piston ring engineer who said that movement of the piston rings is due to thermal distortion. He said when the engine heats up the ring gaps finds its way to the most distorted part of the bore. The reason I found out about the ring gap issue comes from a problem I posted about 2 months ago. I had a strange rattle noise I had that could not be identified. The motor is now all torn down.


Blue Fastback
 
#8 ·
The rings are supposed to rotate, otherwise the small ring end gap would wear a spot in the cylinder wall. Rotating rings wear the cylinder bore evenly (at least thats the idea) The reason they rotate is due to the cross hatching of the bore, as the piston moves up and down it makes the ring rotate. Also the design of the ring itself promotes rotation (how the ring "twists" in the piston groove as it goes up and down). I don't think it's possible to prevent the ring gaps from lining up sooner or later, but they shouldn't stay that way. Unless of course, you use gapless rings.

Just my $.02
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