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WTF causes rings to all line up??

Started by jmorton10, May 13, 2019, 08:39:11 AM

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biggzed

I just put a set of rings on my Dad's 106" (4.5" stroke). The bottom ring is dimpled. The dimple goes down and must be in the wrist pin gap. It's supposed to keep it from rotating out of that gap. I'm pretty sure this is unique to pistons which have rings covering the wrist pin gap, so probably not 100% applicable to this conversation.

Zach

Quote from: Boe Cole on May 13, 2019, 09:29:39 AM
I've often wondered why 4 stroke motor pistons are not pinned.

kd

Quote from: biggzed on May 22, 2019, 09:20:05 AM
I just put a set of rings on my Dad's 106" (4.5" stroke). The bottom ring is dimpled. The dimple goes down and must be in the wrist pin gap. It's supposed to keep it from rotating out of that gap. I'm pretty sure this is unique to pistons which have rings covering the wrist pin gap, so probably not 100% applicable to this conversation.

Zach

Quote from: Boe Cole on May 13, 2019, 09:29:39 AM
I've often wondered why 4 stroke motor pistons are not pinned.


That's an interesting feature I was not aware of.  Thx
KD

Admiral Akbar

http://blog.wiseco.com/ring-grooves

QuoteThe cross-hatch in the cylinder walls induces rotation of the rings.

kd

KD

rredneckn2

If you don't like what I say DONT read it

Moparnut72

When I worked in the Radial Aircraft Engine shop the clearance between the rings and the lands was a major aspect of our rebuilds. Since new pistons were virtually unobtanium we had to do things differently. The boss would true up the ring grooves on the pistons we had. He would order rings from a special supplier we used that were just oversize in circumference and in thickness. We would grind them in a surface grinder to fit in the lands at the low end of the allowed tolerance. Then we would file them to get the correct ring gap.
kk
If you find yourself in a fair fight,
You didn't prepare properly.