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Piston Ring placement discrepancy

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Willy Nilly View Drop Down
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    Posted: 06 Oct. 2022 at 4:35pm
In my CJ2a Service Manual, page 35 and 36, it says to install the beveled compression ring in the first compression groove, with the bevel up.   The You-tube videos say to put it in the second compression groove with the bevel down.  The Hastings instructions in the box are very limited and say to put the dot on the top of the ring, and the bevel at the bottom, but doesn't specify first or second groove.

What is the story here?
1946 Willys CJ2A military clone
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dasvis View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dasvis Quote  Post ReplyReply Direct Link To This Post Posted: 06 Oct. 2022 at 5:27pm
The dot always faces up.
  the top groove in these Willys pistons is called a "heat dam" & no ring goes in it.
1947 CJ2A #88659 "Rat Patrol"
1953 CJ3A #453-GB1 11266 "Black Beauty"
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Bruce W View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 06 Oct. 2022 at 5:38pm
  The rings should be packaged and labeled as to which groove they go in. Go by the ring manufacturer’s instructions. And the dot ALWAYS goes up. 
BW 
It is NOT a Jeep Willys! It is a Willys jeep.

Happy Trails! Good-bye, Good Luck, and May the Good Lord Take a Likin' to You!

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Willy Nilly View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Willy Nilly Quote  Post ReplyReply Direct Link To This Post Posted: 06 Oct. 2022 at 6:14pm
I know about the heat groove, and I know the dot is always supposed to go up.  My question was why the book says to put the bevel up in the first compression groove (this is the second groove from top), and everyone else says exactly the opposite, put the bevel down in the second compression groove (third groove from the top).

Oh, and my machinist removed the rings from the packaging, so I can't go by that.


Edited by Willy Nilly - 06 Oct. 2022 at 6:16pm
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 06 Oct. 2022 at 6:53pm
  Different ring manufacturers have different ways of doing things. Some use a bevel, some inside, some outside, some top, some bottom, some use a step or groove, same choices. In the Service Manual, the rings of choice were from the same manufacturer that made the original ones. Each YouTube video instructs you to do it however that manufacturer specifies. Each one can be different. 
  Your “machinist” took them out of the package? ALL of them? He shouldn’t have done that. He had no reason to, and he should have known that you would need the wrappers to identify which ring goes in which groove and which side up. I’d say he owes you a set of rings or at least a set of instructions from the ring manufacturer. 
BW 


Edited by Bruce W - 06 Oct. 2022 at 6:55pm
It is NOT a Jeep Willys! It is a Willys jeep.

Happy Trails! Good-bye, Good Luck, and May the Good Lord Take a Likin' to You!

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 06 Oct. 2022 at 7:07pm
So, neither your machinist or you know which ring is which? Seems odd.

I have no experience with such a thing. With every engine I ever built, I let the machinist do the machine work, but I always build the engine myself, and I open the packages as I install the rings so I don't end up confused.

The DOT goes up, do that and the bevels will face the direction intended by the manufacturer, it is why they put the dot on the rings in the first place. Don't worry about it so much, or what you perceive as a discrepancy with the manual. The manual was written many years ago and references OEM parts which may differ from what is available today. I hope you bought Hastings rings.     

 


Edited by Oldpappy - 06 Oct. 2022 at 7:13pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Willy Nilly Quote  Post ReplyReply Direct Link To This Post Posted: 06 Oct. 2022 at 7:36pm
No, my machinist labeled the rings after gapping them for me.  I know which way they are supposed to go.  Again, I am not asking which way they are supposed to go.  And I know there are manufacturing changes sometimes.  All I am asking is why the difference between the old service manual instructions and todays instructions.  For example, what is the bevel for anyway?  Why did it once work facing up in the top ring, and at some point, now only works facing down in the second ring. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WeeWilly Quote  Post ReplyReply Direct Link To This Post Posted: 06 Oct. 2022 at 8:23pm
 I read or heard quite some time back that the bevel was to allow oil to lubricate the cylinder bore.

   Jim
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 06 Oct. 2022 at 9:18pm
No reason to get testy about it. My comment was based on yours "Oh, and my machinist removed the rings from the packaging, so I can't go by that."

So, you do know which is which. Good news.

The cylinders get lubricated by the oil being splashed up, and squirted up. The "oil ring" wipes the oil from the cylinders on the down stroke, the bevel lets a little oil into the rings to keep them lubricated. 

The Dot goes up. I don't have a set of OEM rings to look at but if they had a dot I would install them with the dot up. 

As to the bevel facing up or down, perhaps there was some change in theory about which works best over the years. Happens all the time. 

Engines used to wear out at 60K, now they can go 300K, some things get better over time due to research. 
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