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Guest Message by DevFuse
 

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Piston rings: which way up?


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12 replies to this topic

#1 Ross

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Posted 12 September 2005 - 12:09 AM

OK, so i believe that oem rings have a mark on the top to indicate which way up they go. The ones i have do not. The top looks symmetrical, while the 2nd ring has a step in it - you can see it in the pic.

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#2 NorthWet

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Posted 12 September 2005 - 12:21 AM

My various manuals either show the rings as symmetrical, or say there is a mark on the upper surface, or to say to follow the manufacturer's instructions on the ring package.


Hmmm... not much help.

#3 Turbone

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Posted 12 September 2005 - 12:28 AM

I'm looking at a EA81 FSM and they show 2 diag. The marks go up, the top ring has beveled edges, the 2nd ring has sharp edges and the oil ring either has a second ridge under the top rail or even rails, so that doesnt make a difference. Do you know the positions and gaps for the rings? I can scan the FSM and post it?

#4 NorthWet

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Posted 12 September 2005 - 12:51 AM

I'm looking at a EA81 FSM and they show 2 diag. The marks go up, the top ring has beveled edges, the 2nd ring has sharp edges and the oil ring either has a second ridge under the top rail or even rails, so that doesnt make a difference. Do you know the positions and gaps for the rings? I can scan the FSM and post it?

His description and second photo show a ring that is chamfered on its outside edge...

#5 Turbone

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Posted 12 September 2005 - 01:12 AM

The ring with the step on it, is the top ring. And the one with no step is the 2nd ring.

#6 Ross

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Posted 12 September 2005 - 02:14 AM

The ring with the step on it, is the top ring. And the one with no step is the 2nd ring.


The packaging says the opposite....

#7 Ross

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Posted 12 September 2005 - 10:23 PM

Yeah, i have a scanned copy of the fsm.
Im presuming the top ring, with chamfered edges, goes up either way, since it seems symetrical and has no markings.
I still dont know what way the second ring with the step in it goes. Anyone?

#8 Turbone

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Posted 12 September 2005 - 11:41 PM

Ok, now I'm cornfused :confused: Both rings have beveled edges, but only one has the one edge beveled? I see nothing of that in the FSM. Not sure, but I would assume the bevel goes down.

#9 Ross

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Posted 13 September 2005 - 12:04 AM

Ok, now I'm cornfused :confused: Both rings have beveled edges, but only one has the one edge beveled? I see nothing of that in the FSM. Not sure, but I would assume the bevel goes down.


Sorry, top rings have chamfered edges.

#10 ShawnW

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Posted 13 September 2005 - 05:05 PM

ID of the 2 rings is easy. The more flexible ring is the top ring. The 2nd ring is the one that REQUIRES a ring pliers and is very much breakable. They should have an N or an R on their top edge near the gap and in VERY small lettering sometimes. Most pistons that I have seen dont allow interchange of rings because the groove isnt wide enough for one of them to fit in.

#11 iluvdrt

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Posted 13 September 2005 - 09:54 PM

Ok, now I'm cornfused :confused: Both rings have beveled edges, but only one has the one edge beveled? I see nothing of that in the FSM. Not sure, but I would assume the bevel goes down.


The bevel goes on the bottom, of the middle ring slot on the piston, and is the compression ring. It is beveled to allow for "collecting" of the oil it is scrapping off of the cylinder wall. You want all of the rings to have a perfect 90 degree flush surface when mating with the top of the cylinder.

The symetrical ring doesnt matter because it is the compression ring.

The oil ring should be wierd looking and it goes on the bottom.

Make shure you space the gaps out, in other words dont line up all of the gaps from the rings in the same place or you will have some sick blowby, possible even no compression.

#12 Ross

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Posted 13 September 2005 - 09:56 PM

great, thanks.

#13 iluvdrt

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Posted 13 September 2005 - 10:01 PM

Not a prob.




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