Piston ring gap layout
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Registered User
Joined: Dec 2014
Posts: 14
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From: Lexington, KY
Piston ring gap layout
Hello,
I'm installing new piston rings on my 2001 5.2. I'm using the service manual and the Haynes book as references. The two seem to differ on how to position the ring gaps. Normally, I'd let the service manual rule, but there also seems be conflicting information there. It's entirely possible I'm reading it wrong, but I've installed the first piston following the Haynes book and I didn't want to go any further until I was sure about what was right.
The Haynes book shows the gaps at basically the same relative positions as the service manual, just rotated 45 deg. The book shows the oil ring spacer gap lined up with the 2nd compression ring's gap. However, the service manual has the 2nd ring's gap lined up with the top oil ring's gap. The service manual also says "Be sure that compression ring gaps are staggered so that neither is in line with oil ring rail gap.". That statement seems to agree with the Haynes book, but conflicts with service manual's picture.
Based on other reading I've done, it looks like the Haynes layout is correct. That is, it's OK to have the oil ring spacer lined up with another gap, but you don't want any of the other gaps lined up with each other. Is that correct, or am I missing something?
I've attached the relevant page from the service manual. The Haynes pic is copyrighted, but it has gaps at the following positions: top ring - 45 deg, upper oil rail ring - 135 deg, 2nd ring and oil spacer gap - 225 deg, lower oil rail ring - 315 deg (i.e., 1st and 2nd rings are opposed, upper and lower oil rail rings opposed, oil spacer lined up with 2nd ring).
Thanks in advance for any and all help.
I'm installing new piston rings on my 2001 5.2. I'm using the service manual and the Haynes book as references. The two seem to differ on how to position the ring gaps. Normally, I'd let the service manual rule, but there also seems be conflicting information there. It's entirely possible I'm reading it wrong, but I've installed the first piston following the Haynes book and I didn't want to go any further until I was sure about what was right.
The Haynes book shows the gaps at basically the same relative positions as the service manual, just rotated 45 deg. The book shows the oil ring spacer gap lined up with the 2nd compression ring's gap. However, the service manual has the 2nd ring's gap lined up with the top oil ring's gap. The service manual also says "Be sure that compression ring gaps are staggered so that neither is in line with oil ring rail gap.". That statement seems to agree with the Haynes book, but conflicts with service manual's picture.
Based on other reading I've done, it looks like the Haynes layout is correct. That is, it's OK to have the oil ring spacer lined up with another gap, but you don't want any of the other gaps lined up with each other. Is that correct, or am I missing something?
I've attached the relevant page from the service manual. The Haynes pic is copyrighted, but it has gaps at the following positions: top ring - 45 deg, upper oil rail ring - 135 deg, 2nd ring and oil spacer gap - 225 deg, lower oil rail ring - 315 deg (i.e., 1st and 2nd rings are opposed, upper and lower oil rail rings opposed, oil spacer lined up with 2nd ring).
Thanks in advance for any and all help.
Captain
Joined: Sep 2013
Posts: 586
Likes: 17
From: Nevada
As snowboundr said, either one should work. I was always taught to not have any gaps lined up, but with my 408 I went against the grain. It went from top to bottom; 90, 270, 0, 270, 180.... I think. Lol. I might have went with 90 on the oil spacer rather than 270, but I can't remember for sure now. I do know the main rings, compression and scrapers, each pointed at a point on the compass- east, west, north, south.
