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DPS DPS is offline
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piston ring orientation w/ 3 piece oil ring

I am preparing to install my pistons into their cylinder walls. Can anyone confirm whether this would be the optimal ring gap location when using a 3 piece oil ring.

Thanks,
Dan


Old 09-10-2015, 09:17 AM
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Looks like they recommend 2 o'clock.
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Old 09-10-2015, 03:10 PM
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Originally Posted by E Sully View Post
Looks like they recommend 2 o'clock.

Ed,
Thanks for the diagram. I may be mistaken but does this illustrate a 2 piece oil ring that utilizes an internal spring? My concern is with the orientation of a 3 piece oil ring.

Thanks,
Dan
Old 09-11-2015, 05:01 AM
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I'd probably go 3,9,2,6,10 starting at the top of the piston. That puts #1 and #2 close to the manual's recommendation and 180 apart and allows a good offset between #2 and the top scraper. They all go where they want to go anyway once the engine is running and the reason for initial offset is to prevent scuffing on initial start, at least that's my understanding on V or vertical engines. Having a one piece oil ring gap at the top or in this case, the scraper gaps, makes sense on a flat boxer though and hope they don't rotate to the bottom. Make sure the expander ends are not overlapped and follow the mfr's. instructions on what side of the expander goes towards the top of the piston. Who made the rings? Have you checked the end gaps?
Old 09-11-2015, 12:23 PM
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I'd probably go 3,9,2,6,10 starting at the top of the piston. That puts #1 and #2 close to the manual's recommendation and 180 apart and allows a good offset between #2 and the top scraper. They all go where they want to go anyway once the engine is running and the reason for initial offset is to prevent scuffing on initial start, at least that's my understanding on V or vertical engines. Having a one piece oil ring gap at the top or in this case, the scraper gaps, makes sense on a flat boxer though and hope they don't rotate to the bottom. Make sure the expander ends are not overlapped and follow the mfr's. instructions on what side of the expander goes towards the top of the piston. Who made the rings? Have you checked the end gaps?

Thanks for the post.

3 and 9 for the compression rings - Is there any issue lining them up with the wrist pin? I thought Wayne’s book stated not to do that.

The rings are made by Total Seal. I read their instructions and they do not appear to be specific for a boxer motor.

It looks like Total Seal is recommending: 6 (top) ,12 (2nd),10 (oil rail) ,6 (oil expander), 2 (oil rail).

I checked the end gaps, they were all within spec.

Thanks,
Dan
Old 09-11-2015, 02:12 PM
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I haven't read Wayne's book but that could be true and the manual agrees with that. So if you clock everything one position then you'd be 4,10, 3,7,11. I'd use that before I went with the Total Seal recommendation just because there's puts the #1 gap right on the bottom of the bore where the most oil is. Hopefully some of the pros who build these for a living will chime in.
Old 09-11-2015, 04:22 PM
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I would clock each of the (3) sections of the oil ring so that none of the ring gaps points down with the gaps pointing upwards, you will provide a dam for oil collecting in the area.

I've been told that once the engine is started up, the rings will rotate and re-index themselves, so I'm not certain of how critical clocking of the rings is during your rebuild.
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Old 09-11-2015, 06:27 PM
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You have 5 end gaps. Space them equally approximately 60 to 65 degrees apart starting at the recommended first position in the Porsche manual. It doesn't matter what the spacing is as long as you an adequate separation from one ring to the other without having two gaps in line for initial start up. Once you start up the engine the rings are going to rotate. Nothing you can do about that.

The reason for staggering the initial ring gaps is to allow for maximum compression and oil scraping upon start up. But once the engine is started up the rings will rotate and as stated there is nothing you can do about that. Hopefully that they will all rotate to less than the 65 degrees and no two gaps will be in line. But there is no guarantee that this will not happen during a running engine. There is nothing in the cylinder or the piston to stop the rings from rotating within the piston ring groves.

Don't over think this just set your ring gaps approximately 65 degrees apart and not have any groves at the piston pins and you are good to go.
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Old 09-11-2015, 07:51 PM
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I see the problem first hand. Just installed my Total Seal piston rings.

The three-piece oil ring, and the two-piece 2nd compression ring present a problem. After thinking about it. This is what I decided made the most sense.



Here is my logic:
The only oil ring gap that really matters is the upper one. That is where the oil will be prevented from going into the combustion chamber. (at least we hope so) .

The expander and lower oil ring are bathed in oil on both sides. My feeling is the gap location is not critical for that reason alone, but they should not line up.

Once the oil ring is put up at the top (1-2 o'clock), the Top ring is set at 10 o'clock, the upper half of the 2nd ring goes 180 from the top ring, and the sealing ring goes 180 from the split in the second ring, which happens to be about the same position of the top ring gap. Probably not an issue.
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Old 09-19-2015, 06:19 AM
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Question Piston Ring Orientation???

Bringing up an old Thread.

So my plan for my CP ring orientation ( all gaped properly ):

10:00 Top Compression Ring
02:00 2nd Compression Ring
11:00 Top Oil Ring
12:00 Expander Oil Ring ( no spring or weight on gap ends, like OEM's )
01:00 Bottom Oil Ring

Does this sound about right?

My first plan was:

10
2
11
6 ( gap at the bottom )
1

TIA,

Jim
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PCA/POC

Last edited by DRACO A5OG; 03-21-2017 at 06:11 PM..
Old 03-21-2017, 05:52 PM
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Okay spoke to CP:

Here is what they suggest, combo of OEM with slight mod:

04:00 Top
10:00 2nd
01:30 Top Oil Shim
08:00 Oil Expander
02:30 Bottom Oil Shim

Stated most Important are the top two compression rings be opposite of each other and away from the wrist pins.

Having the expander gap close to the bottom is of no consequence as the outer shims are close to 180 degrees away at upper portion of the piston
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Old 03-22-2017, 08:35 AM
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I never understood ring positions... when I pulled my 964 apart, the gaps were all over the place.. sure I put them all back the correct way, but I wonder if I pulled it apart again, where would they be this time?
Old 03-23-2017, 01:53 AM
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I think it is only important on initial break in period, after that they are spinning fools

+1, when I removed the old one they were all over the place.
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Old 03-23-2017, 02:04 AM
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I installed new 3.3 turbo Mahle Pistons and Cylinders a few years ago and positioned the ring gaps like the factory manual says in the diagram above.
I posted that diagram a few years ago.

When I pulled the old 3.3 Mahle pistons and rings out the ring gaps were real close to the same positions.. like within 1 to 1.5 inches from the same positions.
I think this ring gap moving around while the motor is running stuff is over rated by internet hearsay.

Old 03-23-2017, 09:27 AM
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