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I'm gonna take a good look. I also ordered a tapered wiseco ring compressor and new wiseco rings, time to do this right. I hate hammering pistons into the bore with cheap compressors.
Reassembly has begun. Using Wiseco xx rings this time, I can tell they are much better quality. Got gaps set last night. Ready to use the new ring compressor.
I put it all back together this weekend and put on 100 miles yesterday. Oil consumption is still there, I can still see oil on top of the pistons too. Even fouled a few plugs.
I would bet that if I pull it apart again the bottom rings will be broken. I made very sure to check and set all gaps and the install was smooth. Any chance this is a piston or bore issue? I didnt measure the whole bores and only checked ring gap 1/2" from top of cylinder. I feel like maybe the bottom rings get tight lower in the bore, butt and break. Anyone have any ideas?
Did you have the block bored or honed before installing new pistons? It's possible you're out of round/taper, but also possible that you've got the wrong gap for the type of piston. Just curious - are you running a 2618 alloy piston?
Ring install - are you sure all your rings are oriented properly? Most beveled rings need to be bevel down/indicator up, otherwise, they will scrape oil into the combustion chamber with each stroke. Does your wrist pin opening cut into your oil control rings? If so, that bottom ring that acts as a support rail will have a dimple that needs to be in the wrist pin opening. When installing the expander ring, are you sure the ends are butted, and not overlapping?
If you put new rings and an old cylinder, it's important to measure the wear. It won't be even from top to bottom or latitudinally or longitudinally.
This picture is related to a diesel engine but you get the idea.
It's new pistons and the bores was recently punched over to 83.50mm when the pistons were installed. At this point it basically has to be a problem with the bores or a defective set of pistons. The only thing i can think of with the bores is maybe the bottoms weren't punched out all the way to 83.50 because the gaps at the top are right but maybe right at the bottom they are butting. It is unlikely but its gonna be something unusual.
Like you said, you could have cracked a ring or maybe the rings did not seat properly.
First set, all 4 pistons had broken oil rings and spacers so not a seating issue. Replaced that set and bought a tapered wiseco ring compressor, installed new rings. Oil consumption the same (1qt/60 miles), oil pooled on top of pistons that I can see through spark plug holes. So all 4 cylinders are using a ton of oil. It is all but impossible that I broke all the oil rings on all 4 cylinders twice although I do suspect they are broken again. Rings not seating I could see if it was a small amount of oil or a couple cylinders. The amount of oil used goes way beyond a ring seating issue. I've rebuild many engines so it is unlikely that suddenly I break the rings every time I install a piston, one piston sure maybe but breaking them all twice? I really doubt it.
Did you have the block bored or honed before installing new pistons? It's possible you're out of round/taper, but also possible that you've got the wrong gap for the type of piston. Just curious - are you running a 2618 alloy piston?
Ring install - are you sure all your rings are oriented properly? Most beveled rings need to be bevel down/indicator up, otherwise, they will scrape oil into the combustion chamber with each stroke. Does your wrist pin opening cut into your oil control rings? If so, that bottom ring that acts as a support rail will have a dimple that needs to be in the wrist pin opening. When installing the expander ring, are you sure the ends are butted, and not overlapping?
All fair questions. Yes, 2618 alloy pistons. Block was bored and honed before install. My ring gaps are correct but I have no idea if the p2w is correct as I left that to my machinist friend. I will say, this engine doesn't have the cold rattle that I typically get with 2618 pistons. Wrist pin opening does not overlap with the oil control ring groove. I made very sure that the expander ring ends were butted and not overlapped.
Here is my piston spec sheet. I notice it says my oil control ring groove width is 4mm however my oil control rings with spacer is 2.8mm....that seems like a really loose fit. Thoughts? Or do they mean the ring groove depth?
I figured out the problem. They sent me 1.0mm 1.2mm 2.8mm rings. The arias rings that should have come with them are 1.2mm 1.5mm 4.0mm. Here you can see what they sent and the catalog where it says what i need.
Oh no, I hope they didn't destroy your cylinder surfaces!
Ya me too! It was fine after the first tear down and I have only put on 60 miles since the second tear down so I'm hoping I can just hit it with a ball hone. I'm working with my piston dealer and arias rep now, will let you know how they handle it. They seem helpful so far, I'm just waiting to hear back from the rep.
Yikes. Presumably they sent you the same ring package twice?
I ordered wiseco rings from another source the second time, but based on the size they sent the first time. I shouldnt have assumed the manufacturer sent the correct size i guess.
05-05-2019, 01:58 PM
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