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Replace piston rings to fix AP1 oil consumption?

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Replace piston rings to fix AP1 oil consumption?

 
Old 06-15-2018, 10:26 AM
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Default Replace piston rings to fix AP1 oil consumption?

So my '00 AP1 is one of those that likes to drink, at least 1L/1000KM. I'm getting tired of having to top off at every gas fill up and the occasional clouds of smoke in VTEC are somewhat ashaming.
I have already confirmed the oil is not going out through the PCV, valve seals are unlikely too as I already rebuilt the head (about 15.000KM ago), and oil consumption was unchanged.

I'm thinking of pulling the head and oil pan, and replacing the piston rings with the engine in the car. I won't be able to hone the cylinders.
Do you think bad piston rings are a common cause of AP1 oil consumption, and could replacing them likely fix it?
Or is it useless to try and more likely to cause new issues, as the cylinder bores could be ovalized anyways, I cannot hone the cylinders, etc..?

I read it's best to go with the newest OEM AP2 piston rings, part number 13011-PCX-024?
And of course I will properly gap and clock the new rings.

Any comments from past experiences or speculative input are appreciated
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Old 06-15-2018, 11:09 AM
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i haven't seen anyone try this. in theory it should help, wouldn't imagine it would hurt.

i'm interested in your results. good luck.
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Old 06-15-2018, 11:19 AM
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Mileage?
Before starting, might consider getting compression/leakdown #s. The absolute values might not mean much right away (unless there's an obviously bad cylinder), but you can do it again afterwards and see if there's any change.
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Old 06-15-2018, 11:52 AM
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With oval bores there is no masking the issue, a hone would also follow the contours of the oval.
Try different oils I guess.
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Old 06-15-2018, 12:44 PM
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Originally Posted by twohoos View Post
Mileage?
Before starting, might consider getting compression/leakdown #s. The absolute values might not mean much right away (unless there's an obviously bad cylinder), but you can do it again afterwards and see if there's any change.
90.000km.
That's a good idea. I think useless for measuring how well the oil control rings seal though? They usually don't affect the numbers from these tests I think. But if I decide to replace the rings, it's a good tool to monitor if the compression rings are sealing.

Originally Posted by noodels View Post
With oval bores there is no masking the issue, a hone would also follow the contours of the oval.
Try different oils I guess.
Exactly, so I'm wondering if it's usually oval bores or bad piston rings that cause the oil consumption.
I have tried multiple oils, a 40 weight seems to use less than a 30 weight. But I think going for a 50 will be too risky for this engine.
Right now I'm just on plain old Castrol GTX 10W-40, as it's cheap.
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Old 06-15-2018, 12:55 PM
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They<Honda>used a block plate clamp in the hone process on 04MY> onwards to solve the problems with oil consumption.
IT worked & my 05 engine uses 0 oil nor did my 04 engine.

Last edited by noodels; 06-15-2018 at 01:24 PM.
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Old 06-16-2018, 02:28 AM
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Rings help for sure but won't eliminate the oil burning. And it won't improve until you break in the new rings. If you're consuming a quart/1k miles rings will cut that consumption to around 2-3k miles/quart. At least from what I've seen. Use the latest rings, most important is the oil control and second rings. The top ring is responsible for roughly 80% of the compression from the piston side, so I'd still change it. Ring gap and orientation is critical.
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Old 06-16-2018, 07:52 AM
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Originally Posted by Slowcrash_101 View Post
Rings help for sure but won't eliminate the oil burning. And it won't improve until you break in the new rings. If you're consuming a quart/1k miles rings will cut that consumption to around 2-3k miles/quart. At least from what I've seen. Use the latest rings, most important is the oil control and second rings. The top ring is responsible for roughly 80% of the compression from the piston side, so I'd still change it. Ring gap and orientation is critical.
An oil consumption reduction of 2-3x... not perfect but still attractive. Was this on your own car, and did the improvement last? Happen to have any tips on break-in procedure and length?

Thinking about maybe trying krank vents first too...
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Old 06-16-2018, 09:14 AM
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Originally Posted by Scigheras View Post
I'm thinking of pulling the head and oil pan, and replacing the piston rings with the engine in the car. I won't be able to hone the cylinders.
If you dont hone/prep the cylinders, the new rings will not seat in. I guarantee your oil consumption will be even worse after a ring job without honing.
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Old 06-16-2018, 09:40 AM
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Agree with Billman. As imperfect as the current piston/ring seal may be, they are mated. I just dont see how putting new rings on (no doubt ovalized) cylinders will improve sealing. I have no personal experience performing this operation on this engine, but logically thinking through this, its a lot of time/effort with high risks of no/to detrimental outcome. I would rather just run it as is until consumption got so bad that it was effecting good running operation/consuming more then current. Honda max spec as ridiculous as it sounds, is 1Q per 1000 miles consumption on the F20. I had a built engine that got down to 1Q every 300 miles and that was my threshold for replacement. 1Q/1000 is pretty rough though I agree. My current F20 with 80k miles on the clock seems to be around 1Q 1500-1800 sadly. Oil consumption does seem to go up as the oil gets a few thousand miles on it. I would just run the 10/40 standard oil as you are doing for cheap/least consumption.

Last edited by s2000Junky; 06-16-2018 at 09:43 AM.
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