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Discussion Starter · #1 ·
So, at 135,000 miles some of our plugs have fouled. My question is this, if the rings spin and eventually line up, allowing oil through to foul the plugs, will they continue to spin if left unchanged? Could I just replace the plugs, put a VCM muzzler on it and hope for the best? Anyone with experience with this? Honda has already told us they won't cover it under warranty... we're 3 months past due.
 

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When you say Honda, is that the dealership or Honda corporate?
I would do as you said. In addition, I would change to 5w30 Shell Rotella Gas Truck oil and a synthetic fiber filter like Mobil 1 Extended Performance M1-110a. Buy a top tier 87 octane fuel for the cleaning additives.
 

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Discussion Starter · #3 ·
When you say Honda, is that the dealership or Honda corporate?
I would do as you said. In addition, I would change to 5w30 Shell Rotella Gas Truck oil and a synthetic fiber filter like Mobil 1 Extended Performance M1-110a. Buy a top tier 87 octane fuel for the cleaning additives.
The dealership encouraged me to contact Honda Corporate. Corporate said they won't warranty the work, so I may be left holding the proverbial bag. They may or may not choose to help us financially with the suggested ring job, but while I wait on them to decide, I thought I'd poke around for solutions. It just seems like new plugs, consistent running, maybe some additives, should keep it running... but I don't really know and was curious about other peoples experience.
 

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I find this very disappointing. It's evident the problem has been there for a long time, these aren't failures that happen in a short period of time. If you are seriously considering getting the repair work done I'd push back on Honda Corporate.
 
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The dealership encouraged me to contact Honda Corporate. Corporate said they won't warranty the work, so I may be left holding the proverbial bag. They may or may not choose to help us financially with the suggested ring job, but while I wait on them to decide, I thought I'd poke around for solutions. It just seems like new plugs, consistent running, maybe some additives, should keep it running... but I don't really know and was curious about other peoples experience.
Getting all 6 cylinders firing 100% of the time will definitely help clean things up. I recommend the Shell Rotella Gas Truck oil for it's resistance to evaporation and the higher oil weight to lessen oil loss.
Have you checked to see if each of your coils are firing?
 

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In my less-than-professional opinion, I suspect that Honda's "rings lining up" reasoning isn't completely descriptive. Rings don't spin in the bores on the pistons -- there's nothing to cause that really. Instead, I think the rings are broken by oil-fired detonation, and eventually the breaks in the rings might line up. That's an effect then, not a cause.

Things to consider....
-- Good synthetic oil is much less likely to cause detonation than conventional oils.
-- Oil passing into the cylinders will continue once the rings are broken. No amount of work will solve this short of dropping new pistons and rings in the affected holes.
-- I'd disable the VCM with the device of your choice, knowing it will help avoid the same problem in the future but won't do a thing for damage already done.
-- You might buy some time with thicker oil and new plugs, but not that much. Driving with damaged rings means the bores will be scored/damaged where the breaks in the ring sections ride up and down with the pistons.
-- A compression test (free-rent the tool from your local Plain Old Local Auto Parts Store (POLAPS) to do this test. Pull the ignition and fuel pump fuses, or add a manual start button to run the starter motor. Compression will be lower on the damaged cylinders and pistons.

You can do some sleuthing with a borescope camera through the plug holes, looking for those scratches and such on the cylinder walls. Those look a LOT bigger on the camera display than they do when looking bare-eyes at the damage. Doesn't solve anything, but might reinforce your diagnosis from the other symptoms.
 
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Discussion Starter · #7 ·
Getting all 6 cylinders firing 100% of the time will definitely help clean things up. I recommend the Shell Rotella Gas Truck oil for it's resistance to evaporation and the higher oil weight to lessen oil loss.
Have you checked to see if each of your coils are firing?
I have not. Right now, solely relying on Honda Dealership's diagnosis.
 

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I have not. Right now, solely relying on Honda Dealership's diagnosis.
I dunno about your dealership. The doom and gloom message is usually given to pressure you into a new car deal. You can buy 6 new spark plugs on RockAuto for about $60 vs the stealership at $380. S-VCM is $95. Oil and Filter at Wal-Mart for $30. I'd spend $185 to call their bluff. While you change your spark plugs you could test each coil for spark and see your old spark plugs for yourself.
 
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In my less-than-professional opinion, I suspect that Honda's "rings lining up" reasoning isn't completely descriptive. Rings don't spin in the bores on the pistons -- there's nothing to cause that really. Instead, I think the rings are broken by oil-fired detonation, and eventually the breaks in the rings might line up. That's an effect then, not a cause.
Having done over 100 rerings on j motors, I have yet to see any broken rings. Probably 30-40% have multiple gaps lined up, but mainly the oil control rings are coked up and not doing anything. Rings do move on the piston, especially when the cylinder is shut down.
 

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Having done over 100 rerings on j motors, I have yet to see any broken rings. Probably 30-40% have multiple gaps lined up, but mainly the oil control rings are coked up and not doing anything. Rings do move on the piston, especially when the cylinder is shut down.
Is fouled plugs the diagnosis for needing rings? Do you do a compression test or camera to examine cylinder wall?
 

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Generally yes, the deposits on the plug tell you what you need to know about what's going on in the cylinder. No compression test, as oil control rings have very little effect on compression. Honda does not view scope photos as valid for diag.
 

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Generally yes, the deposits on the plug tell you what you need to know about what's going on in the cylinder. No compression test, as oil control rings have very little effect on compression. Honda does not view scope photos as valid for diag.
In the OPs case.., Do you feel they have anything to loose by replacing plugs, and disabling VCM at this point?
 

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Having done over 100 rerings on j motors, I have yet to see any broken rings. Probably 30-40% have multiple gaps lined up, but mainly the oil control rings are coked up and not doing anything. Rings do move on the piston, especially when the cylinder is shut down.
Generally yes, the deposits on the plug tell you what you need to know about what's going on in the cylinder. No compression test, as oil control rings have very little effect on compression. Honda does not view scope photos as valid for diag.
Great info!
 
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In the OPs case.., Do you feel they have anything to loose by replacing plugs, and disabling VCM at this point?
No, nothing to loose. Disabling the vcm will slow or stop the rings from getting coked, but will not likely reverse what's already happened. Best option is to put gm top engine cleaner in cylinders 1-3 everyday for 6 or 7 days and let it soak continuously. Gm top engine cleaner is great at dissolving carbon, and Might get the rings unstuck and working properly again.
 

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No, nothing to loose. Disabling the vcm will slow or stop the rings from getting coked, but will not likely reverse what's already happened. Best option is to put gm top engine cleaner in cylinders 1-3 everyday for 6 or 7 days and let it soak continuously. Gm top engine cleaner is great at dissolving carbon, and Might get the rings unstuck and working properly again.
And an oil change a couple days after the last treatment!
 
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Discussion Starter · #17 ·
This is all great information, and really helps me figure out what to do here. I guess the odd part of all this is that we've never seen any evidence of burning oil. Always used the suggested synthetic and kept up on maintenance. It's just odd that all of a sudden we foul a plug... strange. But at least i have some things to try, so thank you. One last question... assuming that Honda comes back with a reasonable offer on the repair, can I assume that this issue will be behind us, and we won't see this problem again for another 50 to 60 thousand miles?
 

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It only burns a little, so you likely wouldn't notice it, cumulative issue. It really isn't all the sudden, it's a slow progression until the plug finally fouled. Yes, you should be good after repair, so far, no returning issues.
 

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Having done over 100 rerings on j motors, I have yet to see any broken rings. Probably 30-40% have multiple gaps lined up, but mainly the oil control rings are coked up and not doing anything. Rings do move on the piston, especially when the cylinder is shut down.
Any idea what causes the rings to move? I have no experience tearing into Honda car engines, but have done more than 11 other engines over the decades. Would seem that ring gaps lined up from initial assembly would be passing oil from that same time, regardless of whether VCM was active on that cylinder. Would show up as oil consumption and maybe plug issues if it's severe.

Here to learn...
 

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It only burns a little, so you likely wouldn't notice it, cumulative issue. It really isn't all the sudden, it's a slow progression until the plug finally fouled. Yes, you should be good after repair, so far, no returning issues.
Safe to say then that just replacing plugs would leave the owner no worse off than when the car was sold new?

I haven't dug into the actual sequence of action when VCM engages and disengages. It would seem logical that you'd want to deactivate the intake valve first, so the cylinder is effectively "under vacuum". Avoids compression heating and pumping losses in that cylinder while deactivated by VCM, but that also means the two top rings don't have pressure to seal, so will pass any oil left on the cylinder walls by the oil scrapers. Carrying that to conclusion, we only have oil ingestion when VCM is active, and if there's no actual damage to the piston and bore, new plugs and VCM deactivated should solve it for this owner. Piston and cylinder condition are no worse than when the car was new.

Thoughts?


Tangent--

My car uses very little to none oil between changes, based on just the dipstick looks. VCM has been disabled since before 10k miles, currently mid 50's. Oil has been synthetic since about 1k, then changed religiously at 50% on the motor monitor. I've had no reason to look at the plugs yet. Should I, while the extended cylinder warranty is still in force? October 2012 build, an early executive promo build. The Pilot is generally our non-summer ride so not many miles on it, old retired white-hair owners. It's in the hibernation slot in the garage right now, with a battery maintainer attached.
 
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