Major engine work - 1st short OCI recommended?

[MarioT]

My car just had its 4 pistons replaced (but no cylinder rework) due to an ever increasing cold engine knock. Job was under warranty and it's seem they did a good job to fix the issue. But, looking at the paperwork, they only "adjusted" the oil level. So I the previous filter stayed there... The oil does currently looks almost new at 500 miles.

Due to the "open heart surgery" and the reused filter, would a short 500-600 miles interval be better than waiting my usual 3k/4months? I consider it to be under the severe schedule...

2005 Chevrolet Optra / 2.0L
(Canadian version of the Suzuki Forenza)

 

[Eddie]

The oil must have been drained to replace the pistons. You need clarification on what they ment by "adjusted". Did they drain and reused to old oil?

 

[Colt45ws]

Yes, I would drain after 500-1000 miles.

 

[GOPHER FREAK]

Originally Posted By: Eddie
The oil must have been drained to replace the pistons. You need clarification on what they ment by "adjusted". Did they drain and reused to old oil?


I can't think of a way to replace pistons with out draining oil. The probably "adjusted" the oil level by refilling. Not really a change as they didn't replace a filter. But why even worry about it. Change it out. With work that major, I'd want that oil out of my car with 500-700 miles. I'm sure someone will tell me I'm nuts, But that's just me.

 

[StevieC]

I would warm up the engine to full operating temperature and do a couple of WOT's while rolling to help seat the rings.

I would also add some MMO or some other UCL to the fuel for the next little while to help seat the rings properly.

As for the oil I would change it out in 500 Miles, then again at 1K then you should be good to go for your regular interval as in your owners manual for your driving conditions. Use the cheapest oil you can find that meets your cars specifications as set out in the owners manual. If 5w20 is ok to use, I would use this as this would be better for ring seating IMO.

 

[wafrederick1]

Change the oil ASAP and it is not good with the old oil filter full of dirt and and metal shavings.My father's friend Tom went through this with a 1989 Ford F150,had the rings changed under warranty and they did not change the oil pouring the old oil back in.The dealer told him that he had to get the oil changed and they poured the old oil in.The dealer said Ford did not cover changing the oil under warranty.The engine puked,a 302 and a Jasper reman was installed.

 

[FZ1]

When in doubtump it out.

 

[bobfather99]

Id change it out now, then again in 1000 miles.

Oil changes are easy, compared to the big stuff....

 

[BuickGN]

No one is going to drop a pan full of oil. Rest assured the oil is new. Did they reuse the rings and only replace the pistons? If they did that, there's technically no break-in but I would change it out now just to get rid of any junk which may have gotten in there from the engine being open and then go back to whatever OCI you were running before.

 

[StevieC]

Originally Posted By: BuickGN
No one is going to drop a pan full of oil. Rest assured the oil is new. Did they reuse the rings and only replace the pistons? If they did that, there's technically no break-in but I would change it out now just to get rid of any junk which may have gotten in there from the engine being open and then go back to whatever OCI you were running before.
There would be break-in if the rings weren't put on the same pistons in the exact same spot as when it came out.

Also the pistons could have been a slightly different size also altering the pressures of the rings against the cylinder walls...

 

[BuickGN]

Originally Posted By: StevieC
Originally Posted By: BuickGN
No one is going to drop a pan full of oil. Rest assured the oil is new. Did they reuse the rings and only replace the pistons? If they did that, there's technically no break-in but I would change it out now just to get rid of any junk which may have gotten in there from the engine being open and then go back to whatever OCI you were running before.
There would be break-in if the rings weren't put on the same pistons in the exact same spot as when it came out.

Also the pistons could have been a slightly different size also altering the pressures of the rings against the cylinder walls...



Ring lands are machined and tolerances are very tight. That's really a non issue.

No mechanic worth their salt would put used rings in a different cylinder than they came out of. They continually rotate so that's not an issue.

 

[hounddog]

I don't think rings rotate.Thats why there is a stagger procedure.I have worked with several auto manufactures booking warranty procedures.All the ones I have worked with on major engine repair always covered oil and oil filter with no issues/claim kick back.

 

[MarioT]

So out the oil goes this afternoon...
I was looking for an excuse to work on the car ;-)

From the invoice left to me, I know for a fact that most gaskets had to be replaced, new oil and green antifreeze used. Also, you seem to confirm the other thing I was thinking. They could have reused the rings: only pistons are listed in the replaced parts.

They mentioned only the pistons measures where out of specs, but no oversize was needed. The piston noise began at 10kmiles... and I waited until 35kmiles to have it repaired under warranty.

 

[StevieC]

Originally Posted By: BuickGN
Originally Posted By: StevieC
Originally Posted By: BuickGN
No one is going to drop a pan full of oil. Rest assured the oil is new. Did they reuse the rings and only replace the pistons? If they did that, there's technically no break-in but I would change it out now just to get rid of any junk which may have gotten in there from the engine being open and then go back to whatever OCI you were running before.
There would be break-in if the rings weren't put on the same pistons in the exact same spot as when it came out.

Also the pistons could have been a slightly different size also altering the pressures of the rings against the cylinder walls...



Ring lands are machined and tolerances are very tight. That's really a non issue.

No mechanic worth their salt would put used rings in a different cylinder than they came out of. They continually rotate so that's not an issue.
Originally Posted By: hounddog
I don't think rings rotate.Thats why there is a stagger procedure.I have worked with several auto manufactures booking warranty procedures.All the ones I have worked with on major engine repair always covered oil and oil filter with no issues/claim kick back.


I wouldn't put it past Dealerships to reuse old rings. I have seen a few engines that had to have parts replaced by dealers while under warranty only to be rebuilt later on after warranty because they had reused things that should have been replaced.

But assuming they didn't then there would be break-in as the new rings wear into place with the cylinder walls and neither the ring or the wall is 100% perfectly matched/round.

As for ring movement, they will move slightly over the course of their life from engine vibration but hounddog is right, they are offset on purpose when put in to stop blowby and oil consumption and generally stay the way they are put in +/- a few millimeters over the course of their life. They move more in the beginning until seated with the walls of the cylinders.

 

[hounddog]

If there was a TSB on the issue it would specify what parts needed.If not I have NEVER seen a tech wanting a comeback.If anything they usually want to use MORE new parts then specified.Thats been my experience over the last 30 odd years.Heck call and ask them or if near go by and ask to talk to the tech.

 

[bustednutz]

Just curious..............what kind of car was this on?

 

[mechtech2]

A dealership is going to be a dirtier environment than a factory engine facility.
change the oil at no more than 1/2 of your normal OCI.

Do rings rotate? They sure can. But some are pinned to prevent movement, and all Mfrs. have a ring stagger for initial assembly.
This indicates that they assume no movement, otherwise why bother?

 

[BuickGN]

Originally Posted By: mechtech2
A dealership is going to be a dirtier environment than a factory engine facility.
change the oil at no more than 1/2 of your normal OCI.

Do rings rotate? They sure can. But some are pinned to prevent movement, and all Mfrs. have a ring stagger for initial assembly.
This indicates that they assume no movement, otherwise why bother?


To eliminate the possibility of the rings lining up at initial startup. Mine always go in staggered and come out random. What manufacturer pins the rings?

 

[BuickGN]

Originally Posted By: StevieC
Originally Posted By: BuickGN
Originally Posted By: StevieC
Originally Posted By: BuickGN
No one is going to drop a pan full of oil. Rest assured the oil is new. Did they reuse the rings and only replace the pistons? If they did that, there's technically no break-in but I would change it out now just to get rid of any junk which may have gotten in there from the engine being open and then go back to whatever OCI you were running before.
There would be break-in if the rings weren't put on the same pistons in the exact same spot as when it came out.

Also the pistons could have been a slightly different size also altering the pressures of the rings against the cylinder walls...



Ring lands are machined and tolerances are very tight. That's really a non issue.

No mechanic worth their salt would put used rings in a different cylinder than they came out of. They continually rotate so that's not an issue.
Originally Posted By: hounddog
I don't think rings rotate.Thats why there is a stagger procedure.I have worked with several auto manufactures booking warranty procedures.All the ones I have worked with on major engine repair always covered oil and oil filter with no issues/claim kick back.


I wouldn't put it past Dealerships to reuse old rings. I have seen a few engines that had to have parts replaced by dealers while under warranty only to be rebuilt later on after warranty because they had reused things that should have been replaced.

But assuming they didn't then there would be break-in as the new rings wear into place with the cylinder walls and neither the ring or the wall is 100% perfectly matched/round.

As for ring movement, they will move slightly over the course of their life from engine vibration but hounddog is right, they are offset on purpose when put in to stop blowby and oil consumption and generally stay the way they are put in +/- a few millimeters over the course of their life. They move more in the beginning until seated with the walls of the cylinders.



Of course, if you have a new ring and a fresh hone, it's going to be a normal breakin procedure. In my engines, the rings do rotate. I set them up exactly the same and they come out completely random. I have no idea if they rotated a couple inches or did complete rotations.

One more thing, it seems like the oil control rings come out in the same place as they went in.

 

[StevieC]

That's interesting because in all the engines we have rebuilt the rings come out almost always the same way they went in. We index them all the same way usually all the time.

I guess it is possible that they moved inside the cylinders but whats the chances they all went back to more/less the way they went in. Slim I'm guessing.

Japanese engines seem to move more than American engines from what I have seen... Whatever the reason is...

Generally if the gaps in the ring all line up in the same spot usually indicates that the piston or cylinder isn't perfectly round or has a weaker/worn area that the rings have found. I have seen this only twice though and have watched/helped my dad with a ton of engines.