Piston rings not seating

[PureHybrid]

I was really hoping to open this thread and see some sort of resolution with the shop. But it seems we are still beating this dead horse.

While we're at it, I'll add some useless info to the blow by debacle. Increasing bore size also increases static CR (all else being equal)

 

[715Hunter]

Wow, tough group. I think it is established his rings are not sealing. Compression is low, blowby is excessive.
On tear down I would want a neutral seat of eyes to see what his piston to wall clearance is. What are the ring gaps. What does the cylinder finish look like. Verify cross hatch is at the 45* angle as stated. Sharper angles make the rings spin fast in the bore. Flatter angles slow the ring spin down. Rings always spin while operating, the spin is created by the cross hatch. It helps the rings seal.

West, I've appreciated the info even where it's not 100% relevant, as I work on all our trucks from light to heavy duty. Engine internals are the one area I've had little experience so I'm enjoying learning.

 

[715Hunter]

I brought the truck to their shop today, and as expected, they aren't willing to pay for any parts if there's an issue. The builder/owner hemmed and hawed for awhile, and I could tell he was surprised (presumably he thought I was exaggerating over the phone). I agreed to switch to Driven DBR for the next 2,000 miles, as I don't have time to tear it apart now anyhow.
If that does not improve it any I'm taking the short block back to them and they are fixing it. I would really like to be there when they pull it apart, to see ring gaps and cylinder wall condition for myself, but I don't know if I'll be able to. If it comes back apart, it will get different rings. Can't remember the brand, but it's something top-shelf. And we'll have argue about who pays for the extra machine work, dis- and re-assembly, and all the wasted oil.

 

[715Hunter]

I was really hoping to open this thread and see some sort of resolution with the shop. But it seems we are still beating this dead horse.

While we're at it, I'll add some useless info to the blow by debacle. Increasing bore size also increases static CR (all else being equal)

It might be a month or so till I have answers. This truck was out of service for eight months the first time, as I did not have time to get it back together. Hopefully the second round will be quicker.

 

[Bdsankey]

I brought the truck to their shop today, and as expected, they aren't willing to pay for any parts if there's an issue. The builder/owner hemmed and hawed for awhile, and I could tell he was surprised (presumably he thought I was exaggerating over the phone). I agreed to switch to Driven DBR for the next 2,000 miles, as I don't have time to tear it apart now anyhow.
If that does not improve it any I'm taking the short block back to them and they are fixing it. I would really like to be there when they pull it apart, to see ring gaps and cylinder wall condition for myself, but I don't know if I'll be able to. If it comes back apart, it will get different rings. Can't remember the brand, but it's something top-shelf. And we'll have argue about who pays for the extra machine work, dis- and re-assembly, and all the wasted oil.

To be clear, the Mahle ring pack is perfectly fine. There really is nothing wrong with it in terms of quality, your issue is stemming from either poor machine work, poor assembly, or piss poor luck (maybe some of all 3?).

You will be able to see the cyl walls yourself when you have it torn down to a short block.

 

[2004LB7]

I'm wondering how this recommended oil is supposed to fix your engine. no break in oil can re-hone a cylinder or fix ring gaps, etc. will this much blow by reduce compression that much?

what will the shop do if the engine doesn't make it the 2k miles?

 

[715Hunter]

To be clear, the Mahle ring pack is perfectly fine. There really is nothing wrong with it in terms of quality, your issue is stemming from either poor machine work, poor assembly, or piss poor luck (maybe some of all 3?).

You will be able to see the cyl walls yourself when you have it torn down to a short block.

I think that's about right. And true, didn't think about the last part.

Also, I went digging and found a couple pics of the short block. Can't really tell much from them though.

 

[Fingers]

From the pics, it looks like the cylinder finish is too fine. But that is just a guess.

To verify the blow-by, use your compression tester kit to pressurize the cylinder with air and listen for blow-by with the piston at TDC and the valves closed. You only need 10-15 PSI.

Keep in mind that the chambers at TCD are only ~40cc. So the length (volume) of your compression tester hose has a tremendous impact on your reading.

As stated earlier, 0.004" in piston to head clearance is about a quarter of a point in compression.

 

[danzick]

any update on this?

 

[715Hunter]

Finally had a couple days to pull this thing apart on get a good look at it. Pictures below. There's no wall glazing, which surprises me. But tons of half-burned oil above the first ring and a bit between the first and second rings, as well as some weird deposits on top. I pulled one cylinder to check gap before sending it back to the shop. 1st ring was .016" and second is .022".

 

[Chevy1925]

Hard to tell in the pic but kinda looks like the second ring is upside down. It’s direction is very important to oil control.

Also, in that pic of the piston, we’re you squeezing the top ring at all or was that completely relaxed?

At any rate, it’s extremely clear there is no oil control on the cylinder walls. Could you feel the home marks with a finger or nail?

 

[PureHybrid]

Measure and document everything. Take pictures of the direction of the rings when you remove them

 

[715Hunter]

Hard to tell in the pic but kinda looks like the second ring is upside down. It’s direction is very important to oil control.

Also, in that pic of the piston, we’re you squeezing the top ring at all or was that completely relaxed?

At any rate, it’s extremely clear there is no oil control on the cylinder walls. Could you feel the home marks with a finger or nail?

One side is marked up, and it was facing up. However, it's a square ring and the bevel was up. I believe it should be down on the second ring. The first ring is a keystone so doesn't matter.

The rings are completely relaxed in the picture. Edit: I forgot which picture this was. The ring is compressed some here, probably about 1/3.

And yes, the honing actually feels pretty good. I don't have much experience to go on, but it was rougher than I expected. I wish I had the tools to check it accurately.

 

[715Hunter]

Measure and document everything. Take pictures of the direction of the rings when you remove them

I'm not doing a full tear-down. The shop agreed to tear down, change rings and re-hone if necessary, and re-assemble, for little more than cost of parts. Which is pretty fair in my opinion.
Edit: unless this is their screw-up. Then it's a gyp.

 

[PureHybrid]

I'm not doing a full tear-down. The shop agreed to tear down, change rings and re-hone if necessary, and re-assemble, for little more than cost of parts. Which is pretty fair in my opinion.
Edit: unless this is their screw-up. Then it's a gyp.

Well that's good news.

I agree on the second ring, if the bevel is on the ID it should go down. I would still look at the top ring for an orientation mark, it might look symmetrical but may not be. Some keystones still have an undercut on the ID

 

[Chevy1925]

One side is marked up, and it was facing up. However, it's a square ring and the bevel was up. I believe it should be down on the second ring. The first ring is a keystone so doesn't matter.

The rings are completely relaxed in the picture. Edit: I forgot which picture this was. The ring is compressed some here, probably about 1/3.

And yes, the honing actually feels pretty good. I don't have much experience to go on, but it was rougher than I expected. I wish I had the tools to check it accurately.

Yup, sounds like they installed them wrong. Bevel should be down

 

[715Hunter]

I'll send some better pics of the rings tomorrow.

 

[Fingers]

Is the backer spring installed on the bottom ring?

 

[danzick]

was this thing burning oil? or just the bad blowby? glad you seemed to have figured it out and it seems like a fairly simple fix

 

[715Hunter]

was this thing burning oil? or just the bad blowby? glad you seemed to have figured it out and it seems like a fairly simple fix

It was burning some, but I did 4 oil changes in 5,000 miles so it's hard to tell.