Urgent: Where's my oil going?

[Piker]

Originally Posted by 3rd stage

Uhhh..... If you put new rings in an engine with a ridge such as the one noted here, the first time the piston(s) come up and over top-dead-center, you'll have an engine full of broken top rings. The reason is that the old rings' top outer corners have been worn "in" to the gradually developing ridge. New rings have a much sharper top corner, which will hit the ridge with a lot of force, breaking the top ring in every cylinder. You can't hone out a ridge of .005, especially with a ball hone. If you can "catch" your finger nail on the ridge, it's too big to hone out.

(30+ years of race engine builds plus a "whoops!" or two when trying to do a quicky re-ring at the track).
Andy

I'm with you on this one Andy... I could see maybe on an old 350 gas engine or something getting away with bores that are incorrect, but on a diesel with 17:1 compression and turbo charged on top of that, I just don't think it's worth the risk.

I don't think I explained in enough detail how bad these cylinders look.

I found a local engine machine shop that comes highly recommended by my diesel mechanic buddy. I can get the block bored and decked, and the head planed and all the valves and seats reground for $600, providing he doesn't come across something else wrong during the rebuild.

It hurts, but it's probably worth it to do it right. Gonna start saving pennies...

-cheers

[rhusak]

Originally Posted by Piker

I'm with you on this one Andy... I could see maybe on an old 350 gas engine or something getting away with bores that are incorrect, but on a diesel with 17:1 compression and turbo charged on top of that, I just don't think it's worth the risk.

I don't think I explained in enough detail how bad these cylinders look.

I found a local engine machine shop that comes highly recommended by my diesel mechanic buddy. I can get the block bored and decked, and the head planed and all the valves and seats reground for $600, providing he doesn't come across something else wrong during the rebuild.

It hurts, but it's probably worth it to do it right. Gonna start saving pennies...

-cheers

Piker..
I have been reading your posts since the start and feeling your pain.. You are absolutely right about the ridge and what it can do to rings.. Back in the "old" days (Gas Engines) we would use a ridge reamer and hone then new rings.. The cost of pistons will add considerably to your overhaul costs..
Apparently you have decided to drop the engine out.. There is a topic here somewhere that is recent about a fellow who did that I believe with a cat.. He made it sound simple.. Older fellow as well.. But it is a big job especially at home..
Did you look around for a used engine from one of the RV salvage yards? May be a lot cheaper in the long run.. Most of these coaches were running on a trip when their demise came about... Just a suggestion..
Keep the faith and good luck with this.. I for one will be watching..
Ron

[Mekanic]

Originally Posted by 3rd stage

Uhhh..... If you put new rings in an engine with a ridge such as the one noted here, the first time the piston(s) come up and over top-dead-center, you'll have an engine full of broken top rings. The reason is that the old rings' top outer corners have been worn "in" to the gradually developing ridge. New rings have a much sharper top corner, which will hit the ridge with a lot of force, breaking the top ring in every cylinder. You can't hone out a ridge of .005, especially with a ball hone. If you can "catch" your finger nail on the ridge, it's too big to hone out.

(30+ years of race engine builds plus a "whoops!" or two when trying to do a quicky re-ring at the track).
Andy

I'm sure he is going to use a ridge reamer on this project to fix that ridge sticking out.
That would be a easily fixed in 30 seconds with a reamer.
I'm sure Piker has it covered.

[Piker]

The culprit:


The damage: No need for narration... the pics speak for themselves.








This rod journal looks ok aside from the rust that I assume came about due to the rv sitting for some length of time. The bearing, however, looks like it has a flake of material missing... I assume from material in the oil getting stuck between the bearing and the crank. The other side of the journal might not be in good shape, but I can't see it, and I haven't put a set of mics on it.





And... my view from up top.



So there you have it... here's where I'm at with this thing. Still not sure it's all worth it.

-cheers

[MnTom]

I can't tell for certain, but the picture of the piston looks kind of like the EGTs were a might bit high for a while. That would also account for the scoring. So, you are looking at sending the block and head out for refreshing, 6 new pistons, set of rings and rod bearings, gaskets, and probably new head bolts (unless they didn't stretch too much) plus a turbo and the labor. That is not going to be cheap to do it the correct way........

[Mekanic]

I think you would be shocked at just how good the compression would be with with a fresh set rings and a piston or two .
Those lines you see in the walls are less then half the damage, the other damage was in the rings.

I think you will find the other side of the crank journal to look just like that side.
If a piece of grit embeds in a bearing it always leaves a mark all the way around a Crank Journal. That crank looked Very good to my eyes.

[Piker]

Originally Posted by MnTom

I can't tell for certain, but the picture of the piston looks kind of like the EGTs were a might bit high for a while. That would also account for the scoring. So, you are looking at sending the block and head out for refreshing, 6 new pistons, set of rings and rod bearings, gaskets, and probably new head bolts (unless they didn't stretch too much) plus a turbo and the labor. That is not going to be cheap to do it the correct way........

I guess it's possible that the EGT at some point got away from me... but I wouldn't say it's likely? I dunno. I've got gauges, and I watch them closely... 1250 has always been the max... measured at the #5 exhaust port in the manifold, so it picks up 5 and 6 where egt should be the hottest. I would not have thought that #3 would have scoring from high egt before #6 would. Maybe slightly high egt coupled with sand did it in... ??

I do know that the black crud you see in the pics is mostly sand, and the burnt oil is basically holding it all together. I would expect oil that has made it past the rings into the combustion area to be burnt regardless of egt? But I dunno... not a mechanic... I also know we did 6200 miles out west through the mountains and across the desert without a hiccup... and only 1 quart of oil usage in that time... and the engine got worked plenty hard, especially at high altitude where egt could easily get away from you if not careful... and never had a problem... never used any oil.

Anyways, that's all kind of a moot point now...

I was quoted $600-$1000 for boring and decking the block, planing the head, and regrinding the valves and valve seats. Rebuild parts from cummins with pistons, rings, gaskets, and bottom end bearings about $1000. I'm guessing I'll need new head bolts... probably rod and main bearing cap bolts too... add a couple hundred.

Turbo cartridge - $500.

Labor... all me... no cost except more gray hair and probably some skin off my knuckles.

I'm hoping the crank is acceptable... if not... add $$. I'm hoping all the crud in the oil didn't damage the injector pump too terribly... if not, good-night... game over. Elvis has left the building.

I dunno. Blackwater sells remanufactured engines for $3100... no turbo, no injector pump. Add $500 for turbo and probably $500 or $600 for freight and your over $4k. That's alot to put into a 20 year old RV.

Geez when you start adding things up... throwing in the towel doesn't seem like such a bad idea... We'll see. There's a part of me that want's to try honing the crap out of the bad cylinders and throw some rings in it and call it good... but I know the bore will end up being tapered. I think this will cause the rings to be constantly in flux, and i'm worried they'll fail and I'll be back inside this thing again. I just don't know.

This is such a bummer!!

-cheers

[Mekanic]

Originally Posted by Piker

......
I'm hoping the crank is acceptable... if not... add $$. I'm hoping all the crud in the oil didn't damage the injector pump too terribly... if not, good-night... game over. Elvis has left the building.

....... There's a part of me that want's to try honing the crap out of the bad cylinders and throw some rings in it and call it good... but I know the bore will end up being tapered. I think this will cause the rings to be constantly in flux, and i'm worried they'll fail and I'll be back inside this thing again. .......
-cheers

I've received cranks back from machine shops that didn't look as good as that one.

Every bore in that engine is tapered, Just like every one in my 94 5.9L is...... if you measure them. They are used engines. If they have been run they will be tapered.

Don't buy it?, think of it this way:
Take a look at a perfectly good cylinder from any used engine. The ridge at the top shows the wear. It is NOT tapered ONLY if there is a equal ridge at the bottom of the bore where the rings stop.
Makes sense, Now right?

Now that I have seen the pics I really can say, I have fixed much worse, with less parts.

[Piker]

Originally Posted by Mekanic

I've received cranks back from machine shops that didn't look as good as that one.

Every bore in that engine is tapered, Just like every one in my 94 5.9L is...... if you measure them. They are used engines. If they have been run they will bee tapered.
Now that I have seen the pics I really can say, I have fixed much worse, with less parts.

Ok... that's it... by golly I'm bringing the bore gauge home tomorrow and I'm going to hone till my little heart's content. I got nothing to lose... if I screw it up, I can always bore it .040 over.

I am worried about the ridge though... I don't think I can ridge ream cause the step doesn't go the whole way around the bore the same depth. One side is almost flush... Is there an out of round/concentricity tolerance for these bores? Maybe I can get it close enough with a hone? I just don't want to scrap a set of rings 1000 miles from home.

I'm having a hard time finding piston to wall clearance figures that aren't hearsay, but I think cummins says you can have as much as .010 per side? If that's the case, I might be able to make this work and still be in fair shape geometrically speaking. No pun intended.

Do you think that 3-stone hone in the picture will work well enough, or should I go for a 4 stone rigid micrometer hone? I'd probably have to buy one of those... I don't know anyone who has one. I tried using a ball hone once... it didn't turn out well.

Thanks everyone, for your thoughts and ideas... and for helping me think this through.

-cheers

[Papa_Jim]

Originally Posted by Piker

Ok... that's it... by golly I'm bringing the bore gauge home tomorrow and I'm going to hone till my little heart's content. I got nothing to lose... if I screw it up, I can always bore it .040 over.

I am worried about the ridge though... I don't think I can ridge ream cause the step doesn't go the whole way around the bore the same depth. One side is almost flush... Is there an out of round/concentricity tolerance for these bores? Maybe I can get it close enough with a hone? I just don't want to scrap a set of rings 1000 miles from home.

I'm having a hard time finding piston to wall clearance figures that aren't hearsay, but I think cummins says you can have as much as .010 per side? If that's the case, I might be able to make this work and still be in fair shape geometrically speaking. No pun intended.

Do you think that 3-stone hone in the picture will work well enough, or should I go for a 4 stone rigid micrometer hone? I'd probably have to buy one of those... I don't know anyone who has one. I tried using a ball hone once... it didn't turn out well.

Thanks everyone, for your thoughts and ideas... and for helping me think this through.

-cheers

I've owned and operated my own diesel engine rebuilding shop for all of my working life. I don't like bearing bad news, but you're not going to have much luck trying to home hone and ring patch this engine. There's too much dust related damage.

The bores are damaged, as are the ring grooves in the pistons. The valve stems and guides are damaged, particularly the intakes. The guides are integral, so the machine shop will have to bore and install new valve guides. So, you need new pistons, rings, valves, guides, ... anyway.

Don't buy OEM Cummins parts unless you have to, or you find the price is comparable to aftermarket parts. In my lifetime experience in diesel engines, the only difference between quality aftermarket parts and OEM parts is the name on the box. The largest purchasers of overseas parts are the OEM parts providers. Your machine shop could be your best guide on this. What parts would they supply you?

Make sure you have the engine model and CPL # when you're talking parts.

The metal flake on the bearing. I've seen that kind of damage on bearings in engines that sit a lot with old oil in them.

It's tough to make a decision. I know the motor home is old enough that its value doesn't warrant this kind of expense. On the other hand, I don't think the motor home can be replaced for this amount of money.

Jim

[Piker]

Originally Posted by Papa_Jim

I've owned and operated my own diesel engine rebuilding shop for all of my working life. I don't like bearing bad news, but you're not going to have much luck trying to home hone and ring patch this engine. There's too much dust related damage.

Jim

Deep down, this is what my gut is telling me too.

[topdownman]

In looking at the pictures, it appears this was all caused by a failed air filter? Am I correct? How long was that filter on the rig?

[PushedAround]

Piker, sorry for your problems but this is a fascinating discussion. I see you vacillating back & forth. How many times are we presented with tough decisions like this? Maybe looking a little deeper into some problem areas and doing a little initial work will allow you to make a better, more informed decision. You did say that the motor was running great until it started gulping oil. Perhaps you should take a good look at the head and valve guides to see if they are still in acceptable condition. Also try to hone out cylinder #3 to see if you can get rid of the ridges. Both would not cost very much at all except for labor & the outcome could make your decision a lot easier.

[Piker]

Originally Posted by topdownman

In looking at the pictures, it appears this was all caused by a failed air filter? Am I correct? How long was that filter on the rig?

Air filter was new 1 year ago... about 10,000 miles on it.


-cheers