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Piston Rings Worn Out, Time for a Rebuild

rustystud

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I suppose these are the piston/sleeve kits in question, and that they all came in their original box, all nicely wrapped and still sealed in plastic?

Of course I could go and open all of mine and measure, but I know beforehand what the results will be...
Still, for peace of mind I might check the only one I had cut open so far, to take those pics.

It's hard to believe that all 6 of the OP's pistons/rings were too small. Or that no-one else has reported similar symptoms like low compression and excess blow-by, if these kits were somehow problematic.



G.
So you have never seen any problems from a manufacturer ? If there is a "run" that got messed up then Yes it is possible. I'm just throwing out possibilities, and until this engine is disassembled we will not know. But you should always check your parts because you never know unless your Gerhard ! :wink:


I forgot to mention all the "factory" recalls of literally hundreds of thousands of defective parts from ALL the auto manufacturers. If you want to believe just because the part is Nicely wrapped that it is OK well then I have some property in Iraq that is a real bargain right now !
 
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74M35A2

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The distance from the king pin to the top of the piston was the same.

King pin? It's not a front axle Jerry. Piston pin to piston top is compression height.

Also, these were not an overhaul kit, they were individual cylinder kits. One of the first 6 we're not the same as the other 5, so they sent an additional that matched the 5.

We need to get solid compression and leak down data on all 6 cylinders. Also inspect where the air is escaping to during the leak check (intake, exhaust, crankcase, other). We did pressure test the coolant system to 7psi (cap rating) and held it for several minutes. I think he said 340psi compression on few cylinders he checked, but it should be nearly 400psi?

I believe the cylinder head gasket fire ring should seal against the cylinder top rim, so pressure could not leak down the outside of the cylinder.

The replacement pistons had one less ring than the originals. Both heads are NOS also with the rebuild.

Sprayed the head gaskets with copper Permatex head gasket spray because when he did the head gaskets just a couple of years ago, it was already pouring oil down both sides of the block at the fire deck joint. Some people are for/against this, but how to stop it from leaking like it was?
 
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rustystud

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Where the rings ever checked for proper "ring gap" before installation ? I know these where sold as piston and liner "kits" and you would assume they where mated to each liner, but did you actually check them ? If they where too long they could break when heated up during operation.
 
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74M35A2

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Understood and agreed. No, we did not measure ring end gap. The kits were shipped with the rings installed and the piston in the liner. Assumed to be field-install-ready. Now easy to say geez, we should have checked every single aspect. We'll make it right. I think by spending time on a detailed leak down check, it will pin point the suspect area.
 

cranetruck

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I believe LDS-465-2 Pistons are 5 rings. Cranetruck posted something back a long time ago showing them.

It has about as much blow by as it did before I rebuilt it... more than any other deuces I have seen, especially since I rebuilt the thing. :cry:
lds-2 piston rings.jpg

Yes, the LDS465-2 pistons feature 5 rings.
The engine is built for slightly higher rpm (max 3,100 or so) than the earlier multifulers. The automatic shifts at 2850 rpm.
 

rustystud

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Understood and agreed. No, we did not measure ring end gap. The kits were shipped with the rings installed and the piston in the liner. Assumed to be field-install-ready. Now easy to say geez, we should have checked every single aspect. We'll make it right. I think by spending time on a detailed leak down check, it will pin point the suspect area.
Yeah I know it sucks but it looks like the engine has to come apart. There is just no way to know what really happened without a complete teardown. aua
 

frank8003

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post 176 are you reading his posts?
Post 178 measure the crankcase pressure
post 196 combustion gas bypassing the liner
post 200 0.125 width of metal to metal seal liner land

I follow the combustion gas paths and seals against wherever it is not supposed to go.
I can't help him "fix" the engine although I would just clean off the clutch and call it done and drive it.

The following attached is just the food for thought, it has to do with all engines with liners especially high compression diesels and "blown engines" and has to do with head lift..

View attachment liner sleeve diesel metal to metal.pdf





post 202
I believe the cylinder head gasket fire ring should seal against the cylinder top rim, so pressure could not leak down the outside of the cylinder.



a

 
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74M35A2

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View attachment 599815Yes, the LDS465-2 pistons feature 5 rings.The engine is built for slightly higher rpm (max 3,100 or so) than the earlier multifulers. The automatic shifts at 2850 rpm.
Interesting. The pistons he purchased did not have a ring pack like that. They had even less rings than the ones he took out. I think these pistons he bought were prototypes and not supposed to go into the market. Maybe from this point his best bet would be to measure the new liners vs old, and try to use the new liners with a fresh hone on them, and with his old pistons with new rings spun onto them.
 

JasonS

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Interesting. The pistons he purchased did not have a ring pack like that. They had even less rings than the ones he took out. I think these pistons he bought were prototypes and not supposed to go into the market. Maybe from this point his best bet would be to measure the new liners vs old, and try to use the new liners with a fresh hone on them, and with his old pistons with new rings spun onto them.
The D4800 and D5000 engines had three rings.
 

Wildchild467

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No way; not for the -465-family of Multifuels at least: the liner has a 4.75" O.D. with a 1/8" protruding rim (5.0" O.D.) which fits into a recess in the block, and sitting exactly flush with the deck surface.
Either the modern 1pc-head-gaskets - or the fire rings, for the older style HGs - keep the liners firmly pressed down in place- and sealed, of course.

G.
Do you think using permatex copper spray gasket sealer on the head gasket would cause it to leak? When I put head gaskets on it the first time, I put them on dry. I don't know if the spray gasket sealer messed something up or not?
 

gringeltaube

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No, I don't think it would make a difference. And even if there still was a minor leak somewhere, this would not explain the consistent, low compression and increased blow-by, on all 6 cylinders.



G.
 

74M35A2

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It was my decision to use the Permatex copper head gasket spray adhesive. Before he tore his heads off, there was black motor oil running down the sides of the block at the head gasket joint, so it was an attempt by me to get an old engine to seal better. I did not know at that time that he did not re-torque the head gaskets when he replaced them prior. I did several coats on both sides of the gasket and let them dry, then did a final coat and installed them wet to really try and glue it together. He did re-torque the heads after a small amount of driving this time. I also don't think the copper spray hurt, as it is not leaking oil down the outside now at the head to block junction, like it was, or at least that part was resolved. I still suspect the pistons/rings he installed. The pistons were so bright and shiny they almost looked like chrome. They seemed spun off a lathe, and not just cast, which tells me they may have been prototypes that were supposed to be in the dumpster, not sold. 1 of the 6 they sent did not match at first. All of them have 1 or 2 less rings than what manuals show for most of this engine in the majority of its applications. They have 3 rings, none at the base, and manuals show 4 or 5 rings, with one even having a ring below the wrist pin. His pistons just have 3 rings, all above the wrist pin, and one is the oil control ring, plus 2 compression rings, same as a gasoline engine (350 Chev for example). I don't think (?) that is enough to hold back diesel engine compression and combustion pressure. He also does not know his boost level. He has the fuel screw turned up and does not over-temp it via an EGT, but he is running a 15psi boost gauge that quickly gets pegged when he lays into it. That means, nobody knows how much boost he is running on an engine which was designed for not more than a few psi, like 5 or so, just to clear up the exhaust. His old pistons had cracked rings on 4-5 cylinders, which should not happen even if old. These new piston rings may be cracked from too much combustion pressure (too much fuel and boost). Not sure how robust the ring packs are in these engines, but even when Ford added a turbo to their 2.3L OHC engine in the 80's, they developed different piston rings for it. I hope it is just the copper spray, as that is an easy fix. I think at this point, he should measure the new liners, use them if in spec, and re-ring his old pistons.
 

74M35A2

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Sorry, paragraph formatting/spacing does not work anymore, not sure why. Now it just all gets jammed together when saved as a post. Looks proper in draft. Ugh....what's wrong with this?
 

rustystud

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Sorry, paragraph formatting/spacing does not work anymore, not sure why. Now it just all gets jammed together when saved as a post. Looks proper in draft. Ugh....what's wrong with this?
There is something screwy going on here on the whole site. Pictures won't up-load, formatting not working. Seems like the site has a "bug" !
 

rustystud

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It was my decision to use the Permatex copper head gasket spray adhesive. Before he tore his heads off, there was black motor oil running down the sides of the block at the head gasket joint, so it was an attempt by me to get an old engine to seal better. I did not know at that time that he did not re-torque the head gaskets when he replaced them prior. I did several coats on both sides of the gasket and let them dry, then did a final coat and installed them wet to really try and glue it together. He did re-torque the heads after a small amount of driving this time. I also don't think the copper spray hurt, as it is not leaking oil down the outside now at the head to block junction, like it was, or at least that part was resolved. I still suspect the pistons/rings he installed. The pistons were so bright and shiny they almost looked like chrome. They seemed spun off a lathe, and not just cast, which tells me they may have been prototypes that were supposed to be in the dumpster, not sold. 1 of the 6 they sent did not match at first. All of them have 1 or 2 less rings than what manuals show for most of this engine in the majority of its applications. They have 3 rings, none at the base, and manuals show 4 or 5 rings, with one even having a ring below the wrist pin. His pistons just have 3 rings, all above the wrist pin, and one is the oil control ring, plus 2 compression rings, same as a gasoline engine (350 Chev for example). I don't think (?) that is enough to hold back diesel engine compression and combustion pressure. He also does not know his boost level. He has the fuel screw turned up and does not over-temp it via an EGT, but he is running a 15psi boost gauge that quickly gets pegged when he lays into it. That means, nobody knows how much boost he is running on an engine which was designed for not more than a few psi, like 5 or so, just to clear up the exhaust. His old pistons had cracked rings on 4-5 cylinders, which should not happen even if old. These new piston rings may be cracked from too much combustion pressure (too much fuel and boost). Not sure how robust the ring packs are in these engines, but even when Ford added a turbo to their 2.3L OHC engine in the 80's, they developed different piston rings for it. I hope it is just the copper spray, as that is an easy fix. I think at this point, he should measure the new liners, use them if in spec, and re-ring his old pistons.
I wondering about those pistons myself. To get every cylinder to have the same amount of low compression tells me there is one common denominator that is the culprit.
 

74M35A2

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I wondering about those pistons myself. To get every cylinder to have the same amount of low compression tells me there is one common denominator that is the culprit.
Me too. We checked the compression heigth from wrist pin bore to piston top, and that was the same. So, at least the low compression is not from that. Plus, that would not shoot leak down figures down the drain like they are. He just checked his lawn mower, and the leak down was like 2%......
 
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