Piston Rings Worn Out, Time for a Rebuild

[Wildchild467]

I only read a few pages... But, did you hone the liners? Did you follow the break in procedure from the TM? Did you happen to use synthetic oil for the first fill?

Sounds like your rings didnt seat!

I did not hone the liners. I read the TM and did not see anywhere where it said to do that. They were smooth and had the cross hatch and looked good. Regular Rotella T oil (white jug) and 2 new spin on filters.

I didn't have a dyno to put the engine on, so I just took it down the highway, trying to simulate the break in procedure as best I could. I didn't let it idle long after I first started it up so that the cylinders did not glaze. only ran for about 3.5 minutes to check for leaks and then I was on the road. I keep thinking about it over and over in my head and I cant think for the life of me why I would still be having blow by and only 350 PSI of compression in all 6 holes when before i rebuilt it, the highest number I got was 400 PSI (number one cylinder, see previous posts for more data). The "LDS" pistons I put in had the 2 hole squirters come with the pistons and the pistons only had 2 compression rings. The manual states LDT pistons had 3 compression rings and the LDS engines had 4 compression rings. As we all know, metals and technology has come a long way since our manuals were made, but I am thinking the cause of my problems is the pistons only having 2 compression rings. Yes, i clocked the compression rings correctly, 180 degrees apart and the oil ring 90 degrees from that.

Im beginning to think that if i was going to do this again, i would not have bought the new pistons kits and only put new rings in. I'm sure it would have been better. Besides that it still does not explain the blow by. What engineer or what engine did they test these pistons in and be satisfied with the blow by if they got the same results I did? I just want more answers to all the questions I have and its frustrating. This shouldn't be happening with all of the new parts I put in this thing.

 

[Jeepsinker]

Those pistons may be for the LDS 465-2, less rings for higher rpm. These engines always have blowby. I know that doesn't make you feel any better after all that work, but I don't know what else to tell you, unless you want to tear it back down and put your old pistons back in with new rings.

 

[Wildchild467]

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.

 

[gimpyrobb]

Did you save your old pistons and liners?

 

[rustystud]

You put the new rings on in the right orientation ? There should have been a mark on the rings showing "this side up" . The compression rings have a taper on them which allows the compressed gas to force them out creating a harder contact with the cylinder walls. Other then that, you just need to apply a load and run it hard to seat these new rings in.

 

[chestypuller1371]

sorry to hear about the bad luck

im sure you will get things worked out.

what compression gauge and fittings do you have? i want to aquire one for myself

also where did you tap into at for the mechanical oil pressure gauge?

 

[Wildchild467]

You put the new rings on in the right orientation ? There should have been a mark on the rings showing "this side up" . The compression rings have a taper on them which allows the compressed gas to force them out creating a harder contact with the cylinder walls. Other then that, you just need to apply a load and run it hard to seat these new rings in.

I never took the rings off the new pistons. I was not sure of the orientation (top of bottom, I'm not talking about clocking them). They should have been set from the factory with the correct side up. I mean why would they install them upside down? It makes no sense. I did though clock the compression rings 180 degrees apart per the TM. They were always placed far away from each other in the TM. Now, when I pulled the pistons out of the liners to lube the piston and liners with oil, not all of the compression rings were clocked the way they were supposed to be. I wanted to check them before I put them in and am glad I did.

If they did orient them upside down, it would have to be all of the pistons then because all of my compression readings are the same: about 50 PSI lower than they should be (given the highest compression test I did before rebuild was #1 cylinder coming in at 400 PSI). So whatever is wrong with low compression, it is with all of the piston/ring/cylinder assemblies. When I performed the leakdown test, I could hear air hissing out when i put my ear up to the oil fill hole on the valve cover.

 

[rustystud]

Are you still driving it ? Have you taken it out and really pushed it ? It really appears your rings are not seating properly. There is an "old" trick for seating rings. I really don't like to use it, but you can try this as your last resort before tearing down the engine again. Get a box of "Bon-Ami" cleaner ( for scrubbing countertops) . Now with the air hose off the turbo spoon out some cleaner and let the intake suck it up. About a 1/4 cup should do. The engine should be running at around 1000 rpm's . After all the cleaner is sucked up, run the engine for about 5 minutes then shut-off and drain the oil. After refilling with new oil take the truck out and give it a good hard run. The small abrasives in the cleaner acts like a small grinder on the rings helping them to reseat. This is really a last ditch effort ! Dealerships used to do this on older engines that where worn out. I should ask before you do this, are your present rings "chromed" ? If so then they will take longer to seat in.

 

[Wildchild467]

i have taken it out and driven it pretty hard. my EGT's get up there around 1150 and I dont want to go hotter. About 2000 miles and they still dont seat? That would be nuts. I would love to find somebody that put these pistons in their engine to see their results. I have thought about this day and night... lay in bed and think about it.... make a list of all the possible reasons it could be having blow by and the only thing i think of is its going past the cylinder wall/piston. If somebody else put these pistons in, i would love to talk to you, I'm out of ideas other than put rings on my old pistons and put them back in.

 

[Jeepsinker]

Maybe those two ring pistons are the old 17:1 fabled pistons? I don't know, just surmising.

 

[rustystud]

Maybe those two ring pistons are the old 17:1 fabled pistons? I don't know, just surmising.

I only heard of the 20:1 and 22:1 pistons. So you say they made a 17:1 also ? That's barely a diesel.

 

[rustystud]

i have taken it out and driven it pretty hard. my EGT's get up there around 1150 and I dont want to go hotter. About 2000 miles and they still dont seat? That would be nuts. I would love to find somebody that put these pistons in their engine to see their results. I have thought about this day and night... lay in bed and think about it.... make a list of all the possible reasons it could be having blow by and the only thing i think of is its going past the cylinder wall/piston. If somebody else put these pistons in, i would love to talk to you, I'm out of ideas other than put rings on my old pistons and put them back in.

If for some reason the rings where "chrome Moly" then you will have a hard time getting them to seat. When using chrome moly rings you need a courser honing job on the liners to help them seat. I don't know if chrome moly is even available for this engine, but if they did then that could explain the problem.

 

[rustystud]

At this point I would try and pull one piston out and see what was used for the rings. I believe you can sneak one out from the bottom. Putting it back will be a challenge though.

 

[welldigger]

I'd also check the heads for cracks.

 

[rustystud]

Did you use the "new" style head gaskets or the older design with the separate fire rings ?

 

[JasonS]

I only heard of the 20:1 and 22:1 pistons. So you say they made a 17:1 also ? That's barely a diesel.

17:1 is the tractor compression ratio. However, this wouldn't 't explain the blow-by. A cracked head wouldn't explain the consistent low compression pressure. Are you guys even reading his posts?

 

[Jeepsinker]

Yes we are, we are just surmising at this point. It really needs to be torn back down to find the problem. A cracked block could cause it, if he were losing water, but that wouldn't explain the low compression across the board.

 

[JasonS]

If the compression pressure is consistent across the board, it points to the same problem/ cause in each cylinder. Not likely to have a crack in EACH hole/ head. Also seems unlikely to have a head gasket sealing issue in EACH hole/ head. Seems most likely a systemic part issue or assembly mistake.

Before I tore it apart, I'd measure the crankcase pressure to have a quantifiable metric. If it really is too much, I agree that it probably needs to come apart to determine why.

 

[Jeepsinker]

It almost has to be the pistons, or the hone of the liners. Worn out engines have compression on par with those readings.

With new heads it couldn't be a bad valve job on every hole, and I don't see valve springs getting weak enough to cause that just from sitting on a shelf for years.

If they were reman heads with worn out guides though, it might cause a similar issue, though that would normally just cause blowby, not low compression.

 

[Wildchild467]

At this point I would try and pull one piston out and see what was used for the rings. I believe you can sneak one out from the bottom. Putting it back will be a challenge though.

They won't come out the bottom because the crankshaft is in the way and the piston oil squirters. If I pull the Pistons out its going to be about $200 right off the bat by the time I buy new head gaskets, intake/exhaust gaskets and pan gasket. That is why I am really trying to think this through and measure as much stuff like compression, leak down and cooling system pressure test. Get as much data as I can to help me find the cause of the problem.