Engine/Transmission (1994 - 1998) Dissecting an 800,000 mile engine

[GAmes]

I finally got around to partially disassembling my original engine. There is nothing that jumps out to tell me why oil consumption was so high, and it may be that all I needed was a valve job. However, it is on a stand, so I might as well rebuild it. Amazingly the crosshatch is still visible on the cylinder walls, and the is no lip at the top of the cylinder. The ring ends nearly touch, so they aren't that worn. The only major flaw I have found is the #6 piston has cracks in it

 

[ewcmr2]

Do the cracks in #6 go all the way through to the bottom side?

 

[Missouri Mule]

Sure does look like it!

 

[NIsaacs]

I doubt it, if they did the blowby would have been horrible, not to mention the cracks would have burnt into huge holes, oil would be everywhere and it would have a dead miss.



Nick

 

[BGlidewell]

very good wear for the mileage. Maintenance schedule?
Ignorant question: Do you leave the liners in when rebuilding? I think that engine has liners?

 

[Bill Stockard]

very good wear for the mileage. Maintenance schedule?

Ignorant question: Do you leave the liners in when rebuilding? I think that engine has liners?

No liners in a Cummins B series . It's a parent bore block. The next size larger C series has wet liners.



To answer your question about rebuilding with liners, the liners are replaced. New liners, pistons, and rings are in overhaul "kits". Easy and quick.



Bill

 

[The patriot]

Look DAM good and clean for 800K. Other than that one piston. :{

 

[GAmes]

Do the cracks in #6 go all the way through to the bottom side?

Without removing the connecting rod I can't say for sure. The cracks extend about 1/8 inch into the bowl, but that dome is pretty thick. After pulling the #6 it looks like my timing couldn't be much better. This is the insert from the rod. The other side and the two from the #5 are not worn to the brass.

 

[HBarlow]

Gary,

I think you got the full service life out of your original engine. A few more thousand miles under heavy load in hot summer weather might have produced a rod bearing knock and hammered out the crankshaft.

 

[GAmes]

I agree Harvey. Just another example of increased HP resulting in shorter engine life. I said a long time ago that I expected the engine to last about 750k, and that is about the time I started experiencing advanced oil consumption.



BGlidewell, my maintenance schedule is on an eraseable piece of laminated cardboard. 5000 mile oil changes (or as close as possible, sometimes 4500 sometimes as much as 6000), Fleetguard Stratopore filters almost from day 1. I use whatever oil is on sale, so I have been from Valvoline Premium Blue to Wally World Super Tech. Fleetguard fuel filters about every 15k. No fuel or oil additives other than anti-gel sometimes in the winter. Valve adjustment checks used to be every 50k, I extended that to 100. Everything else is pretty much fix it as it breaks or leaks.

 

[hsmith]

Hey Gary, Seems that the #6 difinitely runs hotter as your pics show. Wel, duh, I think I already knew that. Still don't think that was your major oil usage though. Guess I am ok for a while with only 222k on mine. LOL

 

[Mikey-KE7LBB]

I'm curious to see how the Dodge part of the deal held up to the miles??? How many transmissions, IP's, rear/front ends etc...



I had a '93 D-250 that I retired for parts at 332k after transmission #2 and rear end #2 finally gave out (mostly due to stupidity and lots of hot-rodding) and I'm currently at 326k and counting on a '92 W-350 and 35k on my '09 with very little issues so far .



I sincerely doubt that you see these kinds of threads over on PowerStrokeNation.com :-laf:-laf

 

[The patriot]

Judging from the way the cracks look, and where theyre located, I dont think they went through.

Just my laymans observation.

 

[GAmes]

I'm curious to see how the Dodge part of the deal held up to the miles??? How many transmissions, IP's, rear/front ends etc...

I lost count of broken NV4500s, the main reason I went to the G56. The injector pump has been in the shop one time for a leaking seal where the little rod sticks out the top. All that was replaced was the gasket/seal kit and the rod. Not one fuel lubed part needed replacement. That was after over 25,000 gallons of ULSD at about 780k. I put that pump on the replacement engine. One set of ball joints, two tie rod ends and a steering box at about 500k. The other two tie rod ends and other steering componants are originals. The Dana 80 got a new pair of seals around 775k and a few thousand miles later I replaced the original rear brake shoes. I have a set of front pads to put on soon. They will be the second (maybe third) replacement set.



The pic of the interior was just taken today. The stack and 5er pics were taken in Apr. I think the Dodge part has held up well.

 

[Mikey-KE7LBB]

Looks like the rest of the rig was well taken care of. Pics speak a thousand words and I can see another 200k+ is not out of reach with this one!!!

Thanks for the info!!

 

[Vaughn MacKenzie]

I was told the cylinder walls last far longer than the oil rings, but not sure if there's any truth to that. Just because the compression rings look OK may not automatically mean the oil rings aren't worn out.

Maybe your consumption was something simple like your vacuum pump pulling more air or your turbo bearing seal is going bad. Was it making blue smoke? Was there quite a bit of blowby and/or oil leaks?

The engine in my '96 is getting tired, more blowby and oil leaks. It has 454,000 on it. Quite a lot of highway miles but many miles of short trips in the winter, running around town, etc. and rarely getting plugged in its whole life.

Last time the head was off about 20k ago the hone marks on cyl #6 were completely gone, mostly gone on #5, the rest still have some hone marks. Most of my cylinders have a lot of strangle mottled-looking pitting too, noticed that when I had the head off 100k miles ago. I know that's letting gasses & oil by.

 

[GAmes]

Vaughn, when the engine was still in the truck I had a thread about oil consumption. The turbo seals are fine, and there wasn't any really visible smoke (at least, not like from the 350 in my Chev after it has sat a while). There were no external leaks and little blowby. I even tried replacing the valve seals to no avail. It is moot anyway, considering the bearing wear. This is one of the pistons and the oil ring.



BTW, I have heard the theory of the vacuum pump pressurizing the crankcase and I don't buy it. I'm not sure it would move enough air to do it in the first place, but if the vacuum system is working there is little to no air moving.



As you can see, the cylinder walls look good. I wouldn't be afraid to just hone the glaze out and replace the rings on the five good pistons plus the one I need to replace if I didn't plan to keep working the truck. I haven't decided yet how much I will do.

 

[GAmes]

I pulled a couple valves out yesterday and found that the intake valves are not straight cut. Instead of the flat angle they are concave where the valve meets the head. I'm wondering if the valves have worn to that shape or if they were made like that to increase the surface area. Just idle curiosity until I take it to the machinest.

 

[GAmes]

Shortly after I posted I answered my own question. The intake valves are cut to a 30* angle, so the valves are toast. If there is no repair for the valve seats then I'm going to need a new head too. :{

 

[hsmith]

Gary, I'm sure you can have seats installed in these heads. Smitty