Engine/Transmission (1994 - 1998) Head Removed for Headgasket repair, cylinder pics

[Bobcat698]

Lets hear some opinions please. Truck has 203k miles



Travis G (TDR member) helped me pull the head off on Saturday after I found my coolant had turned black Thursday :{



Here are some pictures of the cylinders and a picture of Cylinder #6 that has me and Travis a bit concerned.



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Consensus is scored cylinder... Which I cannot do anything about right now $$ constraints. . (Just spent ~$8000 on turbo, injectors and a transmission on a truck that I still owe $$ on :-laf )



I plan on getting the head o-ringed and throwing it back and and hoping for the best.



Here is something I plan to do though. It is my understanding that on the larger trucks equipped with the 5. 9L Cummins, a coolant line is connected at the back of the block (where a freeze plug is placed on Ram pickups) that runs back to the radiator, making the cooling system a flow-through system rather than dead-ending at the back of the motor, therefore keeping the rear cylinders cooler. I plan on buying the kit from Cummins and installing it while I have it torn apart.

Has anyone done this?



Let me know what you think.

 

[Bobcat698]

To clarify, the 3rd & 4th picture are of #6, the 2nd picture is of #2.



Someone suggested to me to drop the #6 piston to the bottom, put a rag over the piston, and lightly hone the cylinder to see if I can clear it up a bit. .

Any opinions on that?

 

[JoshPeters]

I think I'd leave it or pull it and do it right. To hone the cylinder and leave the slug in there your going to taper the cylinder a little. The rings and piston have matching grooves in them. Your better off leaving them be till it becomes more of an issue.



Josh

 

[mhuggler]

I wouldn't wait for it to get worse. Right now you could pull the pistons and hone out the cyls. (you can usually take about . 005" and still be in spec. ) Replace the pistons/rings and your ready to go again. Remember, these are parent bore blocks. If it gets worse(it will very quickly) you'll be pulling the motor to have it bored . 020" or fitted for a repair sleeve!

 

[Headshot zod]

That coolant kit sounds interesting. What part number and what might it cost?

 

[CumminsPower98]

That doesn't look good at all and the piston likely looks worse. It might be the first signs of a plugged piston cooling jet. I sure do understand the no money to fix it right part though but I would be hard pressed to put something looking like that back together. Is that a Fram filter I see on there? That could be your downfall right there... Something to think about.

 

[Vaughn MacKenzie]

Interesting pics Bobcat. I had the head off of mine at 386,600 miles and most of my cylinders had some fine vertical scratches, but nothing like what you have (at least on #6). I came to the conclusion that hard carbon buildup on the side of the top of the piston breaks off and gets caught by the top ring and grinds ).



Do you think it's excessive heat causing the scoring? Maybe you ran it to the limit once and were a heartbeat away from meltdown.



I noticed cylinder #6 on mine had the most wear. Still had hone marks on all cylinders but #6 were pretty well worn away. Here's a pic of cyl #4 and #6. The difference isn't as significant as the pics make it look, probably lighting angles. Incase anyone is wondering I think the pitting on #4 was from coolant, but it was very light.



Vaughn

 

[Gary - K7GLD]

I've not seen detailed pics of the piston/wristpin area of our engines, but wonder if what Bobcat has is somehow related to a wristpin or button that is being worked into the cylinder wall - those wear marks look pretty well outlined and defined to be from a random or variable source.

 

[Bobcat698]

Interesting pics Bobcat. I had the head off of mine at 386,600 miles and most of my cylinders had some fine vertical scratches, but nothing like what you have (at least on #6). I came to the conclusion that hard carbon buildup on the side of the top of the piston breaks off and gets caught by the top ring and grinds ).



Do you think it's excessive heat causing the scoring? Maybe you ran it to the limit once and were a heartbeat away from meltdown.



Vaughn

Thanks for the pics and input.



I've heard a few theories:

1: high coolant temperature combined with high power

2: high egts causing cylinder "scuffing"

and a few others so far.



I'm sure I've ran it to the limit more than a few times. . I used to hit 1800 degrees daily. .

Sure looks like I'll be paying to play! :-laf



I'm curious when this might have happened. . Theres no telling really... It could have happened before I even got the truck!

I know when I did an oil analysis at 195k miles all the wear metals looked fine. I'm almost at 203k now and I don't think I've done this kind of damage in the last 2 weeks with my new injectors and turbo.



Its never used a lot of oil and the engine has given no indication whatsoever that this damage was present. . (no oil usage other than what it leaks from the vacumn pump). .

Who knows!

 

[The patriot]

If it were mine, I'd button it back up with new gaskets and start saving for a new shortblock. I find it suprising that the crosshatch pattern is still in the cylinders.

I actually dont think anything will happen that soon but then again I dont run mine that hard either.

 

[JGheen]

I'm with the Patriot on this one. You can definately still see the crosshatch so that is a good sign. I would just make sure you keep everything real clean... ... brake clean and scrape the block deck real good... . use a vacuum cleaner very frequently in the cylinders and for everything you scrape off. Wipe the cylinder down with some WD-40 or oil and roll it over a couple times. If you feel any resistance, obvisouly stop but I think your fine. I was worried about my #6 on my recent HG swap with the rust ridge that formed from the coolant in the cylinder and after cleaning everything real well, put it all back together, engine is running fine and oil is very clean.

If you want to replace it anyway, a piston and new sleeve aren't that expensive, it's just very time consuming to get one changed out IMO.



Joe

 

[Berrigan]

I've not seen detailed pics of the piston/wristpin area of our engines, but wonder if what Bobcat has is somehow related to a wristpin or button that is being worked into the cylinder wall - those wear marks look pretty well outlined and defined to be from a random or variable source.

Gary that was my thought also, hard to tell from the pics but is all the scuffing on the front and backs of the cylinder walls (in line with wrist pins)? Bill

 

[biggy238]

a piston and new sleeve aren't that expensive

It's expensive to sleeve a parent block...

 

[Jim Fulmer]

Bobcat, that scuffing is from high EGT's..... been there done that! When I pulled my head the first time back in 02' I had the same thing then I put it back together as is and put another 40K of very hard miles on it. When I pull the motor for the short block change last year the scuffing was almost gone from wear.



This is type of wear is normal to me when running that type of temps but it's your call.



Jim

 

[JoshPeters]

I'm with Jim. I think just put it back together, clean up all the other surfaces properly and you'll be fine.



Josh

 

[24valver]

What is a parent block? I know it isn't bad to change a piston/sleeve assembly in a Deere diesel. Sorry for the dumb question.

 

[JoshPeters]

What is a parent block? I know it isn't bad to change a piston/sleeve assembly in a Deere diesel. Sorry for the dumb question.

The best way I was explained it was... . a throw away block. It's not designed to have sleeves. Our little Cummins don't have sleeves. It's like a..... (dare I say it) 350 Chevy. The bore is cast with the block, then actually bored to tollerance. Unforuntaly it's not as easy as a "big" diesel where you can just throw in new sleeve/piston assemblies.



Josh

 

[24valver]

Thanks Josh for clearing that up. I thought that that was what it meant, but wasn't sure.

Jim

 

[w-cummins]

Cummins makes a sleeve for the B motors. It's a dry sleeve and made to repair the block back to the stock bore dia. When I rebuilt my first one back in 1990 they had only metric over bores (cummins parts ) I don't know if some one makes inch over bores. The cummins stuff was 0. 5 mm and 1. 0 mm over I did mine 0. 5 over

William Cummins.

 

[mhuggler]

Cummins makes a sleeve for the B motors. It's a dry sleeve and made to repair the block back to the stock bore dia. When I rebuilt my first one back in 1990 they had only metric over bores (cummins parts ) I don't know if some one makes inch over bores. The cummins stuff was 0. 5 mm and 1. 0 mm over I did mine 0. 5 over



William Cummins.

The block has to be stripped and the cyls. bored out to do this. Mega $$$$ if your the one paying for it. I've done dozens of them when I worked in the machine shop. Also, I'd like to reiterate that I don't recommend running it as is. Once a piston starts scuffing, it goes quick!