Burning oil after new head install

[IrishKW]

Need some input on why I would go to burning 1 gallon of oil every 3500 miles after a new head was installed.

2007 CM870 8520cpl

Took to a local shop because I had a miss and was pushing a little antifreeze out of the cap, passed a cutout test so they pulled the injectors told me there thinking was bad o-rings. Injector cups were leaking antifreeze, so they installed a Cummins reman head, plus new cams and rocker arms. It had a oil leak on the front cover before and only used a half a gallon of oil in 18,000 miles. As soon as I got it back it was burning oil, you can smell it in the exhaust. Now that shop wants to charge me to diagnose the problem and said no warranty on labor only parts. It took them over 50 hours of labor last time plus I was down for 3 weeks. I told them I can't afford for them to work on my truck! And they never did find my miss, I found it myself with a injector leak test I learned on this forum.

Wish I would have found this forum before I bought this truck, I have ran b model cats the last 20 years and always did my own mechanical work, even rebuilt injection pumps. Probably would still be running them but the company I'm with wanted me to go to a elog compatible truck. Found a 2007 T600 set up like I needed supposed to only have 200k on overhaul and transmission and price was right, thought I'd give Cummins a try.

I checked the turbo, no oil on either side. Can oil get in through an injector? Could a valve guide seal possible be defective on a new reman head? Going to start taking it apart to replace the injector. Just needing input on what I should be looking for.

Thanks for this forum, I'm learning a lot about these red motors, for a while I thought maybe I just needed to get some yellow paint :confuse:

[JMBT]

I think you may be onto something with that yellow paint idea!! My brother still runs an old 2WS Cat, and has no where near the crap I have with this POS Cummins! In my opinion the last good motor Cummins made was the N14, but rest assured you are far better off with your 871, then those of us suckers who have 2250's and 2350's.

With my limited knowledge, I would say oil could get past an injector O'ring if they nicked or damaged it when they installed it. But since the fuel pressure is higher then the oil pressure I would suspect fuel in the oil would be a more likely result.

As far as the valve guide seals, if they are made like the updated ones I just put on my 2250, I cant see alot that could go wrong as long as they lubed them good before they installed them. If they are the same style as mine, the spring actually holds the seal down to the guide, instead of the seal just being pressed onto the top of the guide.

Did they touch anything on the bottom end at all?? pistons, rings, liners???

Good job eliminating the turbo. That only leaves worn rings and liners as a culprit. Could the shop have done anything when removing and replacing the head to cause damage to the rings or liners??? Like, knocking loose soot, carbon, or dirt onto the tops of the pistons and not cleaning it off before reinstalling the head. Thus allowing it to score the liner walls or damage the rings on startup..?? I am just spitballing here man, so take it with a grain of salt.

The only other thing that comes to mind is I have heard many of the gurus on this forum strongly discourage using a reman head on these motors.

[Rawze]

Does it have a lot of b lo-by too when you pull off the oil fill cap?

have you checked for oil in the air system?

Is it smoking badly?


Did they do any bottom end work like replace rod/main bearings?

[IrishKW]

It has a little blow-by, nothing more than when I took it in.
I saw the liners when they had it apart, still had good crosshatch in them.
No oil in the air system.
It has a little smoke you can see idling if you are looking at it in bright light, it kind of puffs not a even flow.
No smoke when under power.
If you get downwind when it's idling you can really smell the oil, doesn't smell like diesel.
They pulled the pan and checked it over, but didn't do bearings.
They put a new gear fuel pump on also, but I wouldn't think that would have anything to do with my oil consumption.

[IrishKW]

I pulled the valve cover and see these supposed to be new rocker arms, they told me they changed them all but the Jake. Don't look to good to me for only 18,000 miles​.   

I ran the bubble test again to make sure what injector was bad, I necked down the tube as in Rawze's video, that works very well. Both 1&2 put out a lot of bubbles, 3 had just a few, none on 4 thru 6. Pulled 1&2 debating on whether or not to do 3.

Took a light a looked in down the cups, #1 looks like it is grianey on top almost like sand, 2 looks nice and smooth. This picture is of #1   

The injectors I pulled are 4088725, according to quickserve my CPL calls for 4088665. Do I need to change them all to what the CPL calls ​for? Or just get a couple like I have?

I haven't made any discovery to the cause of my oil usage yet.
I'll pull the exhaust manifold to see if I can see any oil this weekend if I get time

[dhirocz]

U sure it's using the oil and not leaking it? I caught a leak out of the rear cam cover before...

Might have a stuck ring since the head was off?

Other than that, I'm curious if it's blowing out the exhaust.

[IrishKW]

(01-30-2018 )dhirocz Wrote:  U sure it's using the oil and not leaking it? I caught a leak out of the rear cam cover before...
No oil residue anywhere on the truck, that much oil would make quite a mess.

Might have a stuck ring since the head was off?
That might be the reality of it(hopefully not!) Kind of odd it didn't use any before and went to using as soon as I got it out of the shop.

Other than that, I'm curious if it's blowing out the exhaust.

I pump off alot of loads and can really smell it if I'm downwind, even see a light haze looking through the exhaust into a bright light.

[Rawze]

(01-30-2018 )IrishKW Wrote:  ...
Took a light a looked in down the cups, #1 looks like it is grianey on top almost like sand,
...

Hardened "sand" on the piston crown is known as "fuel impingement'. - Its most basic explanation is that liquid fuel (or additives) is allowed to stay in the cylinder in liquid form long enough to settle / sweat (or drip from a leaking injector) onto the metal surfaces instead of staying in an atomized form. It is more complicated than that but that is the basic premise.

It can be caused by a lot of different things including a leaky injector, bad spray pattern, actuator issues, injection timing issues, bad fuel, using fuel additives, etc. etc.

If it is on only one or 2 pistons, then it is most likely an injector issue. If it is in all pistons, then it could be someone using fuel additives, it can be injection timing problems on a bad delete (very common), cam slippage, or other issues.

It can also be a coolant issue, where a leaky injector cup allows coolant to drip down onto the piston crown too... but this is usually accompanied by accelerated wear to the liner cross-hatching.

A tiny bit of impingement here or there on the edge of the pistons over time is almost to be expected as an engine gets a lot of miles on it due to cold starts, etc. - It is the nature of them, but it does not take very much of an issue at all to cause rapid problems within the newest engines. They are significantly more sensitive to impingement problems.

====


This picture almost looks like someone dripped liquid metal down onto the the piston directly below the injector. This is a fine example of fuel impingement buildup due to a leaky injector...
   

-- Obviously, that injector is bad and needs replacing, regardless if it checks out ok otherwise.

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And here is one that had impingement problems due to too far advanced injection timing programmed into the engine (a bad delete program). In this case, ALL 6 CYLINDERS looked similar to this and this CM2350 engine was programmed to run about at more than +5 to +9 BTDC (before top dead center) in the mid-rpm band at its highest torque/fueling output. It also had as much as +11 degrees in its lower fueling regions, using EGR+timing settings without any EGR gas avail. any more.

The piston is covered in it because the injection timing was simply too high. It is also evident in the pic that fuel over-spray was getting outside the bowl and onto the outer edge of the piston. With injection timing that high, it has time to also settle on the metal surfaces and collect into droplets before it starts to burn... resulting in fuel impingement.
   

I.E.> An equivalent description of fuel impingement = When you are at the super-market and you stand there with the freezer-door open, looking at all the ice-cream.. that sweat and fog on the inside of the door building up is moisture Impingement. - Same thing happens inside a cylinder on the piston and other metal surfaces, if the temperatures are not right, or if the fuel is allowed to mix for too long.

===
Fuel impingement buildup itself causes many secondary problems. As deposits build up, it increases the compression ratio of the cylinder(s) significantly.

With a high compression engines like a 2350 (18.9:1)or X15 (19+:1), it does not take very much of it to cause the combustion ratio to get so high that it eventually causes a head gasket and other failures.

Another common problem that fuel impingement causes is accelerated valve seat wear. The fuel impingement that gets into the valve seats, eating them up. Eventually the valves recess into the head so far that they can no longer be adjusted. That or a valve breaks off/cracks due to the vavle-seat area being worn out so thin. The result often destroys the entire engine when a piston strikes the broken/cracked valve.

- Again, this is extremely common in bad delete programming where some fool incorrectly decided that the "Alpha1, EGR+mapping" factory injection timing was ok to use after the EGR has been plate off. - This is an improper assumption and a BIG BIG MISTAKE on the part of the moron who made the program.

last but not least,.. the more modern an engine is, the more difficult it is to control and keep fuel impingement at bay ion the combustion chamber. This is due to both higher compression ratios and due to newer injection strategies and designs, where the fuel is more atomized, much higher pressure are sued, and the fuel becomes more volatile as a result.
(more on these injection strategies): http://rawze.com/forums/showthread.php?t...8#pid15548

Tags:

fuel problem, fuel impingement, crud on cylinders, sand on cylinders, bad injectors, timing issues

[IrishKW]

That's good information!

Never heard of that before.
The knowledge on this forum is amazing!