Cummins 480 CE 6CTA. White smoke and knocking

[JJM]

Hey guys need some input. Think I have an idea what’s up but would like to bounce it off Tony and the other guys. So today driving home cruising one motor starts stumbling a bit , I start backing down to check what’s up and it stumbled right Down and shut off before I was able to. I changed Racor filter and re primed and after a lot of repriming finally got it to re fire. Motor now runs but has a top end knock and is pushing white smoke.I’m leaking towards the idea it is a stuck injector. But not 100%. Is surely hope it’s not the motor . Stuck going back on one motor

Topic

[JJM]

Update

Tony ,

Did some more looking around and measuring some tolerances.

I have confirmed the valve seat did indeed drop on the exhaust valve. I checked the valve heights of each and the one that had the rocker come off is almost a 1/4 inch higher. I looked at the rocker again and the the shaft which I believed was 2 pieces is supposed to be one solid shaft straight across that supports both rockers that bolt down. It snapped on the exhaust valve side. I took out pushrod again and looked at it very closely and it does have a very slight bend maybe .015. So thats the diagnoses. I got the oil sample back today and confirmed it was antifreeze in the oil. So I am guessing maybe the valve seat when compressed lifted the head?

Now what……..pull head obviously.

I am at a loss. I have heard Cummins helped some people out of the repairs on these engines due to the known failure.

Do you have any advice on that. What would it cost me per motor to to the heads ? I assume maybe a piston and sleeve needed for this one cylinder also.

Other motor runs fine but probably should go ahead and get upgraded heads on too? Can the new heads handle the extra heat or still need to re prop to meet the 450 curve?

Thanks

[Graham Smith]

Newbie Brit here. Nothing helpful to add to this but I’m interested in the outcome; am currently considering a boat that has this engine, have been reading the history.

[Fireisland1]

All sounds good but if a rocker fell off while barring an engine, then the valve hung up from being either bent or the seat came undone. . The seat may have fell back into place . If it was mine I would NOT start that engine. I would take off the head. You have a top end problem.

[JJM]

Not sure if my last post came through Tony. But here goes again.

First off in the end of the day I plan to pull the head off period. But before that I would like to try a few things to narrow down the source and verify the damage if any.

Yes I barred the motor over several revolutions checking each rocker and valve as it went over. Around the 3rd revolution I noticed the rocker just kind of flopped off the mounting post. I inspected it and all looked intact and undamaged. No tuliped valve tip , no bent push rod. Quite odd.

As mentioned I am not a newbie to working on engines but i AM a newbie when it comes to working on diesel engines to this level so that’s why I ask the questions to learn from a expert such as yourself. I am always open minded and ask questions to learn. Nobody knows everything . Together we can learn and educate.

So anyways here is my thought process going forward.

-RE-torque the entire cylinder head to spec.
-reinstall the rocker and retorque all rocker bolts and adjust all valve lash to spec.
– possibly drain antifreeze out of block so as not to induce more antifreeze into the fresh oil I just put in for testing purposes.
– Start engine and verify operation and check for any knocks or odd noises .
– if all sounds normal and no engine knocks, then I could perform a leak down test and or fill the antifreeze system back up and pressure test it to see if the leak is gone. The outcome of the above depends on this.

Bottom line I do not want to pull the head and replace only to find I have a rod bearing or main bearing knock.

– lastly Dissemble head , have it rebuilt and reassemble with new head gasket.

So here are my questions to you.

1) What other sources are there that could induce antifreeze into the motor other then a head gasket? Are there any?
2) Can I drain the antifreeze in the motor and start up only running for a minute or two to get the fresh oil into the bearings and verify sounds and operation ( with a gas motor I would have no hesitation doing this. It would take atleast 30 seconds to a minute to start generating any heat. So I would think a quick start up and shut down would not harm it. )?
3) I actually skimmed through some previous posts and found one from you in 2015 where the boat owner had the same situation and head gasket let go. Your “Specialist” you spoke with advised he retorqued the head to factory spec and solved the problem. Apparently head gasket failures are not as uncommon as we thought. More so on older generations but still there.
4) Is the injector just pressed in with a O-ring like automotive or is it threaded? I would like to remove it from this cylinder to check with a bore scope and possibly due a leak down test also to confirm if valve seat or anything is leak.

I think the main difference between my situtation and others I have read about is my leak happened suddenly while cruising at 2200 rpms and started to fill the crank case with antifreeze before it couldnt fire and hydrolocked causing the rocker to come off and maybe valve damage but unknown at this time and not apparent. Had I caught the leak before it probably wouldnt have shut down.

Open to any all thoughts. Sometimes things get lost here in translation. Thanks in advance.

[Tony Athens]

Barring over the engine at less that 1/4 RPM and a rocker fell off the post, push rod, or valve?

You are kidding, right, with your “diagnoses” ?

Pull the head..

But I really do hope I am wrong……………………….REALLY!

Tony

[Bill Stenger]

Is the top of the valve at the same height as the others? Seems so in the pictures. Strange for the valve adjustment to be so loose that the trunion is able to fall out. Obviously that was loose as well. May need to reassemble adjust valves and check all the trunions and go from there.

1 user thanked author for this post.

JJM

[JJM]

Photos attached. You can see the rocker I am holding that came loose off the mounting post. No visible damage to it or the mounting post. As mentioned the head could use a valve job and lash is a bit loose but ok so that may have been reason it was tapping because of the play in the rocker. None of the valves are mushroomed on the end and show no signs of fatigue so I do not believe they are bent. Push rod from the one cylinder that came off was true and straight not bent.

[JJM]

Bill valve is intact. valve spring and all is in tact. If valve seat dropped and valve it would not be there. Its still sitting tightly intact with the spring and retainers. Just the rocker arm came loose.

[Bill Stenger]

It sounds like Tony is correct ” what a surprise lol”. Seems like it dropped a valve seat on the cylinder where the rocker fell off. So start pulling the head. I don’t know how the coolant or water got in the oil but that very well may be obvious once the head is removed. Stands a very good chance that the pistons are fine and will need the head repaired or replaced.

[JJM]

Thoughts …?

So my main question now is how did the coolant get into the oil. I know the obvious is a head gasket leak but are there other sources or coolers that could have caused this??

Thinking of doing a leak down test but are injectors pressed in with a oring or threaded in? I really do not want to mess with the injectors if not needed…

Other very important thought is we are getting into freezing temps up here very soon. How can I fill block with antifreeze in the sea water side if I cannot start it??

Id also like to circulate new oil into the block but I dont want crank it and have it fire. Any other way to accomplish this?

[JJM]

Update. Pulled some things apart….

So I had an interesting night pulling some things apart to see whats going on. I pumped all the oil out of the motor and flushed a few gallons through it to clean things out. There was definately about a quart or little more of water or coolant when I first started pumping it. The oil sample I took this morning will tell me what it is in a few days. My gut instinct is coolant.

So then I pulled off the inspection cover and the valve cover to inspect. To my surprise all the valves, rockers, springs looked good and intact. So I started to turn the motor over by hand using the alternator nut ( thanks Tony) . I felt no knock when turning or any restriction like a bad bearing I could just feel the compression and hear it when it pushed out the pressure .Suddenly asI continued to crack the motor around by hand I saw a rocker literally slide off its mounting post. It was the last cylinder towards the turbo side. I believe the intake rocker. It literally just plopped right off and layed on the head. I inspected it and found no obvious damage. I pulled and inspected the push rod and did not seem bent or damage and slide the rocker trunion back onto the shaft and could feel a lot of valve lash. The exhaust valve next to it was still intact but had a lot of valve lash also

I then inspected the rest of them and could see there were several rockers that had excessive lash . Rest were fine and pretty tight. Im thinking over due for a valve lash adjustment. The intake and exhaust rockers were very loose with I’d say atleast 20-30 thousands of slop the rest were pretty tight and I would guess around 5-8k play.

I then proceeded to pressurize the coolant tank and could not get pressure to hold what so ever. So appears I have a very large leak somewhere in the coolant system. What I cannot figure out is what item could leak and get into the cylinder. I am thinking maybe the exhaust manifold or exhaust manifold gasket leaking?? I am stumped here now trying to figure out whats leaking.

My hypothesis somehow a coolant leak started and the piston could not compress the coolant and since the valve lash was so loose just from needing adjustment the compression of the piston and coolant caused the rocker to get pushed out of its cradle and then the intake valve had little to no movement so the cylinder was acting dead and just pushing the coolant out of the exhaust valve and not firing hence the white smoke. So I am hopeful once I find the leak and fix it I can retorque down the rocker that fell off and readjust all the valve lash and hopefully the pistons and main bearings are fine. I know when I heard it running it was definately tapping at the top of the motor and not the bottom. I am almost certain the tapping I heard was probably the rocker arm rocking back and forth because it was soo loose tapping on the lifter and valve. The valve doesn’t look mushroomed and neither does the pushrod.

Thoughts. What do I do now. How can I find this coolant leak and what is the routing of the coolant system. What is the procedure and specs for valve lash for the intake and exhaust?

Thanks in advance.

[JJM]

OUt of curiousity Tony what would the cost be if it a dropped valve and 1 damaged piston to do this job labor and materials. ?? This way I have an idea of what I’m looking at.

Also what would cost be for a new long block ?

Thanks

[JJM]

I am really baffled to see the greatly increased oil level in the pan. Near doubled unless it is frothing up from water that some how got it. I do not believe I recall seeing any oil coolers. How else could sea water get in to the oil then ??

. Oil sample will tell us what we are dealing with for sure.

Going to pull the cover tonight and bar the alternator but to see what I can find.

Do you guys sell a service Manual for this engine . I am very mechanically inclined just never worked on these engines before and not overly familiar with diesels other then maintanence

[Tony Athens]

You do not need to pull the injector lines to remove the valve cover

Injectors=YES

I’d be barring the engine over slowly to “feel what is going on.

I have never seen a head gasket on this engine blow like you describe–But I can learn too.

Either way– head needs to come off..

[JJM]

Thanks for your input Tony. I am aware of the proper fuel curve. We were very close to the 450 curve at sea trial and egt temps were in range.

If this is indeed the case a dropped valve, how would the antifreeze in the oil ( blown head gasket ) or water be correlated ?

I’m at pulling a sample today of oil to send out and get tested to confirm wether the added fluid level is water , antifreeze or fuel. I am going to drain and refill the oil today so it’s not sitting in there. Also.

To pull valve cover looks like I need to pull all the fuel rails and injectors correct ?

[Tony Athens]

480CE knocking

DO NOT start it again.

IMO, I think you dropped a valve or valve seat.. You damaged it further with the re-start.

Pull all the injectors and inspect each tip for mechanical damage. Bar the engine over with the valve cover off ( use the alternator nut/15/16″ socket/ratchet—CW) .. You should “feel” the knock and may even see a valve not returning all the way up.

Next–Drain the coolant and the Head comes off….Then the fun will really begin.

Curious–You do know the very colorful history of this particular version of the 8.3, right?

Tony

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JJM

[JJM]

Update

So did some more digging and I believe I have a blown head gasket. Oil level is way up and crud on oil cap. What am I looking at for replacement ? Is knocking from the fact the motor can’t ignite the water or a rod knock ?? Ugggh

[Author]

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