Power loss and smoke from breather tube

[Guy Tarleton]

My 1987 6BT with 2200 hours just started acting up! Seems to run ok initially with no exhaust smoke.   As soon as I accelerate under normal load past 2200 rpm,  the RPMs plummet and it starts throwing smoke out of the breather tube. Whole engine room fills up. Any thoughts?<br />what should I check first? Compression test?<br /><br />

Topic

[Guy Tarleton]

Engine rebuilt, need advice for start-up

My older 6BT 5.9 engine has left the machine shop with new pistons, crank bearings and a valve job. I have not started a rebuilt diesel and need info on the specific steps of the procedure. 

What is the best way to start up and run-in?

how do I get oil pressure up for lubrication? Do I crank with no fuel until pressure is registered? Maybe loosen injectors to eliminate compression to save my battery?

What about break in oil….is this a thing?

specific initial loads and rpms?

Maybe cummins has a manual on this? 

Any help appreciated…..I dont want to screw this up

[Tony Athens]

Can you send me all your past pics ( direct to [email protected]) and send me a current good picture of the exhaust outlet side of your turbo.

I cannot find ( or see them in the thread?) the pics you have posted in the past or sent before.

Smoking Gun = 99% from your engines exhaust system feeding your engine salt water. Need to “SEE” all.

[Guy Tarleton]

engine repair update

OK …so it’s been a while getting that block to the shop but it is apart for inspection. Cylinder 3 pretty scored up and will need to be bored and oversized. Pistons 3,4 and 5 have heat damage and need to be replaced but cylinders 4 and 5 can be honed I am told. At this point, I can spot replace the damage or just rebuild the whole block for 30% more $. On a 35 year old engine, I think a full rebuild is the way to go. 

Injectors went to Diesel injection systems in Santa Maria and they are all spraying “ok” but have some varnish build up so I am opting to get them serviced and cleaned up. Injection pump is working perfectly but that’s expected since it was rebuilt just 10 hours ago. 

So far have not found the “smoking gun” that caused the overheating damage…and that is somewhat concerning. Definitely do not want heat damage issues with the new rebuilt engine. I still have a turbo with some salt water corrosion damage to the exhaust port (Don’t think this would be the cause) I will reconfigure the exhaust elbow for optimal height and proper downhill drainage. Valves looked pretty good but I will get them serviced and put in new seals. The piston oil cooler nozzles were intact. Anything else I should focus on?

Guy T

 

 

[Tony Athens]

That could be easily an issue , but do you have that injector separated to test properly? Taking out  a cylinder like that did not happen in one trip without something obvious before unless you are an operator that has no clue what is going on in your engine room. (sorry, but it is what it is) )

 

Before things went “poo-poo” did you make oil and/or did you have blue smoke at low RPM’s ?

What does your tech say about the turbo?  

How do you know what the valves look like?

Since you have to pull the engine to do  one, ( which is OK) the other 5 need to be checked and if in tolerance, hone a re-ring–IMO, Use only genuine parts unless you machinist has a solid track record using something else on the higher HP engines

 

 

 

 

 

[Guy Tarleton]

#3 piston is in bad shape.

Head is off and valves are not looking bad but #3 piston is a mess. Surface is disintegrating and walls are scores up. Diesel mechanic friend says it overheated from too much fuel because of an open injector failure. What do you think?

machinist tells me he can bore that cylinder and replace the piston and it will run the same as replacing all. Is that true?

[Tony Athens]

Is the head off?  Quit screwing around.. Head on the bench, valves out–That is number 1 

Your exhaust design did your engine in–How bad it is will not come until things are taken apart and inspected.  I’d guess you are in for a full rebuild  and  obviously,  a properly designed exhaust

[Guy Tarleton]

Compression test dismal but is it rings or valves?

Compression test completed on my 6BT 5.9 with heavy blowby.

3 cylinders look ok with compression well over 300. <br />Two are mediocre with compression in the mid 200’s. Adding a squirt of oil only boosted about 10% so maybe rings are OK?

cylinder 3 HAS ZERO COMPRESSION. <br />I will try a leak down test to get a better idea of where my compression is going. It has got to be either burned valves ( with blowby going past the valve seals) OR rings that are stuck or worn. Or even a hole in a piston?  <br />Any thoughts on how I can tell if rebuilding my head will fix all problems. Or do I need to pull the block out for rebuild? 

[Guy Tarleton]

Disassembly underway. Turbo may be leaking

Head is almost off the engine. Exhaust manifold looks quite clean but turbo is concerning. Not only is there the heavy corrosion just past the turbine but also bright yellow beads of liquid (coolant?). See photo. <br />my intake side tube has a thin film of oil coating it and a small amount of pooled oil. Compressor side of Turbo looks clean. <br />Is my turbo leaking oil and coolant?

Probably not enough to account for all my blow-by? But maybe time for new or rebuilt turbo..

[Tony Athens]

Your picture says it all  No more using the boat—- Pull the head before you drop an exhaust  and it costs  you an  extra $10K+,,   

Then, you need to redesign your riser

[Guy Tarleton]

Ok thanks so much!<br />I did, in fact pull the turbo 2 months ago as coolant was leaking at the manifold/ turbo joint. Turns out there was no gasket there, only some silicone. I sent pics to Corey and he thinks My turbo is eating salt water because of the poor exhaust configuration.  I will post those turbo pics. <br />Question: how do we know blowby is from an exhaust valve and not past the rings?

Is salt water the culprit for the exhaust valve damage?

GT

[Tony Athens]

You have a very early 6BT 210 CPL 742 (probably pre-1988) that is being kept up extremely well– Good job! From all posted and the video you sent to Corey, everything points to  at least one or  more burnt exhaust valves that are leaking a serious amounts of combustion into the crank case.    Things don’t last for ever,  although looking at your exhaust I would guess that if you remove the engines wet elbow and looked inside the turbo, we may find the culprit. Head need to come off.

[Guy Tarleton]

I went down to the boat and shot some photos. Even started up my sick engine that idled rough and filled my engine room with grey smoke within a few minutes. Photos show a modified oil catch jug with the breather tube just inside the opening and vent holes cut in in the top. There was just a thin film of oil in the bottom. 

[Tony Athens]

Start by posting good pics of the engine and the “tube” you are talking about  No close-ups–What to see everything

[Neto]

what kind of smoke? did you check blowby? sounds like piston rings are failing 

[Author]

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