cummins 6bta 300hp oil comsumption

[Landon Yacobucci]

Hey guys I have an oil consumption issue and I don’t know where its going. I just recently purchased a boat and it has been running just fine engine sounds and runs great performance wise but about 100 or so hours in of use I started to notice oil lowering on the dip stick. I did have a minor oil leak from where it connects to the engine tightened up the bolt and it went away this could not of been the leak. I thought it could be clogged air filter, pulling a vacuum on the turbo oil seals, because when I bought it was running a paper filter. Changed that and still losing oil. When I started noticing the oil consumption I also noticed black soot accumulating in my engine hatch/room all over. I my oil change per the verbiage I have read on this forum 13.5 quarts. I was going to start with valves then turbo. (reason I am starting with valve tolerances is my friend had similar issues and after thousands of dollars worth of turbo repairs it ended up being the valves needing adjusting.) didn’t make sense to me but I might as well.

The engine has 1250hrs
Not much smoke at all coming out the exhaust

any thoughts?

Topic

[Landon Yacobucci]

pics

So I took it all apart and this is what I have found.

There is about 0.004″-0.008″ up and down play with the turbine.

Compressor side was wet with oil, exhaust side looks to be dry soot. See Pics

There was oil on the outlet of the aftercooler.

I still have a bunch of soot building up even with the Envirovent installed.(was going to do the exhaust gaskets just for peace of mine since I had it all torn apart)

It is rusty on the coolant side of things too.

Moving forward was looking at getting turbo rebuilt and AfterCooler hotbathed

Any other thought while im this far in?

Thanks
Landon

[Landon Yacobucci]

I’ll tear into that this weekend! thanks for all your insight!

Serial Number 44665942
CPL 970

Fingers crossed it’s good…. The boat got repowered with this engine and the guy before me kept it on a trailer with a fresh water engine flush

[Tony Athens]

Just a FYI that you need to think about..

Your engine is a probably a 6BTA 5.9 CPL1929 300/315 B (ND injection system) that is from 1996. or most likely. earlier………….. That means your “doomed to failure” exhaust riser/mixer ( I have seen worse designs if that helps) has been in saltwater for at least 25-26 yrs..

The 1st thing I do is pull the mixer for a good peek inside the exhaust side of the turbo.. Lets “see” what is going on inside there

Post an engine serial number too.

BTW, very tidy for a an engine of this vintage in a boat like this.. Someone is doing a very good job that way.

Tony

[Landon Yacobucci]

Pictures

Here are the pictures. Dip stick is calibrated as follows top mark 15qts middle 13qts bottom 10qts. I doubled checked the oil level marks last oil change. As you can see in the 4th and 5th picture the soot on the engine. if you look at the aftercooler on the 4th I drug my finger on it to show you how sooty it gets. maybe an exhaust leak or sucking the soot in through my vents?

I am over propped right now working on a couple tweeks from acme once I get it removed.

I burn about 1 quart every 20 hrs.

When I first got the boat it didn’t have the soot and ran at 160 engine temp.

My Raw water pump went out and the engine temp got up to 190 degrees when I shut it off.

After that the engine started running at 180 and started to burn oil( I figured the thermostat was stuck open before the raw water pump when out)

The engine starts up within the first crank every time and runs like a dream and skips no beats

[Landon Yacobucci]

Sounds good I’ll get those pictures and post them Wednesday evening

Thanms

[Tony Athens]

Let’s see some really good pics of the engine as installed..All angles, all perspectives, all clear & in-focus………. Need to “see” what you ask asking to to help with. EVERYTHING

Exactly how much oil is in the oil pan, low mark on the stick, engine off?

Have you checked your dip stick calibration per the article on this web site?

[Landon Yacobucci]

still being comsumed

no change after I adjusted valves…. no change after enviorvent system installed

I read on this forum that a compression check is useless is this correct?

Thanks

[Landon Yacobucci]

Alright sounds good. How much oil can actually be lost if this was the case Because I was over 4 quarts low.

Also any thoughts on the “soot/black residue” in my engine compartment… only thing I can think of is possibly sucking in the soot from the exhaust through my engine vents. But I would imgine there would be a trail of soot leading to that.
Thanks
Landon

[donald roth]

You still may be overfilling at 13.5 quarts.
Engine installation angle, boat running angle and slosh factor all come into play.
I’d let the oil level go down to about 12 quarts before calling it a blowby problem.

[Author]

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