Cummins 5.9 6BTA M2

[Tom57]

Just bought a Bayliner 3988 with twin Cummins engines onboard. Hours are 1200 port 1200.1 stbd. Seem to be great engines. However the port engine has excessive blowby. fills the cabin with smoke at low speed 1600 rpm's and lower. Engines sound the same perform the same and the engines will both reach 2800 rpm's quite easy. don't know what to have the mechanic look for. Broken ring(s)? seems to be to low of hours for this. But are these engines prone to this? what else should I look at and be on the lookout for?

Thank you in advance
Tom57

P.S.
Stbd 45197558
Port 45197542

 

[penfold]

What do you mean by blowby? It usually refers to crankcase breathing and that's normally piped into the air intake, but filling the cabin sounds like exhaust smoke?

 

[Sticky Fingers]

You could try posting on the Seaboard Marine Cummins forum. Extremely knowledgable. If blunt.

Forums Archive

 

[Fishtigua]

Fleetguard does a good breather system for the 5.9 if yours hasn't been modified.

 

[Portofino]

Take the oil filler caps off , place the palm of hand over .Rev ( get someone) them up and compare pressures.

The one with gas blowby via the rings , increased crank pressure finds its way to the top and you should feel it on the plan of your hand .

Stuck or fractured rings can be caused by a myriad of things irrespective of hrs .Crap oil , wrong type for the motors , old oil , a duff injector opening too long and washing protective oil film off leaving a sticky gum which glues the ring if stopped for long periods = fractures at the next start .
The above to some lesser extent + leaky valve guide = oil seeps down when stoped , mixed with the residue = another adhesive made sticks the rings when it’s unused for long periods like the winter .


If the pressures are equal then it’s unlikely a ring issue .
In which case check the crank case breather pipes integrity + any filters If applicable?