Engine Room Ventilation 1985 32FB

[Jackman]

Been Awhile...

Does anyone have a connection for custom vents for these old girls? I think my engine room intakes a marginal if not inadequate since my conversion to diesel. I've replaced the turbos once a couple of years ago after the engines were in stalled new in 2007/2008. During the rebuilt turbo install I also spent the beans on a Tony Athens built custom stainless exhaust. I assume that system is as he suggests so I am looking at the other possibilities which led me to engine room vents. I dont think my capacity is large enough and theorize that my engines are pulling so much air that when running might be pulling saltwater vapor in through the filters....even though I have the dryer vent type hose to the floor from my intake vents. These engines take in so much more air then the 454s that I think this could be a reality. Turbos are pricey as we all know...What are your thoughts and do you know where I can get "fitting" custom vents with larger air intakes to reduce this proposed turbo intake of vapor I might be seeing? The evidence I see is a white salt like material on the outside portion of the turbo that is visual just after removing the filter from Tony's CCV enirovent system. Blades seem to have more drag than I remember when rebuilt by a place in Baltimore. See some black smoke...bottom is clean as well as aftercoolers...I assume its happening again!

 

[madhatter1]

What engines?

 

[Jackman]

2007/2008 cummins 330b's 6BTA mechanical not the fancy electronic engines...on purpose.

 

[madhatter1]

2007/2008 cummins 330b's 6BTA mechanical not the fancy electronic engines...on purpose.

100% agree with that. Love my Cummins 6BTA 270's and my DD 8-92's. They can only stop running if actually broken or out of fuel.

Anyway I asked because I had issues like yours with the 270's. Turbo related due to exhaust design. But it takes many years and I don't want to lose the water lift mufflers so to me the turbo is an occasional service item.

Realize that due to exhaust configuration your engines live 2 separate lives. Also on the 270 I had an air intake clogging issue in one intercooler. Since they don't need service like a raw water cooled intercooler they got ignored. One cleaned up and the other had to be replaced. Make sure air side of intercooler is also serviced. As for lack of airflow test with engine hatch off to see if there is any difference in RPM or with the smoke issue. I assume the smoke you are seeing is a very light gray shadow in the exhaust stream but not "black smoke" per say.

 

[Glory]

I do not think that is the issue. The 454, 7.6 liters running at , I'm guessing 3000 rpms will need more air that a 5.9 liter at 3000 rpms, and you are likely closer to 2500 rpm.

You might want to remove the "dryer hoses". Diesel fumes are not an issue, and the hoses are not smooth possibly slowing down the air. Many diesel production boats have no hoses at all.

 

[Boatsb]

Cummins publishes the information you need.

Theres a minimum size of intake and a value for pre and post turbo pressure at certain rpms. If it was properly installed all that should have been done and would be nice to have it documented for future reference.

 

[Jackman]

I think there is enough air for combustion I just think there is so much air pulled into the engine through the small vents that the vapor from the salt water is pulled into the intake of the turbo through the filter. Im pretty sure I'm not getting it from the exhaust side. The blades when I spin them manually by hand seem to have more drag than I remember when new which would effect the boost and not allow me to get up to proper RPMs. Now I have black smoke from one of the engines (slower exterior turbo blades when hand spun) that does not seem to want to get up over 2000 rpms. Both throttles goto stop point, fuel is fine and engines seem to run smooth so I dont suspect injectors.

 

[Avenger]

I'd pull the exhaust elbows and look at the turbine housings. Even stainless elbows can fail and leak seawater. That will rot the turbine housings and kill turbo performance.

 

[Jackman]

I can pull them to inspect but I suspect that they would be ok since I purchased the custom riser exhaust from Tony Athens...the rise is so high and the raw water is on the downside as is Tony's design. I see white residue on the intake side of the turbo which is why I think the engine compartment vents are an issue.

 

[Boatsb]

Back to the volume issue. Higher velocity will bring in moisture to the intakes.

 

[Jackman]

Scott....thats what I'm getting at...maybe I'm not saying it in the best way....Was wondering if anyone else had this issue and had to open the vents to a larger diameter for the intake to decrease the face velocity and "vacuum effect" from the engines trying to breath from such small intakes.

 

[Boatsb]

Like I said there is spec for ventilation and its dependent on the engine.

Who installed it and did they even pay attention to this?

Every engine package has a list of specific needs.

Air intake.
Exhaust size.
Cable size/length
Raw water intake
Fuel line ID
And more.

We have to test all the parameters after an install for warranty on new motors and do the same on rebuilds because theres no way to prove the last guy did.

 

[Jackman]

Now that I think I'm past my head/injector issue I want to focus more on this ventilation issue. I know its currently not adequate. I was contacted by someone from Sams before about custom vents for this boat. Anyone have the contact information? I lost it in my email somehow.