Roots Blower

[ranexs]

I have an B&W Alpha marine engine. 2-stroke diesel, 6-cylinder 260 mm diam each.
There is two roots-type blowers, one feeding three cylinders.
I wonder if the rotors can be "moistured" with oil or must they be clean and dry.
Does anyone have experience of these?

[rpg52]

ranexs -
I know nothing about your engine, but Detroit Diesels are 2 cycle diesels with roots blowers.  I happen to have a 3 cyl, but they were built from 1-16 cylinders and multiples.  The rotors are dry unless the seals are failing.  Any excess of oil can cause the engine to "run away", accelerate without control of the govenor, using the oil as fuel.  They all come with an air flap that can shut off the air in the case of an emergency.  The vacuum from using the flap can cause the rotor seals to fail though so they really are an emergency shut off.  Ordinarily you just shut down the fuel rack which shuts off the fuel to the injectors.

Being manufactured by General Motors for many decades, there is lots of information about them.  How they compare to your engine though I haven't any idea.

Your mileage may vary, etc., etc..   
Ray

[mobile_bob]

check you airfilter restriction, any vacuum will exacerbate the seals leaking as will exhaust restriction.

basically any 2 stroke diesel is like a huge high efficiency vacuum cleaner, and move twice the air per cubic cm or cubic inch displacement than the 4 stroke
engines.

its not unusual to see some grime (oil film) on the rotors of a detroit blower, but if you look inside the intake with a flashlight you can see the end plates
there if you see oil radiating out from the shaft/seals then it may well be time for an overhaul of the blower.

overhaul of a detroit blower is not a DIY project! i suspect your blower is virtually the same.

bob g

[ranexs]

"its not unusual to see some grime (oil film) on the rotors of a detroit blower"

Thanks, that´s what I was looking for.
I´m very pleased.
Regards
Ranexs