New Cummins diesel

[davidms]

I was talking with a local mechanic in a nearby boatyard yesterday about the noise difference between gas and diesels. He said that the new model diesels are much quieter than older diesels and, in his opinion, make gas engines less desirable because one of the main complaints about diesels (noise) has been addressed.

He also said some people don't like the smoke/fumes that you can occasionally get from diesels, but that Cummins now has a "smokeless" marine diesel engine available. Has anybody heard/seen this engine? Is it really smokeless?

Davidms

[dougl33]

I have a pair of Cummins 6BTA's in my 33 Bertram (the boat's and 86 and the engines are early 90's). While I wouldn't call them smokeless, they don't really smoke much as I always leave my block heaters on. Maybe a little on start-up and/or until they're warm.

They only time anyone complains (and its mostly my wife) is when I'm either leaving the slip or backing in. Underway there's zero smoke and no smell.

[In Memory of Vicroy]

The "new" - last few years - electronic controlled common rail Cummins - the QSB 5.9s (same block as the 6BTAs) and the QSC 8.3s (bigger block, won't fit in a B31) are very quiet and near smoke free. I priced the QSB 5.9 rated at 305 hp a year or so ago and bobtail the dealer quoted me 24k a side.

I remain partial to the mechanical controlled diesels, and some Soundown will control the clatter and turbo whine.

UV

[dougl33]

I guess it all depends on how/what they're installed in. My 6BTA's are no more noisy than my old 454's. No clatter and no whine.

[In Memory of Vicroy]

Doug - the 6BTAs in the B31 boxes without Soundown lining the boxes are pretty loud both on the clatter and mostly the turbo whine. Another advantage of the Soundown is it keeps the engine heat from coming thru the boxes and burning your butt while sitting on the boxes. The electronic QSBs are real quiet.

UV

[Bruce]

There's no diesel on the market that is as quiet as a gasser. Not unless you own a gasser with a serious valve clatter.

I have done tests with a DB meter on the QSB vs the BTA and while the QSB registered lower numbers, it wasn't that much lower.

It's the old game of "the emperers new clothes".

One day you may see a diesel as quiet as a gasser, but it ain't here yet.

Less smoke, yes but not smoke free.