Garrett Fulton wrote:
On Tuesday, September 15, 2015 at 10:07:29 AM UTC-4, Lloyd E.
Sponenburgh wrote:
Garrett Fulton fired this volley in
:

? Did you not mean to check out the bearings on the blower? I
believe that would likely be the bigger problem on an old
Detroit.
No; given the relative speeds of operation, and their temperature
domain, those in the turbo are the more likely ones to fail early.
To my knowledge, we never had a Roots failure in our two divisions
of Swift boats, unless one got shot up.

They were rebuilt every time a boat went in for overhaul, but every
moving part in the engines was replaced or re-machined then.

Also, on that thing about the runaway condition -- I think it was
on the Mark II boats (real pigs in performance) that they started
putting a manual damper over the blower inlet, so if the engine
mate was fast enough, he could shut one down very quickly. Prior
to that, the only solution was a very dangerous one... he had to
jump down into the compartment (between the two engines) spin off
the injector cover nuts, and slam the rack by hand! It could have
been the Mark III boats where they began to add that (luxury yachts
compared to the Mark I boats!)

Lloyd

I stand corrected. Was a diesel truck mechanic many years ago, but
never had any close experience with the Detroits. Turbos seemed to
last forever on the Cummins engines, hence my question.

Garrett



Only time I saw a scavenger pump have issues with the bearings it ate
the rotors and locked it up. Turbos on a screamin' Detroit get a LOT
more heat than a 4 stroke.

The 2 stroke design is also why they sound like they are screaming even
at low rpm. Twice as many power strokes per rev than a 4 so it sounds
twice as fast.

--
Steve W.