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Karl Denninger
 
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Default Huh? Diesel engines don't last 800 hours before major repairs??


In article ps.com,
rock_doctor wrote:



"JAXAshby" wrote in message
...
The claim has been made by a poster on this ng who calls himself "steve"

that
diesel engines as used on commercial fishing boats are often torn down for

a
major overhaul after every trip to sea, about 700+ engine time.

Anyone here have experience with diesel engines in commercial fishing

boats?
do those guys really trust their lives to engines that won't go even a

thousand
hours? Anybody know why they do this?


A rebuild is done when necessary (obviously). I have heard that a 2-stroke
Detroit will last around 2500 to 3000 hrs (according to a specific owner).


Depends on the Detroit.

2-cycle DDs that are naturally aspirated will often run well past 10,000
hours with nothing more than routine maintenance and perhaps an injector
change or two.

Turboed engines are another matter. The basic rule of thumb appears to be:

0.5hp/cid or less - 5,000+ hours (10k is not unreasonable)
0.7hp/cid - 5,000 hours is reasonable to expect.
0.8hp/cid - 2,500 hours is reasonable to expect.
0.9hp/cid - 1,500 hours is reasonable to expect.
1.0hp/cid+ - You have grenades with the pins out in your bilge.
Do not drop the spoon.

A 6-71 has 426cid, and a 6V92 has 552cid. Do the math.

I know of one guy who claims 2,500 hours on 625HP DDEC-II 6V92, and is
****ed off that he's smoking a lot at this point and is generally exhibiting
signs that the engines are worn out. My reply to him is that he's been damn
fortunate and that a lot of engines of that size at that rating don't make
1,000 hours before they go "bang".

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