Cummins Engines

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rgsmg53

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I'm about to make the move from a yacht (well, motor-sailer actually) to a motor boat.

I've got my eye on a couple, both with Cummins engines. One has twin "4BT 3.9 Turbo 150hp" according to the broker with just over 1,000 hours on both. As far as I can tell they are of 1990 vintage.

I know there are one or two Cummins experts on this forum and I would be interested to know what forumites think of this engine generally and especially a pair nearly 30 years old and with more than a 1,000 hours on them. What should I be looking out for?

I'm considerieng having a specialist engine survey carreid out before going any further. Does anyone know of a Cummins specialist in the Nottinghamshire / Lincolnshire / Trent area who would also take an oil sample for analysis?
 
Latestarter is the forum expert, but around a million buses can't have got it wrong and each of these would clock way over 100,000 hours. Yours, like mine, are barely run in.

My boat has the 6BT5.9M, which is the 6 cylinder version. There are some known weak points to look out for, which I am sure Latestarter will comment on.

My view is that these are far superior to the Volvo Penta's on my prior boats.

You are in VolvoPaul's home territory - very highly spoken of on here and an all round decent chap.
 
rgsmg53 said:
What should I be looking out for?

I'm considerieng having a specialist engine survey carreid out before going any further. Does anyone know of a Cummins specialist in the Nottinghamshire / Lincolnshire / Trent area who would also take an oil sample for analysis?
Click to expand...
There's a Potential issue regarding the wet liner cylinder seal s -They are sensitive to the coolant .If the wrong type as been used ( 30 y old engines ) then the seal can fail .
There is a test of the coolant to determine if this is actually happening .
I looked into this a few years back when looking @ a Riva powered by Cummins 15 L lumps derived from American dust cart trucks KT something or other .As long as the correct stuff -coolant has been used and changed by the book ,then all should be well -
It's a bit of a left of field -did not see that coming kind of thing - below is tech ---
http://cumminsfiltration.com/sites/...oduct_lit/asia_pacific_brochures/3300963A.pdf
 
The 4B does not have removable liners, so no seals... no need to worry on that score. Cummins had these up to 250bhp, so 150 is going to last, and as superheat says, 1000 hrs is nothing. Just keep them properly serviced, and you should have no issues. Nice and simple to work on as well if you are that way inclined! :)
 
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