12 valve marine motors

[killed300ex]

looking for info on exactly what the differances are between the marine 12 valves and the 12 valve in my 94. Asuming the marine engine is a non intercooled ve pumped engine? I have an option to pick up a marine 12 valve for cheap money. I was thinking about getting it and using the block for a rebuild if I could use my head and pump when it was rebuilt and ready to be dropped into my truck.

[Jim]

Jay Leonard will be the guy to talk to on this, he is in the process of putting a 12V into his boat, so im sure he knows the in's and out's of what they need.

[Ramdriver15]

marine engine has the 370 sticks or 330 stick. most are p-pumped and have different ceramic coated pistons. they also have a different head gaskest in them. The chargers off these engines are water cooled rather than oil coiled and most other than that is should be similar to the 94 p-pump

[killed300ex]

will the head interchange from my truck to the marine block? Hoping so I wouldnt have to oring another head. Think I might have to go and take a look at this engine one night this week. I think about the only thing reused would be the block and crank if its any good.

[JLeonard]

The marine Cummins come in many varieties.
There is a naturally aspirated version I believe it's 120 or 130 hp.
The 220 hp uses a CAV rotary pump and is not aftercooled. rated at 2600 rpm
The older 250 hp used a Denso pump and antifreeze type aftercooler. Rated at 2600
The 270 uses a P pump and has an antifreeze type aftercooler (I had one of those a 1999 model) Rated at 2600
The 330 and 370 are also P pumped with a sea water aftercooler. Rated at 2800 and 3000 respectively.
The heads should interchange. Some of the valves supposedly have rotators and there might be some other subleties to survive the duty cycle (read that heat) that is much more severe than automotive.

PS..I need the external marine parts so if you buy please contact me I need heat xchanger, marine flywheel and bellhousing and starter (those are different than automotive). I have a turbo but might consider it anyway. Thanks.

BTW I am converting a 1st gen to marine with the goal of 200/220 hp. I was told by a Cummins marine expert that I will do much better with the VE pump than the CAV.

[Jim]

I told ya he would be the guy:smilielol:

[JLeonard]

I told ya he would be the guy

But don't call me jarhead just cause I know about marines.....:stirthepot:

Can we get a 40 ft ugly boat to Seekonk to dyno??? Oh crap...I can't spin the rollers with a propeller.....:dunno:
Never mind::97DodgeCTD:

[killed300ex]

cool good info thanks I am going to go and take a look at it tom afterwork. I will bring my camera and take pictures and get numbers off the engine.
Hope I can make a deal and have a new project :smilielol: Just what I need

[JLeonard]

I just read some more info about marine vs automotive heads on the boatdiesel site and I offer the quote below from a Cummins "guru" out of England.....Hope it clarifies.


"Cummins B Series marine engines out of Darlington had 'premium marine cylinder heads' by 96, ......

Prior to the premium marine head Cummins used the same head as some automotive. It does not work reliably in many applications past 1000 hrs. Because of the high temperatures in marine engines the earlier engines could be prone to valve breakage. The solution was the premium head. This has valve seat inserts and valve rotators. "

[killed300ex]

i can tell ya for a fact its pre 96 it has a rotary pump on it and I think the head is cracked from the sympotms Im told. (when run hard air bubles in the overflow tank but fine when at idle or cuise speeds.) Guy sent me pictures but i still gotta go see it one of these days if I ever get some time off.

[JLeonard]

Rotary pump....probably a CAV pump rated at 210/220 hp.
I think a complete head is not that expensive. I plan on going with a new head when I do my marine conversion.