Hi all - im getting nailed left and right across platforms for asking what the differences between truck and marine 12v cummins are- so i you wanna dig into me more go right ahead.

I am on a super tight budget and want to put two 12v 5.9s (i already have one) in my 33 sport fisher. Im gong all mech VE pump style- I will tune them between 250-330 hp each and see how it all goes. I want to know if a truck flywheel will be ok or if I can put a marine/industrial flywheel (i think they are much heavier) on the truck engine.

Thanks

Some opinions here: what would be involved in marinizing a cummins 5.9 out of the dodge trucks? say they are the same.

I know there are some differences in piston design for marine, heavier ring lands, possibly different pistons to match the spray patterns etc but honestly im not gonna nit pick too much- just gonna send the truck engines. I want to know about flywheel compatibility etc-

Engine swap in a boat and tight budget do not go together, you get to pick one or the other. Flywheel depends on what type of coupler/transmission you use

Even if you do all your own work, there will be multpiple issues that come up. Many small costs add up fast.

Closed cooling and cooled exhaust manifold systems are the big ones.

The 6B Cummins has issues with poor airflow with the ridiculous cast in head intake system. You're not running big power, but better ducting to reduce airflow restrictions will help out EGTs.

What RPMs were you planning? Peak/Cruise.

There may be some better continous duty turbos that would be better suited for your application.

As long as you can mate up the flywheel/coupler with the bellhousing, you'll be gtg.

What drives were you plannjng to run?

some links.

https://www.offshoreonly.com/forums/do-yourself-boating-budget/335665-diy-duramax-marinisation.html


48 Fountain Project twin 600hp Cummins

https://www.offshoreonly.com/forums/general-boating-discussion/287864-cummins-6bta-5-9-performance-build.html


https://www.offshoreonly.com/forums/general-boating-discussion/301252-what-would-involved-marinizing-cummins-5-9-out-dodge-trucks.html

repost

DIY - Duramax Marinisation

CamaroMan,

This will cost money, and you have to look forward to spending that money for the glory of making it work.

If you are on a tight budget - and while there are different definitions of tight budget just like there are Iron Duke Camaro men and ZL1 Camaro men - it will be more economical to sell any leftover truck engines and use that money towards complete marine driveline packages.

There is a very liquid market for leftover truck engines, that will allow you to get your money's worth, while patience will allow you to make bargains on boat stuff, as that is a less liquid market.

I have a pair of Duramax LML’s with only test hours if your interested.
They run great, but I repowered with new 370 yanmars. I don’t like the way I set up the intercoolers and heat exchangers remotely. Got them back on stands to try to integrate everything as one unit to simplify plumbing.