: Northstar for marine use?

06-20-06, 03:57 PM
What does the group think about the using a northstar in a boat?

Of course the engine would have to marinized for safety. Not to mention the cooling and the computer changes( or lack of computer).

Given that all this could be done well, I was wondering if the northstar is a good match.

From what I have read, marine engines need to be able to run hard all the time. WOT, or close to it is very common.

All of GM's marine engines appear to be based on the vortec, http://www.gm.com/automotive/gmpowertrain/engines/specialized/marine/index.htm , with the latest one, the 6000, based on the same engine as the engine in the Escalade. Makes me wonder why the Northstar was not used in the Escalade.

06-20-06, 04:33 PM
It has already been done. I remember our old Guru talking about it.

06-20-06, 04:44 PM
Thank you, I will search some more.

06-20-06, 05:57 PM
See post #23

06-20-06, 06:07 PM
hope youre considering a heat exchanger with sealed coolant.
Also will need to waterlog the exhaust manifolds.

06-20-06, 06:54 PM
ty, I found this one too. http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/13260-northstar-plane-engine.html

The thread is about planes, but has a blurb by bbob on the Northstar for marine use. Basically he says that its been done and worked well, but that boats are better suited with larger displacement engines.

06-20-06, 08:42 PM
Probably not the greatest idea. A Northstar is a small displacement, high revving engine. Boats are best motivated by large displacement engines that can provide the needed torque at lower RPMs. A Northstar will work in a boat...but larger engines work better. That is why you see the Vortecs in marine applications.

The Northstar was marinized for a "boutique" application with MasterCraft. It worked fine but needed to be revved hard all the time to really move the boat fast. Unless you prop the boat to rev the motor hard it will be very slow and you will be unhappy..... Vortecs with larger displacement and greater torque at lower RPM's can pull a taller prop and move the boat with much less RPM.

The Northstar is all aluminum so it is not the best situation for cooling the boat to pump the lake thru it (corrosion problems). The MasterCraft application had a closed cooling system that ran 50/50 DexCool/water with a seawater heat exchanger in the system.

The wet jacketed exhaust manifolds were also developed and cast in conjunction with MasterCraft.

If you are really interested in doing a marine Northstar contact Indmar Marine. They did the actual marine conversions for MasterCraft and supplied them the engines. Indmar would probably have some of the wet exhaust manifolds and the sea water pump set up. Otherwise the engine was a completely stock 300 HP 1999 Northstar as installed in the cars. The mass air flow sensor was eliminated and the system was run by a speed density delphi controller. Indmar would probably have the controller and wiring harness I suspect.

In a small ski boat or other performance boat this would be a neat application...just remember to prop it to run at peak HP at 6000 RPM....

06-21-06, 08:31 PM
Yep, wrong motor for most marine applications.

While I love my N* in my STS, for most heavy boat applications you need to go w/the twin GM big blocks, or more preferably large diesels.

Don't get me going on gas prices on the water...

99STS 126K
98 Tiara 2900, Twin 7.4L's (they make you feel good about America, and life in general when you fire 'em up!) Bawoom, Bawoom!