6.5 litre diesels

[Hei mateau]

Hello all, I’m new to the idea of trawler life and have started an aggressive search. Looking at a Mainship 370 with twin 6.5 litre diesels. They are not the GM screamers.
The boat is a 1996, original purchase in 1998. Any information / conversation would be greatly appreciated.

 

[rslifkin]

The 6.5 is the old GM 6.2/6.5 pickup truck diesel. There's still 1 company out there that supports the marinized versions (Unique Diesel). They're not necessarily bad engines, but the base engine has a somewhat mixed reputation and they're relatively uncommon in boats.

 

[Hei mateau]

That’s what I’ve found. Starboard has a new longblock 100 hrs ago, while the turbos have been refitted on both. The turbo cooler failed, causing an overheating issue. The work was done in Laconnor and Tacoma.
Why were they discontinued in marine settings? Did discontinuation occur when Mainship sold? Or new drives were less expensive, more efficient?

 

[Comodave]

Boatdiesel.com may be a good resource for you to do some research on them. I would be very wary of buying an engine that has so limited production in boats. If you do proceed buy it for a very low price because the resale may be really low in the future. To say nothing about parts if there is indeed only one source for the parts. You will be hostage to their pricing.

 

[rslifkin]

I think those engines actually carried on in marine user longer than GM used them in trucks (other than the military HMMWV).

 

[smitty477]

I still remember those engines in some trucks we had and the concern/worry about which revision block and accessories we were dealing with. If memory serves me well we 'wanted' the blocks with an "F" in the block casting number and wanted to avoid the blocks with a "Z".
In my opinion best to avoid them altogether.

 

[gsholz]

I have the 6.5l non-turbo version in my Humvee. Very simple, pre-combustion chamber equipped 150 hp engine with glow plugs. Believe the turbo version is rated at 180hp. Lots of parts for the core engine still available. Marinized parts might be an issue.

 

[dannc]

I had a Chevy truck using the 6.5L turbo and the engine left me on the side of the road a couple of times. This was decades ago, but from memory, I think it was from a relay issue on the top of the engine. I heard on Car Talk, if anyone remembers that radio show, that this was a known issue on the engines which where used in Humvees. A caller said when he was in the Army the engine would stop because of the relay and they would "fix" it by pouring cold water on the top of the engine. Sounded worrisome to me.

I would think there is quite a bit of information on the engine on truck forums.

Later,
Dan

 

[sean9c]

Isn't that the base engine in a Peninsular diesel?

 

[rslifkin]

Isn't that the base engine in a Peninsular diesel?

Yup. The current supporter of the marine versions (Unique Diesel) bought up the remains of Peninsular when they closed up shop.

 

[Hei mateau]

Thank you for your responses. All information is good information. Still on the fence - unique diesel is in fact supplying parts, the boat price is good (unnegotiated), and she checks many boxes.