36' GB engine choices

Considering two GB 36 boats.....late 80's.They have twin Lehman 135's and Cummins 6BT5.9 engines respectively. For this exercise we will pretend they they have both been maintained appropriately.....they both have close to 2000 hrs on the meter. BUT if they have not both been looked after.....which would be more "forgiving"?
Lets not get into the discussion of singles vs twins for this debate, but help me if you can, understand the advantages of either engine for my circumstances. I do not plan to do work on them myself........but pay the big bucks instead. Will be cruising coastal routes and not interested in going over 7-8knts on a regular basis. Dependability is key.
What abt availability of parts etc etc.? Assume 135 would be easier for me to understand in a pinch? Any decent diesel mechanic can cope with either? Have not seen either engine room re space available for me!......I am not a small guy!
Look forward to your two cents!

About 6 one way. About half dozen the other.

everything being equal , it never is, I would lean towards Cummins. Parts and mechanics everywhere.

As a long-time owner of a GB36 with Lehmans (FL120s) and having chartered a GB36 with a single Cummins, I would lean toward the Cummins for the reasons Bayview states. The Cummins also has more power which one can take advantage of with the GB36's semi-planing hull.

A good pair of Lehman 135s in a late 80's Grand Banks .............I'd rather still be wanting a boat than settle for less.

I like both engines. But all else being equal, I would go for the Cummins. Easier to get parts, mechanics super familiar, more modern design. Variations of the Cummins are everywhere, and they are still available in reman/new in case you need a whole engine.

Regarding running characteristics, fuel economy, reliability, durability, noise and smoke- both are fairly similar. That is, both very reliable, etc, and both a bit smoky at start/idle.

Cummins gets my vote. I would pay several thousand dollars, maybe ten more to get a pair of Cummins for all of the reasons Ski mentioned above.

Don't be put off by the turbocharger. This is almost certainly the 210 hp non intercooled engine. The turbo is just one extra part and they rarely fail unless caused by something like a bad exhaust system design and I don't think that is a problem on the GB.

David

As a former owner of a GB 36 with a single Lehman, I'm fond of the Ford (although my experience was with the 120). I think the question was which is more forgiving--is not the Lehman simpler, and therefore less likely to have damage from abuse, or perhaps be easier to fix?

Don't know anything about Cummins, but I know I can can any part for my lehman's shipped overnite. If you need info or have questions, you can get the Godfather of Lehman engines (Bob Smith) on the phone or through email. Not sure you can get that through Cummins. Good Luck!

Cummins, far and away. Its a no brainer if you're not gonna be working on them. Any decent diesel mech can do it. Not so much with the Lehman. Both great engines but I would pay a premium for the Cummins.

No argument against the Cummins here--while I like the Fords I agree that the 5.9 Cummins is rock solid.

The ones that survey the best and are attached to the boat that surveys the best.

BandB said:

The ones that survey the best and are attached to the boat that surveys the best.

Click to expand...

+1

And Lehman's are very simple diesel engines. So any even half assed diesel mechanic should be able to work on them.

BandB said:

The ones that survey the best and are attached to the boat that surveys the best.

Click to expand...

Which one has leaks in and around the windows, decks and anywere else?

Which one has the cleanest and neatest ER?

Which one has the most up to date electronics?

Which one has the nicest looking shaft log and rudder post?

And, what anchors are they equipped with??

Wow, not what i was expecting from the group.

Granted my knowledge base is a fraction of some of the others here i expected the group to favor the ford.

i am looking for a boat now, in the process of looking i am seeing that 50% of the boats out there with twin Cummins have at least one of them rebuilt. not bashing...just an observation.


I know i can get a long block 120 ford from Bob for about $6000. Bob also supports parts and can get you any part for any Lehman overnighted at a reasonable price.

Not necessarily an advantage because so can a Cummins dealer.

From what i understand (incorrectly?) a long block 5.9 is a little more than double that.

I guess if someone were to ask me i'd give the answer that i prefer the Ford...because cheaper rebuild/long block, simple as a hammer.

Here's another thought: If you believe as many do that diesels are happiest when working harder, then the lower powered engines are more appropriate for the desired cruising speed.

Hard to imagine either engine needing overhaul unless overloaded or with a bad exhaust design. Both are surprisingly common. Overload is a matter of degree but bad exhaust design is just dumb.

Some parts are no longer available new for Lehmans. I believe the most critical of these is the cooled exhaust manifold. The only way to get a replacement for an FL120 is to get one off an engine being parted out. Don't know about the FL135 in this respect, however.

I'm not familiar with the Cummins- but there is obviously a lot of support on the board for them. I AM familiar with the Lehman 135 and they are a very simple- very durable engine. I don't think you would go wrong with Lehmans. I guess I need to see a Cummins make an Atlantic crossing...... ?


1983 Present 42 Sundeck
Twin Lehman 135's

Cummins , hands down. Millions of those engines in service, techs in every city, will be supported for years to come.

Not to knock the FL, but a no brainer in my book.

We have two 1989 6BT5.9Ms, 3300 hrs. They have a turbo but no after coolers. Very simple and basic engine that anyone can figure out. We have owned for five seasons and put 700 hours on the engines. The only issue I have had is stop solenoids that leak and had to be replaced. The engines are spotless and don't leak after 25 years. I have no experience with other engines but I have had good luck with these.

reality is that a Lehman is so simple just about any decent diesel mech will tackle a Lehman...especially with decent manual available.

I agree with the camp that says both are rather equal in durable design for this application. Now the Ford camp has very good support, my only concern would be what happens if that one place decides it doesn't want to do this anymore, Cummins is world wide and very large infrastructure for support, just something to think of.

Many thanks for everyones two cents......probably should have included thai I intend to be within US waters all the time.Mute question however the 135's went into contact the day after me posing the question!

Was that "contract"?

If so, happy cruising!

Yup...was into contract.....unfortuately I was not part of it!