Michael1

I think real world examples such as this show just how difficult it is to get light duty diesels to last in the marine environment, where they undergo long hours of heavy load. The diesels which have the longevity reputation are heavy duty, and are very heavy (weight).

Also when comparing diesels to gasoline engines, we often forget how underdeveloped the marine gasoline engines are for economy. The manufacturers have always run them very rich to prevent detonation, which kills economy. They are also using inefficient Chevy V8's, such as the 350, which were engineered decades ago, and have long been replaced in cars for emissions and economy. I hope to see more sophisticated engine control systems soon, and new engines. GM has two new LS series marine engines on their website, but I have yet to see anything from Mercury Marine using them. I know Raylar has one for sale, and perhaps Ray can chime in here and tell us what he is seeing for efficiency improvements.

I don't think you are going to see much in the way of diesels in small performance boats until they can get the cost and weight down, and the performace and durability up. If it was easy, it would have been done a long time ago.

Michael

HabanaJoe

Your boat seems a little slow and I might have some answers for you.

First are your engines painted green or does it look like they were ever painted green (under bolts, chips etc)?

Second, if memory serves me your engines are rated at 2,800 rpm not 2,600 rpm. So, check no load rpm should be close to 3,000.

If your engine are/were green then your pumps were taken off at Super Hawaii and recalibrated (don't ask why, long bitter story mainly against Cummins engine co) and it is very likely they are short of 300 hp.

I will try and find pump setting for you in some old paper work to give you about 360 hp if you want?

Also, is the transom flat is there a notch? If it's flat, look and see if there's an insert and check that, I would guess there is a hook there?

Joe Gere

THERUSH

Joe,

The engines had been painted green at some point. I have checked the no load and I agree I think the pumps are not allowing me to make rpm. Attached are a few shots of the boat that should answer your transom questions. I think that someone had done some work on the bottom as there is no gel on the transom "plug" it is only painted.

I would love the higher horsepower but I have a concern about managing heat in the engine as I know the late 80's early 90's vintage 6B's had some cooling problems. The engines also have had their issues as when I pulled one down to freshen it up I found a mismatch of std & .20 over pistons. Any advice you could offer on the heat & horsepower issue would be appreciated.

Thanks,

Rich

Doug E.

Therush'

If you have any questions about your 6BTA's check out Boatdiesel.com. there is a guy on that site by the name of Tony A. he knows as much as anybody about Cummins engines.
The reason I know about that site is we have a pair of Cummins QSM - 11's 635 hp in our boat. Had some issues with them and he was able to steer me in the right direction.

HabanaJoe

THERUSH,

Ok you have the "green" engines, let me guess the .020 pistons are #1 and/or #2. Tell me if that's where you have them and I'll post a drawing of how to fix the pistons next time you have them apart forever. People don't really understand why the older B's had problems, we burned up 4 engines in a row on the dyno within 10 minutes of running loaded (500 hp + in 1991) we damaged them. A couple calls to Columbus to figure out what the hell was going wrong, machine a set of new pistons and the next gen pistons look like our test/race pistons

Also, I'll explain why you have those heat problems, etc, etc, etc and what to do to get that boat running like it should!

You really need to check the last couple feet for a hook. Payton on here had a hook, took it out and says he picked up several mph? I have found the Arneson's need a little rocker on a non-step bottom to work best?

RIK - help me out with my comment above, I'm going by personal experiences, you have hundreds of applications, what do you feel about this?

THERUSH

Doug E,

Thanks for the lead.

Habana Joe,

I am checking with my engine builder to see which holes had the +.020's. We actually sleeved the block to get the bores back to standard so that we didn't have any balance issues.

At this point all cylinders are standards. I have factory recon heads (with the smaller diameter injector nozzles) as both heads were cracked due to heat. Both turbos have been gone through as one lost a bearing and I had them both rebuilt as I wasn't in the mood to lose any more sea time.

Like I said I believe most of the limitations of this engine is the heat. If you have some solutions I would love to pick your brain. I am not opposed to opening the engines up again if it means increased longevity & performance. It is certainly a more attractive option than the $70K for new 485hp Quantum engines that Cummins has quoted.

As the water is a little hard this time of year in Ohio I have the boat in heated storage so I will do a little closer looking to see what kind of shape the bottom is in. I agree that the non-step ASD boats do like a little rocker to counteract the transom lift from the drive.

Thanks for all your input.

Rich

Rik

Check the bottom as HJ stated. Hook can be a bad thing on some hulls not such a bad thing on others depending upon setup.

You have a fairly shallow reduction ratio. A 1.54 would be a better option and still be within the torque limits safely.

I would also look for a new set of propellers as your slippage is high. You are either over trimmed/ over propped trying to pull the pitch or there are some issues with those propellers.

If these are 2800 rpm engines and with the #'s you are over pitched as you are 200 rpm short and with your slip #'s this means a different set of propellers and this will not cause your engines to load as much creating your heat concerns.

007joe

habana joe , rik you guys really know your stuff..... this was a great read.... i love deisels... there is acompany that just put a 7.3 diesel in a 20' or 22' and had awesome results it was in a magazine, gotta get the info.....

Propster

The new diesels seem like a good fit for performance boats.

The Duramax is a lighter diesel motor with aluminum heads. Banks is getting 1000 hp out of the Duramax motors and is working to make them live at high rpms. Seems like if Banks detuned the 1000 hp motor to 750 hp and marinized it, they would be excellent for performance boats. Turbo Diesels work great at under load at part throttle under boost. Can't really hear the diesel over the turbo.

Love the sound of the turbo!

HabanaJoe

Guys the Duramax is not your answer and you can't compare a Banks drag race engine to what goes on in a boat.

Go to any tractor pull and you'll see diesels at 4-6 hp per cubic inch. That does not mean it can be detuned and live - they are race engines nothing else.

When it comes to racing diesels Banks is behind and has been for years.

Does anyone watch the racing trucks in Europe? Those are performance diesels, those guys know there stuff!