More Power! I must have more power!

My boat has a Cummins 6BTA5.9M 210 hp engine. Can I add an aftercooler? What else would I have to change?

That's not in the spirit of trawlerism. You already have 2.5 times the power needed.

Sign up for boatdiesel.com for $25 (the best $25 any marine diesel owner can spend) and do a search. I am sure that this question has been asked there before.

My guess is an aftercooler alone won't do much. In addition it will take a new turbo, fuel injection pump and injectors at a minimum. About $5K of stuff and you willl get 270 hp.

David

Mark, I'm so ashamed. You are right of course. BUT I DON'T CARE! I must have more power! (Why isn't there one of those face thingies that means I'm insane?)

David, that makes sense. If you're going to cram more air into the cylinders you've got to squirt in more fuel as well. In addition to your list I'd need a new prop as well to absord the additional power. My shaft and gear box are sized to take the additional power.

I just went on the builders website and I see the standard engine now is a 315 HP Yanmar. When he built my boat, my Cummins was the biggest diesel he had ever put in that size boat.

HopCar-- You've got a semi-planing hull from your avatar photo. If you can get more power you can make good use of it. Just like we can. Mark's just jealous because he can't.

I just went on the builders website and I see the standard engine now is a 315 HP Yanmar.

Yanmar now offers bigger HP ratings on the same size engine.

The shaft and prop may need an additional upgrade.

Is your fuel burn now about 12 GPH?

IF not your present prop might be tweaked to draw more power at flank.

Would 210 hp continuously be enough power for you? If so, think about what to do to that engine to get the same longevity as the higher powered versions running at that hp.

An intercooler would help. Maybe that is all you need. I remember Tony Athens saying on boatdiesel that the 210 Cummins was probably the only recreational engine that could pass the Navy's grueling "run it until it breaks" diesel test.

David

HopCar:

I'll trade you my 330 6BTA for your 210. We don't need 330.

You said you have a 6BTA? Are you sure? Don't the "T" and "A" stand for turboed and aftercooled?

FF, right on the nose. 12gph wot.

Dwhatty, you are correct, I have a 6BT and I want a 6BTA. By the way T & A has a much more interesting meaning as well.

David, you're right the Cummins B series is a very strong engine. They pull 210 hp from mine and 330 hp from dwhatty's same block and they both seem to run forever. Newer engines seem to be much lighter and turn much faster toi develop the same horsepower.

So, how much power do you want, continuosly?

David

Marin said:

HopCar-- ... Mark's just jealous because he can't.

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Maybe, but so far I haven't seen the need to get somewhere in a big hurry.

In it's 210, form the Cummins 6BT engine is almost unbreakable.
I had a pair in an early Riviera 35 SF. The limitation was always the rotary high-pressure fuel pump. In about 1988, a 250hp version was produced with a jacket-water-cooled after-cooler. This engine was not a success because the rotary pump couldn't cope with the increased demand and wore out very quickly. These engines were always smokey.

I've had moderately good success with by twin 330 6B TA's. I need the power these engine produce to plane my boat. But the turbos and aftercoolers add complexity. The aftercoolers especially seem to be a source of problems if not cared for. I would not add complexity if not absolutely necessary.

Some railroads downgrade the diesel engines on their older locomotives when shifting from road to less-demanding switching duties. The object is to reduce engine maintenance costs. Downgrading includes removal of turbos and perhaps some other engine adjustments. Could such a tactic be worthwhile on higher-performance marine diesel engines?

Could such a tactic be worthwhile on higher-performance marine diesel engines?

Depends if the turbo was an after thought.

IF the CR is the same with or with out the turbo , no problem , but a check that the cam is the same would be wise.

Many engines factory set up for a turbo will have a lower mechanical CR.

These can not be downgraded much as the turbo must create positive pressure for the engine to breathe OK.

Hopcar

All rolled up, your answer is imbedded in many of the replies you have received.

But if you are really serious about more power from your 210 HP NA Cummins 6B follow D Marchand's advice and post the same question on boatdiesel.com. Just remember props move boats, not engines as you pursue this question.

IMHO, your cheapest and most realistic option is likely a new boat. You should have no problem selling your very reliable current setup.

Thanks guys! A lot of good info. I will check out boatdiesel.com. Timjet's comment about aftercoolers adding complexity has me thinking I need to do more research into that. At the time I had the boat built (1988-89) they offered the engine in four configurations.
Naturally Aspirated, Turbo (Mine), Turbo Aftercooled w/ engine coolant, and Turbo Aftercooled w/ raw water.
Dwhatty and Timjet, are your 330's aftercooled by raw water or engine coolant?

HopCar said:

Dwhatty and Timjet, are your 330's aftercooled by raw water or engine coolant?

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Mine are aftercooled by raw water, but I fresh water flush my engines after each cruise. They are never stored with salt water in them.
As a further note, I have never had problems with my Turbo and aftercoolers other than a minor turbo oil leak that was fixed by a simple cleaning of the turbo housing. I disassembled and cleaned the aftercoolers after I purchased the boat and since I fresh water flush I don't expect that I will ever have to clean or service them again.
If you take some time and read the threads on boatdiesel.com you will see why I mentioned the concern about adding complexity as the aftercoolers especially seem to be a real problem. But like anything else if taken care of they are not especially prone to problems. If not however they can lead to a ruined engine as water can get into the air side and subsequently into the engine.

But for reliability it's hard to beat a NA Perkins, or so I've heard.

timjet said:

Mine are aftercooled by raw water

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Ditto

Now you guys have me thinking that if I want a 6BTA engine maybe I should see if I can find a good rebuilt engine and swap mine and some money for it.

Take a look at the Cummins Remans. It may be more money than you want to spend but check it out first. It may be cheaper than blowing a poorly hot rodded engine and you will have a fully warranteed engine.

I'll chime in here also. Adding a bigger turbo and aftercooler will not make a 330 or so engine. Certainly not one that will last. There is more to it than that.
The higher hp, 330 or so, engines that you suggested have different pistons, piston oil cooling jets, recalibrated pumps, and a whole host of other changes to make them last and work.
Don't look at the truck hot rodders or boat rodders. They make a short blast of a few seconds and get away with stuff that will blow up an engine that will be expected to run for hours reliably.

I'm no expert but I've seen this question raised many times on Boatdiesel over the years and Tony Athens and Paul Folston, both Cummins experts, will tell you basically the same thing.

You will also need to change the prop and maybe the shaft to take advantage of the extra hp or all will be for naught.

Do some digging and reading the older posts. Sure it's possible but very likely not effectively for long term.