Help! Dodge Cummins in boat

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I've been reading for a while the vast knowledge on this forum and finally decided to join because I could use some good advice/help. I have a 180hp 5. 9 Cummins from a 1997 Dodge (CPL 2022, manufactured 2/15/96) in a commercial fishing boat. I didn't have the funds to get a new Marine Cummins and found an almost new motor out of a totalled truck. The motor has a custom water jacketed exhaust (pipe inside of a pipe) with the original hx35 turbo. A 4" stainless exhaust pipe passes straight up from the motor thru the cabin (no frills on this boat!). Instead of the stock air to air aftercooler on the truck, I found a jacket water cooler from a 250hp marine engine. The engine coolant passes through a pipe running on the bottom of the boat. The motor has 2500 hours on it and still sounds great. Last week my turbo began to make a lot of noise and I am now replacing it with the hx40 (found a brand new one on e-bay). Since I am upgrading the turbo, I wanted to take the time to possibly add a bit more horsepower - this is where I need the help. With the HX40 arriving, what can I do to this motor that will reasonably increase HP (say 30 to 50 HP) without compromising reliability? I want to be conservative because this motor runs under a continuous load - no coasting down hills! I've read all about the TST plate and other modifications, but not sure what the best solution for my application would be. Also, I am planning on insulating the turbo to keep the heat down in the engine room - I've melted a lot of things from the radiant heat - including my air filter - Does anybody out there know if insulating the turbo will do any damage to the turbo???

I know I don't have a Dodge truck, but I do have the best part - the motor.

Craig

 

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I'm no Cummins expert, however I have quite a bit of experience with them and with marine engines. I see no reason the engine wouldn't respond equally well in a marine application. A marine engine thrives on torque, and the Cummins definately has plenty of that ! #ad
As far as these marina clowns trying to tell you that a marine engine is so much different from an automotive application, I say BS ! #ad

They try that with Small Block Chevys too... . they're "Mercruiser", not Chevrolet... What a crock ! Yes there are some VERY minor differences between automotive applications and Marine, but they're bolt-ons such as water manifolds & some stainless stuff. If you have closed system cooling, there are NO major differences. Yes, Marine engines are loaded all the time, no coasting, but the Cummins is made for torque, and that's the load you'll be placing on your engine. Nice smooth torque. I say
"GO For It " !! #ad


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1996 2500 4X4 Auto 3. 54 gears... Cat fell off!!

[This message has been edited by PSInt (edited 01-01-2001). ]

 

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Craig,

What sort of fishing is the boat used for? How big is it? Is it a planing hull or a displacement hull? If it's a planing hull and you go fast enuff to plane it then the more power the better. However, if the engine is running against the governor even with a planing hull you will need to get a wheel with more diameter or pitch or both. It the boat is very big these things ain't cheap. If it's not a planing hull, then there are some other considerations. If it's a dragger do you need more power for the tow? Are you running a lot of hydraulic stuff off of it? If you don't need the extra power for running the fish gear then it would mostly be used to get out to the fish grounds and back. If it's a displacement hull, do you know the hull speed? There is a formula to compute that but I don't have any of my boat books handy to help me remember what it is. If you are already running at hull speed it takes a lot of power to get much faster so you would really just be burning up fuel for little gain. I ran a 46' salmond/albacore troller for a while. The hull speed was just below 10 knots. If we were in a hurry I would just bang the trottle against the stop and let the Detroit 6/71 scream. That would get it up to 11 knots. We paid for that kind of stuff with fuel.

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Joe George
Eureka, CA

'95 2500 CC auto 4X4,3. 54,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,BD valve body,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver

 

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great answer Joe.
The first thing you had better do is install and egt guage, running the high rpms is were you will reach the highest egts and really how you can hurt the motor. I have and also heard its good to cover the turbo and will not hurt it in any way. I acctually makes it work more efficiant. Give it as much power as you want, just remember you can probably make way more power than the drivtrain can take and easily have to chage the prop for a bigger one.

 

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Joe/PSInt,

Thanks for the responses. I need guidance on what I should invest in to increase the HP a bit - for this boat application. By the way Joe, the boat is a typical East Coast lobster hull 34' long. It is considered a semi planing hull. I recently changed the gear reduction and the prop. I have a bit too much pitch right now - so instead of repitching the prop, I wanted to bump the HP - I think I only need about 30 hp to get the motor up to safer rpm's. I use the boat for trapping Pacific lobster and diving for sea urchins in Southern California. The engine also runs hydraulics for an air compressor and trap puller - but this doesn't use much HP and only at just above idle speeds. The boat is capable of 17knots with the properly marinized 6BT Cummins - but you know how much Cummins wants for one of these!. Right now I'm going 12 - and running the motor at only 1700rpm's because there's just too much pitch in the prop at the moment (I could run at 2000, but don't want to burn the motor out - bakcing down 300 hp is getting me by for now). I've gone through several iterations of gear reduction and prop size pitch before arriving where I'm at now. I'm hoping extra HP will save me the pain of pulling the prop off for repitching (again) and would certainly increase my speed.

Any help on what to do to get a bit more "reliable" hp, also if I can wrap insulation around the turbo without hurting it would be great.

Craig

 

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Sound advice - A friend of mine reccommended the EGT gauge a while back - I installed one with the probe just in front of the turbo - unbelievable temperatures - normal, but I'm just not used to seeing temps so hot. I run it a 1100F while cruising out the fishing grounds (5 hours) - I've heard this is safe.

 

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Craig,

You might just move the stock plate all the way forward and see what that gives you. That won't cost anything and if you only need about 30HP that might just do it. Keep an eye on the EGT if you do this.

Another thought. All this messing around with the plate does is increase your fueling. So if you run it at 2000RPM it will be the same thing as you have now. Just less distance on the throttle to get there is all. Same load on the engine. If your EGT is ok and the RPM is above lugging you are not going to "burn the motor out". That's the sort of thing these things are designed for.

[This message has been edited by Joe G. (edited 01-02-2001). ]

 

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SKAG, with adding the HX40 you should see some lower EGTs. I agree with Joe, just push that plate forward and put that new turbo on and you should see at least 50 more hp.

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Eric
GLTDR

 

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Craig, I can't offer any help to you but I am curious as to how many gallon an hour you use at 1700 rpm. Do you have any idea? The engine seems like a perfect match to you boat.

 

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This sounds really interesting. What are you running as far as injectors. Are they the 275 marine injectors ? Bigger ones would certainly give ya more thump. Match with that turbo and wow. Keep us up to date on this project. Bom-ing boats. #ad
#ad

 

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JJP: I burn about 6 to 7 gallons an hour at 1700 rpm.
Jeff H: I have the stock injectors from the truck. I'm going to try everyone's "cheap" reccommendation to just bump the fuel plate forward. If I need more, I'm going to go for injectors.

Craig

 

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What are the safe limitations for continuous running conditions for this motor.
-EGT (before the turbo)
-RPM's
-Boost pressure (I have the HX35, but am installing the HX40 soon).

Also does anybody know where I could get insulation that I could wrap around my turbo?

Thanks,

craig

 

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scag push the plate all the way forward to the max of the adjustments this will give you at least 40 hp if not more.
Max egt is 1300 for long duragtions, you can hold it there all day if you want as long as water temp stays good.
Max rpms, I've gone to 4000+ but I wouldn't be consearned with 27 to 3000 for a wile. Your way under don't worry.
Boost pressure, the max efficiant boost for the 35 is 36psi, after that you acctually loost power from what the experts have said. With the hx40 you are limited to around 50psi but 45 to be safe. The limit to how much boost you can run is around 85psi before you have to o-ring the head.
I got my header wrap from a race shop, but summit and other mags have it. Its not cheap. But it works.
Let us know how it turns out. #ad

 

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Only 1 thing left that Adam didn't cover in his post, that's the max RPM. When I was at CMEP last year they said that the B can run at 3K all day long even though it's where the tach turns red on our trucks. When I was at Scheid Diesel getting some work done they found a bent push rod. They looked at it really funny and said that it shouldn't happen on an auto truck. They said that they usually saw bent pushrods on manual transmission trucks that 1 of 2 things happened to. The first was that someone was going too fast for a downshift and they dumped the clutch. The other time was when someone had a long downhill run w/o an exhaust brake and just let the engine go. Either senario bent push rods when the RPM reached around 4K or so. I hope this info helps and you have as big a smile on your face because of your boat as we all have because of our trucks #ad


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'94, 2500, 4X4, SLT, 3. 54 gears, Prime Loc, Silencer ring in the tool box, DeeZee bright tread running boards, side box boards and mud flaps. Alpine CD player. I cleared 100K mi while the board was down. Jardine Performance 4" exhaust (sounds just like a Pete, it's great) Schied Diesel put timing to *15 (by timing light), put gauges in on the A pillar (trans temp, boost, and egt) They also set my stock plate up (40 hp 150 ft/lb gain) OH, what a difference a day makes :-D

 

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SKAG: If you really want to put the most HP to the water you should get a variable pitch propeller. With a variable pitch prop you would set the RPM's (power) you want and then crank up the pitch until you get 1300 (or whatever) on the EGT gauge. This will give you maximum efficiency and you won't have to change the prop every time you modify (BOMB) your engine.