Early 90s 4.3 to 97+ 4.3 efi

[dohcdelsol93]

I picked up a small cuddy cabin walk around to use while i restore my carver flybridge/vw diesel engine swap (trying to find a way to cool turbo manifold w/o losing turbo performance)

great hull, bravo 1 outdrive, trim tabs, swim platfrom. She's ready for a keys fishing trip other than the motor.

Shes got a tired 4.3 needing a timing chain at minimum. I've got a low mileage 2000 blazer with a bad transmisson. For those unfamiliar with the history of the 4.3 the 97 up has the combo of the balanced block, best heads and best programming for a retune.

Since i have an entire vehicle why not dumb down the harness and have an efi boat?

best of all a cheap auto scanner will work on it. I prefer the torque app with a small tablet/blue tooth dondle to constantly keep tabs on the data logging.

getting the tuning done is not an issue, getting a tuner out of the shop beside a dyno and out to the lake is!

On my 05 passat 2.0 BHW diesel it was an easy affair, send off ecu and came back with exhaust sensor deleted and ready to plug and play in the boat (once i get the manifold cooling sorted, if i had an engine room this wouldn't be an issue)

I don't think the 4.3 is that simple. Are there manifolds that will allow me to run an 02 sensor and if so will i need special waterproof(salt and fresh) o2s?

If the boat is turn key when the tuner hops aboard, can just datalog, tweak and repeat he's more likely to be willing to show up and im spending money on paying him to tune and not watch me turn wrenches because something isn't jiving and preventing a proper tune.

 

[achris]

Anything electrical or fuel system you put in a boat must be marine certified. It's not just a sticky label, it's there to save your life. Don't mess around trying to put automotive stuff in a boat. BAD idea! And that goes equally for your diesel. You are playing with fire, and likely turning any boat you work on into a floating bomb.

Chris......

 

[dohcdelsol93]

Thanks for your concern but...7



A diesel is a little different than a gas motor, no explosive fumes to deal with. No need for "marine" starter or alternator. A small 5 psi electric pick up pump will be in the tank, the diesel has it's own tandem(high pressure) pump that runs off the cam. The danger of a run away diesel is always there however vw has a built in flapper valve that looks like a throttle body which will shut off air to the intake if it senses a run away (too much air/fuel but no throttle) a sticky throttle cable would be much less fool proof. Synthetic motor oil also prevents run away. Large work boats use non water cooled exhaust on diesels with double walled exhaust smoke stacks. Up until the 90s diesels also used road draft tubes. This vented the crank case down the side of the block to the ground. If those fumes were explosive you would see tons of flaming trucks, tractors and other equipment buring to the ground as we speak. The biggest hurdles most have on diesel conversions is gearing, beefing the drive to handle desel torque and galvanized fuel tanks need to be lined or replaced as they won't jive with the diesel. Those big diesel generators mounted in big boxes with enclosed fuel tanks need no more "marinization" than a boat and thousands of lives are depending on those generators at your local hospital when the power goes. A skid loader engine...road draft tube in a steel enclosed box that you sit on top of. Fuel tank also in that box. Diesel fuel is nearly motor oil. When you change the oil in many inboards you dump the oil in the hull and wash it out the drain plug! How many boats have you seen with a slight oil leak that have 1000s of hours without an explosion? To ignite diesel you really need a wick. Throw sparks or lit cigarettes at it. Don't toss a burning rag into a bilge full of diesel. It will burn but wont go boom. Now atomized it and yes it goes boom. So dont boil it with water.

as for the 4.3, i will use a marine starter, high pressure fuel pump, spark plugs and alternator. Asside from those few items a fresh water cooled needs no additional marinization. It's bolt in.

my question is on the tuning (open vs closed loop) anyone have suggestions for keeping the 02 sensors?

 

[Scott Danforth]

do some reading https://forums.iboats.com/forum/eng...history-of-the-4-3-liter-with-casting-numbers

because the motors have been balance shafted since 1992 and the vortec heads came out in 96.

automotive fuel systems have no place in a boat.

while diesel fumes dont explode like gas fumes. its not smart to take an automotive motor and not properly marinize it.

and VW did properly marinize motors - the 1.6 and 2.0 4-bangers, the 2.5 5-banger, the 3.0 V6 and the 4.2 V8, however its a complete water-cooled turbo (including the turbine housing) in addition to both a water to water HX for the cooling water and a water to Air HX for the intake air.

however using a non-water cooled exhaust in a boat is introducing an ignition source for other items in the boat. boat motors generally try to keep all surfaces below 200 F. you cant do that cheaply

 

[dohcdelsol93]

The issue I'm runnung into on my diesel conversion is the water cooled turbo manifold. It grossly affects the turbo as the turbo needs heat to spool, another guy has cast a watercooled 1.9 tdi manifold but it had perfomance issues because of it. It ran much better pushing a 25 ft searay cuddy with no engine cover and water/oil cooled turbo and water injected into the down pipe a few inches past the turbo. The issue is major heat from the exhaust side of the turbo and manifold. Well over 200 degrees. Open jet boats run them open with no issues. The cramped cockpit of a 26 ft flybridge would not allow that. I have looked at an extra large water to air intercooler to control the IAT and enclose the intake and turbo into a box which is then plummed to its own heat exchanger/fan (intake/exhaust are on same side of head) but it's still in the design stage to make it as air tight as possible. 170hp and 300ft lbs of torque from a sub 450 lbs engine is a nice little package once the bugs are worked out. The back of the motor is adapted to match a sbc.

back to the efi, the stock ecu is plenty durable enough for marine use (some salt water a few times a year) and the relays don't care if they are marine or not, nor does the wiring harness. Megasquirt is common in the marine world and is no more or less marinized than modifying the blazer harness for the boat. The meat and potatoes is the tune, most notably the lack of exhaust pressure. Are there o2 sensor compatable manifolds? I realize the differences between 4.3 blocks but its the tuning issues i have questions with on 97 and up motors. These have the easiest harnesses to work with and best ecu to work with.

 

[dohcdelsol93]

I did find a manifold to riser adapter that provides an o2 sensor bung. Now i gotta find a compatible waterproof o2 sensor supplier. Any recomen recommendations? The heater o2 sensor (the 3rs one) can hang in no mans land, may throw a cel. I just need these in place to run the motor in place, work out any bugs before removing to bolt in a wide ban/turn it into a closed loop system.

 

[Scott Danforth]

open jet boats are a different animal. they also have fires often

your playing with fire and no one wants the liability of offering help for a reason

marine SAE J1171 compliance has nothing to do with if it lives in the environment, it has to do will it kill you

megasquirt is not used in the marine world, dont ever try to make that statement.



BTW, 4.3 marine EFI motors have more fueling than auto motors as they are putting out 220hp at the prop (270hp at the crank) and DO NOT use O2 sensors.....wrap your head around that

your trying to re-invent the wheel the hard way. if you want a marine 4.3 EFI motor, buy a marine EFI motor.

 

[dohcdelsol93]

You've never seen megasquirt on a boat?

I realize there are fueling differences hince the need for a tune. Im using the stock blazer ecu as it had no short falls vs a stand alone ecu and many advantages over that of the mercury until. Ease of diagnostics and price being the largest. If you wanna pay the marine mark up margins go ahead.

an ecu is an ecu and short of programming so long as they are property mounted and water proofed one is no "safer" than another. Same goes for a wiring harness. Not sure how im reinventing the wheel with all the holly/other stand alone efi units being installed into boats.


found an outfit out out of Michigan that specializes in gm products, conversions. 200 to tune a vortec 96 up ecu for a boat. 500 or so for a stand alone harness.

a special exhaust adapter (2 needed for 4.3 and v8) that allows stock o2 to be used 95 bucks each.

Drop your 96 to 2011 vortec enfine in, plug and play. You will want the marine starter and alternator for saftey precautions as previously stated and a marine fuel pump.