Truck diesel engines

[rajeshr]

Can someone tell me if it is possible to use the diesel engine and transmission of a truck as inboard propulsion equipment for a small displacement vessel (for a riverboat) with perhaps a thrust block aft of the transmission.

[FAST FRED]

Absolutly !

To lower the costs as much as possable I would recomend a "dry stack' and home made keel cooler.

In Maine many a boat is cooled with two hunks of pipe under the boat tied to the origonal truck water pump.

The exhaust goes out an insulated plate and should be wrapped with insulation outside (so its not a danger).

Hang a bucket over the top of the exhaust to keep the rain out when youre done.

Synthetic oil will help the tranny live as most aren't designed to run FOREVER in lower gears.
Will work just fine , but you DO REALLY need the thrust bearing , and not attempt to push on the end of the tranny!

FAST FRED

[marshmat]

Sounds plenty fine to me!

I agree with Fred about the tranny- good oil and a thrust bearing. I'm assuming manual transmission. An electronic automatic could probably be made to work too. A conventional automatic (vacuum/hydraulic) could pose a problem but you should be able to just put it into Low or D2/D3. Automatic will be less efficient though, and unnecessary, as a boat powertrain is already a fluid drive of sorts.

Marinizing the engine should be pretty easy to do. There won't be much to change on a truck diesel as many are almost identical to their marine counterparts in all but price and paint colour.

[woodboat]

I thought synthetic oil in a marine environment was a big "NO NO" as it had much lower rust inhibative properties than petroleum based.

[FAST FRED]

I thought synthetic oil in a marine environment was a big "NO NO" as it had much lower rust inhibative properties than petroleum based.

In an engine that is seddom used it is certainally a problem. And should be replaced for a off season on the hard.

Trannys are sealed and do not require the rust resistance of engines , as they can simply be overfilled for the off season , with all internal parts submerged , no rust!

FAST FRED

[woodboat]

So it is a problem and great care should be taken if trying to use synthetic in a marine environment? I don't think filling something will guarantee no rust. Certainly water can be in the mix. We all know that a pig encased in concrete will rot. I think it is flawed to believe that filling with synthetic will somehow keep the air out.

[marshmat]

Hmm... is the concern about rust on the insides of the motor and tranny here? I'd think the best way around that is to change the oil regularly (regardless of type) and to properly lay the motor up for storage as recommended my its builder. Which usually means to lace the last tank of the season with an appropriate stabilizer, change all the oils, drain the carbs, and on some engines fog the cylinders. I'd think the engine maker's recommendations would detail what to do for laying up the engine over a long period to prevent rust.

[woodboat]

My only concern was the mention of synthetic. I seem to remember many threads on this forum and the general consensus was that the manufacturers do not recommend sythentics because of lower rust inhibitors. So if you follow the makers recommendations Synthetics will not come into play.

[FAST FRED]

The hassle with synthetic is its JOY.

The stuff drains off fast and completly , leaving the surface exposed to the elements.

In an engine its a big concern ,

in a truck tranny , I doubt its a big deal,

but synthetic mixes give the excellent shear properties needed in a tranny , so perhaps a mix would be wiser.(and cheaper!)

FAST FRED

[seadragon]

Does the starter need to be marinize, or truck starter will work fine, since it's diesel.

[Vince Hosea]

I'm new to boatdesign, so this is six months old. What kind of engine do you have in mind? I have worked in the diesel truck and the marine diesel field for over eight years. Have found the same engines in both applications the same. Need to do some research on the starters and alternators to see if the marinized are made from more corrosion resistant materials and have better sealing. I know Cat 3116/3126, 3208, Cummins 5.9 and 8.3, the Detroit 53,71 and 92 series are the same for both applications.

[FAST FRED]

The only starters that are "marinized" are in gasoline boats.

Diesels are all truck parts.

FAST FRED

[Vince Hosea]

Fast Fred,

Thanks for the clairification. I do pretty much everything on boats, either as a profession or a hobby, and work on so many different brands of engines, propulsion, electrical, etc. that it all becomes a blurr from time to time.

Vince