Auto Diesel engine into boat?

[Emoyeni]

As I evaluate different repower options, one thought I have is to go to a junk yard and purchase an automobile Diesel engine and place it into my boat. Has anyone done this? What would be the drawbacks?

[acem]

Yes it could be done. Most marine engines are standard diesel engines that are converted for marine use. It is possible but the devil has in the details.

It would be much easier and probably cheaper to find a dead marine engine assembly that uses a common industrial or agricultural engine. Then get a good used identical engine and merge the two.

Honestly this is not practical unless you are a good mechanic. If you're a good mechanic you could just rebuild the engine instead...

Thx-Ace

[Bill O]

Yes you could do it but probably not worth the effort for your boat in fresh water.
Many commercial work boat have keel coolers/heat exchangers and do not pump raw water thru the engine. In salt water this is an upside. The drawback is a dry exhaust that is all metal to handle the heat.
Would try to find a used marinized motor if you are on a budget.


Edit: almost forgot, would probably need to change the engine bed and motor mounts to make a different motor fit correctly.

[kenbo]

Yes it's done all the time in narrowboats. But in your case it would be much easier to find a used 2 or 3 cylinder Kubota or Mitsubishi industrial engine that starts easily, doesn't smoke and has little to no blowby. The marinization parts for those engines are easy to find. And since the marinization parts are usually the first to go it's better to start new.

But as was said earlier, there's a bit of a learning curve if this is your first time.

You can buy a brand new, fully marinized Mitsubishi LE2 (15hp @ 3600) with a gearbox for about $5600 (USD)+ shipping as a comparison.

[Woodland Hills]

Anything is possible with enough time and money. But if you have the skill and desire to do this, you are able to rebuild any marine diesel you come across. That would be a lot faster, easier and cheaper.

[kenbo]

Originally Posted by Woodland Hills

Anything is possible with enough time and money. But if you have the skill and desire to do this, you are able to rebuild any marine diesel you come across. That would be a lot faster, easier and cheaper.

I've done it both ways, rebuilding a tired marine diesel and marinizing an industrial engine and I can't necessarily agree on faster, easier or cheaper.

If the marine diesel just needs an engine rebuild and you do it yourself than yes I agree. But typically old marine diesels have end of life manicoolers or heat exchangers, gearboxes, drive plates, fresh water pumps, raw water pumps, mixing elbows and such so the costs tend to get very even especially if you start with a used but solid Kubota or Mitsu.

I don't know what engine the OP has. It could be an Atomic 4 so he may be looking to convert to diesel. In that case buying a used marine diesel tends to be an expensive crap shoot where every reputable used industrial engine seller will start and run your engine before you buy it.

In my experience, and in just my experience, it has always worked out better to start with a solid, used industrial engine with all new marinization parts than a used marine diesel that has the engine rebuilt with the older marinisation parts. YMMV

[FransvanBuuren]

In my 44 ft sailing boat is Mercedes Om615 car engine.
Specialy marinised for a boat. There are kits available to do so for several car engine . ( Drinkwaard Holland )

[Scubaseas]

Originally Posted by kenbo

I've done it both ways, rebuilding a tired marine diesel and marinizing an industrial engine and I can't necessarily agree on faster, easier or cheaper.

If the marine diesel just needs an engine rebuild and you do it yourself than yes I agree. But typically old marine diesels have end of life manicoolers or heat exchangers, gearboxes, drive plates, fresh water pumps, raw water pumps, mixing elbows and such so the costs tend to get very even especially if you start with a used but solid Kubota or Mitsu.

I don't know what engine the OP has. It could be an Atomic 4 so he may be looking to convert to diesel. In that case buying a used marine diesel tends to be an expensive crap shoot where every reputable used industrial engine seller will start and run your engine before you buy it.

In my experience, and in just my experience, it has always worked out better to start with a solid, used industrial engine with all new marinization parts than a used marine diesel that has the engine rebuilt with the older marinisation parts. YMMV

What Kenbo said. I've done this both ways also. If you are looking for a 20 to 30HP Diesel you're not going to find one in a car or truck. Marinizing an engine is easy, the hard part is the connection from engine to transmission and the transmission itself. You can easily address the cooling and exhaust systems and even the mounts but the tricky part is the flexplate and what gearing you need for the engine. Lots of small stuff comes into play and how much will depend on what you are capable of and willing to do.

What boat and what's in there now? C&C 30 with what?

[Emoyeni]

Originally Posted by Scubaseas

What Kenbo said. I've done this both ways also. If you are looking for a 20 to 30HP Diesel you're not going to find one in a car or truck. Marinizing an engine is easy, the hard part is the connection from engine to transmission and the transmission itself. You can easily address the cooling and exhaust systems and even the mounts but the tricky part is the flexplate and what gearing you need for the engine. Lots of small stuff comes into play and how much will depend on what you are capable of and willing to do.

What boat and what's in there now? C&C 30 with what?

It’s got an atomic 4 in it now. I’m debating between going electric vs diesel repower. I think given the mechanical complexity of a diese engine, I will go for electric.

[atoll]

lancing marine sell marinization components for many common diesel engines,ship world wide

https://www.lancingmarine.com/index.html

[Bill Seal]

If you have access to a machine shop (or a machinist who likes a challenge and free beer) it would be a piece of cake to stick almost any gearbox onto any engine. For my T-Bucket roadster, I mated a 1938 Ford V8=60 flathead to a junkyard Toyota Celica 5-speed.

[Cheechako]

Many auto brand have been used in boats. Most are too big unless you have a big boat. Marinization costs can be pretty expensive. Transmissions are quite expensive. Although you can find universal type heat exchangers to use.

Diesel vs electric I think you will find diesel more useful.

[Reel Love]

You could easily be chasing a solution with diminishing returns. Yes, all diesel blocks are pretty much similar, but that's about where things end. I ran an engine remanufacturing plant many years ago. Any engine can be converted to do one thing to another, but there are differences in how they are designed to operate.

IMHO, start with an engine block that you know is going to fit in your boat, on the mounts that are already there. Then rebuild away to your hearts content. In the end, you will not find yourself having to be adapting: gauges and reporting units, wiring harnesses, engine mounts, water cooling hose locations and connections (a bigger deal than you might think... I had this problem in a boat that drove me nuts), heat exchangers, risers, exhaust manifolds, the alternator and the related wiring connections, transmission mounts, shift and throttle cables, U-joints, shaft lengths, propeller (different transmission gear ratios will force you to change the prop) and god only knows what else you will run into, like the damn thing will not fit.

[Scubaseas]

OP, Good luck with your research. Lots of info on electric conversions here and other places. If you are cruising electric may be limiting but I suppose it really depends on what you are using the boat for. Cost wise the cheapest might be to rebuild what you have.

Beta Marine conversions are easy and may be the best from a resale perspective. Also may be best if long distance anything.

[Gypsyjon]

Yup easy enough to do.

I took a Perkins 6-354 out of a Massey Ferguson tractor and put it into a 34 foot steel hull.

I ordered a water cooled manifold from Perkins, put a raw water pump on the front of the engine, got a Vetus waterlift muffler and VOILA! Nice quiet Perkins in place of a screaming 6-71 with dry exhaust.

The boat had homemade compartments on the bottom of the hull that were used to "keel cool" the 6-71 but I opted for the simpler solution, which was the Vetus muffler, water cooled manifold and pump.