Diesel Benz motor. Conversion?

[spamman450]

Hi everyone. My other hobby besides tinkering with boats, is fixing and enjoying old Mercedes Diesel cars. My favorite motor being the OM617 turbo diesel. I always thought a 617 turbo diesel would make a good boat engine. I am very comfortable with these motors, and can obtain parts for them very cheaply. This brings me to my question. please bear with me, and feel free to critique this idea, tell me i am completely insane or shoot it out of the water here goes.

I have a 1972 Bayliner 19ft boat with a Volvo aq170 motor and a 270 outdrive (pic below). The boat was given to me and is in decent condition. The thing is, i don't like the aq170 that powers it. The engine is a dinosaur and parts like water pumps are prohibitively expensive.Not to mention the triple carb setup.
I would like to put the OM617 in its place. There is a company called 4by4 labs that makes an adapter plate and flywheel that makes the end of a OM617 essentially the same as a Chevy 350, so it should bolt up to the 270 outdrive with out too much work. The exhaust manifold for both engines comes out on the same side so i would be able to fab up a connection and make it work. Raw water would be handled with a belt driven pump, and i would have to install some sort of heat exchanger. custom motor mounts would be in order as well as anything else i forgot to mention. I like big projects, have access to lots of equipment, and i think i can make it work mechanically.
What i want to know is if the motor is strong enough to move the boat. A OM617 has 125 hp, 180ft pounds of torque, and red lines at 4500 rpm (not that you would want to go that high). The aq170 Has 170 hp, around 170 ft pounds of torque?, and i don't know what it revs to.
I would love to hear some feedback. This is just a thought exercise at this point, so i wont do it if its technically impossible.
Thanks for reading

 

[86 century]

Re: Diesel Benz motor. Conversion?

Sounds like a cool idea

Two things that could be big problem are the exhuast manifold(finding or making one that is water cooled)

The coupler
I depends on how they make the convertion flywheel some simply change the bolt patern witch is where some couplers bolt on.(not sure on the volvo 270)
Good luck keep us posted if you decide to do it.

 

[Scott Danforth]

Re: Diesel Benz motor. Conversion?

you also need to have a water cooled turbo or wrap it to keep the ignition sources to a minimum. since the engine is not a marine engine, and wont be coast guard approved, you may have insurance issues.

 

[spamman450]

Re: Diesel Benz motor. Conversion?

Thanks for the replies guys. I was thinking that using a wrap post turbo might work, or have a water cooled exhaust fabricated. This thread on Peachparts.com is what originally got me thinking. http://www.peachparts.com/shopforum/diesel-discussion/275657-617-turbo-into-boat.html
The outdrive he is using is a Mercruiser, i assume it would work with a volvo 270, although further research is needed.

 

[Luhrs28]

Re: Diesel Benz motor. Conversion?

Spamman: I also used to own a Mercedes with the OM617 engine. I have 3 thoughts about the conversion:

1) It's going to take a lot of custom fabrication.

2) Have you compared the weight of the OM617 to the original engine? That Mercedes motor aint light.

3) The boat is going to be slow. And noisy.

See my Luhrs 28' thread in the restoration section. I'm putting a gasser engine back in mine this year because I wasn't happy with the diesel.

Whatever you decide, good luck with the project.

Bert

 

[QC]

Re: Diesel Benz motor. Conversion?

I echo Mr. Danforth's comments on the water cooled turbine housing. I see some discussion on the link regarding after the turbo, but not the turbo itself. That needs to be addressed. Blanket is possible, and they are made commonly in the industry, but not marine from what I have seen.

What i want to know is if the motor is strong enough to move the boat. A OM617 has 125 hp, 180ft pounds of torque, and red lines at 4500 rpm (not that you would want to go that high). The aq170 Has 170 hp, around 170 ft pounds of torque?, and i don't know what it revs to.
I would love to hear some feedback. This is just a thought exercise at this point, so i wont do it if its technically impossible.

I think the RPM range is actually a plus and I suspect that you will have to run her near "redline" which I would like to call "rated" RPM if that is indeed where it is rated for the 125 bhp. Do you have a horsepower/torque curve that I could look at? Despite previous comments of mine that are often misunderstood, the higher "peak" torque will help, but only to get this lower powered combo up on plane. After that we're going to have to have to consider what the impact on top speed will be. This will require a propeller pitch change assuming the great ratio will stay the same. What's your pitch today? Gear ratio? WOT RPM? Top speed? Need all that to try and zero in on the feasibility from purely a power standpoint. Any weight difference is huge as well. If you are not nearing 40 MPH today, I think this may be really bad . . .

BTW, this is a great example supporting what I have been trying to explain for the entire six years I have been posting here. Although the Mercedes has a higher peak torque value than the Volvo gasser, it has lower "rated" power and the boat will be slower. Bert's boat is another perfect example, yet this battle rages on . . .

 

[spamman450]

Re: Diesel Benz motor. Conversion?

Here are the horsepower and torque curve graphs. The OM617 is in dark blue. From this thread if its too small to read. http://www.peachparts.com/shopforum/diesel-discussion/241922-project-gm-benz-has-begun-9.html
I am not sure of the propeller pitch, i will find out tomorrow morning when it is light out. I assume that the prop would have to be changed. I am also trying to hunt down the aq170 torque graph and weight of the boat . I did find out that the max RPM for the aq170 is 5000. I understand that torque is not as important as Horsepower in an application like this, thanks to some heavy reading on this forum. I have yet to have the boat in the water, so i am unaware as to how fast it goes or what rpm it operates at. I am planning on taking it out in a month or so. If i could get the boat to do 20-21 knots without the engine straining and screaming, i would be a pretty happy guy. If none of this is feasible, i may just invest in the aq170. Thanks for the responses so far.



View attachment 121686View attachment 121687

 

[spamman450]

Re: Diesel Benz motor. Conversion?

Spamman: I also used to own a Mercedes with the OM617 engine. I have 3 thoughts about the conversion:

1) It's going to take a lot of custom fabrication.

2) Have you compared the weight of the OM617 to the original engine? That Mercedes motor aint light.

3) The boat is going to be slow. And noisy.

See my Luhrs 28' thread in the restoration section. I'm putting a gasser engine back in mine this year because I wasn't happy with the diesel.

Whatever you decide, good luck with the project.

Bert

The OM617 weighs about 600 pounds.

Having driven a 240D for the past ten years, i have gotten quite used to slow and noisy lol.

 

[QC]

Re: Diesel Benz motor. Conversion?

Still need to know how fast she is now and what RPM at WOT. Very important info. Also need existing prop specs.

 

[spamman450]

Re: Diesel Benz motor. Conversion?

The prop size is 14 R 19. I am trying to contact the previous owners to get an idea of how fast she was. Research shows that the aq170 maxed out at 5000 rpm. Should i run mine briefly up to WOT to get a reading?

 

[QC]

Re: Diesel Benz motor. Conversion?

If she's right, that is the only way to get useful data on what 170 bhp can do. Very hard to be accurate with something that old. Who knows how many ponies she's actually making today, but it would be nice to have some data to work from . . .

 

[MCL]

Re: Diesel Benz motor. Conversion?

Im doing something similar but with a om606 engine.And I would suggest using that engine as its stock output is 185hp,its very durable.Considered to be one of the best engines mercedes ever built.I would however suggest using the om603(its predecessor) injection pump to get rid of any electronics.The om606 injection pump is electronically controlled.

If your not hunting for horsepower you can use the stock turbo but it needs to be shielded,manifold needs to be watercooled and a riser needs to be fabricated.Otherwise you can use a watercooled penta tamd/turbo of similar output.

 

[ricardo mann]

Re: Diesel Benz motor. Conversion?

Hi i have 2 om606 in my boat . i did all the work this is a good set up i have on bravo 3 with 2.2-1 ratio fast go to link www.youtube.com/watch?v=VNFAvPYvVKU

 

[MCL]

Re: Diesel Benz motor. Conversion?

Hi i have 2 om606 in my boat . i did all the work this is a good set up i have on bravo 3 with 2.2-1 ratio fast go to link www.youtube.com/watch?v=VNFAvPYvVKU

Could you tell me a little bit more about your setup?Like intercooler,oil cooler etc.When does the turbo start to spool up?What boost?Im going to build a pretty similar setup,using a hy35 instead of the hx for better spool up.
Ive seen a dyno sheet of a om606 with custom manifold,a k27 turbo(54mm/60mm,similar size to the hx35) with a large intercooler and bigger elements pushing way past 300bhp on a car.Not saying you want to push the engine in marine use at that level,but your hp seems a bit low for the setup

 

[ricardo mann]

Re: Diesel Benz motor. Conversion?

Hi. All the parts to marines the engines i fabricated my self.
The oil cooler is from a company. Bowman in the UK.
the intercooler is fabd up by me. the inner cor tubs are from bowman and the rest is just aluminium pipe
i got a bit of help from a tech man at bowman
a lot of this is just common sence and a bit of gets work
The turbo charger spools up as soon as the motors start to get a bit of resistants at about 1500 2000 rpm .i did a lot of chopping and changing with gear ratios and props.
all in all the boat is a 28 ft baja force 1985. it is 7000lb. fast hull. This is the best combo for this type of boat. 2X bravo 3 . 2.2-1. 20"p props. Boat chugs along at 40 mph all day. gets on the plain fast and good
i am at about 3800 rpm 40 mph max for now. i will improve on this soon .
i am going to work on the boat this weekend so i will try and post sum clips of the motors runing . sins the last clip i have fitted brand new turbo units i managed to get them directly from the factory in Huddersfield for a good price

 

[Luhrs28]

Re: Diesel Benz motor. Conversion?

If you'll forgive me a short thread hijack: Ricardo that's a really clean installation. Very professional-looking.

 

[spamman450]

Re: Diesel Benz motor. Conversion?

That is a really neat conversion! The OM606 or 603 seem like better candidates indeed. I need to look into this and see if the adapter would work on a om606.
More food for thought

 

[ricardo mann]

Re: Diesel Benz motor. Conversion?

Hi i managed to make an adapter plate first from plywood then transferred to 10mm aluminium plate witch i cut to shape with a good Jig saw. the flywheel housing is mercruiser from v8 gas motor

 

[HorizonblueDK]

Re: Diesel Benz motor. Conversion?

I'm also working on a marine conversion on a couple of Mercedes engines. I will be using a pair of OM603 Turbodiesel.

Until now I have been using a 603 n/a, as a "dummy", for fabricating an adaptor, so the engine can be bolted on to a GM V8/Volvo Penta SX bell housing.

http://horizonblue.dk/22kvartal.htm

 

[aerobat]

Re: Diesel Benz motor. Conversion?

my only experience with this engine was on a displacement 41ft charter yacht some years ago. in this boat the engine appeared weak and tended to overheat when forced to maximum over a longer time. on the other hand it never let us alone on the charter trip.

next year we had a similar yacht but with a naturally aspirated DAF617 engine, rougly comparable power output. the daf was tons stronger doing it with much lower revolutions ( e.g to reach 12 kmh you had to rev the OM617 about 2800rpm when i remember correct and the daf did it with about 1500 rpm. )

on the other hand i must say the om617 , especially at idle and low power, was qieter than the daf and had a smoother sound .

dont expect wonders when it comes to power, do you expect to glide in your 19 footer with it ? on the other hand this engine seems bulletproof , as long as it has oil and fuel it runs. ( but the same is true for the daf617 engine)

cheers !