Mercedes OM603 FJ80

[anonymous]

I think its all about having the engine in the sweet spot

There were several variations of OM603, including 3.0 and 3.5l turbo and non turbo, the only older gwagen I ever saw had was non turbo.

The one I have is from a w124 chassis and is Turbo.

don't underestimate the potential of small diesel engines allot of VW guys are getting 300 LB ft of torque out of 1.9l 4cly engines and that's more than any stock gm 6.2

I will defer any more speculation until after I have the engine in.

I think i mentioned fuel economy in a previous post but will say it again.
I swapped a 6.2 GM diesel in a 94 FZJ80 with a 700R4 and 33" tires, I was running about 2,000 rpm at 65-70 mph, this is about 200 rpm out of this engines sweet spot for economy but I was still getting around 20 mpg and was running a WVO blend so maximum economy wasn't that important to me.
About a year after building the 6.2 80 I found what I thought was my dream vehicle, a Mercedes G350DT, the OM603 engine with a factory intercooler putting out around 165 hp. Powerwise was fine in the G Wagen, very similar to a 3FE powered 80 but the mileage was never any better than 15 mpg! The previous owner swore to me it got around 25 mpg which I knew going in was probably off by a bit but I really expected more than 15! I always suspected the gearing, it was running around 3,000 rpm at around 70 mph but it was a factory engine, not a swap so I assumed that is the way it was designed to be. I even tried some trips at 60 mph for a full tank of gas, dropping the rpm down to around 2,500 rpm and still the same 15 mpg?
Anyway, I did like the engine, great if WVO is what you want to do, the engine was very quiet at idle, especially compared to the 6.2 diesel but on the highway, they were about the same, the OM603 turning 3,000 rpm was possibly noisier than the 6.2 running at 2,000 rpm.
If I were to do it all over again, I would probably still go with the 6.2 diesel, I loved the way the the 80 felt with that engine, nice V-8 torque which you will never get with the OM603, felt quick off the line, again, you will never get that with the OM 603.
Just my thoughts, hope it helps.
On the other hand, I am currently restoring my 78 FJ40 and would love the OM617 in that!
Good luck with whatever you decide, if I had the OM603 though? I would give it a try.

 

[rtarh2o]

What rpm are you running at 70 mph in your sedan? I really think the OM603 (mine was a 94 with the 3.5 liter, factory rebuilt engine) should be capable of at least 20 mpg, even in the G Wagen, or a Land Cruiser, seems like cruiser closer to 2,000 rpm would make all the difference.
Good luck, keep us posted
Rusty

 

[lt1fire]

Considering the 617 or the 603?

2 different bell housings

I would guess that the 603 should best the fuel economy of a 6.2/6.5 gm motor if the gearing is right, from the research I have done the 603/606 should be just about the most advanced IDI diesel available.

both really

I have an 87 300sdl and I think the motor would push the cruiser around without much problem.

where would you be getting the adapter plate made ??

 

[anonymous]

I started making an adapter for the flex plates, I am going to mount the Toyota flex plate behind the Mercedes flex plate with the adapter centered in the Mercedes crank. The 603 starter is in the lower 3rd of the bell housing on the drivers side toward the engine with most of the flex plate in the engine side of the bell housing.

What I really need before I decide how to go about this is a 3FE engine back plate, so I have been looking for one near by.

both really

I have an 87 300sdl and I think the motor would push the cruiser around without much problem.

where would you be getting the adapter plate made ??

 

[Dougal]

Low gearing kills fuel economy. Go down a gear or two in the 6.2 so it's turning 3000rpm and try a fuel economy run.

There is talk all over the internet of OM617 transplants, but there's absolutely nothing on finished conversions and fuel economy figures. I think the OM617 would be fine in a hilux size vehicle, but I wouldn't put one in a landcruiser.

 

[lt1fire]

Low gearing kills fuel economy. Go down a gear or two in the 6.2 so it's turning 3000rpm and try a fuel economy run.

There is talk all over the internet of OM617 transplants, but there's absolutely nothing on finished conversions and fuel economy figures. I think the OM617 would be fine in a hilux size vehicle, but I wouldn't put one in a landcruiser.

well this is true but at 65mph i'm only turning about 2200-2300rpm..... that seems to be the sweet spot for these engines according to every diesel mb board i've been on, i know it is for my car (actually a tad higher). So that is perfect for me because I don't like driving a 6000lbs cruiser much faster than that with the crappy drivers here in NC

 

[Dougal]

Here is the BSFC chart for an OM617. The big question is, how much power does it take to move your vehicle at 65mph?

 

[lt1fire]

That's the most confusing BSFC chart i've seen. I can't tell where the gears or the speed interconnect.

Besides we are talking about a OM603 here for the most part but I do believe a 617 would work also.

 

[Dougal]

There are no gear or road speed on BSFC charts, they are all about engine load, speed and efficiency.

You need to know how much power you require and what your rpm is. Follow those through and you find the operating point.
For example if you only needed 30kw, follow the 30kw curve and the lowest point is around 1800rpm where it just misses the 245 g/kwh island.

 

[anonymous]

using 11.6 KW/KG for diesel that puts its peak at 35% efficient, which I think is pretty good if it includes drive line losses from the auto trans, rear end and tires contacting the dyno rollers, though it notes auto in 4th gear so probably TC locked.

I would love to see the effect of different A/F ratios on the BSFC for a given power/RPM.

 

[Dougal]

using 11.6 KW/KG for diesel that puts its peak at 35% efficient, which I think is pretty good if it includes drive line losses from the auto trans, rear end and tires contacting the dyno rollers, though it notes auto in 4th gear so probably TC locked.

I would love to see the effect of different A/F ratios on the BSFC for a given power/RPM.

That 35% is engine only. No transmission, no differential, no rubber tyres, no dyno rollers.

You can work out A/F ratio changes from a BSFC plot. But not the absolute numbers.

 

[lt1fire]

That 35% is engine only. No transmission, no differential, no rubber tyres, no dyno rollers.

You can work out A/F ratio changes from a BSFC plot. But not the absolute numbers.

You sure about that that one is supposed to be for 4th gear only according to the text on it.
That is what threw me off every one of those i've ever seen has gears and mph thrown in with it like this one

 

[anonymous]

That's what I am seeing, it does note auto trans 4th gear.

You sure about that that one is supposed to be for 4th gear only according to the text on it.
That is what threw me off every one of those i've ever seen has gears and mph thrown in with it like this one

 

[Dougal]

You sure about that that one is supposed to be for 4th gear only according to the text on it.
That is what threw me off every one of those i've ever seen has gears and mph thrown in with it like this one

The only part on that graph relating to the installation is the dotted line. That is the demand curve the engine follows in that car and 4th gear.

Everything else, fuel consumption, power, torque etc lines is engine only.

That TDi graph has had the road speed and rpm lines added afterwards by someone else.

 

[addicted56]

Well I am jumping on this bandwagon as well. In College and a few years afterwards I had owned quite a few MB diesels (OM616 and 617 and Turbo's). Loved my 76 300D the most but the wagons with the turbo were nice. Currently drive a bluetec but would be way to expensive and difficult to transplant. Love the power and TQ though.

I think the 40 has a lot going for it and that the OM617 will be a good way to go mileage wise. Mine will be going in an FJ43 and Luke now makes an adapter for the H42/1 transmission (will be done in a few weeks he says). Making the swap that much easier. I'm doing it becuase I fell in love with the engine and want something unique in my FJ43. But being able to run it on anything I find (I used to do WMO and lots of WVO) will be an added benifit and it will probably take over my truck as my daily driver.

At about 3700lbs as long as you keep the parastic drag down (drive slow) you will get great mileage. In my case I'm going to stick with the stock H41. I will still get the 4.9 first gear but also have the 1:1 final drive. Combined with 3.73 gears instead of the US 4:10s I should be able to drive down the road just fine. The fact that the OM617 likes to rev like the stock gasser 6 is great as well. I would like to go to 33" tires but it would rev a bit low. With 31's and at 55 MPH it will be 2250 RPM. Same with the 33" tire is 2100 Which from what I remember is just fine for that engine.

The engine is also shorter than the stock 6 so that leaves some room in the front for an intercooler. I'm thinking I will put an Air to Air intercooler in and then move the radiator back. I will be putting in A/C as well so I've got to make room for that. I'm going to use an electric fan to save some room as well. I figure by the time that is all said and done I will still have quite a bit of room. I've also had a buddy who turned up his pump and used a different turbo in conjuction with an intercooler and he could squel the tires on his SD with the automatic and ad 3600lbs. I don't know exact mileage but with some tall skinnies on there and cruising down the road at the above RMP/speed I think the low 20's could be achieved. Best I ever got on my turbo car was 28 MPG and that was 65 MPH straight and level the whole way. So I figure at 50-55 before the wind drag gets obsurd the light FJ40 would do great.

I have to wait until we move at the end of the year to get started but I'm excited none the less and plan to purchase the adapter here in October just after our move.

Regarding the 603 I think it would be fine. As long as you have no issues getting an adapter I don't see why it would be any worse or better and engine than the 617. Would love to see how your build goes.

 

[mrmati]

How is the adapter plate coming around?

Which trany are you using? Is it electronically controlled or hydraulic? I dont understand your setup two felx plates? any pictures? Would it be better to go with a manual transmission? What about engine hight and clearance with front diff?

I am really interested in this project. I have a donor car ready to go, freshly rebuilt engine 603 (tranny slips, bad body). Yet I still dont have a 80 for it . Soon though, I want to plan it out first.

I started making an adapter for the flex plates, I am going to mount the Toyota flex plate behind the Mercedes flex plate with the adapter centered in the Mercedes crank. The 603 starter is in the lower 3rd of the bell housing on the drivers side toward the engine with most of the flex plate in the engine side of the bell housing.

What I really need before I decide how to go about this is a 3FE engine back plate, so I have been looking for one near by.

 

[lt1fire]

How is the adapter plate coming around?

Which trany are you using? Is it electronically controlled or hydraulic? I dont understand your setup two felx plates? any pictures? Would it be better to go with a manual transmission? What about engine hight and clearance with front diff?

I am really interested in this project. I have a donor car ready to go, freshly rebuilt engine 603 (tranny slips, bad body). Yet I still dont have a 80 for it . Soon though, I want to plan it out first.

he is using a hydraulic transmission.

 

[lt1fire]

Any updates??

 

[lt1fire]

updates??

 

[mercfan]

To keep this thread going, the OM603 engine is @ 26in tall (at deepest portion of sump, front 1/3) 19 inches tall rear 2/3's, @32in long (rear flange too front of crank pulley, with an 11.5in diam flywheel. I measured the weight at @535 pounds complete long block..

How do these specifications compare to the stock 1FZE engine? Also, how's the progress on your project coming?