[oldbeaver]

Well, thank you for posting.

The Nissan RD28 6 cylinders in line, is running fine on my Mercedes, very well, after a series of adjusting moves. Not easy!

First of all, this engine fits exactly in the Mercedes 300E engine space. I used a Jatco automatic transmission, which is slightly bigger than the original MB. So, some "hammering" must be performed below to fit that in. But the mount of the transmission matched the one of the car.

The engine mounts do not match, so some adapting work must be done for that.

The beam that goes from the transmission to the differential (I don´t remember the name in English) has to be cut and soldered, and balanced.

I put new original front shock absorbers, as to support the 80 k increased weight of the engine.

An air filter must be added. I adapted a Peugot diesel air filter.

The engine starts easily, after putting new "spark" plugs (I don´t know the name in English).

The battery was upgraded from 65 to 80 Amps.

A good electrician was necessary to make instruments work. He couldn´t make tachometer to work, though. I discovered that the RD28 has a tach signal output which I manage myself (with the help of some internauts) and a local MB mechanic) to transform to drive the MB original tachometer.

The air conditioning was taken out, as it means a lot of weight, takes space, and consumes fuel. Here in the coast of Chile, air conditioning is not necessary.

The vent bents with high rpm, so it reached the old radiator and broke it a little. A new hand made radiator for the engine was made from copper, same size but three rows instead of two. A new MB radiator was more expensive than the Nissan engine. I have to move it slightly forward to fit in. Some differences on the water input and output, to match ports in the RD28 engine.

After all that, the car run reasonable well and smooth. But it was too slow climbing hills. Reason: the final ratio was long too far. In fact, the MB original differential has a ratio of 3.07. The Nissan Skyline diesel that comes with this engine had a final ratio of 4.

I searched a lot and the best I could get was a MB differential for W124 with a 3.47 ratio. Made the swap and Wow!, now I have a good car.

The transmission is still smooth and uses the same original lift handle. The car is fast to start on a traffic light, go up hills very well, and has a very good kick down response.

Engine rotates at about 2000 rpm at 100 km/h and 2200 at 110 km/h. That keeps the engine cool. Maximum speed I have tried was 160 km/h at about 3200 rpm. This engine can run up to 4500 rpm, no problem.
A. Transmission has 3 speeds, plus overdrive. It locks at about 95 km/h. So, you feel like it has 5 speeds.

On the road, the car yields 14 km/lt (39,55 mpg) at 100 km/h (62 mph). It yields a good 12 km/lt (33,9 mpg) at 120 km/h (75 mpg).

This is a lot more than the original MB gasoline engine. Considering that diesel is cheaper than gasoline, I have a saving of about 40%.

Finally, I added an extra AT oil radiator to keep transmission well cooled.

Summarizing, I am very happy with the car. However, it cost about 4,000 USD to make the swap. I sold the old engine and transmission in about 800 USD. I may recover the investment in about 4 years.

I do not recommend to do the same to everyone. It is too risky, has a lot of trouble. For me was very pleasant as I put a lot of me on the work. But I think it is better to most people to fix the old MB gasoline engine, or even better, fit in a refurbished MB diesel engine. There are some Korean engines which claim to be identical to MB ones. I couldn´t get one.

But undoubtly, Japanese Nissan RD28 is better than any Korean engine.
It may be even better than a MB in many aspects. Specially cost, noise, vibration. But a refurbished MB in the US must be easy to get. And it will fit just away!

The sound of the RD28 is very pleasant and vibrations are very little. It is a smooth engine, appropriate for a Mercedes. In fact, noise is less than that of Mercedes diesel engines for the model.

The engine was made on 1996, and it will probably last more than me. I love my car. I wanted a smooth, stable and secure car, but cannot afford an expensive car.

Here you must pay a yearly permit for using a car, which is very expensive for a new Mercedes or any less than 10 years old cars. Maintenance of Korean or Japanese cars is expensive too, and they don´t run like a Mercedes.
I permit for a new MB will depend on the model, but it may cost as much as a small new car, and more (USD 10,000 a year). I pay 80 bucks.

That is what I can tell you about my car.

What else do you think I may do to increase the yield of my car? Aerodynamics, hydrogen, forced air intake, an electric motor?

I would like to hear from your experience with diesel cars.

Best,

Old Beaver