Das MB-trac Forum

Im sorry for my use of english in this forum, but my German writing is very poor...

There is no problem in reading German, so do not feel obligated to write English if you can answer!

My problem is a 1978 MB trac 800 (Grey(White)/Red).

The engine is kaputt, makes a terrible noise, and consumes a lot of oil. The engine is a OM 314, and the gearbox has shifters between the legs.

A man I know has an MB 711D (1986) with a good engine, but the engine is a OM 364 with turbo and about 120ps(?). The rest of the car is trash! The car has just passed 131.000km.

As the engine is very cheap, I started wondering if it is possible to fit it to my old 800?

And when I am sitting here writing: Is it possible to modify this gearbox so the trac will go 75km/h+?

Hi there,

I think it might be possible to put the engine in your Trac 800!But Im really not sure if the Gearbox will fit to the engine:confused: :confused:
A friend of mine from Poland just puttet an OM352 into his MB Trac800. heres a picture I've got arround, I'll post some more later.
Im not sure about the gearbox. How fast is your Trac actually driving? It depends on which gerabox you have right now. We have discussed this in several other Threads, and there're a few things you've got to check before you'll start working at it

So, heres the pic, and as I said I'll post some more
If u want u can also give me ur Email and I'll send u some


Greetings
André

The trac does 40km/h now, and the gearbox has about 32 (can't remember exactly) gears both ways.

The main (engine)question is if its possible to do the job relatively easy, or if its very difficult.

I have heard that I have to use a lot of the parts from the 314 to make the 364 fit, including fuel pump... And the flywheel doesn't fit?

Hallo oleness,
Ich schreibe dies in deutsch, da diese Frage auch für andere User interssant ist und du , wie du selbst schreibst deutsch gut lesen kannst.
Ja, den Motor kannst du nehmen. Die Einspritz-Pumpe passt nicht, da es sich beim 711(D) Baumuster 669.3xx um einen Motor mit RQ-Regler handelt und im Trac RSV-Regler verwendet werden, es sei denn du findest eine mit RQV-Regler. Die Pumpe von deinem OM314 kannst du nicht umbauen. Sie passt von der Einspritzmenge sowie Druck und Zeitpunkt garnicht, weiterhin ist der Spritzversteller anders verbaut. Schwungscheibe hinten, Schwingungsdämpfer, Ölwanne und Auspuffkrümmer passen auch nicht. Bei der Wasserpumpe bin ich nicht sicher. Alles in allem kannst du also nur den Rumpfmotor nehmen. Außer der Ölwanne kannst du von deinem alten Motor nichts am OM364 verwenden.

Hello Helmut

What is the difference between RQ and RSV?
Will the pump not fit physically?

The exhaust manifoild is no problem, we already have a plan for that...

Will the oil pump from the 364 fit in the oil pan from the 314?

I guess it would be a lot less work to find a 314...

But I live in Norway, and the access to used engines like these is a bit tricky...

---

Does someone have pictures of the OM314 and the OM364 engine? Especially from the flywheel-side...

I guess we'll start removing the old engine this weekend, but it would be great to be able to compare the two engines on images!

---

here is a small video of the noisy engine...
http://youtube.com/watch?v=02ci4UotsM4


Found the problem, by the way! The ball-bearing of the first piston is all over the oil pan :eek:

We found this when we removed the top of the engine, and looked at the pistons... The first one stops 3-4mms from the top while the fourth goes up to the top and down again And when it reaches the bottom of its cycle there is a klank => the noise when running...

What to do :confused: ? The parts for rebuilding the engine costs about 1400 euros here in norway. And if we can get the OM364 from the MB 711D to fit, it only costs about 600...

The engine is now in place, and we had a little test run last night.

The OM364 engine fits the trac with no problem, and a lot of the parts from the 314 engine fits right in!

The flywheel, oilpan, oil filter housing, clutch housing, clutch and so on is bolt on from the old engine, as the shortblock is identical in the 314 and the 364.

In a comment it is mentioned that the fuel pump is not suitable for the trac as it has different torque at different rpms in a 711d than in a trac. In the 800 however, the torque from the old engine is a lot lower in any part of the rpm range anyway, so I don't think this will be a problem for us.

The exhaust is made very easy right now, with a flex-pipe from the manifoild without any silencer. This is a bit noisy, but the turbo keeps it at a useable level. In the future we may make something different here, but it works for now.

I will be happy to answer questions, and this topic may even be so interesting that it would be an idea to translate? As written earlier, my german is not too good, but feel free to translate if someone feels like it.

Hallo oleness,

ich habe jetzt dann im Winter auch vor, in unseren Mb-Trac 800 BJ. 76 den neuen OM 364 als Turbo einzubauen. Den Motor dazu habe ich zwar schon in Aussicht, aber noch nicht gekauft.

Hat bei dir wirklich die gesamte Kupplungsglocke und alles gepasst???

Was mich noch interessiert: Wie hast du das mit der Welle für den Drehzahlmesser gemacht. Hatte der OM 364 auch diesen Anschluss?


Grüße Michl

As written above, the shortblock of the engine is the same in the 314 and the 364.

So the Clutch-housing fits right on, but we had to use the MB-trac oilpan because the 711 oilpan did not have a gasket seal against the -trac clutch housing.

The flywheel is also bolt on from the 314 to the 364, but have in mind: it will only fit on the crankshaft in one direction, the holes are spaced a bit different around the center. It will in other words fit, but you may have to turn it around and try a bit before all bolts go in...

when this is in place, the engine will fit the trac.

When it comes to the rpm-gauge, the connection on the engine is behind the fuel pump. But if the donor vehicle does not have an rpm-gauge (like the one we got), there is no connection for it... The solution is however very easy, but we did not discover it before we had put the engine in the trac The thing that turns, and gives the signal to the gauge inside the trac, is mounted on top of the oilpump! So we will loosen the front mounts of the engine in the trac, and raise it a bit so we can remove the oilpan, and replace the oilpump with the one from the 314.

I hope my answers are understandable... If not, please ask again!

Hallo,

vielen Dank schon mal, das hilft mir schon sehr weiter.
Was mich noch interessiert:

Habt ihr den Ölfilter auch vom alten Motor hergenommen?

Und wie schaut es mit dem Luftpresser aus?

Leistungsmäßig wird der Trac im Vergleich zum alten Motor eine Rakete sein, oder?


Grüße Michl

The engine from the 711D had a oil cooler connected to the oil filter assembly(water cooled). This did not fit in the frame of the trac because it was mounted downwards. The oil filter assembly from the old 314 was also bolt on, but we lost the oil cooler

We have already made new connections with hoses to install a front mount, air cooled oil cooler on the trac, but have not found a suitable cooler yet.

The air compressor is identical on the 800 and the 711D, but the 711D has it connected as a vacuum pump instead. We switched the top of the compressor, and used the one from the trac. To make it fit we had to create a smaller bend on the intake side, because the fuel pump on the 364 is almost twice as big as the old 314.

The connection rod between the gas pedal and the fuel pump we bent to make it shorter, but I guess it is possible to get a suitable rod from later trac models.

The power in the new engine is enormous! +43hp and more than 100nm extra

And the old engine was quite exhausted, so I guess the power output was nok like the original 72hp...

Driving on road now, the trac pulls good in 8th gear everywhere, even with load.

If we had bothered, I guess it would be a good idea to make it go faster than the original 40,9km/h, but as I understand, it is quite difficult with this trac

The trac is away for repairs on the rear axle (oil leak) right now, but I will make a video when we get it back (tuesday, maybe), to show a bit of the new engine.

Hallo Ole,
An der Einspritzpumpe ist vermutlich ein RQ-Regler verbaut. Bei LKW ist dieser normalerweise so eingebaut, da eine Zapfwellendrehzahl-Regelung nicht erforderlich ist. Das Reglergehäuse ist größer als der RSV-Regler vom MB-trac.

Good evening Helmut

Please describe more about the difference, my technical german knowledge is quite bad... If you have pictures to post on this topic, that would be a great help!

Hello Ole,

what do you think, is the oil cooler really necessary?

I will buy a OM 364 Engine from a 709 D, because I'll get it very cheap with only 80.000 km.

Further i have buyed a turbo charger few months ago for this engine. I hope I can get about 115 HP from this engine.

And thats real enough in my eyes.

Why do you know your Engine power so exactly?


Greets Michl

People I have asked, said that since the engine was equipped with an oil cooler originally, they would recommend it. The turbo will heat he oil a lot more than a engine without this, but maybe it has better air cooling on the trac than it had in the truck.

Is the turbo charger for this engine?

With the correct turbo the only limit will be the fuel pump, I guess.

It is enough for our use anyway...

As I remember the 314 had 72hp and about 220nm originally from the 3,75l engine.
The 364 engine from the 711D has 115hp, and 378nm from 3,9l!

I searched the net for this info, and I guess there is the same info on the 709D.

Hello Ole,

Thank you for our good information. I get the engine about in three weeks and then i will see if my engine has a oil cooler or not.

If yes, i will surely build that in my trac, too.

Yes, the turbo charger is exactly for this engine. I want the turbo charger only for more fun and more Torque in the region between 700 - 1600 upm, not especially for more hp.

100 HP are really enough for our and my use, Im sure.

What do you have payed for your 364?


Greets Michl