407d truck comments and info - PeachParts Mercedes-Benz Forum

esmitty · #1 04-13-2007, 11:42 PM

I am new to the group and would like to talk about the 407d trucks and the rest of the mid-size line. Specifically, I have a 407d, underpowered by a 2.4 liter motor, and governed at 80kph. It seems to me that the governor doesn't control "over-revving" in the first three gears, only fourth. Which makes me wonder whether it is really meant to govern RPMs, or whether it is meant to keep the men from the Motherland from crashing into the mountain due to excessive speed? I live in California, and 80kph is not sufficiently fast for our type of driving.

winmutt · #2 04-14-2007, 08:34 AM

Quote:

Originally Posted by esmitty

I am new to the group and would like to talk about the 407d trucks and the rest of the mid-size line. Specifically, I have a 407d, underpowered by a 2.4 liter motor, and governed at 80kph. It seems to me that the governor doesn't control "over-revving" in the first three gears, only fourth. Which makes me wonder whether it is really meant to govern RPMs, or whether it is meant to keep the men from the Motherland from crashing into the mountain due to excessive speed? I live in California, and 80kph is not sufficiently fast for our type of driving.

Its probably a limitation of the fuel map. Either way a 2.4 with that much mass isnt going anywhere fast.

kerry · #3 04-14-2007, 10:23 AM

To my knowledge, the governing of the trucks and vans is performed by the laws of physics. I have owned a 307d and a 409d. Both topped out around 68mph. The problem you describe is probably one of the reasons why MB never officially imported their trucks and vans to the US.
One thing you will never have to worry about with these vehicles is crashing into the mountains due to excessive speed.
By the way, there aren't a lot of people on the forum who have experience with the trucks and vans. Parts can be hard to find sometimes. I used www.eurocarparts.co.uk. There is a supplier in the northwest US though and I think I recently saw a website in the US offering parts for the trucks and vans.

esmitty · #4 04-14-2007, 10:48 AM

It has been recommended by some who may or may not know enough that I change out the rear end for something with a higher ratio. Or a 2-speed. Or someone has suggested a "brownie" which is some sort of aftermarket overdrive. Any experience in any of those areas? (The solution I am working on is that I have put it on ebay.)

esmitty · #5 04-14-2007, 10:52 AM

I used www.eurocarparts.co.uk. There is a supplier in the northwest US though and I think I recently saw a website in the US offering parts for the trucks and vans.[/QUOTE]

Thanks, too, for the parts sourcing info. I have used Jim at Eurotech Services in Oregon and have nothing but nice things to say about his service and his product availability. I will look in to eurocarparts.

TMAllison · #6 04-14-2007, 11:39 AM

Seems like it should go faster than 48mph at least on level ground.

Assume you've checked obvious things like clogged filters and binding in throttle linkage.

kerry · #7 04-14-2007, 02:06 PM

I think typical top speeds on these models is around 90kph. I doubt if a brownie is going to help you much due to the low power of the engine. It's geared low due to the limited power I think. I don't know what gear ratios were available for the duelly rear end. I could get about 65mph on a flat road or dowhnill out of my 307d which was a 22' class A motorhome with single wheels on the rear. Since you have a '4' it means you have an extra ton of chassis rating so I'm sure it's geared lower for that reason. It might be worth changing the gear ratio in the rear end but I'm guessing it's going to be quite hard to find a different set of gears. Best bet is probably a European junkyard.

dkveuro · #8 04-14-2007, 02:38 PM

Nah.....it's never goin' to suit you.....give it to me...I don't need anything going over 80 kph anyways !

2.5Turbo · #9 04-15-2007, 03:43 AM

Wonder if a 617 turbo would fit? That would speed it up a bit...

Gurkha · #10 04-15-2007, 03:49 AM

The rear differential used in my Gurkha is from 407d, makes it capable of hauling 3.75t certified.

kerry · #11 04-15-2007, 11:23 AM

What is the gear ratio in your Ghurkha? Since you only have single rear wheels, it seems to indicate that the gears are interchangeable between singles and duals. So, perhaps a different gear ratio in the rear end might solve his problem. How expensive are the gears in India?

airbus · #12 04-15-2007, 11:42 AM

Quote:

Originally Posted by 2.5Turbo

Wonder if a 617 turbo would fit? That would speed it up a bit...

The 407 has a 240D engine, putting in a 617 would make it a 409, So techincally a 617 engine with turbo should fit, I don't know about the turbo only. Aren't there some guys around here who tuned up their 240Ds?

kerry · #13 04-15-2007, 11:49 AM

There's no room under the doghouse for the turbo. I think it would require a different set of manifolds. But in any case, the speed would not improve because the issue is the gear ratio and the turbo 617 is not going to turn any more rpm's. In fact the 616/7 put in the trucks and vans are set up to turn higher rpm's than the car versions to begin with.

Bruce Kennedy · #14 04-15-2007, 09:35 PM

I know where there is a couple of these mb vans for sale. They are duallys with the 4 cylinder engine mated to manual 5-speed. Any chance these trannys will mate to a 617?

Gurkha · #15 04-15-2007, 09:42 PM

Quote:

Originally Posted by kerry edwards

What is the gear ratio in your Ghurkha? Since you only have single rear wheels, it seems to indicate that the gears are interchangeable between singles and duals. So, perhaps a different gear ratio in the rear end might solve his problem. How expensive are the gears in India?

Kerry,

I have the OM616 turbo in my Gurkha, the gear ratios are as follows:

I-4.70
II-2.40
III-1.44
IV-1.00
V-0.81
final drive ratio=4.89

ZF gears are not that expensive, if you have anyone coming to India, it would cost you way less as shipping is the only hurdle here.