Unimog engine replacement options

1

1700camper

New member
Hi people

Has anyone seen other types of engine successfully fitted to U1700's such as Nissan , GM , Isuzu etc ?

I am hoping to find a new engine for a 1990 U1700 that has a higher RPM limit to improve the current 90 kmhr top speed , better reliability and also cheaper on spares

any ideas ?
 
T

toylandcruiser

Expedition Leader
1700camper said:
Hi people

Has anyone seen other types of engine successfully fitted to U1700's such as Nissan , GM , Isuzu etc ?

I am hoping to find a new engine for a 1990 U1700 that has a higher RPM limit to improve the current 90 kmhr top speed , better reliability and also cheaper on spares

any ideas ?
Click to expand...

Don't do it. Get high speed axles.


Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety.
Benjamin Franklin
 
Tennmogger

Tennmogger

Explorer
How long have you had your U-1700? Do you use it for the reasons for which one should buy a Unimog? If speed is the primary requirement, maybe you have the wrong truck?

Even with fast axles, overdrive, and larger tires, (for all of which you will invest $10k or more) the U-1700 really isn't a high speed truck. You will put lots of wear on other running gear, and tire mileage will suck.

Sorry to be blunt, but that's reality. You can easily spend a day reading threads on Benzworld/Unimog forum (where you asked the same question), all in pursuit of speed. Optimizing what you have might be more realistic.

Bob
 
1

1700camper

New member
Tennmogger said:
How long have you had your U-1700? Do you use it for the reasons for which one should buy a Unimog? If speed is the primary requirement, maybe you have the wrong truck?

Even with fast axles, overdrive, and larger tires, (for all of which you will invest $10k or more) the U-1700 really isn't a high speed truck. You will put lots of wear on other running gear, and tire mileage will suck.

Sorry to be blunt, but that's reality. You can easily spend a day reading threads on Benzworld/Unimog forum (where you asked the same question), all in pursuit of speed. Optimizing what you have might be more realistic.

Bob
Click to expand...

Thanks for your thoughts , and I have seen the posts by members screaming obscenities at those wanting to increase the speed by an extra 10-12%

This is not a suburban toy ,it might have a camper body but its a working vehicle used in outback conditions where going from A to B is a 3000 km trip
 
Tennmogger

Tennmogger

Explorer
Hi 1700camper,

I sounded a little like that too. It comes from seeing many years of people buying Unimogs because they are cool and then immediately wanting to turn them into something different, and a maintenance nightmare by modifying everything. Sorry.

What size tires are you running? Can you increase the OD on those? The 1700 can handle monster tires.

Would you be willing to spend $6000 to $8000 for a Claas overdrive?

Would higher road speed be worth maybe $2500 per portal to rebuild with taller portal gears? Rebuilding your portal ratios might be the only axle option because finding full replacement axles already equipped with tall gears would be more challenging than the needle in the haystack.

MB did install Cummins Diesels in a few 'mogs back about the turn of the century. The story I heard was they wanted to get some fire apparatus contract and needed the power for faster response. I have no idea what happened to those but, bottom line, MB chose to not continue the idea.

About the same time they had a couple of U2450's set up with Twin Disc Corp auto-shift transmissions with two over-drive gears and with the OM-366A engine tuned to well over 250 hp. The transmission was reported to have been $14k still on the pallet. The goal there was to be able to drive the vehicle in hydrostatic mode while maintaining high engine speed = high pump speed for fire fighting. High road speed was a side benefit gained by the two overdrive ratios.

I drove one of those U2450's from Oregon to Indiana and it was an eye-opening jaw-dropping experience. It also used up about 25% of the tire tread on those huge tires (don't remember the size, maybe 15.5 x 20's).

So, the options are there. Just get out your wallet. :)

Bob


1700camper said:
Thanks for your thoughts , and I have seen the posts by members screaming obscenities at those wanting to increase the speed by an extra 10-12%

This is not a suburban toy ,it might have a camper body but its a working vehicle used in outback conditions where going from A to B is a 3000 km trip
Click to expand...
 
Last edited:
1

1700camper

New member
Thanks tennmogger

The portal axle mod would be technically more sensible as it will decrease wear on every other transmission component due to decreased shaft speeds but I like the two speed ranger splitter too , not just because its cheaper at $1500 but also it gives those closer gear ratios for more refined hill climbing .

The Claas is not out of the question but how durable are the standard portals with 10-15% higher RPM if I went with that or the ranger splitter alone ?

I can't go to bigger tyres , its already on 12R x 20 mil spec issue , if I went any bigger it becomes top heavy and unstable at speed anyway.
 
1

1700camper

New member
Thanks tennmogger

The portal axle mod would be technically more sensible as it will decrease wear on every other transmission component due to decreased shaft speeds but I like the two speed ranger splitter too , not just because its cheaper at $1500 but also it gives those closer gear ratios for more refined hill climbing .

The Claas is not out of the question but how durable are the standard portals with 10-15% higher RPM if I went with that or the ranger splitter alone ?

I can't go to bigger tyres , its already on 12R x 20 mil spec issue , if I went any bigger it becomes top heavy and unstable at speed anyway.

This engine is going to need a reco soon so the concept of a late model transplant engine is not off the table either
 
1

1700camper

New member
Tennmogger said:
Do you have a PTO? If so, do you want to keep it? Come on over to benzworld/Unimog and read this:

http://www.benzworld.org/forums/unimog/1380746-retrofit-domestic-overdrive-into-mog.html

So, if your truck already becomes "top heavy and unstable at speed", why are we .........oh never mind...;-)

Bob
Click to expand...


It is not top heavy or unstable at speed now ........ I am saying i dont want it to become unstable by fitting bigger tyres . would you like that knife back ? insults are not poor mans humour

I dont need a PTO . my winches are electric

The problems experienced by the OP in your link above would have been predicted within 10 minutes by us and a better solution created
 
1

1700camper

New member
I thought I replied to this already but . . .

I didn't say the vehicle was unstable now

If you read ' the English translation' of what I wrote it states I don't want to go to bigger tyres as it would tend to become top heavy

Unnerstan gubna ?

Now would you mind removing that knife from my back ?
 
whatcharterboat

whatcharterboat

Supporting Sponsor, Overland Certified OC0018
1700camper said:
Hi people

Has anyone seen other types of engine successfully fitted to U1700's such as Nissan , GM , Isuzu etc ?

I am hoping to find a new engine for a 1990 U1700 that has a higher RPM limit to improve the current 90 kmhr top speed , better reliability and also cheaper on spares

any ideas ?
Click to expand...

Howdee. Where are you based? Have you contacted Dan at UNIDAN on the Gold Coast? . They specialise in modifying ex-ADF U1700's.....have all the answers. I have found him very fair, does good work and he really knows his stuff.

Some of the U1700's he builds are super trick
image.jpg
 
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