Which engine for 406 Unimog swap
 

I'm looking at re-powering a 406 Unimog, not sure which engine to use.

It has to be M-B diesel.

I know that all of the earlier engines are mechanically injected and can easily be turned up to obscene levels, I'm thinking that the 603 is a nice engine and fairly easy to find. What engine would others suggest considering that this truck uses a significant amount of power and RPM to cruise at 70mph or accelerate? Which engine is the best balance of reliable and powerful for truck use?

It'll mostly get around-town use but will be intended for some off-road and some heavy hauling.

- Jeff
190DT and projects

Take a look at ForcedInduction's thread on Mercedes SUV. What engine is in that thing?
Cruise at 70mph in a Unimog? Has any Unimog actually reached that speed?
There's a shop member with a 617 in a Unimog. He could tell you a lot about its functionality.

Lots of Unimogs came with gas engines, such as the Swiss army ones, much cheaper to buy than a diesel one and easier to find. A conversion sounds like a likely project. I'm not sure what engine the 406 diesel is but it is likely more of a truck engine than what I'm considering, ... or I might find a nice diesel one at a reasonable price (doubtful).

70mph is about top-speed with the high-speed gearset on the diesels, would depend also on the engine's max. RPM.

- Jeff
190DT and projects

You need to talk to Dennis at 720-344-1877 or his site at:

http://lindenengineering.com/mercedes_main.asp

He has done many of the conversions. He also gives phone advice. Here is a quote from some info asked by someone I know looking to do the same thing.

Ron


Cory

To answer your cost question on the conversion, the median current price for a turn key job is $7500.

There are a lot of variables that can alter the cost; I will touch on a few of the salient areas of the conversion.



Due to the size of the engine, the unit has to be canted over to the passenger’s side by a few degrees, that entails the use of a new bell housing. The diesel flywheel has to either be machined to accept the Mog clutch set up or a new flywheel used.



The old F&S finger clutch is best junked in favour of a diaphragm style pressure plate. I use the original bronze segment clutch plate but one customer stuck with the organic faced regular plate for his conversion.



The engine has to be “re-mounted” on the front tube cross member, that entails a welding/drilling exercise to accept a set of mounting brackets.



So now that the engine is in the frame (as it were) here is a treatise of things that can be done or must be done.



Change to radiator core for a higher output unit.

Alter the M617 coolant flow pattern and employ and external thermostat set up.

Fix the original fan to the crankshaft via an adaptor.

Alter the fuel pipework and install an electric fuel pump.

Install an exhaust system.

The cab will have to be altered at the passenger’s floor area to clear the turbo and inlet manifold, then an alteration to the engine covers will have to be addressed. Finally the cab raised 3/8 of an inch at the mounts

The intake system we have developed is pulled through the existing side vent and filtered by a paper element and pre-cleaner on the side of the windshield near the mirror.



Now a decision has to be made on electrical power.

The starter on the M617 is 12v

The original Mog generator is 24v (usually) so what level of voltage do you require.

Option 1

Do you want to stay 24v, if so a starter/compact alternator has to be sourced in 24v.

Or a split 24v/12 system installed.



Alternative

Go all 12v, Then certain parts of the vehicle has to be addressed like wiper motor(s) and heater fan unit etc.



If you have an air assist brake system, the compressor drive will need to be altered, if you have vacuum brakes the engine driven vacuum exhauster is a fairly easy system connect up and we use the stored vacuum for engine stop controls etc.



As a foot note the engine included in the price is based on a good ‘take out” having no more than 100,000 miles on it. The engine is quite capable of ¼ million without a problem so quality units can be sourced from rusty cars. Over 90% of 5 banger turbo diesel production came to the USA so there are plenty of units out there. What’s more you can run them on Bio Diesel mix and with fuel tank heat 100% Bio.(made in your own back yard???!!!) Lovely



We are almost at the stage of providing kits for DIY’ers so if you are interested contact me and I can go over the specs you want one.

Dennis

Linden Engineering Inc

How about using an OM352?

That's what they came with.

Where does one find an OM352?

http://www.unimog.net/exchange/ complete OM352 motor, new rings, 834 hrs, $3,000

Cummins 4b. Sorry couldn't resist. Still my vote regardless. :rolleyes: :D

Don't see too many Unimogs cruising the freeway ;)

wont fit a 404 and some of the post in here (like the Linden stuff) is about 404's

The question was about 406. and the 4b Cummins has been done if my memory serves me correctly. have heard this to be a very nice swap!!