Mercedes Overland Building/Tuning

RoamIt

Active member
I'm perilously close to importing a MB firetruck, I have some pic's & description, but I'll get first hand confirmation of condition/specs in a few weeks. As I prepare myself mentally for what could be the colossal mistake of thinking I can convert this monster into an overlander, I thought I would reach out and try to learn something.

Just to level set, I'm fairly handy with a wrench, welder, etc., having rebuilt a few cars over the years.

1.) Who in the U.S. is the goto for engine tuning? The truck in question is a '95 1224 with an OM421 turbo V6. It's 253hp/556ftlbs(not 100% sure on the torque) stock, but I've been told that 300hp is just a fuel pressure tuning(?)
2.) Of course, I'll need to convert to super singles, because I don't want my truck to be shunned by the other rigs because of it's little tires. Any recommendations of kits/rims, etc.?
3.) I would like a CTIS system, I've seen some aftermarket set ups. Anyone try them?
4.) Parts sources? I expect to have to order things from Europe. Any suggestions/sources would be most appreciated!
5.) Besides the factory manuals, are there any books/websites/YouTubes channels focused on these? (in English ;))
6.) Suspension- I'm thinking I may need some lifting blocks, new shocks-thinking remote reservoir, springs? I don't know if they are parabolic or perhaps add air bags to smooth the notorious cab-over ride?

Trying not to get too far into the weeds here, but the focus right now is to go through the truck and replace all rubber/seals/hoses, etc., anything that 26yrs would dry out. (This is a German firetruck, kept indoors, maintained, 60Kmiles)

And I'm sure I missed a lot, so feel free to chime in with any first hand experience you may have.

Or just talk me down from this idea....
 

Joe917

Explorer
Rob Pickering at Terry Lee Enterprises.
Don't get too exited about boosting hp on these trucks, its overrated.
We have parabolics and air bags on the rear and a massive 13 leaf stack front suspension, rides smooth as silk.
CTIS is a waste of time and money since all the aftermarket systems are external and very exposed to damage. I removed ours in the first year! Through axle CTIS is a whole different beast
 

RoamIt

Active member
Rob Pickering at Terry Lee Enterprises.
Don't get too exited about boosting hp on these trucks, its overrated.
We have parabolics and air bags on the rear and a massive 13 leaf stack front suspension, rides smooth as silk.
CTIS is a waste of time and money since all the aftermarket systems are external and very exposed to damage. I removed ours in the first year! Through axle CTIS is a whole different beast
So, I shouldn't go with twin variable vane turbos with meth injection? Your just sucking the fun right out of this...;)

On the CTIS, I did see some systems that were obviously overly exposed to damage, but thought surly there's a system that works, but perhaps not, that's why I'm asking! thanks.
 

VerMonsterRV

Gotta Be Nuts
I am sure but I am guessing the 1224 has an om366la engine. If so it is an I6 and not a V. We have the 204ho variant of that engine and I am working towards a turbo upgrade for a bit more HP. Hoping for 230-240hp. Depending on how you build the 1224 the stock engine may very well be ok. The biggest drawback of these trucks is gearing, a bit slow for US speeds. Other countries not an issue. Joe's truck is a bit rare with options I haven't seen on any other trucks. I have replaced all springs with parabolics. The factory leaf springs in the front felt more like I beams than springs. Currently have upgraded shocks being shipped from Germany to complete the suspension upgrade.

Well, that's my 2 cents 😁.
 

DiploStrat

Expedition Leader
Joe beat me to it. I went straight to Rob Pickering (via an exploded wheel) and had him change every fluid and belt I could.

Jon beat me to it. After the wheel failure, I, too, ordered 22.5" wheels from his contact in Germany. (See if you can order and have them all shipped at once.) 8 lug singles are hard to fine, but the Kronprinz wheels are perfectly round. There is some viewing with alarm at the stiff 365/60x22.5"R tires, but they are commercially available and, according to my Australian bubbas, can be aired down in sand if you are careful. Much, much better than any MRAP or other solution that I tried. Set with 5 rims 11,75x22,5/8-hole/ ET110 ACCURIDE (EUR 249,-/piece) - Expedition truck (expeditions-lkw.de) (P.S. Order the lug nuts as well.)

Upgraded the alternator, first to 100A, and now to 150A with units from Nations Alternator and Starter: Nations Starter & High Amp Alternator- Best Quality Starter & Alternator Supply! (nationsstarteralternator.com) Physically plug and play. Took a tiny bit of wiring work.

Just replaced the factory shocks with Marquart shocks from Germany. Reasonable price and insanely fast shipping. They explained why they don't use pressurized or external reservoir shocks on big trucks. Reinforced Shock Absorbers - Marquart Shockabsorbers

For tech support, fire up your browser's translation package and see: Forum - LN2-Forum.de

Would still buy a Chevrolet, but welcome to the madness.
 
  • Like
Reactions: mog

RoamIt

Active member
Thanks for the info/Links! I'm short on hard specs right now, thought by '95 they had moved to the 400 series of engines? I will have eyes on it in October. I was sent the VIN number, and some other info, but it's in German, so working through that.

This is the one of the pic's I was sent, shows 10lug wheels. This is the heavy SK chassis, I was told. Will be confirming this, but supposed to have the front locker and no speed governor, which seems rare, but certainly desirable for deep mud/sand.

I would like to hear more about your suspension mods. Did you use any lift blocks on the axels? Did you get a custom spring pack made with parabolic springs, or are they out there?

Great idea about having them ship shocks/wheels with the truck, but really thought wheels would be easy to source. From my car racing, there are companies that will build any spec wheel you want. But that is for cars, not heavy trucks. But I was supposing that wouldn't be problem. On tires, want to go with a size that is readily available globally.
 

Attachments

RoamIt

Active member
Just got the purchase agreement, engine is a OM366LA. There's a question if it has the front locker or not. Anyone know what code 731.603 means? I have the VIN number, the Vin number site I tried didn't work. Any suggestions?

OM366LA has 240hp/428ftlbs. The torque value seems very low too me, after reading about challenges getting up big hills, I'm a little concerned about the HP/TQ ratings. Hence my question about tuning. Turbos have come a long way since '95, I wonder if a variable vane would help. Most turbos are sized to work within set parameters and are not necessarily optimal for both low rev's and high rev's. A variable vane could give me more HP/TQ on the top end while not sacrificing the bottom.

At least that's how it works in sports cars...
 
Last edited:

DiploStrat

Expedition Leader
Oh yeah! Lots of companies will build you any wheel you want! :mad: And then tell you it is your fault "because you ran it flat." Note the ten, yes ten broken bolts. Talk to Fabian about wheels. Ten lug may be easier.

Believe me, this was not fun at 80 kph.
 

Attachments

Joe917

Explorer
Our truck has the OM366LA tuned to 170hp.Plenty of torque but lacking hp. You will have to get your head around the fact that these are big slow beasts. The OM366LA can be brought up to 240hp with a larger turbo and greater fuel delivery at the expense of fuel economy. A 1224 (with an OM366LA)is already at its max hp. 240 hp will be plenty.
 

RoamIt

Active member
Ok, looks like the the max torque is 740-750nm which is 545ftlbs, which is better. I'm getting different numbers from different sites. It doesn't help MB had so many versions of these engines.
 
Top