Mercedes Overland Building/Tuning

RoamIt

Active member
Thanks, I'm going back in this weekend to go after the belts. I went ahead and ordered a new 80amp. I want to get the thing moving again as it's not in the ideal spot right now. After it's where it needs to be, I'll have plenty of time to track down parts, rewire different plugs, etc.

New EGT gauge kit showed up today, so need to decide where to install the sensor. I think the dash is going to get a major overhaul as there are a lot of switches that are disabled. I have some carbon fiber pattern panels left over from my last race car build that will make for a 'racy dash' with new gauges/switches.
 

VerMonsterRV

Gotta Be Nuts
Thanks, I'm going back in this weekend to go after the belts. I went ahead and ordered a new 80amp. I want to get the thing moving again as it's not in the ideal spot right now. After it's where it needs to be, I'll have plenty of time to track down parts, rewire different plugs, etc.

New EGT gauge kit showed up today, so need to decide where to install the sensor. I think the dash is going to get a major overhaul as there are a lot of switches that are disabled. I have some carbon fiber pattern panels left over from my last race car build that will make for a 'racy dash' with new gauges/switches.
For ease of installation I installed my EGT sensor in the turbo dump pipe. It will read a bit lower than if it was installed in the exhaust manifold but it works well. There is a flat spot on the forward side on the dump pipe, just drilled and tapped it. Since I upgraded the turbo I also installed a boost gauge, with the pickup tube going to the aft end of the intake manifold where the boost line was for the injection pump.
 

RoamIt

Active member
What kind of temps are you getting Jon? I had my engine IP tweaked/injectors bench flowed. And I know you did a turbo upgrade.
 

RoamIt

Active member
The air pump/power steering pump belts should come right off. For the alternator belts you need to pass them by the fan blade one blade at a time. Reverse the procedure to re-install.

For USA belts look at the Gates HD green belts, I think you need the 13mm x 1025mm for the air pump and 13mm x 1350mm for the alternator. If possible you should double check with the belts on your truck. Gates has a belt sizing chart on the web with the belt part number on it.

From my research it looks like Mercedes used the same alternator mounting style on a few of their engines, so a specific part number is less important than the "foot" of the alternator size.
Got the belts off, (hidden bolt tensioner took a minute to find/get to) same size belts as yours. For some reason, my Google-**** was not working and the Gates green belts in the right size were not coming up.

The existing belts are Optibelts LA's and I found a source in the US: https://www.bdiexpress.com/us/en/Mechanical-Power-Transmission/Belt-Drives/c/BeltDrives

They also showed a Continental alternative and a Optibelt TM alternative. The TM is their 'Marathon Truck' line and were a couple more $$. So I went for it, ordered 2 of each. Although the belts I took off actually are in very good shape.

With the compressor looking very new, good belts, it's clear there was some recent maintenance done before it was retired. Hoses look good too, but still leaning towards just replacing everything so I have a baseline for maintenance moving forward.
 

RoamIt

Active member
OK, a mystery to solve. While 'roaming' around under the rig, saw this swinging in the wind. On the passenger side of motor, can't find any obvious place it goes. Could be part of what was removed from truck to decommission it? I was told it was German law to take all firetruck lights, etc. off.

Thingamabob.jpgThingamabob2.jpg
 

RoamIt

Active member
It looks like a sensor of some type to me. There's no hole in the ends for any air passages. I'll remove it when I get in there again and see if there are any clues.

FYI, the BDI link above I provided as a belt resource. Their inventory said in stock, but they just informed me it will be October before the Optibelts would be back in stock , and the alternative Conti belt is no longer available :rolleyes:

Anyway, I was able to find some Continental belts (new old stock?) and cross reference the Gates Fleetrunner belts. So when they come in I'll compare and report any observations.
 

VerMonsterRV

Gotta Be Nuts
OK, a mystery to solve. While 'roaming' around under the rig, saw this swinging in the wind. On the passenger side of motor, can't find any obvious place it goes. Could be part of what was removed from truck to decommission it? I was told it was German law to take all firetruck lights, etc. off.

View attachment 727459View attachment 727460
We had something similar on our truck when we got it. Ours was still bolted to the block though. Ours looked like some sort of air actuator. We also have a couple of extra temp sensors that go nowhere. Maybe they all were attached at one point to the rear fire pump to monitor/shutdown the engine from that station. There was still an engine idle adjust back there when we got ours. I pulled the air actuator off as it didn't do anything. Figured this truck was 30 years old when we bought it and probably had a few modifications in its life before we got it, and sometimes they didn't bother to completely undo an old modification when they upgraded.

I just attached the Gates belt part number PDF. If I remember right I just ordered ours off Amazon, but I would also assume you could get them though Napa. We use the HD Green Belts.

For EGT temps, we top out around 900 F, but that is only for short periods. If I downshift to raise revs on hills the temps decline. I did do the turbo swap but have yet screwed up the courage to adjust the injection pump for a bit more fuel, which would raise temps.
 

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RoamIt

Active member
Thanks for the info! Still thinking about where to install the EGT. Although turbo's are typically good for 100K miles, I'm debating replacing mine at 57K, then using it as a spare. If I do that, I'll install the probe on the exhaust manifold.

Part of the decision making process I'm using is thinking about service on the side of the road. Hate to find out then that a bolt that's been on there for 25+ years is just going to snap off/round off. If I take things off now, clean up, replace with new bolts then repairs when I'm 'out there' will be easier.

The 9530HD Green Stripe Fleetrunner belt showed up today, says 13x1357 on the pack, online Gates chart says a 9530HD is 13x1347 :rolleyes:

The belt I pulled off was a 13x1350, so I went 3mm shorter, now it's 7mm longer. Don't think it will be an issue.

I was able to order right off Amazon, along with the Continental belts.
 

RoamIt

Active member
Another FYI- (I know you pro's may find this old news, but for the sake of any other new owners, or part # changes, I thought I'd share)

My truck only has 57K miles on it, but I'm considering replacing the turbo. Again, wanting a baseline for maintenance and will rebuild or have rebuilt the one I pull off as a spare. Plus with my fuel/timing/injector mods, I want to get the most out the engine in case I race any of you for beers :LOL:

When trying to track down a new one, this is what I was told is the replacement: Garrett T04E66-4.
 

RoamIt

Active member
Wow, typically turbos are good for 100-150k miles. Of course my experience with them is on my turbo sports cars, not on a low rpm diesel engine. I could put the $1K towards many, many other things I need. I just keep thinking about a part failure out in the middle of nowhere and me trying to track it down, cross reference numbers, etc.
 

Geo.Lander

Active member
Another FYI- (I know you pro's may find this old news, but for the sake of any other new owners, or part # changes, I thought I'd share)

My truck only has 57K miles on it, but I'm considering replacing the turbo. Again, wanting a baseline for maintenance and will rebuild or have rebuilt the one I pull off as a spare. Plus with my fuel/timing/injector mods, I want to get the most out the engine in case I race any of you for beers :LOL:

When trying to track down a new one, this is what I was told is the replacement: Garrett T04E66-4.
there are old OM turbo trucks I’ve actually seen and driven in Greece with over a million kms with their original turbos. I wouldn't worry about it..
 
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