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The following is a 1st draft only and we will try to share our experience with other Diesel-Experts like Kai Serrano, etc....

The trip to Moab (Utah) served as a tune and test-drive for our new Diesel Unimogs (orange 416 Crew-Cab). I tuned the injection pump for more inject-volume (110 hp tuned to 130 hp) and for higher RPMs (2800 tuned to 3050). This allowed me to achieve a top speed of 60+ mph with 14.5x20 tires. A comfortable traveling speed is 50 to 55 mph (uphill/downhill no difference). While I was watching the pyro-gauge climb to 1250 deg F I was able to manage a very long stretch of 6% uphill (5 miles) between 35mph to 40 mph. I could have gone faster, but because of the exhaust-temp I was not allowed to.
If you put less aggressive treaded tires on you will loose the feeling that you are flying in the middle of a bombing squad with a couple hundred other bombers flying next to you. The Diesel-Knock is also significantly decreasing below 55mph (except up hill). The motor-oil consumption will be in more moderate limits if you don't rev the engine constantly at it's max. Over all, the 416 performed really good and beyond my expectations. The 4-wheel-disk-brakes with air support help you to stop your 3.5 ton Unimog within a reasonable range (but it's still a good practice to leave a nice safe distance). Power steering, what a nice invention and we have it. The gas pedal reacts very touchy because of the RPM-control per degree of accel-lever-movement (a little step and the 130hp are moving)

Warning:    Do not attempt to hot-rod any Diesel-Injection pump without a previous Installation of an Exhaust Pyrometer (When Kai got asked about how to tune the pump he said he will only release the info after a Pyro-gauge got installed). You can and will fry the engine with the wrong adjustments without the appropriate exhaust-temperature monitoring capability. If you are unsure about the whole procedure, please consult your local Diesel-Mechanic for a 2nd opinion.

Details:    Before you make any changes, please mark the original positions, just in case if you want to reverse your experiment. Please install the Pyro-gauge at the very beginning and run a base line (original setup readings) before you proceed. The RPM increase can be done by adjusting the acceleration lever limit screw to allow more travel (about 2 to 5 turns, please try it in steps). It will require a re-adjustment of the accel linkage as well. In most cases you will have to remove the protective plastic cover over the adjustment screw. Do NOT turn it up too high because this is the only mechanism which prevents the engine form a run-away. To turn off the ignition doesn't work with a diesel. If your throttle linkage gets stuck at full load you have to push the clutch, come to a stop and then choke the engine by releasing the clutch in high gear. If your RPM limiter is to high you will damage the engine doing so. The engine is never supposed to reach higher NO-LOAD-RPMs than 3250 (full throttle and clutch pressed or neutral).
The higher inject volume is more touchy than the RPMs. You need to remove the square cover plate at the lower back side of the injection pump (to get to it you might have to remove the complete oil-filter assembly and the air-compressor cylinder-head). Some of the 4 screws could be tamper proof. Remove them and replace them later with M6x10 hex bolts. There you will find a governor assembly (don't touch it) and a small adjustment screw with a locking nut. Loosen the nut, and turn the screw inwards 1/4 to 3/4 turns for the stock 110hp engine or 1 to 1+1/2 turns for the 80hp engine (the 3/4 as well as the 1+1/2 setting are absolute max values and are not too much recommended, unless you want a melt-down). If you live above 3000 feet of elevation do it 1/2 to 1/4 turn less. If you turn it too much the engine will smoke excessively and run much hotter which is NOT good. If it smokes under full load, than turn the inject-volume screw back out 1/4 turn at the time and re-test it. All this applies only if you don't have an engine-load-test-stand. One final test is the following: Warm up the engine and drive up a long hill and keep an eye on the Pyro-gauge. A safe setting will not let you exceed the 1250 deg F by much (don't exceed it on a regular prolonged basis). A real hot setting will exceed the 1250 deg F and you will have to monitor the Pyro-gauge every time you have a longer hill to climb up, so no real gain in the long run.
Excessive smoke during full load situations will not give you lots of more power but only a higher risk of internal engine overheating, lousy fuel economy and pissed tailgaters (eventual cops too). So please if the warmed up engine smokes under load, tune it down until you see just a bit smoke under full load and don't let the Pyro-gauge jump into the unsafe ranges
We also recommend to advance the inject-timing by a few degree. There are 4 17mmHex bolts with 2 of them on each side of the injection pump. 1st mark the original position of the pump with a scratch, etc... 2nd loosen the bolts slightly (The 2 inner ones need very long extensions and a U-joint). Turn the pump about 2 to 3 deg outward which relates to twice the amount on the crank (counter-clock-wise if standing in front of the engine) and re-tighten the 4 bolts. You will notice an increase in the diesel-knock, but at 50 mph with medium power the engine should hum very peaceful once warmed up. The advance settings can be a bit tricky because I don't know what your original setting was. It can be anywhere between 16 to 23 degrees on the crank. The desired value is about 25 to 28 degrees.
All of my suggested values are pure empirical and it's a very good practice if you try it in little steps, don't overdue it in one big move.

diesel4.jpg (56357 bytes) diesel3.jpg (41308 bytes) diesel8.jpg (21892 bytes)
Injection pump top view (engine on left, pump on right, top is front of truck). The screw is NOT brass, it's the additional lighting. This adjustment screw limits the RPMs. Normally a few turns (3 to 5) adds about 10% higher RPMs. The small plastic cap which protects the RPM adjustment screw from tampering
diesel5.jpg (86523 bytes) diesel2.jpg (68621 bytes) diesel1.jpg (62528 bytes)
Side view from the passenger seat. See square cover at the lower rear of the pump. Back side of pump with cover removed. View of the inject-volume adjustment screw (lower one). 406-80hp 1+1/4 to 1+1/2 turns / 416-110hp 1/2 to 3/4.
advance.jpg (39227 bytes) inject timing advance / retard

There are also 2 nuts/bolts on the back side of the pump. Use long extensions with U-joint and 17mm socket

Caution:    Once you tune up your injection pump it's essential that you use the installed Exhaust-Temperature-Gauge (Pyrometer) to monitor the exhaust temp. It's very critical that you watch the gauge religiously going uphill for a longer stretch. Kai and myself do not recommend to exceed 1250 deg F for any longer periods (maybe 10 to 15 seconds or so). Your pyrometer will become at least as important than your speedometer. After a few days you will get more acquainted with it and it should become 2nd nature to keep an eye on you pyro-gauge (for the hotter pump-delivery settings).

diesel6.jpg (62212 bytes) diesel7.jpg (56520 bytes)
Pyrometer gauge, VDO # ......, electronic type (not mV type), $150.-- Pyrometer sensors & location

Summary:    The following table are some of our notes on the way home. We have no data available on the trip to Moab and we did some of the final adjustments in Moab itself. We did a little off-road at a friends place in Minden (Nevada) and therefore the slight increase in mpg's. Our trip was done on Hwy 50 west and we covered more that 10 summits with an average elevation of 7000+ feet. We kept the pyro at 1100 to 1250 deg F most of the time and the average speed was 50 to 55 mph except uphill. We were able to sustain 35 to 40 mph during most 6% uphill grades (pyro steady at 1250 deg F and NOT full throttle). The engine-oil consumption was 3+1/2 quarts of oil, with some being lost through 2 small leaks which I'm trying to fix in the next few days.

3.78

1.61

km

km

litre

l/100km

miles

miles

gal

mpg

Moab

132434

82257

Salina

132653

219

62.37

28.48

82393

136

16.5

8.24

Delta

132755

102

26.84

26.31

82457

63

7.1

8.92

Ely

132974

219

66.15

30.21

82593

136

17.5

7.77

Eureka

133084

110

32.51

29.55

82661

68

8.6

7.94

Fallon

133338

254

71.44

28.13

82819

158

18.9

8.35

Minden

133481

143

44.98

31.46

82907

89

11.9

7.46

Stockton

133649

168

46.87

27.90

83012

104

12.4

8.42

Los Gatos

133829

180

51.03

28.35

83124

112

13.5

8.28

1395

402.19

28.83

866

106.4

8.14

Disclaimer: The tune-up/hot-rod procedures can and will put more strain and wear on your engine and drive-train components. If not observed and handled properly it can roast your engine or parts of it. It serves only as a guideline of what your 406/416 Unimog would be capable of. Unimog-Forever does NOT recommend it and can not be held responsible if anything goes wrong. Sorry about this, but it seems the appropriate way in the US to protect your A.. from the unforeseen.

 

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