The mileage project

[JimmieD]

Thanks! So, "Simple fuel adjustments, only adjustments, raise hp to 200, torque to 400." should read, "...can raise hp to 160..."

[mcinfantry]

1967 m715.

i drove it stock for almost 2 years.

i read garbee's site and lou chou's info on-line.

i bought a frito truck for 700 w/ a blown clutch and sm465. i pulled the engine and tranny in one piece through the side door. i got rid of the truck for 500 complete (in one piece).

the 4bt was >140,000 miles cpl 858 which is 105hp and 265tq

i bought a dodge adapter/nv4500 and divorced 205. i couldnt get much help from the net at the time and geared the truck how i THOUGHT it should be. 4.56 gears (m1008 cucv axles). i had already been running the michelin xl's.

i ran into alot of interesting solutions based on reading, other peoples ideas/experiance and dumb luck. i had almost no diesel experiance other than a 1986 diesel jeep cherokee that was an absolute pos.



the m715 was swapped to saginaw power steering. a cummins 4bt runs the power steering pump by a gear. no belts to stretch, break or slip. i ran hydroboost brakes and a rear proportioning valve and 4 wheel discs. i also ran a hydraulic 'steering assist' ram. this made the steering light and easy.

i ran vintage air a/c with heat and defrost. i ran the ford taurus electric fan and a stock m715 radiator.

i ran the m715 w/o a lift. since it would clear 1100x16 michelins then i coudnt justify raising the cog. at the time i had never heard or seen a spring under open knuckle chevy d60. i made one.

[mcinfantry]

i ran a dodge nv4500 by removing the dodge slip yoke rear and replacing it with a GM fixed yoke to run the divorced 205.

i took the truck down to the frame. a buddy of mine started with a bare frame and 3 full days of work had it almost complete and turning the engine over.

we (i) mis-wired the fuel solenoid and we tried over an hour trying to get the thing started. i ran 12 volts to the starter and that didnt work. i was agitated and frustrated and thought the engine was turning to slow. we craked injector lines, cussed and swore. we called everyone we know that knows about diesels (3 people) and they said we werent getting fuel. i ran 24volts to the starter. the engine turned faster, but wouldnt run. after another 20 minutes or so i finally had ebough and ran 36 volts to the starter. it turned over so fast, it honestly made me nervous. after i burned one set of jumper cables up and melted the terminals off of two batteries i checked my wiring.

it fired right up!

i let it idle and it took 53 minutes at idle to reach 180 degrees. not too bad.

i then started playing with driveshaft angles. i tacked the rear spring mounts down, and tighened the ubolts. i put it in 4wd high and let the clutch out slowly. i spun the read axle up, and tore the ears off the yoke and didnt move an inch!

i replaced the yoke, tacked the rear better, and tightened the ujoints. i drove around the block!. i made another pass with a buddy to show him. we were grinning ear to ear!. i blipped the gas and spun the axle AGAIN destroying another yoke! i was no longer grinning!

put the thing together to try and get a little road time. i dont think i had it on the road more than a week when i stopped to check on a guy who had driven into a ditch. i was rear-ended by a mitsubishi montero doing 55mph. she totaled her truck. she bent one bumperette (slightly) and knocked a hole in the nv4500 5th gear cover.

i got it back together in time for land between the lakes kentucky.

[mcinfantry]

a buddy of mine and i trailered it to LBL for the m715 meet & greet. i hadnt had it on the road enough to comfortably drive it.

we had a few issues with blown steering o-rings (it was a burr on the ps box output flange)

we offroaded the thing for three days. i burned 5 gallons of diesel and the gas trucks burned 1 to 2 tanks. i ran in second low range the entire time. i never used first. i was told i was going so slow at idle i was forced to take up the rear.

the 4b was quite the hit.

my buddy, not a diesel nut, had his doubts from day one. after the ride he was so impressed he has sworn off gas motors. he is attempting to put a 4b into his blazer, but it may end up in a 86 2wd chevy 1500.

observations.

the truck ran too cool in the winter. no heat for the heater.
the truck ran too cool in the summer, and the elec fan only came on for the a/c

the truck probably could have had the engine gone through, but i never did. i never felt it needed it.

all in all you could easily find a 4bt for 2000, and a 4sp sm465 for free or $100. grab a divorced 205, or keep your 200 and regear your axles ( i would swap).

i think you could do it for <4000. i know i can.

[mcinfantry]

i scaled the truck.
2500lbs rear axle
3650 front.

full tank, no troop seats.

i was 285lbs at the time, so figure me and co-driver pushed the curb weight over 7000 with chains, straps, gear.........

[MoparNorm]

....put the thing together to try and get a little road time. i dont think i had it on the road more than a week when i stopped to check on a guy who had driven into a ditch. i was rear-ended by a mitsubishi montero doing 55mph. she totaled her truck. she bent one bumperette (slightly) and knocked a hole in the nv4500 5th gear cover.

i got it back together in time for land between the lakes kentucky.

This then, is your rear damage?!

[mcinfantry]

that is! she slid into me. she said she was scared to death, until i got out in uniform and she said she knew i wouldnt hit her!

i broke the seat back, the shifter (with my leg)

hers was totled.

[IHWillys]

mcinfantry

Did you ever turn up your 4BT or was it still at the fuel rate as when pulled out of commercial service?

I have two 3.7TD Hercules sitting in my garage that I'm not sure what to do with. They're 108HP/240lbft as they are not aftercooled. The aftercooled Hercs are rated 125HP/265lbft. Either way they are similar to the 4BT in the same application, stepvans, with the Cummins 3.9 rated 105HP and 120HP but with more torque than the Herc 3.7.

I'm flipping back and forth as to what size application is appropriate for one of these engines. I have a range from an old Scout up to a full size 4x4 van. I don't take these vehicles out on the interstate. The vast majority of driving in them is at 50 mph or below, brief periods of 65 mph but it's not necessary to be able to get to that speed to use these trucks the way I use them. Also I live at 5K feet altitude and weekly go to 7K feet, with multiple trips a year up over 10K feet. I'm used to my carburetted gassers really taking a hit on power by 7K feet. I think the turbo diesel will fair better due to the normalizing affect of the turbo. I don't tow anything so that's not a factor for me, just an occasional full load of camping gear with my wife and 4 kids along.

Anyway, your and others' posts are very informative and help guys like me to form an idea of what to expect before hand, which is of great value.

Ken

[MoparNorm]

Ken,
I don't have a 4bt, but I've had my Cummins 6 up over 13,000 ft. it ran just fine!
A non-turbo will start spewing black smoke under load at about 6,000 ft. the turbo, as you say, compensates.

[mcinfantry]

mcinfantry

Did you ever turn up your 4BT or was it still at the fuel rate as when pulled out of commercial service?

I have two 3.7TD Hercules sitting in my garage that I'm not sure what to do with. They're 108HP/240lbft as they are not aftercooled. The aftercooled Hercs are rated 125HP/265lbft. Either way they are similar to the 4BT in the same application, stepvans, with the Cummins 3.9 rated 105HP and 120HP but with more torque than the Herc 3.7.

I'm flipping back and forth as to what size application is appropriate for one of these engines. I have a range from an old Scout up to a full size 4x4 van. I don't take these vehicles out on the interstate. The vast majority of driving in them is at 50 mph or below, brief periods of 65 mph but it's not necessary to be able to get to that speed to use these trucks the way I use them. Also I live at 5K feet altitude and weekly go to 7K feet, with multiple trips a year up over 10K feet. I'm used to my carburetted gassers really taking a hit on power by 7K feet. I think the turbo diesel will fair better due to the normalizing affect of the turbo. I don't tow anything so that's not a factor for me, just an occasional full load of camping gear with my wife and 4 kids along.

Anyway, your and others' posts are very informative and help guys like me to form an idea of what to expect before hand, which is of great value.

Ken

i never turned a knob, screw or bolt to increase ANY power

[CGarbee]

Just to add my recent experience (every now and again I actually run the numbers on my truck...):

Fuel consumption, or, why I like my Cummins... I participated with the East Coast Convoy to the Aberdeen MV Rally in May. Round trip to Aberdeen with the ECC in my M37 with the Cummins 4BT, ZFs5-42 (0.76:1 fifth gear), 4.89 gears. Hardtop, bows mounted over cargo area, but canvas not mounted. 900r16 Michelin XZL tires (35" diameter). Max speed for trip about 55mph, had to keep it down due to trailing M35A2C for entire trip (mine, driven by my buddy Chuck) and due to the rest of the guys in the Convoy having similar pace vehicles so average was around 50mph (what I tried to hold it at)... Only had a M37 cab, a winch, and fourteen one gallon cans of string beans and potatoes in the bed for the ride up, ride back I had a M37 hardtop and a generator.

It was a 758 mile roundtrip. I burned 30 gallons of fuel... works out to 25mpg...
My "normal' leadfooted driving habits around town and on the highway yield an average of 17mpg, but I routinely am running at 75mph down the Interstate to work and/or doing the stoplight dragraces downtown...

FWIW: Current price of diesel in Raleigh is $2.85 gal, Unleaded regular is running $3.02 gal. Midwinter, diesel was priced the same as midgrade gas...

Every now and again I think that an ISB3.9 would be nice in my next rig, but I like what I am running. Never have turned anything up on it, but I am thinking that the higher rpm governor spring would be nice (be able to wind it up a tad more for the 3-4 shift when starting from a dead stop at the bottom of the hill a half mile from the house that has a stoplight at the bottom for instance, not because I want to run down the road any faster...).

[Gordon Maney]

Do you see any disadvantages to the ISB 3.9, other than cost and computer controls?

I imagine it would be quieter and more powerful? Does it have less vibration?

[mcinfantry]

finding adapters/accessories and such. how many have epa approval for road use? any?

[CGarbee]

Do you see any disadvantages to the ISB 3.9, other than cost and computer controls?

I imagine it would be quieter and more powerful? Does it have less vibration?

The ISB3.9-175 was installed as the standard power unit in the Freightliner Custom Chasis P3000 step vans (same as the old Chevy P30's, just Freightliner's version) with an Allison automatic until a couple years ago when Freightliner switched to a "Detroit Diesel" engine that actually is a Mercedes unit with a different valve cover... In other words, there are ISB3.9 engines that are just as EPA certified for use in a M37 or other repower application as the 4BT/BTA takeouts that folks are already using...

Cummins has not been paying much attention to the ISB3.9 in the US recently due to the efforts they have been making on the newer design ULSD engines, but they are still making the ISB3.9's in England, and elsewhere, and the parts are very available, you just have to have the $$.

That said:
Downsides other than the cost and electronic controls are that since they rearanged the components on the engine (fuel injector is driven off the flywheel instead of the front gear cover, for instance) you can't use the Dodge application ISB5.9 flywheel adapter, flywheel, clutch, or transmission like you used to be able to do with the 4B when you could use the 6B parts off a Dodge Ram. Bassically, Cummins made a special version for Dodge so that they could keep using the New Venture transmissions. Every other ISB can share parts, but they don't cross with the Dodge versions (as far as injector pumps, flywheel adapters, etc.).

Upside: A tad smoother, cleaner, more places to hang accessories, more power straight from the factory, setup to run with a SAE #3 flywheel adapter (negating the transmission problem mentioned above for my uses as I would go with either a Spicer 3053A or some other SAE transmission...). They also share the same block mounting points as the 4BT so they "should" be able to use the same frame mounts...

In all honesty, I have talked to a guy who has one that is being installed in a civilian Power Wagon, and I've looked at some data from Cummins, but until one falls off a tree near me (or I score a wrecked FedEx truck cheap), I'm not looking too hard at them...

So, an update to this post...
I just went over to the FCCC website and noticed that they have changed things again... Current "small" walk in van (step van) is the MT45 with the CumminsŪ 6.7L ISB07 200-hp 6-cylinder EGR diesel as the standard powerplant. So, no more little four bangers from them...

Incidently, for Mopar Norm: They have a page on their page that list ten reasons whey diesel is better in a bread van than gas... Follows closely some of the arguments that have been made on this site already.
See: http://www.freightlinerchassis.com/wvHome.asp

[MoparNorm]

Thanks for the 10 reason link Cabell!

I'm pretty certain that the decision maker in the post from Doc was tied somehow to the salesman for the gassers. Only nepotism or corruption could explain that decision!