M715 Motor Swap

[LCieri]

Hi all. I came across this site when "googling" M715 6BT motor swap. What a wealth of knowledge. If you don't mind I would like to tap into that knowledge.

History:
My father and I both come from a fire background. We bought the M715 from a fire department in upstate New York. They were using it for their wildland brush truck. It's our intent to continue using the Jeep for that purpose. We own land in Montana and that is where the Jeep is destined. Hopefully sooner rather than later seeing how the State is on fire.

The truck is stock with the original 230 Tornado motor. It runs smooth and Dad was able to fine tune it. Currently outfitted on the bed of the Jeep is a 100 gallon tank, water pump and 150ft of hose.

The Question:
We were questioning the reliability and power of the 230 Tornado and whether or not its a motor that should be used for this field of work. The motor will be used in high altitude mountainous terrain. If not, the motors we were thinking of were either a 350 Chevy or a 4BT or 6BT Cummins.

I do have access to a 6BT powertrain. I have not purchased it. My fear is the weight on the front axle and its versatility for off-roading.

Thank you in advance for the suggestions and advice.

[Don Cavey]

I am probably not the person to talk to but...

I am a believer in keeping the truck stock. My reason is that if all is well today and the normal maintenance is performed, they seem to do well. Getting into engine swaps etc. involve engineering and that is already done by Kaiser back in the early 60s. One complaint is power or lack thereof. But as a society, I think we have gotten used to lots of power, power steering, power brakes etc.

They worked for me when I was in the army, Utah, Germany and I had no issues with breakdown. Of course, the truck was only two years old.

Let others weigh in here, just my opinion of course.

[Mikel]

Welcome to the site. Where in CT are you?

[venominjected]

power, power steering, power brakes etc.

engineer and tinkerer.... this is the exact reason for my axle swap, engine swap, transmission swap.

While the 230 tornado did do its job well... 50 years ago.... unfortunately vehicles have continued to progress.

My reasoning behind the complete powertrain swap was to make my 715 useful on todays roadway speeds (highway).

Run the 230 and orignal NP200 at 70 mph for 2 hours(you cant) and things go south quickly.

While yes you can backroad the 715 if it works for you.. sooner or later highway is unavoidable with any type of usage..... going 15-20 mph under the speedlimit on todays interstates is also a danger to yourself and everyone else.

All comes down to what you what your end use m715 to do... in todays world.

I know 4 wheel disc brakes, diesel, 5 speed OD trans, power steering, hydro-boosted power brakes will make me use my 715 more than simply jumping in my daily driver GMC Sierra. I did all of my modifications with the intent though that from 10 feet away (when you cant count the lugnuts [8 vs 6]) you'll never know.

My 230 let go... so the decision was made for me.

[LCieri]

Welcome to the site. Where in CT are you?

I live in Cromwell.


Thank you Don Cavey and venominjected for the quick response and suggestions.

[Mikel]

Tell us more about the intended use for the truck. If it's going to be a farm truck, you don't need highway gears and you'll likely never drive the distance required to justify a diesel swap (if fuel savings are your goal).

In that case a good running 230 may be all you need, although 50 year old engines can be finicky, specially if run by people who don't know how to deal with them (I'm assuming other people will drive the truck).

[LCieri]

The truck is going to be used for Wildland firefighting in high altitude mountainous terrain. It will be used mostly off-road as the area of Montana we have property are dirt roads.

[Mikel]

The truck is going to be used for Wildland firefighting in high altitude mountainous terrain. It will be used mostly off-road as the area of Montana we have property are dirt roads.

In that case, the truck is very nicely suited for that purpose. Add a SBC for added power and reliability and you'll be in good shape. Niceties like power steering and power brakes are very easy to add.

If you come to Colebrook on Oct 1st you can see some 4BT and 6BT-powered M715s.

[Nailhead]

The truck is going to be used for Wildland firefighting in high altitude mountainous terrain. It will be used mostly off-road as the area of Montana we have property are dirt roads.

FWIW, I live at about 5300 ft, and the 230 acquits itself pretty well up here, especially with mid-grade gas. It's no fireball, but it stays out of traffic's way in town & on country roads.

If you're looking to get a fast-attack on the road quickly, you might stick with the 230 and evaluate its usefulness for that purpose on the job, so to speak, and swap when & if you think you need to.

Put a locker in the back, though, whatever you do: you can't fight a fire you can't get to, and these trucks need lockers for mountain duty. They don't articulate enough with their stiff suspension.

If I was still living in the hills of SE Wyoming, I'd have a stock M715 for a fast-attack-- I think it would work pretty well, locker-equipped.

[LCieri]

Thanks Mikel and Nailhead. I appreciate the input.

I'll be sure to be there October 1st. I enjoy being in that part of the State. I go to Lime Rock regularly for the races. See you October 1st.