M-725 common engine swap advice

[bcowanwheels]

About 5 minutes of loud detroit diesel and it will get your goat...... Lol got ear muffs???????
Bob

 

[yeroleunclefritz]

I've had an M-725 for 11 years.......drove it from Washington State to Eastern Nebraska in 2003, then down here to South Mississippi in 2008, a little over 2,600 miles total. The odometer shows a little over 16,000 miles.

I kept the speed around 55, no problems of any sort, spent most of the time on I-90, I-70 and I-55. Pissed off a bunch of truckers but Oh Well.

I'm 63, spent from '67 to '70 in the USMC....most of it in South Vietnam....don't remember much of these M-725s from those days because the USMC didn't have any, and we were far, far from any Navy installations. I was in LVTP5s (AmTracs).

This old girl came from a little town volunteer Fire Dept and is painted the popular "Yellow-Chartreuse"....it has 9.00x16 "Mileage-Maker" tires on it....good ones...has been licensed, insured & safety inspected since I've had it, and I would trust it anywhere. That little Fire Dept also installed a Braden LU-4 power-take off winch on the front of her, and converted the majority of the electrical system (lights) to 12V. Put new brake shoes, brake hoses, master cylinder & all new wheel cylinders on it last year but as you know, still takes awhile to slow her down.

I may go as long as two months before I go out and fire her up. Two good Interstate batteries in her, pops right off like I just turned her off twenty minutes ago. I DO have to take her out on the road for awhile to keep those tires "round"!

Have no plans to EVER sell this old girl....no reason to.....she looks right purty parked next to the 1958 Willys Station wagon (4-WD, lockout Warn hubs, PTO Winch on front also).

Like all military things mechanical.....don't overdo the RPM's and maintain and take care of them....they'll take care of you. It's not FAST, but neither am I these days....

Yer Ole Uncle Fritz

 

[bcowanwheels]

I hate to inform you but if you drove it at 55mph you did overdo it in rpms, basically you drove it well beyond overdoing it. Do the rpm/speed calculator thing. 45mph is wide open, yes they will do more because these engines dont know when to quit by design. Jmo
bob

 

[kvflyer]

So I guess that this speed was a little excessive, right Bob? It was taken on the Autobahn in Germany, 1970 on the way from Heilbron to Neu Ulm. I wasn't driving, just the "Picture Taker". But it was my truck.

BTW, The windshield leaked at the seam back then as well...

 

[bcowanwheels]

Yep. 45 mph is wide open. They will go faster because there id no lifters to float but valve springs will and thus puts valves into pistons. These engine are very hi-perf by design and extremely durable but they need to be taken care of. Its like a thurobred race horse, it will run its self to death if the operator lets it. 5.87 gears rev the engine out quickly. I run 4.56 gears and 38: Tall tires to make the truck road friendly. There not designed for highway speeds but rather to fowwow a tnak across country.
Bob

 

[kvflyer]

Yep. 45 mph is wide open. T...

,,. There not designed for highway speeds but rather to fowwow a tnak across country.
Bob

Bob,

You are right and that picture was taken when we were teenagers stationed in Germany. I would NEVER subject this very wonderful engine to that kind of stress. For that matter, it is just more enjoyable to drive at 45 and listen to the whine of the gears. That is what I remember and can't wait to drive my truck (when properly restored) in its new home, Fernandina Beach, Florida.

BTW, thanks again, take care of yourself Bob!

 

[yeroleunclefritz]

Anybody have any idea where I could locate the spare tire holder assembly that goes in the rear of the frame, under the body for an M-725? I've tried all the places I could find in Supply Line and MVM and their reply is......are you ready for this?......"They're hard to find!"

thanks.....that 9.00-16 takes up A LOT of ROOM in the back of this thing......

 

[kvflyer]

I just looked in the 34P manual and they don't seem to have a different listing (that I can see) for the M725 vs. the M715. So, maybe they are the same? I am sure one of the members will have one for sale...

 

[bcowanwheels]

there the same. $150.00 + shipping
bob
423-384-8938