Expedition engine?

[Third From Texas]

A straight driveshaft is not necessarily a good thing. In fixed applications it's standard to build 7-15 degrees of offset into cardan shafts because you need oscillating motion to keep them lubricated. My experience is transmission between to fixed locations.

Well by "straight" I meant not pointed down at a 45 degree angle like the A0 trucks.



*I sometimes exaggerate

 

[flatwerx]

You should check out Neil's build. One of my favorites...

He too retained the bed so the truck is still multi-role. Used a S280 and set it up so he can drive it on/off.

I love his build! Chatted briefly with him on FB.
Not sure what his 280 weighs now with the cage and stilts. He added Eco Hubs too which is my plan.

 

[Ronmar]

Yea, Neil did a fantastic job!

Cutting the DS RPM in half with the eco hubs actually brings them onto the angle/max RPM chart...

 

[coachgeo]

You should check out Neil's build. One of my favorites...

He too retained the bed so the truck is still multi-role. Used a S280 and set it up so he can drive it on/off.

View attachment 902731

will see if he changes bed route. Think he has two trucks now so he does not HAVE to keep the bed. In past he had too remove it cause truck was also used for business. (plowing)

 

[coachgeo]

@87cr250r they don't make Cardian joints for rigs this big unless they are specialized..... which is anti the plan for military trucks to be mostly off the shelf commercial parts.. Think the high pinion axle..... was how they compensated for that reality.

 

[Third From Texas]

will see if he changes bed route. Think he has two trucks now so he does not HAVE to keep the bed. In past he had too remove it cause truck was also used for business. (plowing)

I don't know why he would remove the bed. Just more work and money building a subframe where none is needed.

That is his new truck pictured, btw

 

[coachgeo]

I don't know why he would remove the bed. Just more work and money building a subframe where none is needed.

That is his new truck pictured, btw

these chassis medium duty (with a little more strength than average) / like most all medium duty chassis are made to occasionaly haul heavy loads. These also with ruff terrain in mind. But that is NOT all the time loads and that is not loads that are solid (aka they haul bunch of heavy thangsss tied down that can move independent of each other slightly..... ) For single solid framed object..... fixed to chassis with little to no flex in object..... problems will eventually happen if you dont have some sort of way for the chassis to flex under the solid object. Though avg. person might sell it before that happens and then next person takes it in the shorts.

 

[Third From Texas]

these chassis medium duty (with a little more strength than average) / like most all medium duty chassis are made to occasionaly haul heavy loads. These also with ruff terrain in mind. But that is NOT all the time loads and that is not loads that are solid (aka they haul bunch of heavy thangsss tied down that can move independent of each other slightly..... ) For single solid framed object..... fixed to chassis with little to no flex in object..... problems will eventually happen if you dont have some sort of way for the chassis to flex under the solid object. Though avg. person might sell it before that happens and then next person takes it in the shorts.

First, has Neil mentioned somewhere that he's removing the bed. Because I've not heard him say anything in regards to this.

If you're saying that the bed or any sort of sub-chassis is absolutely required, I tend to believe that may not always be the case with the S&S LMTV. One of the first builds on here that I fell in love with was made w/o the bed or any sort of sub frame. Duckworthe was in the RV building industry and understood the tolerances needed. He was a firm believer that the LMTV frame was plenty rugged w/o any subframe torsion relief. And he drove that truck places most of us will never see much less take our truck. As far as I know, he never self destructed his build.

M1078 camper in the Glamis dunes Thanksgiving 2016

Morning everyone. I was trying to post some pics yesterday but the site kept locking up and not responding. Will try again today. I took camper out to Glamis sand dunes here in SOCAL. It is always a great time. First time taking the truck out into serious sand dunes. Everyone was asking if I...

www.steelsoldiers.com

But again, what makes you believe that Neil is going to lose the bed? He just got finished mounting all those boxes, tanks, etc to it. I can ask him to chime in for clarity I guess. But I've never heard him say he was going to lose the bed....

I thinkwe're discussing a "what if" scenario that simply doesn't exist.

 

[GeneralDisorder]

these chassis medium duty (with a little more strength than average) / like most all medium duty chassis are made to occasionaly haul heavy loads. These also with ruff terrain in mind. But that is NOT all the time loads and that is not loads that are solid (aka they haul bunch of heavy thangsss tied down that can move independent of each other slightly..... ) For single solid framed object..... fixed to chassis with little to no flex in object..... problems will eventually happen if you dont have some sort of way for the chassis to flex under the solid object. Though avg. person might sell it before that happens and then next person takes it in the shorts.

The S280 shelter is designed to be chained down to a military truck - deuce, 5 ton, LMTV, FMTV, etc:

https://tonymoradian.com/wp-content/uploads/2021/02/S280CG.pdf

And for the military this is not an "occasional" mating. I was motorpool and my sergeant wanted a field office that wasn't a tent and our section wasn't authorized such a thing so we went down to the DRMO yard and picked up a shelter (older radio enclosure of unknown designation - something from the 80's as I recall) and we turnbuckled it to a truck bed from which it was never removed as long as I served in that unit. Went to and from plenty of field sites and never had a single issue that I'm aware of besides the usual issues of Army equipment that is hot as hell, cold as ice, and wet as a swamp all at the same time regardless of the local climate or the time of year.

I've seen enough shelter installations and builds to know that with the frame doubled by the bed and a basic shelter enclosure on it, there's not enough weight to flex the frame to any significant degree. Also military shelters are themselves VERY rigid as they are designed to be airlifted by a shithook.

 

[coachgeo]

First, has Neil mentioned somewhere that he's removing the bed. Because I've not heard him say anything in regards to this.

If you're saying that the bed or any sort of sub-chassis is absolutely required, I tend to believe that may not always be the case with the S&S LMTV. One of the first builds on here that I fell in love with was made w/o the bed or any sort of sub frame. Duckworthe was in the RV building industry and understood the tolerances needed. He was a firm believer that the LMTV frame was plenty rugged w/o any subframe torsion relief. And he drove that truck places most of us will never see much less take our truck. As far as I know, he never self destructed his build.

M1078 camper in the Glamis dunes Thanksgiving 2016

Morning everyone. I was trying to post some pics yesterday but the site kept locking up and not responding. Will try again today. I took camper out to Glamis sand dunes here in SOCAL. It is always a great time. First time taking the truck out into serious sand dunes. Everyone was asking if I...

www.steelsoldiers.com

But again, what makes you believe that Neil is going to lose the bed? He just got finished mounting all those boxes, tanks, etc to it. I can ask him to chime in for clarity I guess. But I've never heard him say he was going to lose the bed....

I thinkwe're discussing a "what if" scenario that simply doesn't exist.

Maybe am thinking German boxes.... thought it was s280 too..... dont they mount with a tie down chain that has a spring or similar item somewhere along the bar, chain, or cable that allows for some flex?

Word I got is a retired engineer that was part of the design for M1079 when in discussion with one of the small biz that converts these trucks to campers... was specific that with out some flex mounting of a solid box... the chassis will stress crack. IMHO does not matter if box is mounted to solid bed.... or box has a solid sub chassis.. both the same net result. You need something to allow chassis flex. Its not Unimog 404 flex...... way less. but it is still there.

 

[GeneralDisorder]

Maybe am thinking German boxes.... thought it was s280 too..... dont they mount with a tie down chain that has a spring or similar item somewhere along the bar, chain, or cable that allows for some flex?

Word I got is a retired engineer that was part of the design for M1079 when in discussion with one of the small biz that converts these trucks to campers... was specific that with out some flex mounting of a solid box... the chassis will stress crack. IMHO does not matter if box is mounted to solid bed.... or box has a solid sub chassis.. both the same net result. You need something to allow chassis flex. Its not Unimog 404 flex...... way less. but it is still there.

We always just tied them down with chain and ratcheting load binders or turnbuckles.

As to the stress cracking - I'm going to need to see a cracked FMTV frame and what accomplished it to believe that. Maybe if grossly overloaded past their "off-road" rating. I could see problems with an LMTV running a shelter and loaded with 10,000 lbs of plutonium. The off-road rating being widely accepted as half of what the chassis could do in ideal conditions...... civilian uses for an expedition rig with a much lighter composite habitat are not going to break the frame or likely even be heavy enough to cause any significant deflection.

I removed ~750 lbs of steel plating from the inside of my 1079 shelter. That was just bolted to the floors and walls for anchoring desks, shelves, gun racks, etc. These things are WILDLY overbuilt. I just installed 12' awnings on either side of my shelter and just drilled/tapped the mounting plates directly into the corner rails of the shelter. In some places it is a 5/8" thick sandwich of steel and two layers of aluminum. It's honestly absurd in a lot of ways.

 

[coachgeo]

We always just tied them down with chain and ratcheting load binders or turnbuckles.

As to the stress cracking - I'm going to need to see a cracked FMTV frame and what accomplished it to believe that. Maybe if grossly overloaded past their "off-road" rating. I could see problems with an LMTV running a shelter and loaded with 10,000 lbs of plutonium. The off-road rating being widely accepted as half of what the chassis could do in ideal conditions...... civilian uses for an expedition rig with a much lighter composite habitat are not going to break the frame or likely even be heavy enough to cause any significant deflection.

I removed ~750 lbs of steel plating from the inside of my 1079 shelter. That was just bolted to the floors and walls for anchoring desks, shelves, gun racks, etc. These things are WILDLY overbuilt. I just installed 12' awnings on either side of my shelter and just drilled/tapped the mounting plates directly into the corner rails of the shelter. In some places it is a 5/8" thick sandwich of steel and two layers of aluminum. It's honestly absurd in a lot of ways.

no cracked frames to see.... they were built properly and boxes put on them with this in mind. There is I think only four or five solid boxes on LMTV's out there right now... but only about 4 years?? at most of minimal use..... time will tell... Id expect damage not to show up till 10+ years.... maybe less with full time travel.

chassis is suppose to flex a little..... when it is not allowed to flex as designed it will crack over time. As you describe the M1079 ... this is a good example..... of solid built; non flexible big box. Has nothing to do with weight. Box has no movement in it and prevents whatever it is attached to from moving as well. ..... thus if bolted "solid" direct/indirect to truck chassis, it prevents truck chassis from flexing........ thus it will eventually crack something. Even possibly transmission case. Particularly since front half of truck is trying to flex a bit as designed; while rear half is being prevented from flexing. Hence why 1079 has captured springs. Type flex that is the issue is chassis twist.

A not so solid box... opposite happens..... the truck will do its thangg and flex..... making the box flex too.. causing whatever is solidly attached to the box walls to slowly rip apart.

if anyone is interested... I have brainstormed on how to go about it different. and mount interior parts in a way that allows camper box to twist w/out damaging them .... then build box that has some flex... enough to not limit truck so much... just different way to skin a cat. Not sure though how to build a box that can over its life time be happy twisting .... yet be able to insulate it well... much less not crack the box frame.

Don't think our frames flex this much..... but this video shows the point. He addresses off road being better allowing truck to twist.... but he does not address that it could overtime damage truck chassis by preventing flex truck is suppose to have.

PS-- if you want good reading on chassis and expedition truck stuff.... this has been argued to adnauseam on Expedition Portal

 

[Third From Texas]

no cracked frames to see.... they were built properly and boxes put on them with this in mind. There is I think only four or five solid boxes on LMTV's out there right now... but only about 4 years?? at most of minimal use..... time will tell... Id expect damage not to show up till 10+ years.... maybe less with full time travel.

chassis is suppose to flex a little..... when it is not allowed to flex as designed it will crack over time. As you describe the M1079 ... this is a good example..... of solid built; non flexible big box. Has nothing to do with weight. Box has no movement in it and prevents whatever it is attached to from moving as well. ..... thus if bolted "solid" direct/indirect to truck chassis, it prevents truck chassis from flexing........ thus it will eventually crack something. Even possibly transmission case. Particularly since front half of truck is trying to flex a bit as designed; while rear half is being prevented from flexing. Hence why 1079 has captured springs. Type flex that is the issue is chassis twist.

A not so solid box... opposite happens..... the truck will do its thangg and flex..... making the box flex too.. causing whatever is solidly attached to the box walls to slowly rip apart.

if anyone is interested... I have brainstormed on how to go about it different. and mount interior parts in a way that allows camper box to twist w/out damaging them .... then build box that has some flex... enough to not limit truck so much... just different way to skin a cat. Not sure though how to build a box that can over its life time be happy twisting .... yet be able to insulate it well... much less not crack the box frame.

Don't think our frames flex this much..... but this video shows the point. He addresses off road being better allowing truck to twist.... but he does not address that it could overtime damage truck chassis by preventing flex truck is suppose to have.

PS-- if you want good reading on chassis and expedition truck stuff.... this has been argued to adnauseam on Expedition Portal

So what you are saying is that Neil isn't deleting his bed...

 

[flatwerx]

I've read a lot about removing the beds vs zero torsion frames. Have any of these rigs cracked a frame?
Lots of loaded rigs in active duty with comm shelters and other heavy loads and they seem to keep going. Also, I've seen a few S-280's pretty built inside (camper builds) that are simply mounted in the bed of the truck. Some even throw campers in the bed.
The beds don't allow flex? Can they be refashioned with captive springs? Do they need to be in something like Neil's setup?

 

[coachgeo]

.... Can they be refashioned with captive springs?...

absolutely and fairly easily. Just copy M1079.... 99% of the parts are already under the bed.

 

[coachgeo]

So what you are saying is that Neil isn't deleting his bed...

not sure why your even making something of that.... never said he was.... only said with two trucks now.... he has that option to consider now; more so than he did previously. He is always updating/improving stuff.

 

[TechnoWeenie]

One thing that I've thought about is the computerization of modern engines. You hear a lot of people say that the older mechanical engines are more reliable (e.g. M35 Duece vs M1078 LMTV), but the statistics clearly show that the newer engines get significantly more reliable as they become more computerized. (There are other non-computerization engineering improvements going on too, of course.)

So why do people perceive it that the mechanical engines are more reliable, when they aren't (not even close)? My guess is that it's the way in which they fail. The mechanical engines may start to fail, but they don't die completely, and you can still drive it until you can fix it. The newer electronic engines have sensors and components that are very reliable, but when they fail, you are just totally stuck (e.g. the engine won't even start without the ECU). As many of our trucks are old, those components have reliably run for 20+ years, and now the plastic/rubber and other delicate portions of them are failing, so do we see a steep increase in failures?

This is pure conjecture, but something to draw your own conclusion on.

View attachment 902504

Interesting there's no 800 or 900 series on there...and there's no M44 series A2.

 

[Third From Texas]

not sure why your even making something of that.... never said he was.... only said with two trucks now.... he has that option to consider now; more so than he did previously. He is always updating/improving stuff.

This is where the topic somehow shifted to changing beds and options.

I was just wondering if Neil had said something that made you think that was his intention.

But I'm quite positive that if the OP wants to drop an S280 on the bed, there are ample examples of it working just fine (Filner's truck, Neil's truck, the Army, etc, etc).

 

[Ronmar]

I've read a lot about removing the beds vs zero torsion frames. Have any of these rigs cracked a frame?
Lots of loaded rigs in active duty with comm shelters and other heavy loads and they seem to keep going. Also, I've seen a few S-280's pretty built inside (camper builds) that are simply mounted in the bed of the truck. Some even throw campers in the bed.
The beds don't allow flex? Can they be refashioned with captive springs? Do they need to be in something like Neil's setup?

Well in the case of a shelter box or camper placed in the bed, the bed structure(all 2600 pounds of it) acts as the subframe, and its components allow for some flex without transmitting all the frame twist into the box. The box of course needs to be able to withstand or tollerate any flex it does receive.

Besides all the weight, it adds height. if your goal is to make a camper out of it, it would be more efficient to remove that 1.25T bed structure and weld 4 captive pockets to the upper frame rail just like they did with the M1079 installation. Then build a sub-frame that rests in the 4 pockets(2 bolted, 2 with captive springs) and then attach the box to this subframe. This concentrates the box load onto 4 points, but this was precisely what that upper frame rail was designed to do, distribute concentrated loads over a wider area of the lower main frame rail.

frame twist is a factor of weight applied so lowering the weight also reduces frame twist…

Pretty sure you could do this sort of setup at half the weight and several inches shorter overall height than with the bed. But you of course loose the functionality of the bed…

 

[flatwerx]

Well in the case of a shelter box or camper placed in the bed, the bed structure(all 2600 pounds of it) acts as the subframe, and its components allow for some flex without transmitting all the frame twist into the box. The box of course needs to be able to withstand or tollerate any flex it does receive.

Besides all the weight, it adds height. if your goal is to make a camper out of it, it would be more efficient to remove that 1.25T bed structure and weld 4 captive pockets to the upper frame rail just like they did with the M1079 installation. Then build a sub-frame that rests in the 4 pockets(2 bolted, 2 with captive springs) and then attach the box to this subframe. This concentrates the box load onto 4 points, but this was precisely what that upper frame rail was designed to do, distribute concentrated loads over a wider area of the lower main frame rail.

frame twist is a factor of weight applied so lowering the weight also reduces frame twist…

Pretty sure you could do this sort of setup at half the weight and several inches shorter overall height than with the bed. But you of course loose the functionality of the bed…

I don’t have to keep the bed but I would really like to. My goal is similar to @tennmogger ’s setup with an Alaskan Camper. They’re fairly lightweight and it’s a non cabover, 8’ long. This allows me to keep the bed for when I need it and keep weight down.
Removing the bed, building a lightweight flatbed/torsion bed would save a ton of weight. Going that route would make me want a trailer for the bed stuff when needed.
Appreciate the info and recommendations!