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not my project but i thought i should share: my buddy Terry has been working on converting his m37 to propane. not wanting to sacrifice box space he modified the rear x member to fit the tank and dropped the stock hitch for a receiver.
DSC02079 by robynneedsparts, on Flickr
terry did not want to compromise the approach angel so to get the tank to fit he had to raise the box by 2 inches

DSC02081 by robynneedsparts, on Flickr

DSC02080 by robynneedsparts, on Flickr

terry was concerned that the truck would not look right having the box up 2 inches, but i think it looks great especially with 1100 16s
IMG_0899 by robynneedsparts, on Flickr

with the box being up he needed to get the lights up. so he fabed up some new light brackets
IMG_0897 by robynneedsparts, on Flickr

in this pic you can see the box spacers he made
IMG_0898 by robynneedsparts, on Flickr

now that the back is coming together its time for engine fun....
wanting to get the most out of the propane terry decided to block off the heat riser to keep the intake cool. it turned in to a big job.

IMG_0905 by robynneedsparts, on Flickr
a little heat helped get the studs out but the two bolts in the exhaust manifold were rusted in. more heat and beat was needed
IMG_0904 by robynneedsparts, on Flickr
the four bolts holding the intake to the exhaust were jacked in place and had to be drilled out
IMG_0921 by robynneedsparts, on Flickr

thats all the pics i have for now my camera packed it in i will post more pics when i get a new camera.
have any of you converted to propane what are your thoughts ? yes i know its sacrilege to cut up a MV, but in terrys defense he did not wreck the truck and it can go back to stock. he has a replacement rear x member and no new holes were drilled.
he is going to try out the propain on the stock manifold for the summer and over the winter he is planing on making a new manifold maybe even turbo propane.

pics of rust repair i did on his truck

DSC02084 by robynneedsparts, on Flickr

DSC02143 by robynneedsparts, on Flickr

DSC02145 by robynneedsparts, on Flickr

RMS,

That can't be in Canada...........there is no snow on the ground.

I like the looks of what he is doing, it's a clean install of the tanks.

Bert

T. Highway wrote: That can't be in Canada...........there is no snow on the ground.

you must be thinking of eastern Canada, here on the wet coast we only have two seasons rain and construction

i like terrys tank install too, especially the receiver hitch . im waiting to see how much range he gets out of the propane. if its good i will convert one of mine to propane. im tired of bogging out on steep grades, Chrysler cant make a carburetor

Work effort looks good!

The propane will help out with the steep hill issues, since there are no floats/float bowls to deal with, but the range will decrease. Propane has less BTU's for the buck/volume vs gasoline per equivalent unit volume. Meaning less power. And guys try to turn up the timing on propane-burning engines to make up for the lower power vs gasoline, but often end up doing more damage to motor due to advanced timing.

Remember the properties of propane, it has an octane of 104, meaning that in addition to other characteristics, the fuel has a long burn duration. If the ignition sequence is not initiated at the proper time, the combustion is still occurring when the exhaust valve opens, superheating the valve. This can cause tuliping of the valve, and once it breaks the valve seat seal, the seat can recede. Being a dry fuel, it may lead to more valve seat erosion if your valve seats were not setup to run unleaded fuel.

i would think most motors are not suited for propane but wouldn't the Lhead be a good candidate especially a military or full flow marine block with their stellite seats and sodium filled valves. wouldn't the longer burn from the propane on a slow spinning long stroke motor such as the 251 or 265 perform well ? would it still have the lug-ability( hill climb @ 600-800rps? what would the max base timing be? 2-4 degrees ? I have a friend with propane on his m37 and i like how fast it starts. i also like the amount of parts taken off the truck. granted i have not gone wheeling with him since he converted.
im interested to see what the right turbo propane system would be like on the old flatty. not a big turbo but a little guy that will spool up fast with a massive gate to dump it quick.

I HAVE CONVERTED TO LPG SINCE I GOT MY M37 BACK IN 1999. I DID NOT REMOVE THE GASOLINE SETUP, RATHER BOTH SYSTEMS ARE FUNCTIONAL, AND I CAN SWITCH FROM ONE FUEL TO THE OTHER AT A FLICK OF A BUTTON. MILAGE IS ROUGHLY THE SAME PER QUANTITY OF FUEL. ADVANTAGES OF THE PROPANE ARE, YOU CAN NEVER FLOOD THE CARBURATOR, LPG DOES NOT EVAPORATE OR GO STALE IF STORED IN TANK TOO LONG, AND HERE IN GREECE, ITS HALF PRICE THAN THE GASOLINE. DISADVANTAGES, MAJOR SPACE IN MY BED IS CONSUMED FROM THE LPG TANK, AND LPG CAN NOT BE HAD ALONG THE TRAIL AS ONE MAY CARRY GASOLINE IN A JERRY CAN. ADVANCE TIME WAS SET AT 2 DEGREES BTDC, BUT AFTER I FOUND OUT THAT THE MANUAL HAD BEEN REVISED TO 4 DEGREES I HAVE BEEN WANTING TO CHANGE IT. SINCE CURRENTLY I AM NOY DRIVING THE M, I DID NOT DO IT YET, BUT IT WILL BE DONE IN THE SUMMER ALONG WITH A FEW THINGS MORE I NEED TO DO TO IT. THERE ARE PICTURES OF THE CONVERSION IN THE GALLERY, FILE SOTIRIOS VENETIS.

I am running gasoline, but my timing is 10 degrees BTDC at 8000', and the truck runs great. Any take on that?

ZGjethro wrote:I am running gasoline, but my timing is 10 degrees BTDC at 8000', and the truck runs great. Any take on that?

i wish my flatty would spin to 8000rpm lol as long a she dont ping it should be good.


months since the last post but the truck is road worthy and went on its maiden voyage.

back to frame mods to get the tank in and save box space. rear X member was cut for clearance and a lot of steel and bolts added.
lots of drilling was required
the receiver hitch mounted

tanks in and all zincked up

to get the box to clear the tanks terry used some 2.5" box with rubber pads to make it clear
then it was on to modding the light brackets

frustrated with the stock covers terry made some out of aluminum
he also came up with a better way to attach them
now isn't that nice
even looks like it could be factory.

back to propane. more pics on modifying the manifold to keep the intake cool
brazed up the heat riser

and made an air gap between the riser and the intake with the aid of a piece of stainless
drilled out the intake to allow air flow

more drilling
then it was all about clean up port matching and paint
got to love belt sanders