Welcome to my Propane Conversion Write-up
The question of "Why convert your Jeep to Propane" is discussed at great length on another page. This includes other sources of information and links.
The parts I'm using are as follows:
OHG 450 and X-1 Mixer and Converter, from ebay. $600 new, $300 rebuilt, mine was $53 for both.
Manchester 13x13x32 33.5 gal (25.9 Liquid) tank from Roy at www.propaneguy.com (also has mixers and converters) in Canada.
Steel from a local industry source, $.40 to $.60 per pound. Cheap and Cool.
Hoses and used remote fill box from a propane supplier in Washington State.
Information primarily from Franz Hoffman and Tom Jennings
Wish these guys had been around when I started this: www.gotpropane.com
I'm mounting the tank in the place of the original gas tank, I'm glad I could find one that fit for less than a bazillion dollars. I've fabbed up a mount and then a skid plate & cage to protect it from the Rubicon's rocks. This is the hardest part, so it gets done first. I've also lifted the body 1" to bring the tank up as much as possible. I really don't like dragging parts on rocks!
Next hardest is the remote fill location, because it involves body work, which I'm ... not too good at, so I just hope it works out.
I've mounted up the mixer and the converter, then measured for the hose I need. At $3.00+ per foot, you don't want to make any mistakes on the measuring!
I'll then put an oxygen sensor in the exhaust pipe and get an autotronics closed-loop oxygen controller #4045.
Then it's off to the dyno, because that's all there is to it.
Further mods would include an ignition upgrade, in the MSD/Crane/Holley category, but that's much $$$ later.
18 April 2003: IT RUNS! After advancing the distributor over 15 degrees, it fired! The cooland lines weren't run, and it was 45 degrees and raining. It took about 15 seconds for the converter to freeze up like a block of ice! More writing later, but here are some pictures of the setup as is:
12v filter lockout, mounted to plate which bolts up to the tank
remote fill box, used is better than fabrication - a little sand paper and some spray paint fixed it right up :P
tank mounted, plate down
converter and mixer installed, water lines not run
June 03 - I've run it enough to have run out of "gas" - luckily I was about 20' from my RV camper when it happened. I pulled the 20# horizontal tanks off the camper, flipped them over, hooked the "cheater hose" up to the Jeep, and got enough fuel to get to a propane supply place. Quite a lunch-hour, but it could have been MUCH worse! AAA don't speak propane. I'd better get that fuel sender hooked up before I drive too much further.
I can't answer the MPG question yet, but I think I got about 10 overall on the last tank. Note that I had significant tuning problems, which caused me to have to lift the hood and prime the system every time I started it ... that had to be a serious detriment to the MPG ... But it's fixed now (a simple turn of the idle mixture screw fixed it - thanks to Franz and his tuning info on his website). It idles much better, starts better, and when I get the computer hooked up, it'll be squared away fo sho.
Summer '03: Still left to do: fuel sender (asap:); skid plate for tanks; relocate the remote filler into the body panel; take it wheelin'!!! Later I'll replace the dual exhaust with a Y-pipe and single 3" to the back. I'll put in the O2 sensor at the Y (connecting the tuning computer in the process), and probably a high-flow cat unless I can prove that cats don't reduce what little emissions I am now producing. Research research research.
July '04: Still limping the old engine block along. I've got the fuel sender installed, works perfectly. I got a couple of 200 mile runs out of the tank, but now it's down to 120~ ... a testament to how broke-down this engine is. It's blowing-by as much as it's putting out I think. I've begun experimenting with just how far I can go after I manually shut off the fuel lockout. I can usually get about a mile just on the 10' of fuel line running up to the front of the Jeep ... not bad!
April '05: I'm still running the old tired engine. I'm trying to decide if I should just get a new remanufactured AMC 360, which runs 9.5:1 compression, or go for the more propane-friendly 11:1ish compression by rebuilding what I've got with lots of (rare and expensive) AMC high performance parts. Time vs. Money I guess.
July 06: I'm in the middle of a serious upgrade - a Magnum 320HP Crate engine and 4 speed automatic. It'll still run on propane, and I'll get the Autotronic put on finally. I'm also going to run an MSD Digital-6 ignition and move the filler location while I've got it all torn down. The main info page for this rebuild is here.
I'll continue on with some more propane-specific notes:
This is a place holder, but I found a good writeup for propane timing: http://cars.rasoenterprises.com/Propane-Ignition.htm here's another wheeler's page http://www.patooyee.com/propane/propane_1.htm