Propane systems

Roccrawler · Apr 27, 2006

TMFabrication said:
I'll be converting over to propane after Memorial Day, working on finding the tanks and brackets (for cheap) and will get the other parts through propaneguy. I'm thinking about swapping some smaller chambered heads on to get the compression up over 10:1. I'll be losing some valve size (2.02's now.) What are your guy's opinion on higher compression vs. smaller valves. I think it may run better low to mid range with a better intake velocity and how often do you really run a V8 into the upper RPMS for an extended amount of time around here with all the trees:redneck:

1.94 intake and bump up exhaust to a 1.60

zig80toy · Apr 27, 2006

where is a good place to buy the forklift tanks/other propane tanks? I have heard the choices are very limited to the sizes of tanks you can buy... I want a huge one. Where do i find it? and of course, cheap is good.

TMFabrication · Apr 27, 2006

I decided to go with multiple forklift tanks. 2 in the rig and 2 in the tow rig.

Roccrawler · Apr 27, 2006

I have bought 6 off ebay $55-$150 ea
go aluminum they are way nicer

two main sizes 8 and 10 gallon

Roccrawler · Apr 27, 2006

call this guy 516-747-0651

he had like 50 aluminum tanks sellin for 55 ea

zig80toy · Apr 27, 2006

Thanks, now the question is where is the spare tire going to go.

Roccrawler · Apr 27, 2006

zig80toy said:
Thanks, now the question is where is the spare tire going to go.

always wheel with a buddy who has one :redneck:

zig80toy · Apr 27, 2006

Can these propane tanks be mounted under the vehicle in the position where the gas tank are located?

Toyotanut · Apr 28, 2006

If you are worried about tank size you could also look for an old vehicle that was converted and get the tank out of that.

Roccrawler · Apr 28, 2006

Toyotanut said:
If you are worried about tank size you could also look for an old vehicle that was converted and get the tank out of that.

the bad part about a built in tank is you have to take the whole vehicle to fill it.. you cant just keep spares in the tow rig. or if your campin its alot easier to throw the tanks in the back of your truck and run into town, than towing vehicle to town? $.02

Toyotanut · Apr 29, 2006

roccrawler said:
the bad part about a built in tank is you have to take the whole vehicle to fill it.. you cant just keep spares in the tow rig. or if your campin its alot easier to throw the tanks in the back of your truck and run into town, than towing vehicle to town? $.02

Good point, but how big are the old built in tanks? I'm sure they are way bigger than the 8 or 10 gallan fork lift ones

briejer · Apr 29, 2006

Cro-mo rings..... I had issues with mine not seating. My motor did sit for 5 years before it got fired up. I'm sure the hone marks got a bit rusty. 10-15 times on it's side running and a few times up to 275 degrees and it has seated fine.

I run a vialle reg and a techno carb copy for a mixer. I have zero issues. I did have my distributor curved to advance pretty much instantly.

Also helped a friend put a 225 impco on a 22r....it works flawless from the very start

A real good benifit from pane is you get a lower idle and very consistant throttle response.

zig80toy · May 1, 2006

briejer said:
Also helped a friend put a 225 impco on a 22r....it works flawless from the very start

A real good benifit from pane is you get a lower idle and very consistant throttle response.

Did you make an adapter to mount the 225 impco on the 22R intake or did you buy one>?

Roccrawler · May 1, 2006

zig80toy said:
Did you make an adapter to mount the 225 impco on the 22R intake or did you buy one>?

they made it..........

briejer · May 1, 2006

zig80toy said:
Did you make an adapter to mount the 225 impco on the 22R intake or did you buy one>?

A chunk of aluminium, a drill, and a router. Adapted to a stock Toyota carb baseplate

heepofajeep · May 2, 2006

Alright, I am coming in pretty late to this thread, and I only skimmed through the pages...

I did the conversion to the 258 engine in my CJ. I took the time to do it right, recurved & upgraded the dist. Ran a impco 300 mixer, model E vaporizer, century electric lock-off valve.

The most important part of the conversion imho is the ignition. You really need to spend some time to tweak it to get the maximum power out of your rig. Remember you want to have all your advance in by about 3000 rpm = softer dist. springs. Also, you need more final advance = notching out the stop on the dist. that sets the overall advance. No need for Vacuum advance.

As for the performance, I noticed better throttle response & seat-of-the pants feel (bottom-end torque), but less overall HP. Gas mileage dropped from 18 (gasoline) to 14 (lpg) in regular driving conditions. I probably could have squeezed a bit more out, as I kind of gave up on tuning the ignition to an extent.

As far as someone mentioning that LPG is lighter than gasoline, you are correct, but you are forgetting the tank! IMHO weight is a major concern with LPG because the pressure-rated tank weighs much more than a gasoline tank of twice its size. Also, with lpg, you are stuck with only a few shapes & sizes tank. I owned, but never used in the cj, a 30 gal tank, and that thing weighed well over 100lbs (empty), just to illustrate the point...

One thing that one of the guys at suburban propane mentioned (they were VERY helpful for me) is that inline motors do not do as well as V motors. I don't know why this is, but after reading a lot of writeups throughout the web, and noting mileage & power for vehicles before & after converting, I tend to agree. This might have to do with the mixer, or flow properties of the intake runner, I don't know, and this is just heresay anyhow. But you will notice on POR that the *most* of the guys with lpg in their Yotas mention the fuel mileage decrease, whereas *most* of the guys with chevy 350s (as a V example), noticed no mileage change... Take it for what its worth, that is just my observation.

As far as the final result? I really liked it for off-road. However, I don't think I would do it again for a dd (like my CJ). I ended up running dual fuel on my CJ, which I was VERY happy with. I also noticed gasoline ran much better after having tuned the CJ's ignition for the propane (mainly because I made it so there was a much hotter spark). Propane is just too big a pain to buy for a DD... No running to the store at midnight & expecting to fill up, etc. Also, the price varies wildly from place to place, so there is really only a few places I opted to fill up at.

FWIW, if you want to check out the CJ, I will be selling it on Ebay in two weeks, lol.

I just sold my 225 mixer on Ebay for $50. Ebay is by far the best place to get your parts. Ktsomethingorother on Ebay from Canada is always selling complete junkyard conversions (that's who I got mine from).

Alright, that is probably enough for now. Have to go take a Mech. Eng. Design final now :censored:

Roccrawler · May 2, 2006

good input...

just FYI the aluminum tanks are way lighter than the steel.. grab some if you can

junkyard jim · May 7, 2006

I have a 225 mixer and several tanks (10 gallon portable, 30 gallon XJ manifold set and a 100 gallon under box mounted tank for my J10) After my stroker motor is broken in, I will be switching to Liquid propane injection (made by Bi-Phase back east)

heepofajeep · May 7, 2006

junkyard jim said:
I have a 225 mixer and several tanks (10 gallon portable, 30 gallon XJ manifold set and a 100 gallon under box mounted tank for my J10) After my stroker motor is broken in, I will be switching to Liquid propane injection (made by Bi-Phase back east)

I would love to hear more details about that! What are the pros/cons to doing that (injection)? How much $$$? BTw, while you're at it, can I get more details on your engine? I am toying with the idea of doing that to my cherokee (since I've got the parts lying around anyway).

junkyard jim · May 9, 2006

Biggest drawback to injection (besides the price) is vapor lock. I have to build a custom intake with a cooling jacket so I can get it running after warm shutdowns.
My motor is 4.0L block (shaved to zero deck for 11:1 compression) and 0.030 4.0L pistons with 258 crank and rods (I would rather get rods 0.030 longer and not shave the deck. Gotta watch out the pistons don't come too far down out of the bore and bind in the hole!) Still trying to decide which cam (currently have the HO stock cam) I'm running the Renix head unless I get another HO one to build (did a 3 angle grind, port and polish the Renix already)
The plan is to use an HO EFI harness and computer to run the injectors, but I hope to tap in and run a knock sensor so I can still manually adjust timing a bit. (adjustable crank sensor, adjustable MAP and a few other goodies) Just trying to find time and $$$ to finish it (had to cough up $2,000 for a new garage to work in)