Propane

[Omahacj]

Anyone here every convert to propane on there AMC 258 i6 / 4.2l . I have looked around and found some good kits but curious about the good and bads before forking out that hard earned dough.

 

[BC CJ]

My AMC 304 is on propane, I like it. Here is a good link for you:
http://www.jeep-cj.com/forums/f2/propane-conversion-tech-write-up-11396/

pros:
-cheaper than gas
-no fuel pump to break down
-presurized vapour fed so no stalling because of slopes like a gasoline carb.
-presurized vapour so no running dry when the vehicle is on a slope for a long time and low on fuel.
-runs cleaner so engine may last longer.

cons:
-initial cost to instal.
-where to mount a reasonable size tank without losing your back seat.
-carrying extra propane to dump into the tank is more of a hassle than jerry cans are for a gas engine. (You also need a special hose).
-Suppossed power loss when switching to propane but I dont fully buy this argument. It's the duel fuel systems that rob power and never run at full potential.
-Propane can be finicky in weather extremes.

Hope some of that helps.

 

[Omahacj]

After reading the great write up I'll still have to do some thinking. I've got most of the pieces for GM TBI and can get the rest for nothing compared to the LPG conversion. The simplicity of the LPG is the part I love. Do you still have to tune it with each season and being in nebraska with some cold winters does that affect the startup??? Thanks again BC

 

[BC CJ]

I'm just going into my first winter with the Jeep, but at work we've had service vehicles on propane and they work fine all winter with a couple tricks. One is using a heat gun or blow dryer on the shut-off key as it can freeze shut (even though there is engine coolant circulating there) Once started though everything works fine. If you are away from electricity pooring hot water on it can help... or as my friend says "take a piss on it!" funny, but might just work in a pinch! On the other side of things if the tank gets too hot, particularly when full, the pressure can get too high and then some safty valve wont open (or something like that) and there will be no fuel delivery. This is solved by painting the tank white and you can always poor some cold water over it to cool the tank. I've also heard very humid weather can effect things, make it run a bit rough maybe... I dont know much about this yet.

 

[CJim7]

I've been running this for a couple of years now. My innitial fear was cold weather fuel delivery. As of yet (2 winters now) I have not ran into any issues with valves or lines freezing.
I have also not had to do any adjustment tuning for weather. Humidity has not played a role as of yet.

One very finicky feature I have encountered takes place at the tank hook-up. It is very important to keep the line/tank gaskets in good condition. Always carry spares (very cheap at any propane supply store). When these leak, even minutely, they will create a frosting condition that will affect engine operation severely.

Over all, it is a modification I would not hesitate to do again. I run two forklift tanks that required removal of the rear seat....that is the drawback, but my Cj isn't a "passenger vehicle" anyway.

I have not experienced a loss in mileage, and power is equal to the gasoline I ran previously....I do however run a high compression engine and propane thrives at a higer compression.

 

[BC CJ]

CJim7, could you give more details about these gaskets? Are they where the hose attaches to the forklift tank? I have tanks that are plumbed directly so maybe this wont be an issue for me? Definately something I want to know about. Thanks!

 

[CJim7]

CJim7, could you give more details about these gaskets? Are they where the hose attaches to the forklift tank? I have tanks that are plumbed directly so maybe this wont be an issue for me? Definately something I want to know about. Thanks!

Exactly. There is (usually) a single gasket on the hose couple and a single gasket at the tank side...if I remember correctly. A quick inspection of the hose end and tank will show you what you need...and any propane supply store will have them. The problem is they dry out from the raw propane and eventually shrink some. I've only had to replace them once, we'll see how long they go.

I have not seen tanks plumbed with a permanent hose....pics?

 

[BC CJ]

And I haven't seen forklift tanks used on a vehicle before It may have to do with our laws in Canada.

For a propane powered vehicle to be legal here it must have a permanently fixed automotive grade tank. Which means the tank has thicker walls and is bolted to the vehicle only to come out for repairs. These tanks have reinforced threaded holes where go the filler valve, spitter valve (or lines to these if remote) and the supply line. The supply line must use a special shut-off valve so the tank can be issolated from the rest of the system. These valves also have a special internal valve that will automatically close if the propane moves past it too fast (such as in the event of a line rupture). Newer tanks also have a feature that stops the filler flow when they hit 80% water capacity so they can never be over filled. So lots of safety built in to a legal set up. I'm learning all about this now as I'm working on installing a second tank.

Only dodgy part is my tank is under the vehicle where the original gas tank was; exposed to rocks and rear-end colisions. But I guess thats why we have to use the beefy tanks. A friend of mine says he has beat the out of propane tanks on his 4x4s and never had an issue. So that sounds great but I'm still going to do my utmost NOT to test that idea!

So the hose isn't actually part of the tank but once it's all installed it cant be taken in and out like a forklift tank can be. So do you usually take the tanks right out of the Jeep to fill them?

 

[CJim7]

Ah, ok. I know the tanks you are talking about, I actually was going to use that type, but the extreme weight and the fact I would have to position it differently due to the size made me go with forklift tanks. Much lighter for my application.
The forklift tanks have all of the safety features needed. They are date stamped and regulated at filling stations. Inconjunction, propane conversion kits should also use safety cuttoffs whether vacuum or electrical.
I remove my tanks for filling. My wife got me a new set of straps with quick disconnect clasps which makes it faster and easier. My original straps bolted together which was a pain in the butt when it came to removing the tanks.