..have a 400M on propane now with headers and RPM manifold.
I believe propane can take more compression but not cirtain how much. Any experiences or hear-say on the subject?

 

propane has a very high octane rating, I think somewhere in the vacinity of avgas. Ie, you can run very high compression; eg, 14+:1 but check the exact figures before you bolt 15:1 pistons into your 400

 

I would be interested in hearing more about this setup. Cost, how hard it is to install, is it worth it, etc.

 

My dad once had propane in one of his farm trucks, it works great but he had to convert the truck back over to gas so he wouldn't have to drive to town every time he needed a refill.

Just so you know, Propane burns cleaner in the cyclinders and thus you will have less carbon build-up on the piston so you will get better wear and longer life.



82' Flareside: zoom zoom doesn't even begin to describe it
2/4 Drop
Soon to have 325hp 351 Clevo
(maybe more,in a 3600lb truck)
Backed by a C6 with a 2000 rpm stall and a 3.50 9 incher
American Racing AR-23 (series 23) wheels
Upgraded interior
Soon to have a kick @$$ stereo

 

Not meaning to sound sarcastic, but if Propane is a good system, why isn't everyone using it? Too far out of the mainstream?

 

Not as available as gasoline and you have to have room for the tank to. I heard that the 300 I-6 responded really good to propane and really high compresion (like 14:1)

There is one bad thing bout propane though, the exhaust valves don't get lubricated enough and they burnout and you have to replace them with so special sodium type valves (i think)


82' Flareside: zoom zoom doesn't even begin to describe it
2/4 Drop
Soon to have 325hp 351 Clevo
(maybe more,in a 3600lb truck)
Backed by a C6 with a 2000 rpm stall and a 3.50 9 incher
American Racing AR-23 (series 23) wheels
Upgraded interior
Soon to have a kick @$$ stereo

 

[updated:LAST EDITED ON 24-May-02 AT 08:28 PM (EST)]Propane only makes about 80% of the power per gallon as gasoline, but it is also cheaper, at around 70cents a gallon for non road taxed fuel. Propane is very popular here in the midwest farm country. Impco makes any equipment you would need to burn propane. I ran propane for years on several different trucks.

Here's how it works: You put a big tank in the bed of your pickup,, around 100 gallon is normal. The propane carb has no bowls since propane is a vapor when released, so you bolt on a carb adapter on top of your present gas carb. this bolts onto the top of your current carb in place of your air cleaner, and hangs off the side. To this adapter bolts the propane carb, then an air cleaner. You hook up a propane regulator which changes the tank pressure into a low pressure supply to the carb. You hook up a hose of course, from the tank to the regulator, then from the regualator to the carb. You install two solenoid switches, one on your gasoline source to your current carb, and another on the propane source to the propane regulator. These are wired in such a manner so that they work off the same switch, so when you choose propane on the switch, it opens the propane solenoid and closes the gasoline solenoid. To run on gasoline, flip the switch the other way and open up the fuel flow to the gas carb and shut off the flow to the propane regulator. It's easier even than it sounds here.
The equipment to convert one will run you around 1000 bucks if you buy everything new. The tank will cost about 300 to 400 of that.
Propane is a dry fuel, with no additives, so expect for normal valve seats and valves to burn out sooner. My 70 F100 was built for propane, with special pistons and hardened seats installed in case I ever convert. Now that I recently installed a projection, it will be very easy to add propane.

The pros:
Propane is cheap
Since propane is already vaporized, it does not have to change into a vapor, so on a cold morning your engine does not sputter and cough and run rough till it warms up.

Cons:
Propane cannot be found at every gas station.
You are carrying 100 gallons of high pressure fuel in a metal tank in the bed of your pickup.
If you use a normal carb, the gaskets tend to dry out while you are running on propane, so when you switch back to gasoline sometimes you may have carb leaks.

 

Thanks for the replys.
Up here in British Columbia we have many outlets selling propane. Lots of fleet vehicals use it. For some time in early 80's there was an incentive program where the provincial goverment subsidized the conversion to propane. Many of the cab companies use it. Back then the cost per litre was about 20 cents (equal to 75 canadian cents / us gal or 38 u.s.cents / gal at todays u.s. dollar)
Anyways, when I bought the truck it was already a dedicated propane system. At some point will rebuild the engine and want to gather info and experiences to make decisions.

 

If you are building an engine for propane, Ertl makes special pistons for propane fuel. I believe they have a hardenend compustion surface, plus they are about a 9.5: 1 compression ratio, over a stock ratio of about 8.5: 1

With propane just up your compression ratio by about a point.

Also, have your heads cut for hardened exhaust seats, and get hard valves.
That's all you need to do!

 

> Ertl makes special pistons for propane fuel.
Who, what & where is Ertl?

 

Gee what's stopping one from using these 9.5 comp. propane pistons in a gas engine ????

 

if i remember 9.5:1 pistons in propane are close to the same 8.4:1 pistons with gas. propane has different compressability rates, thus the higher cr.

 

I may be wrong, but when I bought my Badger FlatTops for my 400 the guy told me they were mostly used for propane conversions.

Later
Riley

 

Tom Thrall-----Do you know anybody there in the heartland who fills their truck "UP" from the propane tank behind the barn---and when they were caught ---how much was the fine for not paying road tax on the propane????Here , in texas , propane is basically just as expensive as gas cause when you have to pay road tax----just courious???fd

 

Yeah, it happens i'm sure. Here in Kansas and also in Oklahoma, if you get caught, you may be liable for the entire mileage shown on the speedometer.
But, the road tax is about 48 cents a gallon on propane, and if the base cost is 70 cents, that still computes to 1.18 a gallon versus 1.45 for gasoline.