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Author Topic: Propane powered engine question  (Read 2287 times)

Stewart Van Petten

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Propane powered engine question
« on: March 07, 2010, 04:09:23 PM »

Today I was playing around with a pickup truck that I purchased a few months ago that runs on propane. It had a slight misfire now and again at mid to higher rpms so I started checking the ignition system from the distributor down to the plugs for any obvious problems. Found a loose spark plug wire on the dizzy and fixed that but carried on with my inspection.
 
I pulled a spark plug to see what the condition of it was. It was a little bit dirty but not in bad shape so I buffed it up on a bench grinder wire wheel, adjusted the gap and reinstalled it. The next plug was extremely tight and I broke it off unfortunately.  I was able to remove it though. I am going to be more careful with the rest. Also I plan on doing a compression test while I am at it. 
 
Anyway this leads me to my question as I have never owned a propane powered vehicle before this one. Does a propane engine prefer a different heat plug than when you run gasoline? Do they like hotter plugs or colder plugs? I have some colder plugs than what were in it but if it requires the hotter plugs I will go purchase some new ones. I will mainly be using this truck for plowing snow in the winter but will probably also use it to pull the occasional trailer load.
 
Thanks guys!
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Steve

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Propane powered engine question
« Reply #1 on: March 07, 2010, 04:14:04 PM »

That is a question for SJak.  He's our resident Propane user.  Well in Finland he is.
 
He ran an Imperial on Propane for as long as we've known him and he's converting his 71 Fury to Porpane.
 
He'll know
 
Broke a Plug?  Must be a Chebby
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Stewart Van Petten

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Propane powered engine question
« Reply #2 on: March 07, 2010, 04:40:04 PM »

Yup, she is a 1974 Chevy BB 454 in an 85 Sierra 4x4. I was looking at the engine rebuild sheet and it was over bored .030...so probably a 460 ci now! lol I was not using a very good extention on my spark plug socket and I side loaded the plug...

It starts and runs very well but I am sure that after I finish tuning it will run even better. I doubt it has been tuned since it was put together roughly 30,000 kms ago. There were a lot of deposits in the distributor cap so I will get new parts.
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Steve

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Propane powered engine question
« Reply #3 on: March 07, 2010, 04:56:15 PM »

Heh  How did I know. . . . .
 
Try PMing him  Sjak is in and out, but you'll get quicker answers.  Send him the link to the thread too
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Snotty

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Propane powered engine question
« Reply #4 on: March 07, 2010, 05:47:21 PM »

I believe Firedome has had experience with it as well.
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Propane powered engine question
« Reply #5 on: March 07, 2010, 07:11:23 PM »

Propane runs at  100-110 octane, so a hotter plug would be best, higher compression is an advantage, but not necessary (9-10:1 works well), and it can take a little more advance since the octane rating takes more to make it explode without a spark.
 
Amazing what you can find with a little bit of a search, but I still imagine Sjak has a little more info than this. I saw one article on a diesel that was dual diesel/propane. A combination of the two was able to improve mileage, especially in towing situations better than one or the other only, with a 50/50 mix, which I thought was pretty cool, kind of like an igniter for the diesel or something.
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Stewart Van Petten

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Propane powered engine question
« Reply #6 on: March 08, 2010, 06:27:30 AM »

Thank you for the help with this machine! I did a bit more research yesterday and found out some more useful things about propane engines. Lots of things I have heard through the grape vine, but it is sure nice to know the actual facts and also hear from people who have direct experience!
 



After I do a compression test I will know more about the engine to determine what compression ratio it has. Judging by how it runs and sounds I believe it to be running around 10 to 1.
 
I have tried running propane in one of my old Mack trucks many years ago to mainly help fuel economy but also to add a small amount of torque. I found that it did help a bit with fuel economy by adding a small amount to the engine's intake system. Some diesel engines respond better than others to this mod from what I have heard and read. The Mack engines that I have are fairly efficient already but I did notice enough difference to keep injecting propane for certain jobs. It definately cleaned up the burn and I also noticed that the oil stayed cleaner.
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Leaburn Patey

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Propane powered engine question
« Reply #7 on: March 08, 2010, 07:44:37 AM »

What propane does to diesel engines is what nitrous does for gas engines.
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Propane powered engine question
« Reply #8 on: March 08, 2010, 08:11:56 AM »

Propane, like natural gas, and alcohol, all run very clean and don't require oil changes as often.
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Steve

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Propane powered engine question
« Reply #9 on: March 08, 2010, 08:16:38 AM »

What about those Hydrogen generators?
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Propane powered engine question
« Reply #10 on: March 08, 2010, 08:20:57 AM »

Quote from: POLARACO
What about those Hydrogen generators?
I haven't seen anything on the market producing enough hydrogen to make it worth the cost yet. Chrysler was doing some minivan conversion things 5-8 years ago, but I think DBAG stole that, too.
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Stan Paralikis

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Propane powered engine question
« Reply #11 on: March 08, 2010, 09:05:59 AM »

Quote from: POLARACO
What about those Hydrogen generators?

 
It's already been done.  And they still can't get it to work...
 

 
 

Riyad

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Propane powered engine question
« Reply #12 on: March 08, 2010, 09:30:21 AM »

there is a very good success in running LPG on these engines in Holland, the imperial ran on LPG only from 1999 until 2009, Sjak went racing with LPG powered engine!
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Jacques

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Propane powered engine question
« Reply #13 on: March 08, 2010, 11:36:34 AM »



Regarding the initial question, try the original spec sparkplugs, but of a good quality, like NGK. Usually, you will be fine with a stock engine on LPG.

After a few thousend miles, you will be able to tell if the plug choice is good or not.


Quote from: dana44
Propane runs at  100-110 octane, so a hotter plug would be best, higher compression is an advantage, but not necessary (9-10:1 works well), and it can take a little more advance since the octane rating takes more to make it explode without a spark.
Regarding the octane rating and compression, for a normally driven vehicle, it is better to keep on the safe side. In theory, you could run a 12:1 compression, but EVERYTHING has to be PERFECT ALL THE TIME. For a racing engine, that's not a problem of course. However, in real life, fuel is not "straight" propane but a mixture (e.g. in our area it is about a 50-50 mixture of butane and propane) or has contaminations of some other gases seriously influencing the octane rating (propene is bad)

Also, when intake charge temperature rises, the octane rating will decrease, making a high compression engine very susceptible to knocking or worse under load in hot weather.

A very usefull upgrade on an otherwise stock vehicle is a stronger ignition and a recurve of the distributor. Propane has a much higher combustion point than gasoline, therefore is more susceptible to ignition troubles. In case of malfuntion, start with checking ignition parts (plugs, calbes, cap+rotor, ECU, coil), then start looking for vacuum leaks. Also, check airfilter.
Sjak Brak2010-03-08 16:36:46
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Stitcherbob

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Propane powered engine question
« Reply #14 on: March 08, 2010, 01:58:39 PM »


Quote from: Commando1
Quote from: POLARACO
What about those Hydrogen generators?

 
It's already been done.  And they still can't get it to work...
 

 

Hey that car would work for some of the guys here if you changed that balloon to an enema hose........

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