propane (1 Viewer)

Has anybody on here done a conversion to propane? My dad and I were working on the 55 the other day and he jokingly said why dont you just convert to propane. So I just thought I would find out if anbody had if so what all they had to do. Id assume new lines and tank and a propane carb anything else? Also how would that compare $ wise with regular gas.

bout the same pricewise.

Search on propane and you will find a TON of info..

PLEASE go to the FAQ......

Sorry guys feeling lazy and didnt want to search.

Also known as LPG.

Propane makes sense for an urban vehicle, particularly a work or delivery vehicle.

I can't see it making sense for an off-road or vacation vehicle.

1. The propane tank weighs a considerable amount, because it is pressurized.

2. Gallon for gallon, you get less range with propane than you with gasoline, and less power as well. This is because propane has less BTU than gasoline.

3. Propane is not as plentiful to find as gasoline, particularly in the boondocks. And, some stations refuse to pump propane into vehicle fuel tanks, because of road tax issues. Some states have no issue with propane being pumped, but charge more for registration to make up for lost gasoline road taxes.

4. You can carry spare propane fuel tanks, but these are your BBQ style tanks, and you have to have your system modified to allow them to be plumbed in.

5. It is possible to run a dual propane and gasoline system using a carb bonnet and a solenoid to shut off the gasoline delivery. This is a compromise but it can work. However, it preclused building the engine with higher compression to try to extract a bit more work out of the low BTU of the propane, since propane has a higher effective "octane" rating, if you will, than gasoline. Unless you want to use a higher grade of gasoline, of course.

6. If you think unleaded gasoline is hard on valve seats, try propane. It has zero lubricity. That was a major cause of problems with older fleet delivery trucks that were converted to propane in the 1970's. Many required stellite valve seat inserts and very high quality valves. I'm not a fan of valve seat inserts because they tend to raise valve temps, because they don't convect heat as good as the unmolested head does.

7. Propane DOES respond very well to turbocharging. Being a gas, and being that it's in effect a cooling charge, it works to lower the dense and heated air charge.

8. Propane works well regardless of what angle the engine is at.

The latter two might be pluses to a trailered rock crawler, especially one with a dry sump oiling system. Other than that, I can't see propane being worth the hassle.

I got a propane setup off of ebay that I'm going to run duel fuel so that when I'm crawling I don't have to worry about my stupid carburetor and just run gas on my way to the trail.

Brian in Oregon said:

Propane makes sense for an urban vehicle, particularly a work or delivery vehicle.

I can't see it making sense for an off-road or vacation vehicle.

1. The propane tank weighs a considerable amount, because it is pressurized.

2. Gallon for gallon, you get less range with propane than you with gasoline, and less power as well. This is because propane has less BTU than gasoline.

3. Propane is not as plentiful to find as gasoline, particularly in the boondocks. And, some stations refuse to pump propane into vehicle fuel tanks, because of road tax issues. Some states have no issue with propane being pumped, but charge more for registration to make up for lost gasoline road taxes.

4. You can carry spare propane fuel tanks, but these are your BBQ style tanks, and you have to have your system modified to allow them to be plumbed in.

5. It is possible to run a dual propane and gasoline system using a carb bonnet and a solenoid to shut off the gasoline delivery. This is a compromise but it can work. However, it preclused building the engine with higher compression to try to extract a bit more work out of the low BTU of the propane, since propane has a higher effective "octane" rating, if you will, than gasoline. Unless you want to use a higher grade of gasoline, of course.

6. If you think unleaded gasoline is hard on valve seats, try propane. It has zero lubricity. That was a major cause of problems with older fleet delivery trucks that were converted to propane in the 1970's. Many required stellite valve seat inserts and very high quality valves. I'm not a fan of valve seat inserts because they tend to raise valve temps, because they don't convect heat as good as the unmolested head does.

7. Propane DOES respond very well to turbocharging. Being a gas, and being that it's in effect a cooling charge, it works to lower the dense and heated air charge.

8. Propane works well regardless of what angle the engine is at.

The latter two might be pluses to a trailered rock crawler, especially one with a dry sump oiling system. Other than that, I can't see propane being worth the hassle.

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Buncha old info here.

1. Propane liquid is almost the same weight as gasoline.. If you are concerned about weight then don't drink as much beer...

2. Only reason you would lose mileage is cause the motor was not set up for it. All power/mileage losses can be taken care of with a couple of mods.

3. Most states consider propane as an "alternative Fuel" so you actually can remove the smog requirement. Additionally, you can claim the conversion on your taxes cause it is an alternative fuel. But he is right, not as many places carry propane as Gasoline. However, Filling is easy with a forklift tank.. Any propane place can fill it. And no road tax..

4. Well, you can use the BBQ tanks as spares, but it is a PITA. Much easier to just get Forklift tanks.. Heck, in need you can use the little coleman green things as well..

5. LC six cylinder motors are so innefecient that you would not notice the loss in power in a dual fuel comversion. Trust me, I ran one for a while. It is nice in a couple of ways to have an alternative fuel source. But it does not give you the potential power that is available with propane.

6. Trucks in the 70's were designed for leaded gas.. They did nto have hardened valve seats. Cruisers do.. Propane is easier and cleaner on a motor than gasoline. Valve seat inserts don't cool as well huh.. EVERY modern car has hardened valve seats. including a Stock LC. This statement holds no water...

7. Yep.. Propane does not run hot typically. Which is another reason Hardened valve seats are not an issue.

8. Yep. Runs at whatever angle you want... Ask me how I know..



The only thing that sucks about propane is that no one knows how to set it up properly and it is ahrder to get than gasoline. Other than that. It is all plusses....

i am looking at converting to propane myself . not a dual fuel tho just run propane all the time , propane is very easy to find in canada , all our taxi's and limo's run propane . i think it is a great idea . if worried about loss of power just build a hopped up small block . propane has a octane of 104 or something like that ?? and no need for a ECU and all the sensors that come with it ??

Brian in Oregon said:

Propane makes sense for an urban vehicle, particularly a work or delivery vehicle.

I can't see it making sense for an off-road or vacation vehicle.

1. The propane tank weighs a considerable amount, because it is pressurized.

2. Gallon for gallon, you get less range with propane than you with gasoline, and less power as well. This is because propane has less BTU than gasoline.


4. You can carry spare propane fuel tanks, but these are your BBQ style tanks, and you have to have your system modified to allow them to be plumbed in.

5. It is possible to run a dual propane and gasoline system using a carb bonnet and a solenoid to shut off the gasoline delivery. This is a compromise but it can work. However, it preclused building the engine with higher compression to try to extract a bit more work out of the low BTU of the propane, since propane has a higher effective "octane" rating, if you will, than gasoline. Unless you want to use a higher grade of gasoline, of course.

8. Propane works well regardless of what angle the engine is at.

The latter two might be pluses to a trailered rock crawler, especially one with a dry sump oiling system. Other than that, I can't see propane being worth the hassle.

Click to expand...

1. My 65 litre tank weighs about 20kg - that's not a great deal.
2. About 90% power, 90% mileage - not enough to be an issue - raised compression gives about 100% in both cases.
4 - run dual fuel - I now have an extra 65 litres of fuel over the stock petrol tank
5 - mine runs 10.5 compression and dual fuel. I just run high octane petrol (and that's for emergencies only) without any issues.
8 - I can also testify to this - runs perfectly when on it's side!

For me, LPG is 75c a litre, premium petrol around $1.20.
Way cheaper to run LPG - plus I get better performance (but have optimised the engine for it).
Even before I rebuilt the motor, I found it much more tractible on LPG - I could be crawling at around 300rpm, give it the boot and it would pull smoothly away. The carb would never do that.

Hey Mace, can you mention some tricks in tuning a propane engine? I recently decided i'm going to do propane, and have been doing a lot of reading, just want to get a head start in the knowledge area. From what I have read, larger gap on plugs, and more advanced timing.

It is a pretty easy conversion. You just need to know what you are doing when you do it. I have converted my old forklift to propane and it works just as good as it did before. It was an old L134 continental engine and it runs smoother than it did with 130 octane aviation fuel. I am thinking about doing it to the cruiser.

Buncha old info here.

1. Propane liquid is almost the same weight as gasoline.. If you are concerned about weight then don't drink as much beer...

*It's not the weight of the fuel it's the weight of the container. A short range rock climbing rig would not have an issue with a small propane tank. A vehicle that had to take into consideration long range between fillups would need a large propane tank, perhaps much larger than a comparable gas tank, and that really starts to add weight. Of course, a 4x4 pickup can handle a much bigger tank than an FJ40 will.

2. Only reason you would lose mileage is cause the motor was not set up for it. All power/mileage losses can be taken care of with a couple of mods.

*Correct. You will lose power if you just convert an existinig stock motor. You need to set up a motor specifically for propane. That's the point.

3. Most states consider propane as an "alternative Fuel" so you actually can remove the smog requirement. Additionally, you can claim the conversion on your taxes cause it is an alternative fuel. But he is right, not as many places carry propane as Gasoline. However, Filling is easy with a forklift tank.. Any propane place can fill it. And no road tax..

*In SOME states you can do this. Others are anal about removing any smog equipment, propane or no propane. And yes, some states do allow it as an alternative fuel. Some don't. But the road tax issue is not so easy. In Oregon, ELECTRIC vehicles get hit with a higher registration fee because they - bingo - pay no road tax on fuel. Some states are going to get their road taxes one way or another.

4. Well, you can use the BBQ tanks as spares, but it is a PITA. Much easier to just get Forklift tanks.. Heck, in need you can use the little coleman green things as well..

*Yeah, forklift style tanks work fine too. I forgot about them. In fact, a neighbor has a whole roof full of them plumbed together on his 65 Ford van. Looks weird but whatever works.

5. LC six cylinder motors are so innefecient that you would not notice the loss in power in a dual fuel comversion. Trust me, I ran one for a while. It is nice in a couple of ways to have an alternative fuel source. But it does not give you the potential power that is available with propane.

*I've never run a LC six, so I can't comment on them and their lack of power. I suspect they are close to a Chevy six, though, since the designs are similar. The engine should ideally be set up to make full use of whichever fuel is considered to be primary.

6. Trucks in the 70's were designed for leaded gas.. They did nto have hardened valve seats. Cruisers do.. Propane is easier and cleaner on a motor than gasoline. Valve seat inserts don't cool as well huh.. EVERY modern car has hardened valve seats. including a Stock LC. This statement holds no water...

*ALL* LC sixes have hardened valve seats? Even from the 1960's? I know Toyota is innovative, but that would surprise me.

7. Yep.. Propane does not run hot typically. Which is another reason Hardened valve seats are not an issue.

*Sorry, it is an issue on earlier heads. Seen plenty of it on fleet heads. Lack of lubricity from either lead or substitutes and heat took its tool on the valves and valve seats. And you can get the heat raised back up with higher compression and the heavy work being done with work trucks. Perhaps this is not an issue with comparatively low output engines like the LC six. It was with large truck sixes that were worked hard and often lugged.

8. Yep. Runs at whatever angle you want... Ask me how I know..

The only thing that sucks about propane is that no one knows how to set it up properly and it is ahrder to get than gasoline. Other than that. It is all plusses....

*True. Propane sometimes requires a different ignition setup. Some engines readily take to it, and some can be real bears. It usually makes for a lot easier starting in the winter. Interestingly, oil usually gets thicker, not thinner. This is because the oil gets thick with dirt, but doesn't get dilluted from unburned gasoline making it past the rings.

bustanutley said:

Hey Mace, can you mention some tricks in tuning a propane engine? I recently decided i'm going to do propane, and have been doing a lot of reading, just want to get a head start in the knowledge area. From what I have read, larger gap on plugs, and more advanced timing.

Click to expand...

Get an O2 sensor and put it in the exhaust pipe. Only way I found to really know what was going on with the motor.. F'n propane runs at almost any mixtue the carb can throw at it...

More gap and timing are a good start. You want 32* advanced TOTAL. Then your initial timing stays basically where it stays...

Bump up your compression. 104 effective octane can handle a lot of compresison...


To "convert" a motor all it takes is a bit of tuning in the ignition dept (propane actually likes a "cooler" ignition system. Stock works well. MSD's are not necesssary. and advance the timing. More compression is a nice thing but not absolutely necessary. Fundamentally there is no difference between a gasoline and propane motor. They just have some minor tweaks...

Brian, I am sure there is a lot about LC engineering that would suprise you

bustanutley said:

Hey Mace, can you mention some tricks in tuning a propane engine? I recently decided i'm going to do propane, and have been doing a lot of reading, just want to get a head start in the knowledge area. From what I have read, larger gap on plugs, and more advanced timing.

Click to expand...

Actually - many LPG installers suggest reducing the plug gap - LPG is harder to ignite so needs a shorter, stronger spark.

Advancing timing is also a tricky one. LPG wants a modified curve.
Compared to the petrol curve, LPG starts a lot higher, ramps up fast, but then levels off at LESS than the petrol curve.

SO if you just advance the timing, to give good low end torque/power, you sacrifice the upper end because the timing is then too advanced at higher revs.

I put an HEI on mine because it's so much easier to adjust the curve and started palying until I got it fairly good. It's still not perfect, but I'm planning on putting a programmable ignition system on in the near future - then I'll get it perfect

Brian in Oregon said:

Buncha old info here.

1. Propane liquid is almost the same weight as gasoline.. If you are concerned about weight then don't drink as much beer...

*It's not the weight of the fuel it's the weight of the container. A short range rock climbing rig would not have an issue with a small propane tank. A vehicle that had to take into consideration long range between fillups would need a large propane tank, perhaps much larger than a comparable gas tank, and that really starts to add weight. Of course, a 4x4 pickup can handle a much bigger tank than an FJ40 will.


7. Yep.. Propane does not run hot typically. Which is another reason Hardened valve seats are not an issue.

*Sorry, it is an issue on earlier heads. Seen plenty of it on fleet heads. Lack of lubricity from either lead or substitutes and heat took its tool on the valves and valve seats. And you can get the heat raised back up with higher compression and the heavy work being done with work trucks. Perhaps this is not an issue with comparatively low output engines like the LC six. It was with large truck sixes that were worked hard and often lugged.

Click to expand...

As previously mentioned, my 65 litre tank weighs slightly less than 20kg (with mounting straps) - that's not a biggie - my spare weighs much more than that!

Lack of lubrication? - yes valve recession can be an issue even with hardened seats - however, help is at hand...
http://www.moreyoil.co.nz/productPDFs/PowerBooster_MoreInfo.pdf
was developed for exactly this purpose (but for CNG which is even drier) - proven over many years

Converting to and running solely Propane you will notice your engine oil stays cleaner MUCH longer. Gasoline is a very dirty fuel compared to Propane.

Cool, thanks for the hints guys. I was thinking I would copy Mace with the turbo while i was at it, I'm tired of going 30 MPH up vail pass . I was thinking I would switch to propane first then turbo, but maybe it would be easier to just get it all working at once. What kind of O2 sensor are you using Mace? The hand held ones I see after a quick search look pretty spendy Also anyone know where you can get pre bent piping and turbo piping connectors for reasonable prices? I have access to a bender, but the mandrels we have are 6.5" radius which I think is way too wide to work. Also mace, the one object in your system that I don't have specs for is the waste gate.

Thanks a bunch, and I hope I didn't hijack to hardcore

I'm running an Edelbrock O2 sensor kit on one of my non-Land Cruiser vehicles that was being a royal pain to adjust. (1971 Chevy 3/4 ton pickup with a 454 V-8.)

I found out VERY quickly that these sensors are EXTREMELY sensitive. They will show extremely small amounts of oxygen. It will clearly show a miss at idle, it's that sensitive.

I thought at first I had bad grounds between the engine, frame and battery. I grounded the head directly to the battery negative. Still had a problem.

I then found that a couple of spark plug wires - BRAND NEW spark plug wires I might add - had enough dielectric breakdown that the spark was not hot enough to completely fire a couple of cylinders. This let a very small amount of unburned fuel and a very small amount of oxygen through the cylinders and into the exhaust system, where the sensor picked them up. Once the offending wires were replaced under warranty, no more problems with wildly changing sensor readings, and the real carb and distributer tuning could begin.

Yes, O2 sensors like the Edelbrock are spendy, but they are darn well worth the money if you really need to know what is going on in your engine.

The Edelbrock sensor has a much wider indicator range than the Holley. The Holley is pretty useless, really.

I think the $140 to $150 is money well spent. And, you do not have to permanently install it. You can just weld on an 02 sensor bung, run the sensor to set the engine up, then remove the system, and put a plug in the bung. Weld a new bung in another vehicle and transfer the system to it for testing.

140 isn't bad, I was seeing G figures