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Slant 6 Propane Conversions https://slantsix.org/forum/viewtopic.php?t=26290	Page 1 of 1

Author:

FrankRaso [ Tue Dec 18, 2007 1:14 pm ]

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Slant 6 Propane Conversions

Every once in a while I see that the topic of propane conversions comes up on this board. In case you're doing a lot of driving and there is a supply of cheap, readily available LPG along your way, I've created a propane monofuel conversion kit for 1 bbl and 2bbl engines:

1 bbl 225 Slant Six carburetor
2 bbl 225 Slant Six carburetor

A basic components package would be then required to make an underhood conversion kit:

Model E Converter & Electric LPG Lockoff
Model E Converter & Vacuum LPG Lockoff

A fuel tank is also required. I recommend using new Canadian-built tanks (if you're in North America) because these tanks are built safer than American tanks. Sleegers will ship a tank directly to you. The Woodward catalog has a good technical information section.

A slant six conversion would be very similar to the 1963 Rambler conversion. I've included a slightly larger carburetor than what was used on the Rambler. If your route takes you by a Flying J truckstop, you can usually find cheap LPG there. Visit my Propane Conversions page to find out if a propane conversion has any payback for you.

Author:	66aCUDA [ Wed Dec 19, 2007 6:09 am ]
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Frank Thanks for the links. I have been really considering a DD on LPG as here its ALWAYS much cheaper than gasoline. Usualy $1.00 a gallon or more. I also have a liquid fill tank for fueling my tractor. Frank

Author:	FrankRaso [ Wed Dec 19, 2007 7:50 am ]
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Typically, conversions with the Impco propane carburetors get somewhere between 75% to 80% of the vehicle's gasoline economy. If you get 20 mpg on gasoline, you'll get around 15 - 16 mpg on propane. The overall savings comes from the difference in fuel price. If you can buy propane for $2.00/gallon and gasoline is selling for $3.00/gallon, your car running on propane will COST you as if it were getting 22.5 - 24 mpg on gasoline. That is: 15 x 3/2 = 22.5 and 16 x 3/2 = 24 Obviously, if you need high octane gasoline for your vehicle, propane makes even more sense. Remember, propane has an octane rating of 104. Newer commercially available injection systems get closer to 80-90% of a vehicle's gasoline economy but these systems only work with an existing gasoline EFI system. Whatever you do, do NOT use portable DOT lift truck tanks on an on-road vehicle. They are illegal and dangerous for this purpose.

Author:	66aCUDA [ Wed Dec 19, 2007 4:36 pm ]
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Yeah we have idiots around here that have regular 250 gallon home tanks in the back of thier pickups, not even strapped down. I heard one of these explode during an accident on the other side of the county last year. Thanks Frank PS Does anyone know if Propane is legal at Drag Strips???

Author:	66aCUDA [ Wed Dec 19, 2007 4:41 pm ]
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Double post

Author:	Charrlie_S [ Wed Dec 19, 2007 8:30 pm ]
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Quote: PS Does anyone know if Propane is legal at Drag Strips??? As long as the system is DOT legal, it is allowed at the track.

Author:	FrankRaso [ Thu Dec 20, 2007 6:16 am ]
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Propane vehicles MUST meet the requirements of NFPA 58 (Liquefied Petroleum Gas Code) in the USA or CSA B149.5 (Installation Code for Propane Fuel Systems and Tanks on Highway Vehicles) in Canada. Anyone performing a conversion on his own vehicle should have the work inspected and approved by a qualified mechanic before ANY fuel is put in the tank. To avoid any confusion, just because a portable lift truck tank is known as a DOT tank does NOT mean that it is DOT-legal for propane vehicles. These tanks are designed for lift-trucks and similar vehicles that rarely get into collisions. I do not believe that DOT tank brackets are required to meet any g-force requirements. For on-road ASME motor fuel tanks, American NFPA 58 requires the tank manufacturer to design to 4 G in any direction, not acting simultaneously. Canadian regulations require that design calculations be submitted for approval confirming the brackets are capable of withstanding 20 G in the forward direction and 8 G in the other two directions, not acting simultaneously. DOT tanks are also not designed for installation in enclosed areas (like trunks). Trunk-mounted tanks must have a vapour box around the fittings (or otherwise be isolated from the vehicle's interior) to prevent sparks from igniting any leaking fuel.

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