I'm now in the middle of the process to convert my 73 Riviera to burn only LPG. At this moment it still can use regular gas or LPG with the Impco 300A on the Q-jet; but why should I use gasoline (with or without ethanol) at over $10 p/gln when LPG cost me only $3.00 gln. (I admit there are no environmental, only economic issues for this change. Still LPG burns a lot cleaner than gasoline) Having the 455 use LPG with the 300A decreases power with about 10%, but now converting to Impco 425 (uses only the Q-jet"s throttle plate, so now I can use the original air filter housing) there won"t be any power loss. LPG preferably needs cold intake air, so I converted 2 air filter housings (the big ones from a 75 Big Buick with the duct going to the front of the car) to one with dual snorkel (need to replace the battery a few inches) The 455 in the Wagon will get the same next year
There is an additional tank in the trunk for 27 gallons )which can be filled, due to a safety device, for only 80%. I will upload some photos later. In fact I can get rid of the original gastank and add another 20 gallon tank
That was exactly my plan aswell. Using only the Throttle plate will certainly increase power and mpg. You can also install the right advance curve for lpg now. With you wagon, you could have the advantage of placing a tank at the place of the original. That way, you don't loose space and if your car has that, could keep a functional 3rd seat. Keep us posted!
the tank issue for the wagon remains, for I will have to use a tire shaped (ring) tank which has a few cons. Still got a few months to come up with a solution: 3rd seat has to stay and no tank visible from the outside of the wagons!! This is how the LPG set-up in the 73 Riviera looks now: You can clearly see the evaporator (with cooling hoses to/from heater) and the "LPG-arm" with the air filter: LPG-tank in the trunk: And for the spare tire (I used the smallest tire to fit a 5x5 7j Buick wheel): switch on the lower dash: LEDS as fuel gauge for LPG and a switch between LPG or Regular
BTW: this is the air filter housing I made from 2 others (had to cut one snorkel and welded it upside down). It will provide cooler air than the original air filter (there will be duct added to the front of the car). The throttle plate from the Qjet and the 425 added:
Interesting... I have never seen detailed pictures of a LPG conversion. Can you buy cars that are sold new that use LPG?
I don't think I have seen them new from factory (but please correct me when I am wrong), but I have seen them new from the dealer. That is actually a real step forward. On new cars, the system is intergrated with the injection system and before, if you had some trouble, the dealer would point to the LPG converter and vice versa. I have now seen lpg conversion done by the Chrysler dealer for free, when purchasing a new car. CNG cars can be bought new from the factory though. I have seen them from Fiat, Volvo, Saab etc. Often called ECO, or Bi-Fuel or so. Great advantage is the intergration of a tank into the car design, so no loss of space.
Senri, I got this link from here: Supposedly an LPG Mustang from the Netherlands http://fordsix.com/forum/viewtopic.php?t=27167 But it didn't work, so I backtracked the URL and found the most detailed restoration in pictures that no words could describe: http://home.hccnet.nl/e.pilage/ What you might do when you get home is ask him about the LPG.
LPG octane rating FYI lpg, propane typically, has an octane rating of 110 to 114, so you can run some ungodly high compression ratios. I have seen 12.5 to 1 on several street cars with no problems. With higher cp's and advanced timing you can gain back most of the power lost to the change over. Dual fuel conversions make it tougher to make that power back.
I do a LPG conversation on my 73 Estate Wagon for 5 years ago. I have a lot of photo on a thumbdrive, and will post them later. Someone mean that LPG will destroy heads, but I open the heads just for looking at the valve seat,( after driving 30K ) and they was absolut fine. .
The reason why everyone thinks "regular gasoline" cylinder heads don't work with unleaded or LPG is the lead factor, the tetraethyl lead added as an anti-knock compound. The prevailing thinking is that the leftover lead protects the valves from wearing out, which on much older cars from the 1930s to the early 1960s, was a problem. But with newer alloys in the cast iron and the steel in the valves, it's my opinion that unleaded fuel either does not affect them or only affects them so little as to not be noticed. I've never pulled '74 and earlier heads off engines in the last 20 years after running unleaded fuel, to find sunken or burned valves. I've seen sunken and burned valves more on leaner-burning unleaded engines.