Posted by BeepBeep on Friday, February 01, 2002 at 8:13PM :
There seems to be some interest in propane (LPG), so I’ll briefly run through a “standard”
installation for those interested. As mentioned elsewhere, I strongly advise against a dual-fuel
primarily because it’s very difficult if not impossible, to feed the engine efficiently on both
without making constant “tweaks” to satisfy drivability, power and milage. With that in mind,
the information provided below assumes a single fuel install of LPG only. Of the numerous LPG
installs I’ve waded thru, I have found Impco products to be my first choice. Impco’s CA 125
single bbl. carburetor is designed for 150-200 ci engines but gives excellent low speed
drivability (and milage) on 230-250 ci engines, while sacrificing upper RPM horsepower. The
CA 225 single bbl works best for conditions requiring upper end horsepower (freeway jaunts,
trailer pulling, etc), but at a noticeable loss of milage. Both carbs can be found with excellent
designed universal linkage connections for ease of installation (some even have ball bearings on
throttle shaft) . The next piece needed is an Impco model “E” exchanger/regulator. Many fork
lifts use a Impco model “J” which is just too small for most 3000+ pound vehicles. Rounding-
out the package, you’ll need a lock-off (an electric or vacuum safety shut-off valve), enough 3/8
high pressure LPG ONLY hose to connect to the tank, and a fuel tank. The regulator will need a
constant supply of engine coolant (via heater hose connections), to prevent it from icing up, and
preferably mounted as close to the carb as possible. Impco’s LPG carbs are well designed and
widely universal by simply changing the removable mounting base, meaning you can install it on
your 230 ci. PW or install it on your Datsun L16 pu by simple buying and changing to the correct
base. It’s interesting to note, that Impco carbs have only ONE moving part.... the diaphram.
Which means complete carb overhaul requires removing only a half a dozen screws and
discarding the old diaphram.... WITHOUT removing the carb from the manifold. BeepBeep