Doug checking in. I am rebuilding my original Solex. But I did purchase the 'new, improved, ‘drop-in replacement’ carburetor' from Gordon Imports (9/1/2020). Gordon lists it for $395.00 (mine was on sale for $295). The new carb is great! Installation was easy. The car started immediately with the settings as purchased. Only some minor adjustments were needed. The carb helps the car start easily, run smoothly, and accelerate well.
I found it to be an easy drop-in replacement, with only a few minor install modifications. Here are the steps I used, for the very easy install. Some are from the helpful notes from other posters. Perhaps these notes will be useful if others take this route.
Steps
- If you’re unfamiliar with the carburetor setup, photograph and diagram the old carburetor, as it’s installed in the car. Note connections for accelerator, choke, fuel line, vacuum line. Note spacer and gaskets at base. Note flame arrestor.
- Remove old carb. Retain all parts.
- Fuel line – Mount the new flex line on to the new carb. Use an authentic clamp. Make sure the connections are tight.
- Phenolic spacer between the carb & manifold –The spacer goes between the carb base and the intake manifold to insulate the carb from the heat. Use the two new gaskets provided, on either side. Note the new carb has a slightly thicker base, so it may be necessary to back out the manifold studs to lengthen them, or replace them with longer studs. In my case, there was no problem.
- Mount the carb. Tightened the nuts firmly to insure elimination of vacuum leaks. Check again after the first drive.
- Accelerator linkage – Attach the original throttle arm to the new carb, just as the original.
- Choke (now ‘enrichment’) cable – The enrichment connection is on the opposite side of the carb (port) from the standard choke attachment (starboard). I had no problem with the somewhat tighter 180° radius turn. Gordons suggested routing the cable below and up the side of the square tube frame rail. This would make the 180 degree turn more gradual, while keeping it away from the muffler.
- Fuel line – Push back the flare nut on the original steel line. Put a loop in the new flex line, and attach it to the steel line, with a clamp.
- Vacuum line - The vacuum advance port is slightly relocated requiring some minor bending of the vacuum line. I had also ordered a new rubber angle connector, since mine was hard from age.
- Flame arrestor - The fuel input port on the new carburetor is higher on this carb with a "bulb" that interferes with the stock flame arrestor. Just turn the arrestor about 15 degrees, so it does not interfere. If you want it to sit straight, as original, then you’ll need to machine a relief in the FA housing to clear. The new carb has a nylon bumper that fits into the formed groove for the set screws to tighten against.
- Tuning –
- Choke – I only needed about half choke when starting the car.
- Idle speed - the adjustment is on the base of the carb, and works against the accelerator linkage lever (just like the original).
- Mixture - rich/lean – the adjustment is at the base of the carb, at an angle pointing to the right rear (just like the original). Trying turning it in, until the engine runs rougher, then out; find the sweet spot.
- Old carb – Retain it, for originality, or use as a back-up. Get a rebuild kit, and get it ready for use. As many have said, the rebuild is easy.
My new GI carb finally arrived and I started down this list from Doug after removing my old Solex from the car.
I got down to "Accelerator linkage" and that is where the work started and why I decided to post additional information on this particular point.
You will need to remove the base plate & linkage assembly from the old carb and figure out how to make it work on the new one. Being that the choke system is on the linkage side on this new unit, there was interference issues with mine. I had to reconfigure (bend) the linkage many times to get it just right so it would still work smoothly and not touch the choke cable mount.
Next thing I noticed was the plate that is part of the linkage assembly that mounts under the carb. Knowing what a restrictor plate is in NASCAR racing, It looked to me like the opening on the old plate was smaller than the new carb, which it is! You can see from the black line on the plate how much smaller it is. That line is 1/8" wide!
Turns out the old plate has a 1.19" hole and the new carb base has a 1.34" hole. My shoddy math tells me this is a difference of 0.31" of area, and would create a 22% reduction in air flow. Why would I allow this restriction? That would defeat any performance advantage of the new carb, so the grinders came out to "clearance" this material flush.
That looks better! Restrictor plate is no more.
Have not installed it yet, so as I continue down Doug's list I will post any other interesting things I find along the way.