Carburetor Options

DougFromBaltimore

New Member
The carburetor is a new project on my Amphicar. I have the original Solex B30PSEI, and it’s in need of service. I’ve read through every forum post containing the word ‘carburetor’. I believe this summarizes the options.

1. Rebuild my original – Does anyone have a good suggestion on where I could send mine? I called some carburetor shops, and one suggested Omar at Just Carburetors in Florida, who I will contact.

2. Buy a rebuilt Solex. Gord has none in stock right now. Gordon’s lists a rebuilt Solex for $410.90.

3. Buy a new Solex. Gordon’s lists for $523.10. I assume it’s a Solex B30PSEI, but I will ask them.

4. Buy an ‘improved replacement’. Gordon lists one for $395.00. Some older posts indicate it is not a drop-in replacement, and that a few modifications are needed (flame arrestor machined on one end, vacuum line moved, choke/enrichment cable rerouted, fuel line slight modification).

5. Buy a ‘high-performance’ replacement. Gordon’s lists for $593.21. Their photo is so small, that I can’t tell quite what it is, and if modifications will be needed.

6. Twin SU carbs (I have no details).

My preference is to rebuild mine. But any suggestions are appreciated.

Thanks, Doug
 
The weekend special is over, but the new one from Gordon's was very nice looking to me.
Mine runs pretty good, but the anti boil over feature was something that caught my eye.

It is nice to have choices!
 

John Howland

New Member
I have had enough with the boiling gas and the gas dripping on my exhaust manifold when shutting it off because of that ridiculous setup with Intake and exhaust as one cast unit! If Amphicar had waited a couple years they would have gotten 1147's with the dual SUs from Triumph, (right?) So, I got the early Spitfire Intake manifold with 2 H2 SU's, the correct cast iron exhaust manifold that goes with it from a MK1 Spitfire and right now am making up some stainless piping to connect the exhaust as well as a stainless tailpipe! I got a longer accelerator cable from Alan C and just found an aluminized muffler that fits better in that tight area also. Got some great ideas from John B. on making a heat shield for the setup and dual aircleaners with hoses to connect to fan shroud for no water intrusion like original design Hope to assemble and test this weekend.
 

BrianF

Member
Hi Jack
Sounds like you have been busy, no surprise. I look forward to checking out your car next time we get together. How much more power/horse power will this new carb system make. And will it solve the vapor lock hard start problem.
Sorry Doug, don't want to change thread. So Doug, my car is bone stock. I rebuilt the carb 15 years ago with a kit from Gordens, it was cheap, easy to do , and worked well. Starts right up cold, runs ok, but does have vapor lock when hot. I deal with it and have not been stranded yet. It is scary when I stall on a busy ramp, with a car full, and it won't start right up. I would say try rebuilding your carb and see if that works. if not go to the next level.
Good luck
Brian
 
Hi John,

That is a ton of work you did!
I am sure everyone (including myself) would like to see some pictures of this set up.

With space so limited, you had to get creative to make everything fit and work.
 

John Howland

New Member
Started it and kept having a fuel leak, seems to have had a fuel pressure issue, got a fuel pressure regulator and hopefully will have a test ride Saturday!
 

DougFromBaltimore

New Member
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.
 

John Howland

New Member
All assembled and running! With the longer J Pipe I made up, either a GI ( 75to79 Vw) muffler can be used or the smaller (4" aluminized round tractor ) muffler can be used. See pics. It starts right up even after shutting it off for a short time! It idles smoothly. Seems to have more pep going through the gears. Doesn't want to stall anymore letting the clutch out off the line, and most importantly. No More Stench of gasoline filling the house after shutting it off! All I can say is, I wish I did this 8 years ago!
 

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That is a sweet set-up. Space is limited and the custom J pipe seems to help make everything fit.
Thanks for the pictures!

I particularly like the clothes pin in the image above, an old timer solution to overheating and fuel boil over.
 
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.

new 002.jpg

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!

new 010.jpg

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.

new 001.jpg

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.
 
Finally got a couple days above freezing here and got the carb installed. Had to put the larger diameter exhaust J pipe and heat shield back on first.

I also had to replace the mounting studs for longer ones. I found 2 inch ones were long enough to have enough threads to put the nut on properly after incorporating the phenolic spacer and 3 gaskets along with the metal plate for the linkage. Not done yet, so will get some pictures after it warms up again.
 
Got the exhaust, heat shield, and linkage installed now along with the choke cable which had to be lengthened as it was holding the choke in a half open position and smoking badly. (Note the flame arrestor at an angle as I do not want to machine a relief in it, and the air cleaner covers it anyway)

2222222222 002.jpg

It runs pretty good, idles good and have the air fuel mix in a good spot. Now I am having a hesitation from idle when I accelerate hard. Not driving the car yet, but when I rev it hard it stumbles for a couple seconds before it catches up. Looking down the throat of the carb I am seeing the J tube dumping fuel as I hit the accelerator, but it might not be enough for the engine.

Looking for possible reasons for this hesitation.
My list of possible culprits are: Accelerator pump, fuel pressure (flow), vacuum advance, something in distributor, fuel filter, dirt from tank in new carb.

Any other ideas?
 

DougFromBaltimore

New Member
I don't recall having any hesitation when accelerating, and I'm not near to check the car. But I think your first item on your list of 'culprits' is likely the problem. The original Solex B30PSEI, and this new replacement, have accelerator pumps. (The next paragraphs are from a VW forum, but apply to us.)

When you open the throttle, the airflow increases immediately but the fuel (being more dense than air) takes a moment to catch up with the increased airflow. This would result in a lean mixture for a few moments (the car would hesitate), so the carburetor has an accelerator pump built into the side of it which supplies a shot of fuel to ensure smooth acceleration. The accelerator pump connected by a linkage to the accelerator; when acceleration is required, the pump squirts a spray of fuel directly into the throat of the carburetor to momentarily increase the fuel-to-air concentration. You can see it operate if you pull the air cleaner off and look down the carburetor throat.

There is a small bent brass pipe right pointing right straight down the throat of the carburetor-- this it the delivery tube. Grab the throttle arm and pull it firmly (like you were pushing down on the accelerator). You should see a squirt of fuel from the delivery tube straight down the throat of the carburetor.

If you pull on the throttle arm very slowly you'll see that the accelerator pump does nothing -- no squirt. It's set that way because when you open the throttle slowly the fuel flow has time to keep up with the increasing airflow - no extra shot of fuel is necessary.

We want as little accelerator pump squirt as possible to remove the stumble from the engine. Too much gas will wash the oil off of the cylinder walls (wearing out the pistons and rings) and will reduce the miles per gallon. So be conservative in your adjustment of the accelerator pump.

As far as adjustment, I believe the pages that came with the carb describe the adjustment. Or check the Amphicar manual (the adjustment should be the same as for the Solex.)
 
Thanks for the information Doug!

I think you are probably right about the accelerator pump. When I was trying to adjust it, I did see that it was squirting gas down the throat upon hard acceleration. It is possible that the amount of gas going down and the timing of the squirt may need some adjustment. Going to replace the fuel filter and fuel line all the way from the tank to the carb just to take that out of the equation.

While under the hood making the adjustments, I heard something grumbling. Generator? Water pump?
Yep, water pump bearing making fan a bit wobbly. So, now I have the radiator out and water pump off waiting for a replacement part. Carb will have to wait.
 
Interesting comparison.
Looks like quite an improvement using the twin SU system, but would need to replace the pistons to get the 9.0:1 compression ratio to hit those numbers.

My story continues as I shipped that hesitating carb back to Gordon's to have it tested.
They are going to install it on a test engine to try to figure out what is going on.

In the mean time, I have a Pertronix ignition and coil to install.
Not exactly sure where the wires go yet, so any one who sees this who has installed one, I would like some advice if possible for the igniter and the coil connections for the positive ground.coil 001.jpg
 

Jon March

Member
Now help me here - what sort of actual horsepower or torque improvement might I expect on my 1147 , if i keep the same pistons/compression
....basically just change from sengle carb & its siamese manifold......or upgrading to the twin carb and improved/selarate manifolds?





Here’s an excerpt from a 1972 book on exhaust and intake systems. It compares the Herald and spitfire versions. View attachment 2843
 
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