Conversion to EFI

[Dr.Jeff]

You are certainly right Andy. Although I've discovered the complete lack of humidity (like 5% or less here) causes other problems. It becomes impossible to keep hydrated and you constantly experience the early signs of heat stroke, regardless how much water you drink. Also happens if you stay indoors with the AC set in the 70's; AC removes even more moisture from the air so it is actually dryer inside and dehydration is still bad. Yet another factor that I've discovered here is the intensity of the sun, regardless of the temp. It is brutal, must be the off-the-chart UV levels, makes it feel much hotter than it actually is. I prefer the climate I spent my entire life in prior to coming here - in the 60's - low 70's year round, day or night, cool ocean breeze, thin cloud layer to lower exposure, and no rain or other bad stuff.

 

[carl]

Well, I guess we all have to move to San Diego.
Due to the weather my Fatrat has turned into a tinker toy for the garage rather than something I drive. Maybe a new name....garage rat!
My twin IDF manifold arrived yesterday so maybe I'll play with that.

 

[WildWilly]

Well, I guess we all have to move to San Diego.
Due to the weather my Fatrat has turned into a tinker toy for the garage rather than something I drive. Maybe a new name....garage rat!
My twin IDF manifold arrived yesterday so maybe I'll play with that.

Let's see some pics of that new manifold. What carbs are you running with it?

 

[Dr.Jeff]

What carbs are you running with it?

Going by the "rat's" history, maybe four SU's off old MG's?
Carl, it had been too long since I harassed you.

 

[carl]

Dual 40 IDFs I had laying around from the last spider I sold. I'll take pics later. Off to the DMV (for the third attempt!) to get handicap placard for my mom.

I used to tune the triple SUs from my dad's XKE...piece of cake...when you don't know what the hell you are doing.

 

[Dr.Jeff]

I used to tune the triple SUs from my dad's XKE

For some reason SU's have a bad reputation. But I always found them to be easy to work on. Modern (relatively speaking) motorcycles use a similar design of carbs (slide valve) and have become a popular induction upgrade on many 4 cylinder engines. I have a set I want to experiment with some day. Often referred to as the poor man's fuel injection. Very simple but effective design. They have been installed on X's before:

 

[dllubin]

I think some of the bad rap SUs got was likely due to people using a Unisyn to balance them. The Unisyn was a excellent example of Heisenberg's Uncertainty Principle. In the process of making the measurement, it greatly affected the flow rate being measured. I once tried one that a friend had on my DCNFs and quickly went out and bought a decent flow meter.

 

[carl]

Trial fit of the old IDFs on the manifold. Plop right on but I have to work on the carb interlink.

The flat lever that goes between the spring and the adjustment screw is too short, the spacing of the carbs from each other is a tad wider than on a 124 IDF manifold. I'll just weld an extension on the flat tab.

 

[Dr.Jeff]

The flat lever that goes between the spring and the adjustment screw is too short

I'm pretty sure they make longer ones. Below are links to two possible sources. But I'd be inclined to do what you suggested and modify the existing one.

http://www.carburetion.com/sitesearch.aspx?category=IDFlink&Title=Linkage for Weber IDF Carburetors

https://www.piercemanifolds.com/category_s/181.htm

 

[carl]

The problem is that the tang fitting appears permanently attached to the throttle shaft so it's not a matter of just undoing a nut on the end of the shaft and replacing it with something else. No big deal to MIG on an extension.

 

[Dr.Jeff]

Carl, I honestly don't recall for sure but always thought all of the little Weber linkage pieces were a press-on nut-bolt attachment. Although if any of it was originally from a production vehicle it could certainly be different.

Regardless, I'm still with you...just weld it.

 

[carl]

I assume it's a press on as there is no nut above it. Seems every IDF I get (and I have owned many) varies slightly with the linkage.
I'll take a closer look.

 

[Dr.Jeff]

Now that I think about it, it might depend on which end you need to modify. Some models had the linkage bits welded onto one end of the shaft, with the other end removable. So it might be easier to modify one half of the joint than the other.

 

[PaulD]

View attachment 23675 Trial fit of the old IDFs on the manifold. Plop right on but I have to work on the carb interlink.
View attachment 23676

The flat lever that goes between the spring and the adjustment screw is too short, the spacing of the carbs from each other is a tad wider than on a 124 IDF manifold. I'll just weld an extension on the flat tab.

The welding could be a good plan.

Here is what I did in fitting splitting Honda motorcycle throttle bodies to fit the fiat head:

 

[Dr.Jeff]

Here is what I did in fitting splitting Honda motorcycle throttle bodies to fit the fiat head

Paul, that is exactly what I intended to do with the bike carb set I have....that is if I ever decide to run them. Really I'm just curious to see how they will work. But it always surprised me that everyone builds odd configuration intake manifolds instead of splitting the carbs.