Throttle linkage to cable conversion

[richardsonta]

Has anyone done a throttle linkage to cable conversion and kept some pics they're willing to share? I'm ordering some parts and I've talked to a couple of people about how it's laid out and what I'll have to fabricate but it sure would be helpful to have a couple of pics.

Thanks,

[18Fiatsandcounting]

Richard, I have done the cable conversion (on both my '69 and '71 spiders), but I don't have any pictures. However, here is basically the main component that you'll need:
https://www.midwest-bayless.com/p-16621 ... renew.aspx

This linkage assembly bolts to 2 studs on the top cover of the intake cam, so if your cam cover doesn't have the studs, then you would need to find that as well. From the one ball joint on this linkage assembly, you run a solid rod to the throttle lever on the carburetor. Then what you need is a throttle cable that has the right connections on each end. The end to the throttle linkage (on top of the cam) should have the right connector for that ball joint, and the other end of the cable needs the connector for the lever on the gas pedal. On my two spiders, I believe I also used the gas pedal and shaft housing from a later model Fiat, possibly even a 131 sedan. It's been so long, I've forgotten.

I know this may be hard to picture and somewhat confusing, but if you want, I can try to walk you through the confusing areas.

-Bryan
PS: Just thought of this: I believe there is a kit to do this conversion, so that may be the easiest route. A little bit of googling on this forum or the Web in general might find you what you need.

[seabeelt]

Depends on the year. To use the Midwest bayless part ( cam mounted hardware. You need a cam cover from a car that used that setup. Or you have to drill and stud some supports for it. Some folks have said they swapped gas pedals from those same year cars to earlier cars to be able to use all of the above. I believe this not to be the case as the wiring harness is in the exact spot where you want the cable to come through the firewall ( on a 71 anyway) . If folks have photos oh how this works I’d love to see them. I modified my 71 gas pedal ( cut one or two pieces off and re-weld one back on at an angle that would work with my waffle manifold. You then need to make a bracket bolted to the waffle to accept the other end is the cable. And last bu not least make a threaded rod of the correct length and bend to hold the adjustable ball sockets on the cam linkage and carbs.

[18Fiatsandcounting]

I agree that my "solution" can be difficult, and it might not work on the taller 2L engines as the lever assembly on top of the cam could be hit by the hood when closed.

However, with some ingenuity and the right cam cover, lever assembly (such as in Midwest-Bayless), a linkage rod with ball sockets on either end, a cable & housing, a new gas pedal properly positioned and fixed to the inside firewall in the driver's footwell, it can work. Worked just fine on my '71, although I had to come up with a different solution for my '69 since it has been upgraded to the taller 2L engine. Coincidentally, I was just tweaking this yesterday as the cable would occasionally bind and prevent the throttle shaft on the carb from fully returning to idle. But that's another story.

-Bryan

[seabeelt]

Oh. I’m not saying it’s not worth the work. Just takes some tinkering. Much more fun to drive wit dual carbs lol

[slc302]

Reviving an old thread! I’m hoping to solve the bucking issue on my ‘71.

I’ve been diving deep into numerous threads on this, and I feel like a have a good handle on the “upgrade to late 70s throttle assembly” approach. I have had a challenge sourcing the parts I need. Midwest Bayless hasn’t had the renewed throttle body since I’ve been looking. There was a used one available for like a day before someone snapped it up. The complete pedal assembly seems hard to find as well. I’ve found some partial assemblies and a $150 eBay listing, but there has to be something better.

After scouring Google and doing junk yard parts searches, I thought I’d turn to the forum. Any suggestions on other sources for these parts? Or suggestions for good enough alternatives?

Any other throttle linkage solutions that others have done, especially using the original pedal assembly?

[18Fiatsandcounting]

Yes, the "bucking bronco" effect is annoying, but there are a few things that could be making it worse. Worn motor mounts can cause the engine to rock back and forth more than it should. Loose grommets on the throttle linkage can make the problem worse. And, a clutch that isn't engaging smoothly will also make it worse.

One "solution" is to start out in 2nd gear when you can. That helps a bit. Slipping the clutch also helps but this reduces clutch life.

If you want to continue with the cable conversion, I'd sign up on Mirafiori.com, as this Fiat site is a lot more active. Post in the "Wanted" section what parts you need.

-Bryan

[slc302]

Thanks, Bryan. I’ll do a wanted post to see what I can get. It looks like even Brad is searching for these linkages over on mirafiori.

From what I’ve read it sounds like you’ve typically done the swap to a cable from a late 70s car. Are you aware of any viable alternative solutions?

Thanks!

[18Fiatsandcounting]

Yes, I've done the conversion on both my two spiders, a 1969 and a 1971. It's been decades, but I recall searching junkyards for the gas pedal, and I wanna say that I found one from a Fiat sedan like a 131. The gas pedal is actually the trickiest part.

I had to move the mounting location for the two plastic pieces that clamp onto the center "axle" of the gas pedal, and that ended up being about 1.5" towards the center of the car. I drilled new holes in the firewall to secure the plastic clamp halves.

From there, I carefully measured where the hole in the firewall needed to be for the new cable. I recall drilling this from the engine compartment side, with the carburetor removed to make things easier. Stuffed some rags in the intake manifold so as not to drop bad things into the engine like metal shavings.

The "cantilever" assembly that mounts on the cam box cover is the 2nd trickiest part as you've found out. Oddly enough, I've found several parts guys in Canada that seem to have more of these lever assemblies than in the USA. Not sure why, could just be luck of the draw. Anyway, check with some of the Canadian posters like Dinghyguy (Dan Campbell).

The cable and housing isn't that critical as long as it reaches and has the right fittings on the ends. I vaguely recall that my cables are not even from the 124 spider application, but rather from a 124 sedan or the like. Seems to work.

As for the rod that goes from the lever assembly to the throttle lever on the carb, I just got some steel rod of the appropriate diameter, cut it to the right length, and threaded the ends with a die. M6x1.0 threads as I recall.

Hope this helps.
-Bryan

[18Fiatsandcounting]

Forgot to mention other options. I think as long as you could attach a cable to the arm on your existing gas pedal, like the arm for the hand throttle lever, you might be able to run that into the engine compartment and make a bracket on the cam cover to be the end point for the housing. Then run the inner cable down to the throttle lever on the carb. The challenge is getting enough return action on the throttle lever to return the carb to idle, and this issue is usually addressed with additional springs.

A couple decades ago, I played around with a 38DGAS carb, and it's a mirror image of the traditional spider carb. In terms of the throttle levers rotating in the opposite direction. Anyway, I rigged up something with a bicycle cable and some additional return springs on the throttle lever on the carb. Crude and laughable, but it worked.

-Bryan

[slc302]

Thanks, Bryan, very helpful as always!

Sounds like it may take some work to get the parts for the full conversion to a later model throttle linkage setup. Appreciate the rundown on the main steps and challenges.

For the alternative cable conversion, I’ve read of people attaching to the hand throttle lever inside the engine compartment, but I’ve never seen this in a picture. Makes sense in concept and I like the idea of not swapping the pedal assembly, but I’ll keep digging to find examples.