there are actually 3 throttle bodies listed in the S4 parts book.
Two makers, one was dellorto and the other, uhm, I can't recall at the moment, maybe solex ...but there were definitely different manufacturers.

the difference listed in the parts book was between Automatic cars (PN 60555452), throttle rod cars (PN 60519110) and throttle cable (PN 60565066) cars.

If it helps, my early S4 with the throttle rod uses this one, a dellorto:

why the question?

 

Thanks Dom-- I knew I could count on you for the P/N's! So the answer is yes, the later cars with cable operated throttle use a different TB. I sort of suspected that.
I am seriously considering converting my '91 (with the rod/linkage) to the cable operated throttle. I'm going to meet here in town with Conedriver soon, since he has a '92 Spider with the cable type throttle body, and review what parts I would need for the conversion. I also realize the accelerator pedal assembly is different.
Even though I bought my Spider new, I have never liked the rod/linkage feel or action. My wife Irene used to have Giallo, a '93 CE model with the cable throttle, and I much preferred that feel and linear action. BTW, Giallo has long since returned to Italy (Sicily), to a collector with an Alfa/Fiat /Lancia shop.
Mille grazie Amico...

 

Thanks Dom-- I knew I could count on you for the P/N's! So the answer is yes, the later cars with cable operated throttle use a different TB. I sort of suspected that.
I am seriously considering converting my '91 (with the rod/linkage) to the cable operated throttle. I'm going to meet here in town with Conedriver soon, since he has a '92 Spider with the cable type throttle body, and review what parts I would need for the conversion. I also realize the accelerator pedal assembly is different.
Even though I bought my Spider new, I have never liked the rod/linkage feel or action. My wife Irene used to have Giallo, a '93 CE model with the cable throttle, and I much preferred that feel and linear action. BTW, Giallo has long since returned to Italy (Sicily), to a collector with an Alfa/Fiat /Lancia shop.
Mille grazie Amico...

My Motronic has rod linkage and it works great. Well, except when I broke one of those cheap plastic ends off last week. Now replaced with metal.

 

Be aware that someone here already did that conversion (Vin maybe?) and wished he never had started!
It was a nightmare apparently!
Do a search.

 

Yup, that was me.

Glad you found the post I made about NOT recommending the change.

It really was a lot of work with little benefit.

There are a lot of parts that need to be changed, including the throttle body. As I look back now, I get that feeling of "oh what have I gotten myself into this time".

Not only the throttle body, but also the outlet from the thermostat and the intake manifold itself is different as well as the gas pedal you already know of.

Here is a few pictures to help you decide to do your best to improve the throttle linkeage you already have. And there are more!

I rarely say this, but in this case, don't do it.

Vin

 

Right... I skimmed through it, but maybe I should take another look. I do recall seeing the linkage rod across the top of clutch housing was a pain.... Thanks. That's why they make the Saws-All !

 

Interesting project but really I find the throttle rod control on my car just fine.

Ideally you’d need to fit the exhaust manifold with the 2 bosses to take the heatshield ( the heatshield is only there to protect the throttle cable from the heat)
Plus I’ve not seen the cables for sale, so you’d have have one made, preferably a couple of them as one day that might fail.

Parts book lists further differences:
the pedal assy (obviously)
sourcing and fitting those parts alone will not be easy, methinks:

air ducting
plenum
throttle body
Thermostat housing connection
intake manifold
some plenum hoses.

you might be able to work around some of those but it is changing an engineer's design for a rube goldberg one

one plus point with cable throttle is you can fit cruise control...someone here has done that too...JohnM I believe it was

 

I seriously disliked the rod linkage on my S4 when I got the car, but after doing some work it's pretty good now. Few things you need to do:

1) Get all the play out of the system. The rubber bushing at the right side of the crank arm across the firewall is notorious for getting floppy. Beyond that the crank under the throttle can get play that can be improved with shimming

2) Get the rod lengths adjusted properly and ensure the pedal stop is set properly (too high and you won't get full throttle, too low and it'll stress the linkage). When things are set up properly that bushing end I mention above should be held away from the firewall about 0.25-0.5" by the long rod

3) Replace the spring on the left side of that crank arm (behind the cast exhaust tubes) with a significantly weaker one. It is way too strong and messes with the pedal feel. The throttle has a spring (and I believe the crank underneath it has a spring too) so the throttle will still close fine

All that will be a lot easier and cheaper than switching to the cable, and it'll work well when you're done.

 

I'll have to look at the entire scope of work involved, yes, then I'll decide. But the bottom line for me is that I just like the progressive feel of the cable better. As for the parts, I would wrap a reflective insulation sheath around the cable where it passes above the exhaust. And, if this would involve anything more than a different throttle body and pedal assembly, then I would probably back off altogether. I just went through the injectors and all the fuel line rubber last fall, so I have no desire to pull that intake off again just for this idea. From what I remember of working on Irene's Giallo, I did not notice anything else different in the ducting or intake system between our two Spiders. Once I go over George's Spider and compare it to mine, I'll know whether or not this is worthwhile.
Tom, I do appreciate your comments also here, regarding fine tuning the linkage and rods. It just makes sense to optimize that mechanism, if I'm going to keep it. I have new Spruell-sourced HD motor mounts to install, plus rebuilding my driveline and tranny mount, so I'll take a good look at the bellcrank under the intake while I'm in there. Frankly, I haven't checked the condition of those firewall bushings for a long time, either. Thanks Dom, for the pedal assembly illustration, too.
We'll see... thanks to you all for this feedback!

 

Some day, I will tell you about my cable breaking experience and having to boost one from a parts car behind a repair shop to get home on a Sunday.😂😂

 

Alfisti are always welcome at our place. Bluegrass hospitality...

 

And good bourbon.

 

My own comments back some 7 years ago:
"Interesting... I was doing a search on this topic not long ago myself. It was sparked by my son's comments on how nice and smooth my wife's '93 Spider drove (cable) compare to my early '91 (rod). He said it made it easier for him to get used to the car (he's 17, did his first autocross last spring).

He also made the observation that there seemed to be some lost motion in my car's throttle rod linkage, and I checked it and he was right. Like about 1/2" play in the linkage. Lesson: when you're that used to a machine, sometimes you unknowingly adapt to some of the abnormalities that others, less familiar with it, will notice. So, check for excess play and adjust it out, then spray lube the rod ends AND the bushings on the firewall. That made a HUGE improvement in my '91, and Mike gave it the thumbs-up too! Now he enjoys driving mine as much as the '93.

Thanks also for the thoughts on converting to cable throttle. I was seriously considering it, but I now agree it's not really worth all the work and parts."

 

And Vin's comments on that same thread:
"SS4 is right that early 91's had the linkage style. Late 91's and on had cable.

All S4 atuomatics have cable as well.

I have an early 91 and changed from linkage to cable as I was told it was smoother.

I have to say, it might be a bit smoother but not that much. I kept the maintenance up on the linkage so I think that helped.

I would not recommend this change to you.

There are a lot of parts that have to be changed including the intake manifold. More than I thought and also work needed on the inside of the driver footwell as well as on the firewall.

I suppose it would have been easier if the engine was out, but still would not recommend the change. Too much effort for not a lot of payback.

My $0.02

Vin"

Food for thought... I can't imagine the intake manifold being different, but now two fellows here have mentioned that. That would be a deal killer for me. Not worth it.

 

Tom, you may have sold me buddy! I'll make some photos of the cable system parts this weekend, just to document what's there, but this driveshaft work, trailing arm bushings and mounts are the top priority now for my car. The throttle linkage work would not take that much time, as you describe it. Molto grazie...

 

No prob. I just took the spring to the "assorted extension springs" section of the local hardware store and found something about the right length, but weaker.

The only challenge to the whole thing is getting the old spring on and off. It's pretty strong and you need to use some good needle nose pliers at minimum. But it's not rocket science.

 

Good grief Charlie Brown! Vin, if I ever saw a convincing presentation, that's it. I had NO idea Alfa re-engineered this system to that degree. New castings for the thermostat housing, new machining operations for the manifold. New spec hoses and fittings. They even had to alter the firewall tooling for the new style pedal assembly. That does it for me. It's truly not worth the work (and component parts) for such dubious benefit.

Gentlemen... ladies... THIS is what makes the Alfa BB such a terrific forum!

Thanks, y'all. As we say here in Kentucky.

 

Glad I was able to help you make your decision. Like I said before and I will say again, I would not recommend this change. The juice was definitely not worth the squeeze.

Ya, this BB is really great. Could not enjoy my Alfa without it.

Good luck,

Vin

 

The throttle cable S4's also have a different heater hose set up. The heater hose doesn't attach to the throttle body - it attaches to a nipple on the head. A few months ago, I learned that the '91 and '92 are different.

I was told by the Alfa parts guy up north that he had the correct part, but he didn't. I never got the correct part and I was able to get the part for an S2 to fit.

 

the rod system is pretty much bullet proof and has been working on alfas for many decades.

make sure the two "U" bushes on the bulkhead are ok, and not all rotted away is the first thing. They are generally in decent order.

You sometimes can feel some slop due to that bush at the end of the rod that pushes the linkages. Easy enough to tell....just have someone gently push on the gas pedal and you check the throttle linkage moves at the same time.
(when I had my rad overflow bottle removed to clean it up inside during a radiator change, i could get my hand to that bush easily and in mine there was no slop at all, maybe a PO had replaced it)

Then the pedal can feel somewhat hard to push, not a smooth action, gas on gas off, and that is often due to the throttle bell crank under the plenum....this should move freely, but can start to seize up, if not cared for and lubricated once in a while.
If it is starting to seize, you really need to remove it, dismantle it, clean it up and regrease it....it is a bit of a pita to get to, admittedly.

the big return spring (mentioned by a poster above) on the arm is probably also a good idea to look into. You do want some resistance, some feel left, however.

 

The big thing on the rod system on the bosch cars is keeping the bell crank pin and swivel clean and lube well. The factory never lube them and back in the day. We would get at least 4 or 5 towed into the shop with a locked up bell crank. They didn't always lock up at idle either. Big pucker factor.

 

I could see how that could happen, Jim, nobody ever giving that point even a squirt of WD40, much less light oil. It's the little things... little things that make the difference.

 

Vin had me convinced, but I took a close look at Conedriver's Spider yesterday (grazie, George) to just see the differences up close. And what I saw was a total re-engineering of the throttle actuation system by Alfa. There are just no shared parts anywhere, between the rod/bellcrank on my early '91, and the cable operated throttle on his '92.

I'm staying with what is on my car-- after all, throttle plates have been rod actuated since the first functional carburetor, right? While I'm doing the motor mounts, I'll check for play, check the firewall bushings for slop, and replace the original plastic rod ends. I think they're on borrowed time anyway. For the record, here's some photos illustrating the difference in the intake ducting and various rubber hoses. Once again... hats off to the BB!

 

Vin had me convinced, but I took a close look at Conedriver's Spider yesterday (grazie, George) to just see the differences up close...........

When I first opened this post and read this opening line, I started yelling Nooooooooooooooooo!!!!!!! Don't do it.

Then I read the rest of the post

Glad I could help someone not live through this pain.

Vin

 

You're a good man, Vin!