Webers 70's don't fit on the waffle manifold

[thechadzone]

So I've finally got my IDF 70 carbs off of their Waffle manifold, and I've been fiddling for the right approach to modifying the shafts of the carbs. BTW, my carbs say IDF 68 on their bases rather than IDF 70. WTF...


In the shots that Daniel included of the carbs on the manifold, there seems to be just enough carb shaft on each carb to fit each center linkage piece to each carb (without any threads left on the shortened shafts). This seems ok to me because when the carbs are fitted to the manifold, the linkage pieces are then captured in place. Yeah? If I simply cut the shafts flush at the point where they exit the fitted linkage pieces, would I be good to go? Leave threads on one, and cut the other shaft flush at where it exits the linkage?

I've read more than one post about having threads left over after this operation is done, but I've yet to see any pics of the fitted linkage to the still threaded (or otherwise) IDF 70 shafts. May I throw the gauntlet down? I mean, I've seen pics of IDF 70s on our cars, but none with sufficient detail to expose the mystery of the modded shafts.

I thank each of you who participate here. Snarky as I may be above, y'all still know more than I do

This is what I was looking at this afternoon: [url][url=http://www.flickr.com/pho ... .jpg[/img]
Fiat Linkage 3 by thechadzone, on Flickr[/url]


[url=http://www.flickr.com/photos/thech ... .jpg[/img]
Fiat Linkage 2 by thechadzone, on Flickr[/url]

[url=http://www.flickr.com/photos/thech ... .jpg[/img]
Fiat linkage 1 by thechadzone, on Flickr[/url]

[lanciahf]

On My Weber 70s the shafts were cut and retreaded. An don of the shafts he linkage arm had to be welded to the throttle shaft to stop the "wiggling"

[thechadzone]

Thanks so much, LanciaHF. I was guessing it'd look something like this. Welded on one side, and cut before re-threadded on the other. I don't have experience with making such threads, but I reckon the right braising/MIG welding on each mounted throttle piece would get'rdone.

Mark is right that it's a bit nerve-racking to take the Dremel tool to your carbys, but it seems quite necessary. since I've effectively hijacked this thread (forgive me, I'm guessing that the thread author is benefitting similarly here), anyone got more photos of this operation?

[manoa matt]

Before you cut and weld, consider this. The IDF throttle shaft rides on a ball bearing race one each end. On older carbs, or if you soak them during rebuilding, the grease comes out. Without the grease you can have air leak past the bearings and upset any efforts at tuning. The heat generated from welding might melt the grease. Also if the linkage is welded on, it will be extremely difficult to do a total rebuild down the road if there is a problem with the throttle plates.

I would try and switch the carbs and see if the other ends of the shafts are any better, don't worry about the fuel fittings as the carb tops can be switched also.

My advice would be to take them to a machine shop and have them thread the ends of the throttle shafts, so you can get a nut on each side.

The nuts are not supposed to be tight, as over tightening the nut will pull the whole shaft and throttle plates in that direction. If the throttle plates catch or rub on the side of the throttle bore it can cut a ridge. The ridge will also upset tuning and can lead to the plates not closing fully.

Some food for thought.

[thechadzone]

Thanks Matt, well spoken. I hadn't considered the shaft bearings. I'm wondering if one or both of the linkage pieces can be affixed the same way as the shaft bearing cover plate is affixed to the shaft on the other end of the carb. I've removed this cover plate before, and secured it back in place by using a small ball peen hammer to flatten out that bit of excess shaft that sticks out past the cover plate. This appeared to have been roughly how it was affixed previously.

I like your idea of having the shafts threaded, but I've already over-spent on my cars lately. I I'm considering the use of my micro braising torch and some semi-strong solder to hold each piece in place. That way I can use heat to remove them for future rebuilds. Still, I'm looking for as many points of view, and/or pictures of the finished product as I can get before I reach for the power tools.

[manoa matt]

Send me an email, I have an entire folder devoted to pictures of various IDF linkages people have come up with. They don't necessarily have to be linked in the center, as long as the mechanism is good and does not induce slop or open one carb before the other.

matt.scarton@gmail.com

[Daniel]

I've seen some interesting linkages as well but the center interconnect seems to be the easy route
to go and possible the cheapest way .