WEber Internal spring

[Zedyone_kenobi]

i would love to see those pics

[Zedyone_kenobi]

I like where you are going there. As long as I do not uncover a progression hole I could go open more I suppose. Would need to add more fuel though. I wonder though if going down a jet size would lead to a poor idle. I could open up the idle mixture screws but then if I get close to stoich. With the throttle plates open that much I may be asking for a 1600 rpm idle speed.

[Captain Obvious]

Probably never showed them here. Basically I modified a set of round tops so I could drop them "plug-n-play" into my 260 without messing with external return springs, linkage changes, or different heat shield arrangements. Here's a couple pics. The whole story is over at zcar.com. - ZCAR.COM - Round Tops Customized Drop-In Replacement For 260

Edited March 16, 2013 by Captain Obvious
Better link

[Captain Obvious]

I wish I could add some Weber specific input along with Blue, but the only thing I know about Webers is that they're carbs...

I've got some Mikuni (motorcycle) experience, and they've got similar "progression" holes. The only thing I could add that might be applicable is that the more closed you can get the plates at idle, the better. A lot of the problems I see people having with the bikes idle is that they're not truly running on the idle circuit. The bike is running so crappy that the only way they can GET it to idle is to crank the TV open and expose the holes.

And I've been surprised on just how closed you should be able to get the plates for idle. This applies to the z car carbs as well.

Edited March 16, 2013 by Captain Obvious

[240260280z]

Bruce nice stuff... I was thinking about your post when responding above but thought nahhhh, 6 cylinders are pulling on one TV in yours but only one is pulling in Stephen's.

I think it could be related to the seals and surfaces as you suggest. the webers have bearings making it more interesting... however the weber throttle valve shaft does pass through machined aluminum with tight tolerances. Here is an exploded view to bring you up to speed fast:

[LeonV]

Phil,

What we're talking about happens with the linkage totally disconnected! Disconnect the linkage, individually blip the throttles and see if they drop back to idle. Mine hang. Good link on the return springs. I'll have to look back and see what I ordered, but from memory I got the stiffest ones available at Pierce.

OK sorry got it.... just going crazy here in terminal A at Newark ......half reading half feeling hot and uncomfortable argghhhhhh.

The Z I restored seemed to develop the same problem after 500mi.

We are going to address it in a little over a month. Trying the stronger springs is a first step. (FYI the carbs were rebuilt with newer springs from Pierce but they were the 47605.027 medium ones)

FWIW, upon checking I also got the medium (47605.027) return springs. Looks like some testing is in order...

[Captain Obvious]

Here is an exploded view to bring you up to speed fast:

Thanks for the pics. Better than before, but nothing like taking one apart! I just want to make sure I'm interpreting the pics right and then I'm going to get out of the way of the experts...

So they use needle (roller) bearings on the shafts? The bearings are "sealed" according to the parts list, but in the picture, I can see what appear to be the ends of the roller needles. So, is the seal transparent or non-existent? I also see on the diagram that there are O-rings inboard of the bearings and I assume that's to seal engine vacuum?

Am I interpreting this stuff right?

[Zedyone_kenobi]

UPDATE. I installed my stiff return springs on the webers this weekend in between naps for my 2 month old. It is a realtively easy job actually, so I took the opportunity to clean the carbs completely while I had them off. When I put them back on, the force to actuate the carbs is noticeable stronger (I would say roughtly 78.543% stronger). I think I will be able to make these work now. The flappers close with a definite THUD. Next job is much easier. I need to find a very light return spring for the cable now. It becomes a balance between the return force and the actuation force. I think I am zero'ing in on it though.

Keep in mind I also ordered three of the throttle lever return spring kits from the UK this weekend.

It comes with that lever, a spring and an attachment plate per carb. IF this does not work, I still have that set up for anybody who is interested! More to come.

[240260280z]

That is good news. For the interest of all, Pierce Manifolds sell the 47605.009 strongest springs however they do not show up on the website.Just ordered 3 last week.

[Zedyone_kenobi]

yup those are the ones Blue!

They are BEEEEFY

[LeonV]

Good stuff guys, sounds like I need to place an order on these too...

[Zedyone_kenobi]

To quote Archimedes

Give me a place to stand and with a lever I will move the whole world

This is the story of my linkage battle last night. Mechanical advantage is your friend, and enemy. I played extensively with angles and moment arms, and degrees of rotation last night to get a clean pull and balance mechanical advantage with throttle sweep. After all maximizing mechanical advantage is useless if the full pedal travel only gets you half throttle. And getting full throttle at the cost of a rock hard gas pedal is equally useless.

The solution:

The biggest thorn in this whole situation is this. Every linkage kit I have seen comes with three carb actuation arms, and ONE (STUPIDLY SHORT) throttle cable attachment arm. This short arm is asked to do two things and the short length is a handicap in both situations. First it must move three much longer carb actuation rods. I my case, those three longer rods were attached to three VERY hard return springs. Second the return spring is often connected to the throttle cable attachment arm. It is at a huge mechanical disadvantage as well to pull the other arms back to full closed (not much of a problem with these huge internal return springs).

My solution was this. First I used the middle carburetor actuation arm and attached the throttlle cable to it instead of the short throttle cable attachment arm. It is a full 2 inches longer. I had the actuation rods on the shortest setting on the Carb actuation arms for the greatest mechanical advantage. Well this worked well, make that great, my pedal went from hard and springy to light and snappy, with a DEFINITELY end stop in pedal travel. Problem was with the short setting on the carb actuation arm the throttle was only opening 60% of the way.

Next step was to move the actuation rods to the middle setting on the carb actuation arms. This was the sweet spot. I open about 90 % now and the pedal feel is pretty good. A bit heavier than a modern car, but still snappy.

The solution to all of this is to get a longer actuation arm for the throttle cable. Order an extra long arm to compliment your linkage kit and you will get a light pedal with enough mechanical advantage to overcome any internal spring you may have. I have yet to drive it, but am getting a definite snap back to full closed each time.

I am going to order a new longer actuation arm from Authentic Weber Carbs, Manifolds, Conversion Kits, Accessories and More! to get my 90% open to 95% open and leave it at that. I am just a test drive away from being very happy.

Carb actuation Arm - YEAH

Throttle Cable Actuation Arm - Boooo

Edited March 27, 2013 by Zedyone_kenobi