Tuner's Secondary Lever Mods

[rgalajda]

[Papastoy72]

Carb I'm modifying is a 17082227 SMAB. First thing I did was to relocate the front end of secondary link down to about where its located on dual main air bleed carbs. I then modified the slot, I too didn't make it quite as long. Then I measured about halfway between the slot and where the upper part of the lever starts to taper down and drilled the hole for the pin there. The only thing I had to do differently was to bend the first lever so that it will hold the secondary plates closed at idle. Then I bent, as you suggested, the other lever to obtain the secondary plates directly under the baffle as per Tuner. The issue I had was where to locate the roll pin. Once again, many thanks for the pictures and instructions.

[rgalajda]

Your welcome

[10132]

...great instructional....I need to try this now...what is the before and after angle of when the primary begins to pivot the secondary? Also, when Tuner says the early versions had a three point linkage, does that mean it looks exactly like this mod?

[rgalajda]

[10132]

…that is a very nice looking overhaul.
…thanks for clarity Tuner’s info, it looks just like the 70-74 Olds, Buick and Cadillac rear linkage.
I’ll pull one off the shelf to visualize the movement.

[rgalajda]

The order of contact is A then B and C last. Three points of contact ,one after the other. Notice the longer curved slot at "C" on this type of linkage . See Photo below.

[10132]

Edit…not 70-74 Buicks, but yes with Cadillac, Olds, and Pontiac. LOL.
I have never noticed the longer slot (C) in those levers and I have built plenty of them. LOL.
Thanks again.

[10132]

…I played around with a late 70s truck style baseplate yesterday, which didn’t start to open the secondary till about 15/32”(using a typical carb rebuild “L” ruler as a gauge).. this baseplate has the very long late delayed primary pivot arm, so as others have mentioned, I drilled another hole to replicate the passenger version …I than reassembled the linkages and everything needed retweaking….I did the A-B-C synchronization, now it opens the secondary at 11/32”…very nice improvement…I still need to add the relocated pivot “pin” mod…I’m post some pixs when I figure out how to resize to format here.

[10132]

…finally adding the pivot pin…works excellent…it’s now opening the secondary with the 9/32” opening on the primary ,, very nice improvement.