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Originally Posted by Tom Vaught
That is some nice fabricating B-Man.
I would say though that unless the lower lever arm in the rear is about 1.8-2.0 times longer vs the front lower arm you will never get the front carb primaries to open fully. The 1.8-2.0 ratio multiplier gives you some primary movement (about 50%) and will still have all of the primaries to be open at full WOT.
Tom V.
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Thanks Tom.
The rear primary carb linkage arm has 2.4" of linear travel measured at the linkage arm attachment hole, the forward secondary carb arm has 1.7" of linear travel at the same point. This way the rear carb primary throttles are opening about 1/3 of the way before the primaries on the front carb start to kick in. Hoping this makes the car easy to drive around town upon light throttle application.
I did some messing around with a few different thin cardboard patterns while I was figuring out the exact geometry I wanted. I put the pivot points in a place where they would have equal travel distance fore and aft from center, and stay on the same plane at the beginning and ending points of their travel to prevent any binding and provide smooth actuation.
Seems to have worked out so far. Both carbs open fully with no problems and pedal effort is very light, much lighter than I expected. After I got it working I was concerned that it might be too stiff, but after heading out to the garage and actuating my '66 Tri-Power a few times I knew it would take less pedal effort than I had anticipated. Kicking in the outer carbs on the Tri-Power always seemed to take quite a bit of effort when I had that setup on my Temepst, there are some fairly stiff springs keeping them shut.
Of course until I get a chance to actually drive the car with the linkage progressing as it does now I won't know if the front carb seems to be kicking in sooner or later than I'd like.
Bart
