Engine: Edelbrock Carb, no kickdown

[valleyguy]

I have an Edelbrock 500 cfm carb with aftermarket linkage, which is very similar
to the stock linkage. I have no kickdown (downshift) at speed and according to the
manual, that's a carb linkage problem. As you can see, I have a spacer installed to
set the linkage out (away) from the carb, to try to get the right geometry. I have
the return springs installed per manual, and the linkage in the correct hole on the bellcrank. Any thoughts?

Joe D.

[StudeRich]

Auto. Trans. Throttle Pressure with Edelbrock AFB clone.

It is hard to see in your Pic, but it appears you may NOT have the throttle rod in the Large hole in the Edelbrock lever (with a bushing) if you put it in the small hole that it fits perfectly into, it's the wrong one to use.

Also that is not a correct rod end on the Carb. end of the stretch Rod. Any movement of the original position of the throttle rod will cause maladjustment of the Automatic Trans. which of course if driven, will cause slipping clutches, which will cause complete destruction of the Trans. due to debris in the oil.

To begin repairing this, you get the Rod matching the stock one shown in the Throttle Rod adjustment section of the Shop Manual, then proceed to make the stop lever to bellcrank stop screw adjustment, and then the lower rod throttle pressure adjustment shown in the Automatic Trans. section to correct the shift points and kickdown.

I cannot tell if you have made proper adjustment for the height change caused by the adapter (Carb. spacer) if you are using one or not, possibly that could explain the aftermarket forward rod end, I do not know.
Also in the stock setup, the rod goes on the outside of the Carb. lever.
Maybe better quality photos taken with a Camera, would help us help you.

[valleyguy]

Rich sorry about the picture; here are some closer shots. I do have the linkage in the large hold on the carb; not sure what you mean when you say
"not a correct rod end of the carb end of the stretch rod" - it has the same look, swivel end etc, as the original linkage. I have the later
afb style manifold and there is no carb space.




Joe D.

[StudeRich]

OK, my apologies Joe, that is a Great looking installation with better Pics! The only thing that looks different is that the forward Rod End is adjustable and the Stude. one is not, but if you matched the length it should be fine.

Is the Throttle stop lever resting against the Bellcrank stop screw?
That distance is what the Manual says to adjust to 17/64" using a 17/64" drill bit. Then remove the 1/8" pipe plug at the left front of Trans. install your 0-100 or more Oil Pressure Gauge with a hose to the driver's seat, hold service Brake, set parking brake, wheels blocked, and place in "D", then run engine up to 1000 RPM, adjust the Lower Rod to the Trans. to 80-85 PSI.

Good trick if you have really LONG arms! I think the idea is to test, adjust, test, adjust until it is right, believe it or not I have done this several times on different Studes.

It does concern me though as to why you needed such a long spacer to get your throttle Rod lined up with the Bellcrank, I thought the Edelbrock AFB clone was very similar (the same) dimensions as the Carter AFB.

There is something you could check though. I have seen those Bellcranks very "twisted", meaning that the stop lever is bent outboard on the Engine, causing you to move the Rod outboard to allow it to idle against the stop. This sometimes occurs when during the car's long life, someone has left the bellcrank ON the Engine during Engine removal or installation.

[valleyguy]

Thanks much, Rich. Yes I have the required spacing at the bellcrank. (I used a 1/4 drill bit, close enough I guess); I figured if I have
everything right up top then the problem must be the adjustment at the transmission. I think I'll leave that adjustment to
someone who knows what they are doing! Btw, I want to express how much I appreciate the fact that you and other
knowledgable forum members are willing to help out - even on these very basic questions.

Thanks,

Joe D.

[StudeRich]

Or, the alternative is since we know your throttle pressure is TOO LOW, just shorten the lower Rod about 3-4 turns (remembering how many turns you moved it) and test drive. You should have a firmer shift and enough "pedal" to make the 3rd. to 2nd. downshift and even the standing start, floored, 2nd. to Low (1st.) downshift.

[Stu Duglee]

Hey Valley Guy,I have the same linkage set up except for the side piece coming off the carb.I also am using a Edelbrock 500 but mine sits on an Offenhauser intake so the geometry is a little different.After I installed the 4BBL mine wasn't kicking down either so I turned the adjustment on the tranny linkage 2 turns clockwise & boy do I have kickdown now.

[valleyguy]

Stu, so you are saying you don't have the spacer? I used the spacer because I "thought" the original carb setup was wider than the Edelbrock.Maybe
I should eliminate that spacer?? Based on what you and Rich have said, sounds like the trans linkage adjustment is my problem. Other than
that, the car runs fine.

[Stu Duglee]

No I don't have a spacer,I connected the new carb linkage right to the carb( same spot as yours) without any problems.

[valleyguy]

ok after scratching my head over this for awhile, I decided to try one last thing before addressing the transmission linkage underneath. I
put the linkage/reach rod in the inward (inboard?) hole on the bellcrank that is normally used for 2-barrel carbs; lo and behold, I now have kickdown.
As Rich mentioned above, maybe the linkage has been twisted or moved somehow in the past. At any rate, it now works...
Joe D.