Holley vacuum secondary's now opening - HELP? - PICS

[pullrock]

All,

I just install my new engine fresh from the engine builder.  This engine was already broken in and Dyno by the builder.  After installing it and running a few times around the house I have not heard for felt the secondary's open up.  Does this look right?  Anything I can test to make sure I don't have another problem?

•   Holley 770 CFM Four Barrel Carburetor with Vacuum Secondary.
•   Intake is an Edelbrock Troker II 440
•   440 with 500 Peak HP and 520 Peak torque

Thanks,

Eric

[Ghoste]

If the secondary side is set up carefully, there is a good chance you won't feel them come in.  An easy way to check is to put a paper clip on the secondary linkage nust beneath the vacuum canister on the side of the carb.  Take it for a run and then check to see if the paper clip moved.

[pullrock]

I will give that a try but I forgot to add the tans kickdown linkage is not working either.  If that helps at all?  By the way, the carb is brand new.

Eric

[Ghoste]

BEFORE YOU DRIVE IT YOU MUST MAKE SURE THAT KICKDOWN IS WORKING!!  If you don't, you are going to cook your trans.
The kickdown is connected to the primary side so it isn't preventing the secondaries from opening.  Before anything else, I'd do a search on here for threads on kickdown adjustment and make sure it's set first.
BTW, what makes you think the kickdown isn't working?

[pullrock]

The trans shift very fast up to third gear and when i floor it the trans never down shift to any other gear.  Shouldn't the kickdonw down shift for me?

Eric

[Ghoste]

Yeah, that sounds like you need to adjust it Eric.  I'd do that first and then look into the secondary.

[pullrock]

So if the trans is shifting up to third gear would there be a chance i might burn up the trans?  By the way, it used to work just fine with my old 440 that was in the car.

THanks again for all your good info!  I will for sure adjust the kickdown!


Eric

[Ghoste]

Here is a thread that explains the adjsutment a bit better.

http://www.dodgecharger.com/forum/index.php/topic,9634.msg174809.html#top

Part of the problem is that even though we all call it a "kickdown" that is really a secondary and lesser part of it's function.  Chrysler used that linkage to control the throttle pressure valve and the simplified explanation of it's use is that as throttle pressure, and hence engine load, are increased, the fluid line pressures inside the transmission must be higher in order to continue to hold the bands and clutches tightly.  If they aren't held tightly enough, things can slip and then burn up.  The kickdown part comes into play through a valve which is directly affected by the input on this throttle pressure valve.  As to running high enough pressure all the time, well, that would result in higher wear on seals and so forth.  An adjustable pressure system was the smartest compromise for passenger car use.

And I'm glad if I can help but just so you know, there are a couple of guys here who are tranny experts and can give you the real nitty gritty.  John Kunkel is our resident trnasmission engineer and I dare you to ask a question he can't answer.

[pullrock]

I think I understand now.  The "kickdown linkage" is the way to make sure the trans can keep up with the speed of the engine.  That way the more you open up the carb, the more pressure you put on the trans.  Which should let the trans "kicks down" to the next gear.  Which is a byproduct of this linkage.  Am I close?

Eric

[Ghoste]

In effect, yes.  Pull out a fluid flow diagram from an fsm and look where pressure is applied during various loads and it gets a little clearer.

[squeakfinder]

770 Street Avenger? Its what it looks like. Its the same carb I'm running, but with what I think is 400 to 450 hp 440. I had the same problem, kickdown not working wright, wasn't sure if the secondaries were kicking in. I agree with Ghoste, make sure the kickdown linkage is working. It should drop into second when you stomp on the gas, thats probably what your not feeling.

Larry.

[pullrock]

I found this for adjusting kickdown

1- remove linkage@ carburetor
2- put front end on stands
3- disconnect kickdown linkage @ trans lever
4-operate trans kickdown lever to its rearmost position and wire it there
5- pull kickdown linkage all the way back , reconnect to trans kickdown lever, and remove wire
6-go back topside
7-thru assisstance or other means, hold throttle wide open
8-adjust kickdown linkage(they all adjust different, but you'll see what to do) so that the back of the slot in the link just clears the carb linkage stud. This ensures that kickdown(throttle) preassure can reach maximum without impeding WOT.
9-release carb to idle. thank assistant with a beverage
10-reassemble linkage to carb.
11-test operation to make sure nothing binds, sticks,etc.
12-roadtest
This procedure will maximize throttle pressure. Shift points may increase or not. By this time, many muscle car trannys have been replaced by "yeah it fits 440" scrapyard turdflites that shift at 4800RPM. Only internal changes will fix this.

[John_Kunkel]

The above procedure is way too complicated and achieves nothing that can't be done with one-third of the operations.

In many cases adjusting the linkage so that the trans lever is full back at WOT will result in late part throttle upshifts and possibly no WOT upshifts.

[pullrock]

I got it working!  I adjusted the kickdown end that is on the carb shaft.  Twisted it like 3 4 more times and it worked.

Thanks everyone for the advice!

Hope I can return the favor sometime.

[Ghoste]

So where are you at now with the carb?