"dump plates"

[Garyl]

I am new at playing with qjets and am having a problem understanding the way they work.

I have a 26 foot 1978 GMC motorhome with a 455 Olds, .030 over and a mild crower cam.  It is balanced and tolerance blueprinted.  The intake is the stock 455 iron monster.

Question---- When you open the throttle wide (engine running) shouldn't the secondary dump plates open?  Under wide open thottle, tranny in neutral, the plates just barely crack.  Am I missing something here?

[429bbf]

gary the carb is designed to have ether a front or a rear or both i dont know your carb no.choke pull off . which also holds the secondaries top flaps from opening until you loose vacumn any where from 1 to 3 seconds they slso have a little spring on them . sitting in the seat on the left side wound around the shaft for the flaps. directly under the shaft on the same side is a little set screw.on that carb i think its an allen head.if you loosen the screw you can adjust the spring tension appox 3/4 to 1 turn after it makes contact. you dont want it to flop open because as it opens it lifts the secondary metering rods up and give it more fuel.the best thing to do is list your carb no.should be something like 17058212 and then a bunch of good people will help you solve any problems you have .hope this helps dean

[88Southwind]

Question---- When you open the throttle wide (engine running) shouldn't the secondary dump plates open?  Under wide open thottle, tranny in neutral, the plates just barely crack.  Am I missing something here?

\
I had the same question, until I saw this:

http://forums.corvetteforum.com/c3-tech-performance/2427557-quadrajet-secondary.html

I'm just getting ready to do carb work on my '88 28' Southwind Motorhome, with a 454. I will be posting a few questions, very shortly myself!   

R

[Garyl]

OK, that answers question#1.  #2, do all Qjets have the steel blocking plate under them or just the ones that have heat riser holes in the carb mounting flange.  I am not sure about the 455, wether it has the riser holes or not.