'67 Camaro E/SA redo

[R. Thorne]

I applaud your experimentation with the acc. pump and have done a considerable amount of tinkering myself with very little success. That light spring scares me, though, as the purpose of the accelerator pump is to give a very quick shot of fuel before the main wells and/or power valves get "in the game". Squirter size is another consideration, but on a q-jet not particularly important.

A more important consideration is the choke pull off rate of release in conjuction with the air valve tension (and angle) and being able to adjust them quickly and easily.

Also, I have fought some q-jets that seem to defy all logic and not work in spite of a lot of effort. Sometimes, you just have to set them aside and get another core. Good luck, Ron.

[HandOverFist]

Originally Posted by R. Thorne

I applaud your experimentation with the acc. pump and have done a considerable amount of tinkering myself with very little success. That light spring scares me, though, as the purpose of the accelerator pump is to give a very quick shot of fuel before the main wells and/or power valves get "in the game". Squirter size is another consideration, but on a q-jet not particularly important.

A more important consideration is the choke pull off rate of release in conjuction with the air valve tension (and angle) and being able to adjust them quickly and easily.

Also, I have fought some q-jets that seem to defy all logic and not work in spite of a lot of effort. Sometimes, you just have to set them aside and get another core. Good luck, Ron.

My train of thought is this - The duration spring is simply a safety device that comes into play when the throttle is slammed suddenly to WOT. With the given metering orifices the liquid in the wells become a solid obstacle at that point and the duration spring prevents binding/lock-up by allowing the spring to do the pushing of the pump cup instead of mechanical input of the linkage. My theory is to calibrate that spring rate in order to extend the time of discharge...no metering orifices have been altered at this point. What I have done is bore the well to .730 to increase the volume of fuel available and I'm using the larger pump from a 2G. I have been using .150 inlet needle/seat, but I'm thinking of dropping back to a .145.



Cliff Ruggles is sending me some adjustable pull offs and the air door settings will be the normal trial and error scenarios. I'm just so happy to be at this point of actual tuning finally instead of breaking parts.

[brent flynn]

great! you got ahold of him... cant wait to hear how it all works out...

[HandOverFist]

Well, I have three ready for battle...I hope. Taking the car to a bracket race July 5th and hopefully one will get down the track.

[brent flynn]

Your secondaries about 1:1? Worked great on big cube engine... feels good on the 400, but 4.30 just aint enough gear...

[HandOverFist]

Brent - If you mean have I messed with the secondary opening rates that would be no.

[HandOverFist]

Nothing better to do today so I took the remainder of my spare Q-jet parts and cobbled together one more carb to take to the track. The main body is a 207 and the rest of it from carbs unknown....145 inlet, 67 primaries and CL rods on a K hanger. Would'nt it be a hoot if this turned out to be "the one" ?



Going to attempt to tune out any air door bogs on our concrete apron outside the shop on all the carbs before heading to the track.