i got these secondary metering rods for a 1973 350 4bbl quadrajet and i would like to know if i could put them in a 4bbl stock quadrajet from an 86 cutlass,would i have to replace or modify anything else in conjunction with them?
sec. metering rod question
- Thread starter Minion1186
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IIRC all secondary rods are interchangeable. The differences are in the tip diameter and in the profile of the taper. There are probably some charts floating around the web with dimensions, or I could look up the codes in Doug Roe's Q-jet book.
Bill
Bill
Here is where things get a bit complicated. The Q-Jet's secondary metering rod flow is in relation to the jet it goes in to. While you can technically change just the rod, you have to know how that rod will affect flow relative to the jet it can go in to, and not all jets are the same. If the car is dead stock, it is likely that the rod/jet pair is close to optimal and I would not screw with it. Remember that going too rich kills power and going too lean kills pistons.
i have already changed the rods,but i havent had the time to open up the secondaries on the road.I also have read doug roe's rochester carb book and both pairs of rods were interchangable,i have to see how they do,performance wise.
billyjack said:
i have modified the secondary air valve shaft to open 10% more by filling the stop away,modified the secondary metering rod hanger to raise an extra 2mm,removed front choke :lol: ,disconnected secondary air valve lockout vaccum line,about the only other modification i can do to my carb is allow the secondaries to open quicker but moding the secondary air valve linkage,has anyone tried this mod?heres the youtube video of what I'm talking about- http://www.youtube.com/watch?v=uYq4xY9xCoc
I have messed with the spring pressure and cut down the air valve door stop on mine, but have yet to really get into tuning it . It is bogging a bit on secondary tip in, and I think that is because the air valve door spring is set too loose. Remember, that you can have too much of a good thing and the door is meant to compensate for a lean spot during WOT transition. As with everything, you can have too much of a good thing here and it is best to set up your carb to meet the needs of your engine. If I were you, I would put that vacuum line and choke back on. Taking them off will not improve performance on your car, but will hurt cold starts and fuel economy. I have a much more powerful engine and better gearing than you do, and my car runs fine with them. I also set things up for the best overall driveability and not with every last trick in the book. After all, my car is not a drag car, it's a street car. Yours is the same, so do what is needed to make it an overall good car and realize that the "full race" mods people do to Quadrajets do not apply to your application. ( Mine is NOT a computer one, but the operating principles are the same on computer and non computer Q-Jets ( only the primaries are affected by the computer).)
(BTW, I used my Mod powers to fix the hyperlink for ya!)
(BTW, I used my Mod powers to fix the hyperlink for ya!)
My 83 Hurst Olds is rebuilt Perfectly, Runs great.
I'm not sure the Secondary Metering Rods are adjusted correctly.
The screw on the top of the carb, turned out a few turns, and my brother in law says they should be out 15 turns?
Any help or adjust tips would be appreciated, thanks...
I'm not sure the Secondary Metering Rods are adjusted correctly.
The screw on the top of the carb, turned out a few turns, and my brother in law says they should be out 15 turns?
Any help or adjust tips would be appreciated, thanks...
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Markbgt01 said:
There is no adjustment for the secondary rods.
If you're referring to the idle air bleed than no 15 turns out is not correct. You can't even turn it out 15 turns anyway.
i have no clue what he was talking about, it runs perfect, not touching the adjustment.. thanks
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