General Category > Quadrajet Carb Talk and Tips
Float level and other Qs
Cliff Ruggles:
I've rejected every single aftermarket HEI that's been send or brought here for help.
I would obtain a stock Olds HEI and completely/correctly rebuild it. At most it may need a lighter spring on one side or you may get what you want by opening up the "eyes" in the springs slightly.
Always weld in a positive stop for the advance for exactly how much timing you want it to add and so it doesn't keep adding timing at high RPM's.
The current timing curve you have is too slow to get things started. The timing should start moving right off idle and smooth/steady to full advance and not slow up and some point, then take a lot more RPM's to get all the timing in.......Cliff
Macadoo:
I'm not sure I follow. Advance starts right off idle, then a smooth steady curve all in by 2800-3000. And that's where I would want the lock, yes? No more advance after 3000. No quick jump and then slowing way down of the curve, right? Might that be the MSD weights and center plate? I'll play with it in the interim.
I'll start the hunt for a factory unit. Might make a fun winter project.
Cliff Ruggles:
No advance till 1300rpms could use a little help. I like to see the timing start immediately with RPM's right off idle or at least by 1000rpms if not 900.
No need to split hairs with this sort of thing but as engine speed increases timing needs to increase so it has sufficient opportunity to effectively burn the mixture and maximum efficiency of using the heat energy to push the piston down.
The vacuum advance, being a load sensing device helps us at very light engine load and light throttle openings, but when you go to heavy/full throttle the mechanical advance is adding the timing, and if there is a delay in when it starts there can also be a hesitation/stumble/bog or slight lack of power until it starts advancing the timing.
You probably wouldn't notice it at 1300rpm's but I've seen troubled distributors with rusted weights, worn/rusted pins, etc cause issues that acted like carburetor problems when it was simply a spark advance issue.......Cliff
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