Hi Guys,
I have a crappy idle on my newly fired 440. With all vacuum ports into the engine plugged up I have to crank my idle screw in quit a few turns to get the car to idle.
It is responsive to the idle mixture screw adjustments s but I can actually close them and it still runs. With the engine hot, when I partially close the chock butterfly, rpms and manifold pressure go up and it seems to run a lot better.
Seems to be large manifold leak somewhere but I can't find it. Sprayed carb cleaner all around the intake/head matting surfaces and carb and didn't really find anything significant...
It's not easy to get to the underside of the intake, but I used some vacuum hose and sprayed some carb cleaner under there around the mating surfaces and didn't seem to affect the idle.
Carb has some leakage past the primarily butterfly shaft, but I doubt it's enough to cause the problem I'm seeing.
It runs like a beast off idle...
specs on my newly assembled 440:
9.8:1, unmilled 906 heads and oem 4 bbl intake, sealed with valley pan and silicone sealer, heat risers blocked off.
Block is unmilled.
Carb is 8 year old edelbrock carter AFB 600.
Comp cams XE274H 274 / 286 230 / 236 @0.050 .488 / .491
Ignition: oem electronic, 38 degrees total mechanical advance. Vacuum advance unplugged.
Idle vacuum is around 13 psi.
Thanks!
Rob
I have a crappy idle on my newly fired 440. With all vacuum ports into the engine plugged up I have to crank my idle screw in quit a few turns to get the car to idle.
It is responsive to the idle mixture screw adjustments s but I can actually close them and it still runs. With the engine hot, when I partially close the chock butterfly, rpms and manifold pressure go up and it seems to run a lot better.
Seems to be large manifold leak somewhere but I can't find it. Sprayed carb cleaner all around the intake/head matting surfaces and carb and didn't really find anything significant...
It's not easy to get to the underside of the intake, but I used some vacuum hose and sprayed some carb cleaner under there around the mating surfaces and didn't seem to affect the idle.
Carb has some leakage past the primarily butterfly shaft, but I doubt it's enough to cause the problem I'm seeing.
It runs like a beast off idle...
specs on my newly assembled 440:
9.8:1, unmilled 906 heads and oem 4 bbl intake, sealed with valley pan and silicone sealer, heat risers blocked off.
Block is unmilled.
Carb is 8 year old edelbrock carter AFB 600.
Comp cams XE274H 274 / 286 230 / 236 @0.050 .488 / .491
Ignition: oem electronic, 38 degrees total mechanical advance. Vacuum advance unplugged.
Idle vacuum is around 13 psi.
Thanks!
Rob
