Lost low end torque
#1
Hey Guys,

I took my car out for a spin to enjoy the new weiland intake manifold I put it. For some reason my wheels don't spin when I floor the pedal. The car always did before I installed the intake and also after so I know its not that. The only thing that I played with was the timing to get a smoother engine idle but ended up putting that back to about 16 degrees which is where my car likes it. Any idea why that would happen?

Like I said, I could spin the wheels all day long when hitting the gas all the way but last few days that doesnt happen anymore. Is it possible that the carb idle adjustment can have something to do with it?

1969 mach 1
351w 4 barrel
edelbrock 600cfm
hooker supper comp long tubes
pertronix ignitor III / flame thrower III
weiland intake
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#2
If the only thing you have tinkered with was the timing then it has to be the timing. I would double check to make sure you have it back to where you started.
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#3
its back to where it was but still cant rip tires. very strange.
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#4
fixed. I had the idle set too high. lowered it by 1/4 turn
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#5
I guess it's fixed which is good. But I find the scenario a little perplexing because I wouldn't expect 1/4 turn on the idle speed screw to bring back low end torque. First you have flat top pistons on a 1969 351W. Therefore, the static compression ratio should be at or very close to 10.7:1. With base timing at 16 deg BTDC that motor would likely have had kick back while cranking. Then probably ping while accelerating. In my experience on motors with 10:1 or greater static compression ratios, 10 to 12 deg BTDC based timing has been about the max. Advanced any more and the motor won't crank very well or pings when it first fires up. Are you certain the outer ring on the damper has not slipped and the timing is not accurate? Are the block and cylinder heads in fact 1969 or 1970 castings? Other than that and the static compression ratio will be lower. If I recall, the timing changed a lot after installing the Pertronix system which never made any sense. The rotor phasing is might now not as good as it was with the original points. Which I wondered if might have contributed to the rough idle issue you had after installing the Pertronix system.

You mentioned advancing the timing to smooth the idle. Do you have a vacuum leak somewhere? Did you possibly try to use stock intake manifold gaskets with the Weiand intake? Sometimes that creates issues.

I don't know, sometimes when I read posts the solutions don't seem related to the issue. Maybe it's just me.
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