Re: KPack's 1954 Panama
Posted by DavidPackard on 2021/5/13 13:22:19
The carburetor is designed such that zero vacuum is available at idle throttle position. The extra advance could be one of 3 items;
1.) Static timing is wrong
2.) Idle speed is excessive and the centrifugal advance was ‘in-play’, or the centrifugal advance is responding early.
3.) Throttle position was sufficient to provide vacuum to the port and the advance is due to the vacuum advance.
For years the manufactures of carburetors used the same design of ‘NO VACUUM AT IDLE’, but that didn’t stop us from disconnecting the vacuum chamber tube/hose every time. It’s now your turn to keep the custom going for the next generation.
While watching the timing marks accelerate the engine and confirm the centrifugal advance is responding to the change in engine speed. If the engine was still on high idle, because the choke reset the high idle cam, then the centrifugal advance may have been in-play, and explain your results. If the centrifugal advance is at its maximum limit near idle then more investigation is in order inside the distributor.
If you missed the static timing by a bunch I would expect a labored start, meaning the ignition occurs so far before TDC the starter has to overcome the torque that results from combustion. The process you used to set the initial timing is as good as it can get, so that’s not likely the cause, but you can repeat just to confirm.
This time you can hook-up your meter and roll the engine until the continuity is lost, then note the number of degrees of advance.
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