Have engineering question about a distributor cam . I have an old American Bosch distributor with large cam with well rounded lobes ( not worn ) . I have an Auto-Lite distributor that has same mounting dimensions as the Bosch but the Auto-Lite cam has a smaller cam with sharp lobes ( looks like most cam lobes to me). The dwell ( flat ) part of both cams appear to be the same width. It appears the points would be closed the same amount of time for both cams. It appears the points would be open longer on the larger cam with the rounded lobes than with the cam with sharper lobes. The Bosch has an old (large) condenser while the Auto-Lite has a modern ( small ) condenser. Would the Auto-Lite distributor work as well in the motor as the original Bosch ? Since both distributors are for old 6 cylinder cars, should the cam differences make much difference ? Reason for question is cannot find distributor cap for the old Bosch.
Thanks
Bill,
What car's engine do these distributors fit?
Per,
The American Bosch distributor is in a 1925 Essex 6 cylinder. I have no idea what the Auto-lite distributor was for but must have been a Hudson motor or very similar because the distributor base and drive for the two distributors are identical in size and shape. The Auto-Lite distributor will fit the Essex motor but I'm concerned that the difference in the cam lobes ( points open longer ) might mess up the motor or damage it some way ??
Thanks
Either will work fine, but with the longer dwell time of the rounded lobes you may have trouble at higher speeds, due to not long enough time for the coil to develop the required spark. Usually happens when the rubbing b lock get flattened off a bit. Can also cause lumpy idle. A smaller gap will help this, but reprofiling the rubbing block works fine too.
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