Re: TR6 worn distrib
I was recently showing some one how to tune his TR6. I had him set the points
which seemed took forever but he had very little experiance. As I was working
on another car at the time I didn't pay much attention to his progress. Finally
I walked over and inquired about his progress. He proudly assured me that he
had set the points all six places.
"six places?" sez I. "Yah" sez he, "I turned the engine til the points were
open for each cylinder and set the points"
"you only have to set them on one lobe. All the rest should be the same" I
replied
"But they weren't" he said " they were each differant."
I wiggled the distributor shaft. Not much play. I checked the point setting
on several differant lobes. They varied over a range of .010 inch. Depending
on which lobe was selected to set at spec, the others might be in a range of
+-.005 inche which would probably fire sort of. Or it could be +.000 -.010
at which point several cylinders would probably not fire at all. The problem
was a worn cam in the distib. I scrounged him up a better one and he was fine.
A photo electic triggered transistor ignition would have been an even better
fix. Not only will it take the cam out of the system it is also far far less
sensative to worn bearings. (because of the ramp on the cam a few thousandths
of shaft wobble equals may degrees advance or retard. By contrast a .005 inch
of jitter on a two inch diameter photo shutter is roughly a quarter of a
degree of distributor timing.)
On my race car I have an old distibutor and a new transistor ignition. On my
street car I have a newish Mallory distibutor with mechanical points. Each
are better then the old ignitions but the transistor is the better of the two.
If you have the money do both.
/Dick
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