backlash

[Clem Clement]

How much back last is there between the timing gear and the cam?
Meaning I timed my A with the cam/timing gear lash in and the dissy lash out. The car starts poorly, idles well, but won't accelerate. Backfires some as well. Do it again right this time I guess.

[Kurt in NJ]

If you can feel backlash it is most likely too much ---the spec in the service bulletins is .004

in the owners instruction book the paragraph after setting the timing says to check the results --hand crank slowly, the spark should occur at the same time as you feel the pin go in the dimple,

[H. L. Chauvin]

Hi Clem,

This may not be your situation; but, maybe worth mentioning when anyone is timing a Model A:

1. When the timing pin slips in the timing gear, with the spark lever all the way up and retarded, one usually adjusts the distributor cam for proper timing, and tightens the cam screw on top, where during this screw tightening, backlash may .... or may not occur.

2. However, to double check precise timing, (just in case one has the "slightest" bit of backlash ..... "anywhere"), it is never a bad idea to hand crank the engine "again", 360 degrees, allow the timing pin to slip in a second time, and now verify "if" the ignition points are just about to open.

3. Also, never a bad idea to "clean" points and adjust points prior to setting timing. Points develop non-conducting metal oxidation more often in humid areas.

[Charlie Stephens]

Remember when you are turning the engine over to find the dimple in the timing gear if you pass it you need to go around again. Backing up will get you in trouble with backlash.

Charlie Stephens

[H. L. Chauvin]

Model A Backlash and Well Worn Model A's:

A well worn Model A will run great with lots of backlash because once the engine is started, rotating parts rotate in one direction, and all gears are maintaining constant, positive contact.

A Model A with a worn, loose upper distributor shaft and worn top distributor bushing, with quite a bit of shaft play, will run great because the spring on the ignition points will keep the upper distributor shaft to one side and not let it wobble.

One can never experience this phenomena unless one buys and drives a very cheap very well worn Model A that nobody wanted and nobody tried to restore it.

[1931 flamingo]

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This is where the Nu-Rex tool comes in handy. If done correctly, find the dimple, rotate tool 2-3 times, tighten cam. Done. JMO
Paul in CT

[Quigley1930]

Clem save yourself some anguish and more suds time and try a new condenser. I garenteeee it wont be worser

Sewall