Re: setting the timing

Posted by Marco Tahtaras on December 20, 1997 at 00:32:39

In Reply to: setting the timing
posted by Wayne Parker on December 19, 1997 at 19:05:59

Wayne,
I am going to answer your questions in reverse as best I can (from experience).
With an original distributor, carb, and timing cover (not "B"), I know of no reason or advantage to altering the timing. As far as reproduction parts, I haven't worked with them much for some years. With original parts the rotor is almost past the contact at TDC. A Model 'A' will run decent with almost any distributor body, cap and rotor. Originally all these items fit snuggly with no possibility of movement (I have seen some new parts that fit very sloppily). I would check your "rebuilt distributor" in three areas. First, set the points open on a lobe and measure the gap while applying pressure fore and aft on the shaft/cam. Second, measure the gap while moving the distributor plate fore and aft. Neither measurement difference should excede .001" or there is exssesive play. Third, check the point gap on ALL FOUR LOBES(should be exactly the same). Many modern shafts are poorly machined. Most "rebuilt distributors" I've seen were suitable for display items only!
Timing should ALWAYS be retarded when starting. The engine doesn't crank fast enough to start easily when firing BTC. Symptoms of advanced timing include sluggish cranking/starting (worse when cold), and harsh pounding (difficult to describe) under a load. Retarded timing provides sluggish acceleration and a little "poofing" sound from the tailpipe under a load. While it would be ideal for the timing lever to advance with the engine speed (like centrifugal advance), a properly running car will run well under most conditions with the lever 2/3 advanced (horizontal position).
It sounds as if your timing may be slightly retarded. With the backlash accounted for, the points should break or spark with the slightest downward movement of the lever.
The warm starting problem is usually a starting problem that is more noticable when warm. When I have encountered the problem it has been a week spark. In order of probability
Week battery (will start well with hand crank), week ignition coil, poor condenser, and cumulative effects of poor connections and others.
good luck,
Marco
:I have some questions about timing a Model A.
: 1)I have set my timing so that at TDC #1 as the timing pinjust engages the recess in the timing gear, the points just begin to open.If you connect a test light to the point arm and bring down the timing lever about 2 clicks on the quadrant, the light goes on.This is what Les Andrews suggests in his Model A handbook.When I do that, the very right hand tip of the rotor(as you are looking down) is just even with contact point on the distributor body.Some of the books say that the very center of the rotor contact should be be even with the distributor body contact point.My car seems to run OK although warm starting is sometimes a little difficult.(Ihave tried 2 different carbs.)Any opinions about this??
: 2)What would the symptoms be for timing that is too advanced or too retarded?How would it affect starting, especially a warm engine?Should timing lever always be set totally retarded even when starting a warm engine?
: 3)Is it possible that some A's might run better at a slightly altered timing because of valve setting variations or other engine differences?
:I am running an original rebuilt distributor with a repro body.Is the repro body OK as far as the contact location goes?Many thanks for your help.

Follow Ups:
Re: setting the timing Marco Tahtaras December 20, 1997 at 00:56:38(0)

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