Re: setting timing

Posted by Joe on July 23, 1998 at 08:57:53

In Reply to: setting timing
posted by Jack Metcalf on July 22, 1998 at 19:42:13

I normally do it "the old fashioned way" using the timing pin.
With the pin having found it's recess and the engine positively positioned on #1 TDC and the spark lever fully retarded, I then rotate the distributer cam opposite the direction of normal rotation (to take up lost motion) to bring the rotor to the #1 cylinder electrode position.
As you approach and pass the #1 electrode, the points will open at the exact point you want to stop and screw down the retaining screw.
I then rotate the engine in it's normal direction of rotation using the starter handle and reposition the whole thing at #1 TDC again using the pin.This time though, with the engine at #1 TDC, the points should be just ready to open.If you then pull down the retard lever the smallest amount (perhaps 1/4") you should hear the spark of the points as they open and see it also in a darkened garage.This (I think) is the *ultimate test* of timing.
I have never used a timing light on the Model A but used it regularly on everything else until all my cars developed "computerized ignition."
To apply a timing light to the Model A you need some way to transfer the TDC mark from the camshaft gear to the fan pulley on the front of the crankshaft, and a reference mark to compare it to.
There is a kit sold nowadays with instructions on how to do this.The kit includes a bracket with a marked sector which you bolt to the front of your engine so you can see the advance or retarded degrees with the timing light from the mark on the pulley.
The only real advantage the timing light has over the "tried and true" method is that you can quickly make adjustments to the distributer cam position without having to fiddle with getting the engine on #1 TDC each time.
Use of the new "adjustable links" that can extend or shorten the link connecting the distributer upper plate to the bottom of the steering column may allow you to "fine tune" the timing with the engine in operation.However, this may affect the "fully advanced" timing in turn by limiting the travel of the upper plate in the notch of the bakelite distributer cap.
Note that the Model A differs from modern distributers in that the upper plate position is fixed relative to the engine (at the bottom of the steering column) and that rotating the body of the distributer body itself makes little change to the timing.It actually is possible to rotate the distributer casting in the block a little to adjust the travel of the distributer upper plate in it's notch.This can compensate for the notch/upper plate/"fully advanced" travel problem I mentioned above.
The key to it all and the sole source of question for a timing light is to get the timing mark and reference transferred accurately from the camshaft gear to the fanbelt pulley or some other moving part of the engine.If you're wrong here, the whole shebang is "gone south".
I have heard of those who forgo the "bracket and sector" andobserve directly the timing mark recess through the timing hole using the timing light as illumination.Removal of the fan and radiator is required or perhaps a "mirror on a stick." In either case you need an *especially* bright timing light and no fears about getting "up close and personal" with an operating engine.It all sounds kind of problematical.
I hope this all helps.
Best regards,
Joe

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