Timing with a probe light..?

bobpo

bobpo

Well-known member
I just read recently how to time the 'A' Engine using the Pin Method and then a Probe Light. Now that I'm ready to do it, I can't find the Article.

Can anyone describe the Probe Light Method for me..?

Appreciate it...:o
 
This may be what you are looking for.... From Model-A.org


  1. Before adjusting the engine timing, ensure that the breaker point contacts are in good shape and the gap is set to .016 - .020 inches. Also, verify that the rotor gap to the distributor body contact points is between .030 to .035 inches.
  2. Turn ignition key off.
  3. Place gear shift lever in neutral position.
  4. Fully retard spark lever on the steering column.
  5. Screw out timing pin located in timing gear cover and insert opposite end of pin into the timing pin hole.
  6. With starting crank, turn the engine over slowly while at the same time pressing in firmly on the timing pin. When the piston #1 reaches the top of the stroke, the timing pin will drop into a small recess in the timing gear.
  7. Remove the distributor cap, body, and rotor, and loosen the distributor cam locking screw until cam can be turned.
  8. Connect a test light probe between the breaker point arm and an engine ground.
  9. Turn ignition switch on.
  10. Turn cam in counter clockwise direction until the breaker points are fully open (light comes on), then slowly turn the cam back in a clockwise directions until the points just close (light goes off). Next lock the cam by securely tightening the cam locking screw. Be careful not to move cam position, while tightening the screw.
  11. Slowly pull down on spark advance lever. The test lamp should come on (points open) when the lever is about 3/4 down. Sometimes steps must be repeated until distributor cam is properly set.
 
Re: steps 11 & 12 -

Not trying to pick a fight here, but an honest "don't understand" question:

I'm pretty sure I read in Les Andrew's manual that the distributor cam should be set so that the points just break / light comes on when the spark lever is pulled-down ONE Notch ???

Don't want to be setting my timing too "hot"...

?


Thanks,

SC Frank
 
Special Coupe Frank said:
... I'm pretty sure I read in Les Andrew's manual that the distributor cam should be set so that the points just break / light comes on when the spark lever is pulled-down ONE Notch ??? ...
Click to expand...

I share Frank's concern about the last step. It seems like if you achieve that, it will be timed at top dead center while drive at about 3/4 down lever, thus VERY retarded relative to how it should be. -- Brian
 
29 Tudor said:
11. Slowly pull down on spark advance lever. The test lamp should come on (points open) when the lever is about 3/4 down. Sometimes steps must be repeated until distributor cam is properly set.
Click to expand...

I'm assuming that is a typo as the points should break with any motion of the lever off it's stop.


Special Coupe Frank said:
Re: steps 11 & 12 -

I'm pretty sure I read in Les Andrew's manual that the distributor cam should be set so that the points just break / light comes on when the spark lever is pulled-down ONE Notch ???
Click to expand...

Several years ago Les' procedure was quoted on Fordbarn as "two to three notches". I responded that would be 2-3 notches too far retarded! It's my understanding that Les has since taken those comments into account and updated his material.

In reality two to three notches would not be a problem with a high compression head since full advance travel should not be used with much boost in compression due to the faster burn.
 
None of this seems to address the fact that most model A's have backlash in the distributor shaft!!! When the engine is running the backlash will greatly effect the timing. One half inch of backlash is fairly common, especially if you don't have a new camshaft and distributor and oil pump drive gear.
 
I believe Ford specified in the 1932 Service Bulletins that the points should break exactly at Top Dead Center (when the timing pin sets into the timing gear) with the spark lever all the way up. As has been mentioned this would cause the points to break open with the slightest downward movement of the spark lever.
 
I like Marco's method but I also purchased a nu-rex tool that fits onto the cam . You loosen the cam after setting the pin so you're on #1. then "wind" the tool around to the #4 conn on the dist body, tighten cam. This removes the backlash. Worked well for me.
Paul in CT
 
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