Words from Barry: (on how to set engine timing)
1. Disconnect the vacuum advance from the distributor and plug the line.
2. Power time the engine at 3,000 rpm's. That means, attach your timing light with the engine off, then set the idle screw on the carb so the engine is running at 3,000 (a little higher is okay, but not lower). Adjust the distributor for the highest rpm, then back it off by about 2-4 degrees (using the light). You can back the timing off at idle if it is easier, since turning the distributor 2 degrees at idle will have the same 2 degree effect at 3,000 rpm's. That way, you don't have to put your head into a screaming engine compartment to adjust the distributor, and the timing marks will probably be easier to read at idle.
3. Set the idle screw back to a normal idle if you haven't already in the previous step.
4. Make a full throttle run with a hot engine and listen for spark knock or "ping". If it pings, back it off another 2 degrees. Keep doing this until there is no pinging. This will be your maximum MECHANICAL advance. WRITE IT DOWN! (advance at 3,000 rpm's).
5. Now with the idle set normally, adjust the distributor for the highest rpm with no ping, especially when accelerating right off idle. Usually, advance for highest rpm and back off 2 degrees, just like before. This will be your INITIAL setting. Make sure when you are doing this, that the timing marks are steady. If they are jumping around at idle, then you need stronger springs. Rule of thumb, choose springs to BEGIN your MECHANICAL curve approximately 500 rpm's above your idle speed. This will give you a steady idle speed. Recheck this setting AFTER every time you select new weights.
6. With a kit, select a set of weights that will give you the total MECHANICAL advance that you found in step #4. In other words, let's say that you found your INITIAL advance to be 14 degrees, and your total MECHANICAL advance to be 34 degrees. That means that you need to put weights in the distributor that will allow 10 degrees distributor/20 degrees crankshaft advance (remember, you have been measuring CRANKSHAFT timing with your timing light, but the distributor turns only half as fast as the crankshaft).
7. Make a full throttle pass to check your work so far. WRITE IT DOWN!
8. Reconnect the vacuum advance (it has been disconnected until now, remember?)
9. At part throttle CRUISE, listen for pinging. It won't be very loud, so you might have to find a place with a hedge or some other barrier on the left to reflect the sound back to you with your drivers side window open.
10. If it pings, the Crane kit comes with a vacuum limiter (a small flat serrated disk about the size of a nickle that mounts inside the distributor on the vacuum advance unit). Adjust it to reduce the total vacuum advance until it stops pinging. Don't get this confused with the allen wrench adjustment inside the vacuum tube port. The allen wrench only adjusts the RATE of vacuum advance. In other words, how fast the vacuum advance mechanism will move when exposed tio vacuum. Let it happen fast (all the way Clock Wise if I remember correctly), unless it causes ping when ACCELERATING (different than part throttle CRUISE) at part throttle. In that case, back it off 2 turns at a time until there is no ping at part throttle acceleration.
11. The intial advance gives you low rpm torque and drivability, the total mechanical gives you maximum horsepower, and the vacuum gives you the best mileage possible from your particular engine combination.
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