From memory, you just set the advance curve (I think they've moved the switch to a more sensible place), including double-sparking at low revs if you want it, slap it in and set the static timing using the internal LED. Then time for max advance if you feel the need. That's it. It'll do the "mechanical" advance electronically, add in vac advance from the carb, do a bit of spark balancing to compensate for any small difference in compression across cylinders, vary the dwell so your coil doesn't get hot, and turn itself off if the engine's not going round. It can also make tea
When using a timing gun should the vacuum advance be connected? some info I have been looking at says the pipe going to the carb should be removed and bunged. Surely if I removed this pipe then the timing would not alter as I rise the engine revs? As I previously said I have never had to work on engine timing before so any advice more then welcome.
Take off the vacuum pipe and plug the carb end so you don't upset the mixture with an air leak. The dissy will advance using the mechanical bobweights inside the distributor (the primary method of advance). With the gun, you're just checking the maximum advance when the revs go up. It should advance to a certain point, then stop. Have a play - you'll get the hang of it
With a 123 or any electronic ignition you won't notice the difference over a genuine Bosch dizzy and points (set correctly) ...unless it fails ... The 123 is expensive ,what £ 260 -350 and it is still driven off a 45year old worn brass crank gear .... Crank fire systems like mega jolt and similar offer more modern mappable ignition although expensive new can be picked up fairly cheap SH
Some rotor arms fit without grinding , mine does. Couldn't tell you which one the mo. Too much scotch to go looking. Give us a shout tomorrow and I 'll post a piccie.
Well I tried again but the magnet just won't fit. Its needs to push down another 5mm but won't budge. I have removed sharp edges on the magnet with some wet and dry. I put a socket on it a taped pretty hard using my hand but still won't move. The square shaft of the dissy is aligned correctly with the magnet. Currently my dissy is in the freezer I'm hoping this will shrink the metal. I will warm the magnet and try again in an hour. Any one got any other ideas?
Surprised it was that hard. Mine was tight - very tight - but it did go on with some light tapping. Don't know what to suggest. Sure you've got the right kit?
Well I manged to fit it. I warmed a tea towel and wrapped the magnet in this. Pushed on fairly easily once it was warmed up. Runs so much better than before. I got the draper timing light very easy to use. One question With vacuum advance removed advance stops at 30 degrees. With the vacume advance connected the advance increases further still at high revs. I still don't really understand why you would time with vacuum advance disconnected? Surely you would want to check the vacume side of things is working and total advance is correct? anyone know what the timing mark should be with the vacume connected?
Success! Vac advance is only there under certain conditions (when the engine's sucking hard), and isn't easy to control or predict. Mechanical advance (which just increases with engine speed) is what you need to time to: it's there all the time.
Thanks snotty. The advance makes sense to me. I have timed at full advance to 28 degrees btdc and idle at 7 btdc just used a dot of paint on the crank pulley so won't be 100% but close enough. All good and runs lovely. If it helps anyone else I had to get the magnet so hot that I could barley touch it. I think it had softened the plastic enough that some kind if lip or bur within the plastic stopped interfering and allowed it to slide on the dissy shaft. Thanks all another problem solved.
If you've timed max, advance at idle seems to end up at about 10* in my experience, but doesn't mean much. Basic gun and blob of paint is the best method!
