IGNITION TIMING STICK. (from sales and service bulletin Nov 1935)
As promised in the September issue of the Sales and Service Bulletin, we include details of the ignition timing stick for use on 1½ litre engines. The illustration shows the timing stick which is intended for use in conjunction with a measuring clock marked of 1/1000". The majority of dealers will doubtless have clocks of this description included in their equipment, but for the benefit of those who have not, the address of the manufacturers of the clock illustrated is given hereunder
Catmur Machine Tool Corporation Ltd., Caxton Street, London.
The timing stick provides a simple and reasonably quick method of ignition setting and obviates the necessity of exposing the flywheel.
How to use the Timing stick-
1. Insert stick only (less clock) into plug hole on No. 1 cylinder.
2. Rotate engine slowly and watch rise and fall of plunger to obtain T.D.C. position (never rotate engine quickly whilst timing stick is in position as the upward rush of piston will force the plunger out of the stick and probably damage other parts).
3. Place clock in holder and set to zero position. Again rotate engine and note if clock needle moves. If needle gives a plus reading onclock, T.D.C. has not been obtained ; swivel dial to correct position.
4. Rotate engine very slowly over T.D.C. until a movement of approximately 6/1000" is registered on clock. This is the correct engine position for ignition timing, 6/1000" being equivalent to 4° of crankshaft movement.
5. Set distributor fully retarded with contact breaker points just breaking.
Occasions may arise when it is desired to cheek ignition in the fully advanced position. The procedure is as before except that in this case, the correct setting is, contact breaks when the crankshaft is 8° before T.D.C., the equivalent of 8° crankshaft movement on the measuring clock being 25/1000". An approximate reading only is necessary, as carboned pistons etc. will cause variations in readings.
Difficulty will be experienced in obtaining a sufficiently slow rotation of engine and clock movement will be too rapid, unless all sparking plugs are removed to release compression on other cylinders.
Price 10/6 nett (less clock)