Timing ?

[chriscook]

For reference the light I've been using (borrowed from work) looks like <a href="http://cgi.ebay.co.uk/Snap-on-Timing-li ... Item">this one on ebay</a>

[Lynton]

As an auto electrician i spend my life working on all sorts of vehicles diagnosing and repairing all range of electrical and electronic vehicle faults, I therefore like to feel i understand whats going on. I have just fitted a Megajolt to a Ford 1600 OHV kit car. Allthough it started and run ok first time. I experienced the same problem with the adjustable timing light. Ie if you set 10 degree advance on the timing light it actually shows 20 degrees on the pulley. After speaking to the timing light manufacturer, it apears the timing light calculates the advance from the last triggering pulse. On a normal (non wasted Spark) this would be 720 degrees, or 2 revs of the crank. but on wasted spark system it gets a trigerring pulse every 360 degrees. so the timing light has exactly half the time to calculate the advance. This causes the advance to be muliplied by 2. So if you have set 10 degrees advance on the timing light it will set the timing marks at 20 degrees. I spent a couple of hours experimenting with a couple of adjustable timing lights and they both displayed the same (times 2) problem. But If the advance adjuster on the timing light was set at "ZERO" and the normal timing marks used, ie lign the crankshaft pulley mark up between the 8 and 12 degree marks, everything then worked out spot on. The car now runs sweet as nut.
Lynton

[capri_turbo]

I use a Sealy TL93 digital timing light with advance dial... it reads spot on for advance with the wasted spark system, but as expected it reports RPM as twice the real RPM. My brother has a Snap On one... if I get time, I'll try and compare readings from both and get back to you.