[Lostit]

Thought ill put this up and possible get some answers .

Motor went on dyno few days ago and had physical timing set at 32deg.

On lap top was showing this as max timing as well, pulled 5 timing out of it on start up and max timing set to 29.

Timing light showed up 30 deg and when ever l adjusted on lap top timing it would go oppose and just didn't seem to do anything what l wanted besides going opposite.

Also had the motor play up at 6800- 7000 was crystal clear before that and dyno sheets showed no sign that it was playing up but could hear it play up .

We checked all we could , even pulling plugs and resetting to .035

We gave up and pulled off the grid and put a 7al on it , put light on it and straight away noticed timing was at 40deg !

Pulled it back to 30 deg , and motor had no more hiccups at those specific rev range .

In the end using basic 7al turned motor to 8000rpm and 34 deg total and was crystal clear no issues.

The thing with this when it was in car l never noticed these issues previous .

Any comments/ideas would be greatly appreciated

 

[Seattle_Mike]

Timing is what you see with the timing light. The MSD boxes have no idea where timing is at, they only reference from what you tell it. If you tell it it's 30º then it references everything from that point, if you tell it it's 40º, then it references everything from there. Each box, even of the same model may show a little different when you put a timing light on it, so make take a little tweak. Another factor can be the trigger pickup. The engine will run even if the polarity if reversed on the wires. Typically the symptom of reverse polarity is when you rev it up, the timing will start jumping around (very obvious with a timing light on it). If you have a magnetic trigger pickup, that can cause really weird issues as well, sometimes people order the wrong pickup (they look identical) by mistake. Hold a screwdriver to it and it's obvious if it's magnetic or not.