I've read here and elsewhere that the ECU and tuning programs all "assume" that you have the correct timing set for your engine. Spark advance, injector timing, and even knock retard values all are based on your having the correct static timing.

So, why is there such a "leap of faith" that the indicated degrees at the damper and pointer are true???

Is there a generally accepted method of establishing true TDC, so that the damper and/or pointer can be calibrated???

It seems to me that if I get a dynamite setup for my chip, in my car, with my mods, and were to post it and have a fellow member with exactly the same car/setup try it...And get all kinds of knock event counts, then there must be an underlying reason why...

Like a damper that's 2* or 4* off in static timing...

I've seen dampers with degree gradations on them; and timing tape; and even degree wheels...But how do you find *exactly* TDC???...Even a calibrated rod stuck down the spark plug hole is at best an approximation...

???

 

If you want to really split hairs then you'll want to worry about the crank throws being EXACTLY 90d apart.
You have to get to a point where you do make some assumptions.
The NASCAR boys take things to the extremes, hense the 50K+ price on engines. You can blueprint things til you run out of money.

No two engines are identical. You just can't hold machining tolerances close enough to do it. You can even get to the metallergy from one batch of steel to the next varing some.

While you can bastardise a calibraion to run on several similiar engines, that ignores all the driver preferences.

All the more reason for running the min timing possible. As the piston is approaching TDC it is slowing down, so you can get more accurate timing control that way.

This all just helps to point the way that you need to do your own chip, and one from some else will never be right for your application.

Well with one exception but his stuff is only for the 89 TTA

 

All this I accept, and have in fact been arguing against aftermarket chips for just these reasons.

Thanks for the input! At least I know now that we all "start" at the OEM damper & pointer setting and base our mods on that "relative" setting.

 

You crank the engine close to TDC on cyl number one, but not past. Thread in your piston stop. Turn the engine slowly by hand till the piston hits the stop. Mark the dampner at the TDC mark on the timing tab. Crank the engine slowly backwards till the piston hits the stop. Mark the dampner at the TDC mark. The mid point between the two marks on the dampner is TDC.

Repeat to make sure.

If the dampner is good, the midpoint will fall right on the timing notch in the dampner.

 

Sounds good...As long as the damper bolt doesn't back off on the anti-clockwise rotation...Like mine did...OK; I left the plugs in; I should've taken them out...

Thanks! I'll try again in the morning!