Very basic ignition question

[Andy 308GTB]

I'm setting up a distributor, if the 'rotor' is positioned on Cylinder #1, should the engine be at TDC?
Or should the engine be slightly advanced (i.e. to +6 degrees which is the correct advance at idle)

I think I'm answering my own question here but I've completely over thought it.
(V8 engine with mechanic bob weight/centrifugal advance/retard mechanism).

Thanks

Edited by Andy 308GTB on Monday 30th May 14:41

[steveo3002]

yeah like you say...usually tdc is near enough to start then use strobe light to fine tune it

[Andy 308GTB]

steveo3002 said:

yeah like you say...usually tdc is near enough to start then use strobe light to fine tune it

Thanks, this isn't the first time I've set the timing but it was some years ago... I never gave it a second thought, until now.

[tapkaJohnD]

Do not forget that there is TDC , and TDC on the firing stroke.
Check that the valves for No.1 are closed and you're in the right place.
John

[Andy 308GTB]

tapkaJohnD said:

Do not forget that there is TDC , and TDC on the firing stroke.
Check that the valves for No.1 are closed and you're in the right place.
John

I didn't actually check this.
But if I have had the engine running smoothly, can I assume that I got lucky when I did set the distributor?
If the timing was 180 degrees out, would it even start?

[tapkaJohnD]

No!

[Jaz2000]

Easier than checking valves are closed I tape a rubber glove to the flexible tube of my compression tester then wait for it to inflate when coming up to TDC and show if its the compression stroke.

[Ambleton]

Andy 308GTB said:

If the timing was 180 degrees out, would it even start?

Depends if its wasted spark or not...

If its wasted spark it doesn't make any odds if its TDC on either the firing or exhaust stroke (unless its an atkinsons cycle). But most systems are not wasted spark and i csnt thing if any potential cars that would be both Atkinson cycle AND have a dizzy so nothing to worry about.