Posted By : Mark Stradling, 28-Jan-2004, 04:33pm

Having descided to stick with my AC Delco distributer (at least for now) and fit electronic ignition, I'm faced with my recurring nightmare (well two of them actually).

The less important one is the "Why did I leave me <random tool name> in my folks garage" one. Last time was the window weather seal clip insertion tool, his time the timing strobe.

The important one is the "Exactly what ARE all those spikes on the timing cover for?" one.

I remember from restoring the car a few years back that all the timing numbers came off with the rust.

Is it 1 degree for each spike (so each trough is 1/2 a degree), or does each represent 1 degree (so from one spike to the next is 2 degrees)?

Can anyone help me with that one?

Spitfire Mk IV BTW

Followups :

Timing Marks

Posted By : Roger Golland, 28-Jan-2004, 06:09pm

Hi Mark,

The teeth of the timing marker are at 4 degree intervals from spike to spike.

On close inspection you should find that one of the teeth is slightly larger than the others. This is the spike for Top Dead Centre (TDC).

Facing the engine from the front end of the car, anticlockwise from this peg is before TDC and clockwise, obviously, after.

The static timing mark you're after for a MkIV is 6 degrees BTDC up to engine number 25000, and 8 degrees BTDC from 25001 on.

Hope that helps

Timing Marks

Posted By : Mark Stradling, 29-Jan-2004, 11:57am

Spot on, thanks.

Section : Ignition and Distributers

Timing Marks

Followups :

Timing Marks

Timing Marks