Setting crankshaft to 10 BTC and then install distributor

[bronco italiano]

-So my buddy and I hade differing opinions on this. I set his engine to 10 degrees BTDC, installed his distributor and set the rotor to as close alignment for #1 plug on the cap.

-He feels that the truck will be 10 degrees but read "0" at the crankshaft since I set the the damper at 10 and installed the distributor.

-And I still think it will show 10 BTDC on the timing light.

-But I am not so sure now.

 

[m_m70]

it'll show 10*. The light flashes when #1 sparks. So if you line up the rotor with the #1 plug with the pointer at 10*btdc, that's where it will flash at.

 

[bronco italiano]

it'll show 10*. The light flashes when #1 sparks. So if you line up the rotor with the #1 plug with the pointer at 10*btdc, that's where it will flash at.

That is what I thought.
I think my buddy was gaslighting me.

 

[DirtDonk]

It depends on what type of ignition trigger the distributor has, and where it is aligned.
The rotor isn’t always pointed directly at the center of the spark plug contact when the spark occurs. But the spark activity happens at a specific time.
Either as the points start to open, or as an electronic trigger gets to a certain point crossing the pickup.

It’s more common than not to be off by at least a few degrees when setting up a distributor fresh simply by eye.

 

[cldonley]

It'll get you pretty close. Will show something close to 10 degrees.

 

[73azbronco]

is the timing gear set to zero?

 

[ba123]

If your crankshaft is at 10° and that's where you make the spark, then it's kinda of a duh thing.

Nothing else matters. You are telling the spark to go off at 10° BTDC, then that's where the light will flash.

Now if you set the crank there and then don't put the rotor on the dizzy exactly there, then it might be slightly different.