Firing order, timing mark, rotor position, any ideas?

[Healey Z]

I dropped a new long block motor in the car, using my old petronics disti from 240z and dual down draft webers.

It started, but backfired through the carb like an old school bus. It is clear that something was way off, I started fresh with the ignition timing/firing:

- crank position is right on the TDC mark on pulley.

- physical check of #1 piston (closest to radiator) is at TDC

- I then set #1 spark plug wire to where rotor is pointing.

- Went counter clockwise 153624

Car will not even fire now. I then rolled it back in the garage to give me time to think about it. Any thoughts?

Ken

[240260280z]

- Distributor shaft from Oil pump could be 180 degrees out and the piston one at TDC could simply be top of exhaust stroke rather than top of the compression stroke.... recheck

- distributor rotor will have swept past #1 post by ~ 10 degrees advance when crank is at TDC.

[motorman7]

- Distributor shaft from Oil pump could be 180 degrees out and the piston one at TDC could simply be top of exhaust stroke rather than top of the compression stroke.... recheck

.

I've done that. Easy to fix though. No need to drain oil, just remove the oil pump and re-install shaft 180 degrees around. Pull distributor to get the correct angle.

[Healey Z]

Blue, thanks for the reply.

Let me think through this, perhaps my logic is wrong. The crank goes around 2X for every time the disti goes around once. So, the timing marks on the pulley are at TDC twice for every time that rotor goes around compression, exhaust stroke.

Perhaps I did have it right and the timing just needed to be adjusted to get stop the backfiring (or there is another issue going on). I'll get it back on TDC and pull the valve cover to see where the valves are. Hopefully the exhaust valve is open and I simply have the wires off 180 degrees and need to put them back to where they were.

, when the rotor is pointing to a contact within the cap it is always firing and is at the compression stroke.

[motorman7]

I'll get it back on TDC and pull the valve cover to see where the valves are.

.

You should be able to do that without removing the valve cover. If I am not mistaken, you should be able to stick your finger in the oil fill hole and feel the #1 cylinder exhaust lobe if it is timed correctly.

[240260280z]

Yes, for a quick test just move the plugs 180:

Right now you have

153624

Rearrange to

624153

Popping intake could be timing or running lean

[Healey Z]

You should be able to do that without removing the valve cover. If I am not mistaken, you should be able to stick your finger in the oil fill hole and feel the #1 cylinder exhaust lobe if it is timed correctly.

That is a cool tip!

Thanks Blue, hopefull I will feel some lobe and rewire accordingly.