Trigger wheel

Hello guys. I have a Volvo b21, i need to make a crank trigger wheel setup. But before i do That i Wonder If i can use the old setup with Only 2 teeth on the wheel.

If the engine is a 4 cylinder then most common aftermaket ECU's would support this "1 tooth per TDC" type trigger wheel (it will need a single tooth cam sensor as well). However with a low tooth count trigger wheel you will see more timing drift under fast acceleration compared with a higher tooth count wheel.

Thank you. I have a hall sensor in the distributor with 4 teeth.

You will need to cut 3 teeth off the distributor chopper disc to give you a single "sync" tooth.

Okay, thank you. If i cut off Only 1 tooth of the wheel and make it 4-1 Would That also Work?

Next question, If you look at the picture i attached to This thread would That be a 4-2 wheel?

"If i cut off Only 1 tooth of the wheel and make it 4-1 Would That also Work?"

Some ECU's will support a 4-1 trigger at cam speed but that is not a great option - that will mean in the missing tooth area you will have 360deg of crankshaft rotation with no update from the trigger wheel so very poor resolution.

"Next question, If you look at the picture i attached to This thread would That be a 4-2 wheel?"

No, the wheel in your picture is just a wheel with 2 evenly spaced teeth (180 deg apart). A 4-2 wheel would effectively be two teeth 90deg apart, then no teeth for 270deg.