VK ignition coil

[85_Calais]

Hi

I'm currently trying to work through the possible faults in my ignition system so that my car can run properly on gas. I read in another post that a faulty ignition coil can cause a car to run rougher as it warms up to operating temperature which seems to be what is happening when I run on gas. So today I attempted to change the ignition coil.

The coil I bought was a different brand and slightly larger, and didn't quite fit into the bracket and this slightly misshaped the outer casing. When I went to start the car, it wouldn't start. I put the old coil back in and it started straight away.

Two questions:

1) Is a misshaped outer casing likely to have caused damage the internals of the coil; and
2) Is there any difference between the ignition coil used in a VK Commodore and a VK Calais? The workshop manual mentions in the Calais supplement section that a "conventional coil" is not suitable, but the Bosch and Champion websites don't seem to differentiate between the two.

Any insight is appreciated. Cheers.

[VR38]

I know the carby and EFI motor use a different dizzy so maybe the coil is different too, is your motor EFI or carby?

[85_Calais]

EFI. The Champion replacement looks about the same but is a bit bigger so doesn't fit nicely into the bracket. The Bosch one (which is about twice the price) looks totally different. Not 100% sure how it would attach to the block.

[85_Calais]

I returned the Champion one and bought a Bosch one (for twice the price). Put it in and it worked fine.

Has improved the rough running on gas at operating temperature marginally, but it's still backfiring :@