Alfa Romeo Twin Spark cars.

I've had several Alfa wit the 'twinspark' engines, all of which have two spark plugs per cylinder which fire at the same time. As Midas said, I believe it was to improve the burn quality in what was a poorly shaped combustion chamber.

Wasted spark is the usual term for the coil pack arrangement used on lots of engines where each cylinder receives 2 sparks every 4 stroke cycle. Manufacturers are able to save money on coils by using 1 coil for every 2 cylinders. The coil fires every 2 stokes and the cylinders are paired so that every time it fires one of them will be at the top of the compression stroke and the other will be on the exhaust stroke, and so one of the sparks is 'wasted'.

My belief - The Hemi head is actually not that bad a combustion chamber - there were much worse around at the time, the issue is with valve sizes if you do the sensible thing with a Hemi and stick the plug in the centre of the combustion chamber - i.e even flame propagation. This ideal central position means you limit the sizes of valves you can get in as you need to leave room between them for the plug - even if you go for a small plug. Now, if you move the plug to the side of the combustion chamber so you can get bigger valves in you have an uneven flame front. So to even up the burn stick another plug in over the other side and we are back to a more even and efficient burn. Eventually Alfa woke up to the fact that continuing with two valves and two plugs was flogging a dead donkey and joined the rest of the world with 4 valves and one plug back in the centre where there is plenty of room for it without compromise. As stated at the start that was/is my belief about the background - but may well be cow manure.

don't whatever you do, part your 75 TS at the side of a road miles away from most places on a run out to check for a mis-fire, get out with the engine running, open the bonnet and pull off one of the coil leads to see if the note changes . . . 'cos the engine stalls, and the doors lock . . .with the keys inside . . .

I can't remember now how I got back in . . .

That would be a good decision...but be careful, they are addictive!

Yes do it, in fact buy mine, rare and cheap 😁

It would break your heart and empty your bank account but you would still love it like no other vehicle, no other car is like an Alfa Romeo. 😍😂

Recently had a 2.0TS 147 having not had an Alfa for about 25 years. Obviously we had a fair few Alfa issues but that engine was great and it was a lovely drive.