Dizziness

[veryporky]

Friend has just bought a 1978 Euro spec targa SC. We might be pre '74 but there's lots of brains on here that might be able to help. Engine was misfiring throughout the range as well as pinking. First item I went for was the coil to dizzi HT lead. Runs much better now. Does not misfire but it still pinks a bit in the mid range. OK so next check the timing. But where is the vacuum diaphram on the dizzi? No trace but I thought all these engines had them. Does not look like it ever had one either. If this is the wrong dizzi then it could have the wrong advance curve which could be making it pink. Bosch part no. is 0 237 303 003. Or did they fit different types of dizzi to the same basic engine? Can anybody cast any light please................

[Lightweight_911]

I don't have the part numbers to hand but the early ('78/'79) Euro SC's didn't have any vacuum advance unit.

[veryporky]

Thanks Andy so now I know it looks like the correct dizzi. So anybody know what the timing specs are at idle and max advance? I suspect the idle setting may differ due to the lack of a vac advance unit and perhaps the all in at 6k figure too.

[Gary71]

Hi This is the extract from the manual, hope this helps

[veryporky]

Thanks Gary. My information says much the same. This is where the rub occurs. It refers to a disconnected vac hose. My friend's unit has no hose so it cannot be adjusted in the same manner so the values are suspect in our case. That may even be the reason why it's pinking i.e. somebody adjusted it as per vac hose disconnected setting and ended up with an over advanced situation.

[Gary71]

The disconnected vac hose comment is only for the USA version. So hopefully if you set it to 5deg BTDC at a 900 rpm idle as mentioned for the euro version it should work out fine

Slightly confusingly it doesn't state that the Euro version doesn't have vacuum advance, just that the USA does