need some advice

[james butler]

as you all know i was having running probs last year and it turned out the headgasket was on its way out. after i sorted the headgasket i found an earth wire disconnected from the tci switch unit. when reconnected i checked the ignition timing and it had moved a considerable amount (16 degrees before tdc) which i think was the reason the headgasket went in the first place. to bite the bullet i took the car to a specialist to sort the timin and give it an overall check. when i got it back he said "it goes like shit off a shovel n is running fine" so i took it home only to find its now missfiring, so i took it straight back n he had another look. the problem is if you increase the fuel mixture the misfire goes away but results in high emissions (MOT failure) or if you retard the ignition it goes away and runs fine (but is then not in time according to the book) what do you guys think? this tuner guy says to leave it as it is and it will be fine. but a misfire is a misfire and shouldnt be doin it.

[Nate]

i've never set rocco timing "by the book", always done it by ear so that it is running well.

[james butler]

fair enough, will it do any harm to the engine if i retard the ignition a few degrees?

[Nate]

so long as the engine is running ok and isn't "pinking" there should be no bad effects from setting the timing by ear. pinking is normally caused by it being too far advanced anyways...

[MikeH]

It might be that the advance mechanism in your distributor is worn, and advancing too far. It would be good if you can get hold of another dizzy to swap over, but did your mechanic check the max advance, as well as the idle setting? I think there's a spec in the Haynes manual for what the max advance should be, or it could be that the spring in the mechanism is weak, so it's pulling too far on the vacuum advance, rather than the mechanical advance... as a general rule:

- If it's pinking on light throttle openings / normal driving, that's the vac advance mechanism,
- If it's pinking at high revs / full throttle combinations then it's maybe the centrifugal advance, or it could be a fuelling problem.

Retarding the base idle setting can compensate a bit for either of those problems, but it's better to have a good dizzy, and be at the factory setting.

[james butler]

right ok. he checked lots of stuff, he even put a dti in no 1 cylinder to check the tdc was where it supossed to be on the flywheel. im pretty sure the vacuum and mechanical advance is working as you can see it working when you use a strobe light and rev the engine which was done with both the vacuum pipe on and off and all seemed well. but maybe your right and the springs are a bit worn, however it doesnt seem to pink throughout the rev range.ile retard the ignition a bit and see how it goes. one more thing it takes a lot longer since hes tuned it for the temp to rise and never reaches the same place as before, (not sure if thats weather related as its bloody cold) could this be down to not enough retard/ advance?

[MikeH]

I swapped a dizzy on the daily and my occasional pinking problems went away. It could be that it was slightly more retarded, but I think I set it the same.

Rate of heating up is more likely to be the weather, I'd have thought, although badly set timing can be a cause of overheating, in either direction.

[james butler]

retarded the ignition and is purring like a kitten now. its brought the emissions rite down aswell. i suppose if the ignition timing was out then it wasnt burning properly. and as a result i have been able to increase the mixture without compromising emmisions. love it

[Junglist]

Are you running the recommended minimum 98 ron petrol (super)? Apparently the timing is set for that, not shitty regular unleaded, and super unleaded is more economical too so doesn't cost any more overall. You might see improved performance too.

[james butler]

well im using optimax from shell, i checked the timing with a timing light in the bell housing,i have set the timing so when it flashes i can see the diamond stamp mark (that comes before the TDC 0 mark) line up with the pointer on the bell housing is that correct? the mechanic that had tuned it had it set so you couldnt see any marks at all. looked to me like it was very far advanced. i did wonder if hes timed it with the vacuum pipe pulled off the dizzy like you would with the gti? according to the manuals you dont do this with carb cars.