Advance timing

[AlfaCorseChris]

Hey guys,

just a quick question regarding the dizzy ignition timing advance on a 1.7 8v carby engine

My flywheel does not have a "T" marking, but a round stud sticking out for TDC.
then theres a single line (as far as I can tell coz its faded off) and the "II" lines.


As far as I know, to get the ignition timing right, the dizzy needs to be set at +8degrees.

However, I've been playing around with a couple of timing guns and they are both different.

First timing gun is only a strobe light. So I marked out with white the "I" mark , turned the engine on, running at about 1000 rpm, and set the dizzy to hit at "I".

However, as soon as I did that, the engine no longer revs up the way it used to (although the way it used to be it was set too high and I had pinging)


Second timing gun is one of those that you put the degrees you want on it.

So, Do I set this timing gun on +8 degrees, and hit on TDC or hit on the "I" line ?

[KevJTD]

sud engines (1.7 8V should be the same i'd think....) have a T or a notch for TDC, another I for the basic setting at tickover, II for at 2,000rpm & III for at 4,500rpm
hope that helps

[KevJTD]

to answer your last question regarding timing lights that you can dial degs in, you can either set it to the designated angle and look for the tdc or leave the timing light on zero and look for the relevant timing mark. both will produce the same results

[AlfaCorseChris]

I believe from one timing gun to another there are differences.

Had the time attack championship yesterday, and took the timing gun with me.

Turns out, with the dialed in timing gun, the correct timing of the advance was to mark the "I" line, set the gun on 8 degrees, and hit on that line. NOT the TDC.

I know it sounds odd, but thats how it works on the engines I did with the timing gun I had and Worked it did !

Dialed in 2 cars at the track in that way.

First was my 1.7 8v S2 33.
Lap times with timing set to TDC with no dialed in degrees and hit on the "I" line, was 1:29.9
Lap times with timing set to TDC with dialed in 10 degrees and hit on the "I" line, was 1:27 flat


Second was a 1.5 Sprint.
This guy has been racing at this track for the past 3 years, starting from a 1:34 and progressively taking it down to 1:31 something
He asked me to check his advanced timing as well, and it was set to hit at "I" with no degrees dialed in (so the supposed factory mark for 8 degrees)
Did the same with him and he did a 1:27.8, giving him his best time so far and the first place on the podium !


These setups have been made with no pinging or difficulties in turning the engine, and with no overheating issues, so it must be the right way to do it.
Plus both cars feel much more alive on the road, where before they were feeling like they were held back. Not like a boxer would feel like.

[Alfasixnut]

Good result Chris!

[Alfasud1978]

Chris do we have to check my Alfasud's timing as well? Yes?

The car though was feeling very tractable (as far as the 68bhp could give) and I managed to drop last year's track personal time from 1:30:2 down to 1:28:9.

[AlfaCorseChris]

Thats how I did it on yours too. Same process, same results

[Alfasud1978]

Good to know. A big thank to our Chief Mechanic......Chris, for a perfect car preparation!!

p.s. Chris prepared apart from my own Alfasud, his own cars 33 16V & 33 1.7 8V & 75 2.0 and friends 75TS & Sprint QV. All cars took part to the meeting.

[AlfaCorseChris]

my wife and kids were very pleased with that .

hahahahahahahhaha

[NEG]

This is bugging me! I've noticed my 1350 sprint is not eager to rev beyond 4~4.5k. I seem to recall it being quite an eager unit but my memory may be a bit cloudy....so I've looked at the timing and made a small adjustment using an old Gunson strobe and set the timing at the I mark on the flywheel at 900rpm. The timing was slightly retarded before, the new timing has made little or no difference.

Reading the posts above got me thinking. I have 3 marks on the flywheel, a stud, a I and II, if I go for a more advanced strobe and dial in 8deg and time to the I mark then The timing would be 16deg at 900rpm? That sound like a lot of advance to me or am I getting the timing marks mixed up?

Would it be better to dial in 2000rpm and time to the II mark instead?

[KevJTD]

This is bugging me! I've noticed my 1350 sprint is not eager to rev beyond 4~4.5k. I seem to recall it being quite an eager unit but my memory may be a bit cloudy....so I've looked at the timing and made a small adjustment using an old Gunson strobe and set the timing at the I mark on the flywheel at 900rpm. The timing was slightly retarded before, the new timing has made little or no difference.

Reading the posts above got me thinking. I have 3 marks on the flywheel, a stud, a I and II, if I go for a more advanced strobe and dial in 8deg and time to the I mark then The timing would be 16deg at 900rpm? That sound like a lot of advance to me or am I getting the timing marks mixed up?

Would it be better to dial in 2000rpm and time to the II mark instead?

just to make sure....you are removing the vaccuum pipe from the distributer before making any checks/adjustments aren't you?

using a timing light that has no adjustment value (or one that has an adjuster but left on zero) then simply the I is for the timing set at idle speed (around 850rpm), II is for at 2,000rpm, III is for at 4,500rpm

if the car runs worse when it is set correctly then you have issues elsewhere

[NEG]

Yep, vac adv removed and I checked its working. I'll try setting it to the II mark at 2000rpm....

[vecchioalfa]

Is it mis-firing at 4500rpm? if so it could be the rotor arm if it is the type with the rpm cut out fitted to it, I had a rotor arm go faulty some years ago, its a spring loaded contact and the centrifugal force is designed to break the circuit at the set rpm but sometimes they do go out of spec, just a thought if you have that type of rotor fitted.....

[NEG]

No misfire just a reluctance to buzz 'round to the red line. Checked the advance timing today and max mechanical advance occurs at 3250rpm just about spot on with the II mark, there seems to be no III mark. Attaching the vacuum increases the advance above 3250rpm....I suspect there's something else going on...

[NEG]

Found the T mark! It is quite faint, not properly stamped, no wonder I missed it earlier, so it begs the question what is the Stud for?

[NEG]

I've tried a few timing variations and found on my car setting a 10deg advance at 850rpm works best. I bought an Accuspark P8000 timing light which is a neat bit of kit for the price and seems accurate. The car feels it has a bit more zip and torque plus it feels smoother, could just be my imagination though! I tried a more advanced timing of 12~14 deg but the car didn't feel that responsive or smooth plus I detected a bit of pre-ignition.

The P8000 lets you dial in the timing and you set the timing to the TDC mark...setting to the I mark adds 8 deg to whatever you have dialled in on the timing light.

[AlfaCorseChris]

Hang on mate... If you found a T mark which you hadnt noticed before, then is it possible that your timing belts were set on the stud instead of the "T" ? This would explain your hesitation issues.

Best take the cam covers off and have another look at your timing marks me thinks

[NEG]

Good point, I didn't build the engine and given the number of problems I've had to correct caused by the numpty garage who did there's every chance they cocked up!

[NEG]

Seems the numpty garage got it right. Cam Timing set correctly to the T on the flywheel, so still none the wiser on what the stud means/does/represents....TBH the car runs fine perhaps it just needs to loosen up a bit...