Advancing the timing?

[DanW]

I've heard this been said a lot, and will probably do it next time I get the chance to. Only problem is... How do you advance the timing? Which bit's do you move?


On a side note, with the NZ having vacume advance how much does this affect the timing, and how?


Thanks, Dan

[LogIK]

To advance your timing, you need to loosen the two bolts on the distributor and rotate it opposite to the direction it is spinning (therefore making the spark come sooner.) IIRC, this is away from you, as you look at the engine from the front. Bare in mind that the adjustments are only by a few degrees, so don't go mad.

Also, make sure you mark the original position with two scribe marks, just so you know how much you have moved and can move it back if need be.

The advantage of this is that it gives a longer time for the third stroke and therefore more power, as the flame burns longer, making sure all the fuel is burnt. Advantages are only minimal, but worth doing as a fine tune.

You can over advance the ignition and make the spark come so soon that the piston is still on it's way up too much when the spark comes, causing knocking. This will damage your engine and make things a lot worse.

The optimum point is advancing it just before it starts knocking/pinking. I advise you to advance it a few degrees, then take it for a drive, making sure the engine is under heavy load, and listen for any pinking. Keep advancing it until you find the point just before it pinks under load.

Have fun!

[DanW]

Brill will have a go next time then... Anyone know about this vacume advance?

[hardhitter]

You need to put the car in service mode to adjust the base timing. This involves warming the car up to temp and unplugging the blue temp sensor so the revs raise to about 1300rpm. Get a timing light with ignition advance dial in (if poss) and mark on the bottom pulley with tippex, then you can find the timing held at 2000 rpm (get someone to do that). Whilst doing this turn the dizzy to the right position with the degrees set of the light.

The other way of setting it is by feel.

[LogIK]

Doing it using a timing light is more accurate, but you've got to know how much to advance it by. Do you know what it should be Dan (Barnes)?

[DanW]

You need to put the car in service mode to adjust the base timing. This involves warming the car up to temp and unplugging the blue temp sensor so the revs raise to about 1300rpm. Get a timing light with ignition advance dial in (if poss) and mark on the bottom pulley with tippex, then you can find the timing held at 2000 rpm (get someone to do that). Whilst doing this turn the dizzy to the right position with the degrees set of the light.

The other way of setting it is by feel.

aaaah. Rite ok, sure dad's got a timing light somewhere in the garage, only problem if it still works.


On a side note, the fuel mixture screw... It alters the mixture of air and CO2 (doens't it?), so turning the screw one way should (in theory) reduce it, and the other way increase it.

So... Less CO2 = more O2?

or is there a point to which the mixture is best at?


(full of questions tonight )

[DanW]

Doing it using a timing light is more accurate, but you've got to know how much to advance it by. Do you know what it should be Dan (Barnes)?

86c said something like 5-7degrees on porka...

[hardhitter]

The book setting is 5° but you might be able to get away with more upto 7° like 86C said, best with optimax only. The thing with an NZ is the vacuum advance will need disconnecting before setting it.

The CO screw adjusts the mixture at idle and without an accurate way of measuring the CO, like a gas analyser, you are best leaving it alone.

[DanW]

The book setting is 5° but you might be able to get away with more upto 7° like 86C said, best with optimax only. The thing with an NZ is the vacuum advance will need disconnecting before setting it.

The CO screw adjusts the mixture at idle and without an accurate way of measuring the CO, like a gas analyser, you are best leaving it alone.

why optimax only?

I prefer to run the car on RON97 anyway, but usually run it on 95.

[hardhitter]

Well if your sticking more advance on your gonna need higher octane to prevent it from pinking.

[polo_GT]

Am i right in thinking you hold the revs at 2k whilst you turn the ignition timing towards the back of the engine.

[optima21]

you can also advance the ignition too much without any side effects like pinking, but you might end up with more power than you should, but not as much as possible.

on vacuum advance cars the way to set the maximum total advance, was to select a gear and go from about 3k rpm to 6k rpm with the throttle fully open and time how long it takes to get to 6krpm....

....the optimum timing point was either, just before the engine pinked, or the fastest time it too to get to 6krpm.

with an ecu taking control of things, it may not be quite that straighforward though.

[DanW]

with an ecu taking control of things, it may not be quite that straighforward though.

is it controlling timing as well then?

[Tahrey1043]

Yep, particularly if you have a knock sensor (G40... and GT, too?), which effectively has an emergency role to protect the engine against the effects of crap fuel or over zealous DIY tuning, though it cant work immense miracles and will affect performance (by retarding the timing to silly degrees when it detects pinking and only slowly re-advancing it).

I was going to copy a short paragraph out of haynes that i remembered describing the ecu's role in controlling ignition timing and the like, but after having a quick scan it's more like a page and my brain just condensed it slightly....

[DanW]

my brain just condensed it slightly....

into it does stuff, with teh fuel and timing.