ignition timing

[burgo]

ive timed up a few vauxhalls recently and have noticed that when timed up perfectly according to the marks, when taken for a test drive the cars have seemed very flat and hessitent yet when i give them abit of advance it improves them alot. is this down to the timing marks being crap or what??

[meritlover]

a lot of the time the std timing marks are to give a flat power curve and a wide spread of torque with good emissions. advancing too much base timing will improve the power but will upset the injector timing to the inlet valve (not that this is MUCH of a problem)
it goes to say that most new cars are not good at powers and that old cars with carbs and distributors are the best!!!

[Adam]

When i aligned the dizzy mark on my old spi, it drove ****e.
Advanced it a few mm and it drove much better.

I think the marks are just there as a rough baseline to get the engine running.

[burgo]

glad to see its not just me then, i always have prefered the see how it sounds and goes method to be honest.

p.s. 8888

[chimp007_uk]

advance it till it pinks and retard it slightly until it stops...

make it more responsive

[burgo]

advance it till it pinks and retard it slightly until it stops...

make it more responsiveexactly what i did with my saloon, although i set mine up on super and if i run normal it pinks lol. so its run on super all the while now :thumb:

[chimp007_uk]

not a technical way to do it... but a timing light can only tell you the advance...

i usually stick in 4th a low revs and put my foot down and see if it pinks... although i set the manta up on the rollers and removed the vacuum advance. i conencted it up the other day... wasn't wise! lol

[Nick]

I was going to say... a little advance is good but mines advanced so much it pinks on std octane ! I seem to remember 14 was the number when i checked with a timing gun !

[Adam]

But pinking can damage your engine in seconds, so that method isn't recommended lol

[chimp007_uk]

i know... you really need a knock sensor. but in the poor world i live in and you want a cheap fix lol

although you say that... my gte was done like that and it pinked a little till i retarded it and when i tool the engine out of the poor thing the other day the pistons were mint! the chambers weren;t even coked up in the head :) one sweet engine!

[burgo]

But pinking can damage your engine in seconds, so that method isn't recommended loladam when i first picked the saloon up it rattled that much i honistly thought the bottom end was knackered, i opted to ignore it and drove it anyway. i covered probably 200 miles like this until one day i noticed when i put super in it quietened it down so i tweeked the timing abit and solved.... ran sweet as a nut and no more rattles. and made above standerd power on rolling road so cant have done that much damage

[meritlover]

although i set the manta up on the rollers and removed the vacuum advance. i conencted it up the other day... wasn't wise! lol

if i remember correctly its vacuum retard, spring advance.

you should not be using det sensors to tune ign. you need a dyno. advance until the torque stops increasing then back off a bit.

[chimp007_uk]

its definately a vacuum advance!

[garyc]

My 1300 grasstrack car runs 4-6 degrees more advance than std. Yep it is vac advance it only operates at low throttle plate angle openings when there is a high vaccum in the inlet system.

[djbrowney]

did the head gasket on my little work bus a phew weeks back (1.4 astra spi) the timeing is advanced 4 or 8 degress (cant remember which one) as standard, thought i had done something wrong, it drove like crap until my mate told me it had to be advanced, what that all about lol

[meritlover]

i have looked at it. its actually vacuum advance and bob weight advance. less speed or more vacuum just retards it closer to (not further than) base timing.

[Welsh Dan]

But pinking can damage your engine in seconds, so that method isn't recommended lol

I pinked the fcuk out of the last engine for at least 40k, then I was too lazy to replace the valve stem seals so I replaced the engine lol. I fiddled with the dizzy position on this engine and although it still pinks a little at very low revs, it pulls much harder through the rev range than it used to.