17 replies to this topic

[booton]

Ignition Timing Runs Better With +12 Deg.

is it normal for my ignition timing to be so far advanced.

car runs much smoother with the timing, this far advanced.

i do have eletronic ignition.
and a piper 270 camshaft.

its it a fueling issue why it needs to be so advanged, or due to the changed parts.

any info would be great.

thank steve

[tommy13]

I would say that the advance curve built into the distributor is no longer suitable for the engine mods you have carried out or the centrifugal advance mechanism is sticking.
If the advance is not sticking and there is no hint of pinking then I would leave it where it is.

[lrostoke]

factory specs are normally on the safe side, so generally an engine will take more advance than standard

[racingbob]

my mg metro runs 10 -12 seems ok

[booton]

umm so mixed view.

the dizzy does advance when rev are increased so the advance still works.

I would say that the advance curve built into the distributor is no longer suitable for the engine mods you have carried out or the centrifugal advance mechanism is sticking.
If the advance is not sticking and there is no hint of pinking then I would leave it where it is.

if this is the case what do i need to correct it.

[tommy13]

umm so mixed view.

the dizzy does advance when rev are increased so the advance still works.

I would say that the advance curve built into the distributor is no longer suitable for the engine mods you have carried out or the centrifugal advance mechanism is sticking.
If the advance is not sticking and there is no hint of pinking then I would leave it where it is.

if this is the case what do i need to correct it.

The general overall impression I get from the replies is that 12 deg is not really excessive, and if the car is running well at that,then leave it as it is.
I think the Aldon distributors have a advance curve more suited to cars with tuned engines, and perhaps someone with more experience than me can advise you on this.
The all singing and dancing cure is fully mappable electronic ignition eg Megajolt, which is labour intensive and expensive.

[Pigeonto]

Booton:- I am interested to know if you have tried more than 12 degees.I would guess that the more you advance it the better it will idle even with 12 already. I'm always seeking knowledge as we all are and I use the 270 as well. I have to tell you I use alot more than 12 degrees to get the best idle and would also like to know why. No one has ever been able to explain it to me. What is your compression ratio.

[booton]

hi i have tried more and it does seem to idle better but it shouldn't. goes against all theory really

that why i used 12deg as it closer to 0deg.

unsure of compression ratio soz. do to having a pocketed block.

i will use more if you have had better results. what dizzy are you using

[booton]

also wonder pigeonto, what carb are you using.

i have a choice of three. unsure which to go for really. SU2 on/ Hiff 38 On mini sport manifold or weber dhoc on my custom built manifold.

i have the SU2 on atm as i know the set up works.

[dklawson]

12 degrees or more is not against theory. As was mentioned above, the factory specified advance figures are conservative as they must address tolerance in all the engine parts and variations in fuel octane.

I never set my advance at idle. I warm the engine after adjusting the valves, then bring the RPM up to about 4000 using the idle adjustment screw. With an advance type timing light I set the timing to about 32 BTDC and tighten the distributor clamp. Then the idle speed is reduced to the desired value and the car is test driven. Place the car under load in too-high a gear (like accelerating uphill in 4th gear starting from a very low road speed). If you hear pinging or knocking, stop and retard the timing a couple of degrees then repeat your road test.

Timing with the max advance and load testing will give you the maximum advance your engine can handle for its general condition and the fuel you are using. If you go back and check your idle advance after setting the timing this way I can almost guarantee that you will have more than 10-12 degrees.

[booton]

ok, after 12deg its very hard to tell what it is at due to not have any gauge.

but i will try advancing the timing more.

thought i might do some damage. so i kept trying to retart it. never mind live and learn

[bmcecosse]

If that is 12 degrees 'static' then you will have problems getting it started in cold weather.... I suspect it is 12 degrees when idling - with the vacuum still attached ??? As above - you will want 32/34 degrees at decent revs (4000 sound about right) - and you should then roadtest and set it so it's 'not quite' pinking. If that setting gives too much static advance, to the point of difficult starting, then you need to increase the mechanical advance inside the dizzy by cutting a little off the stop 'nose' on the advance weight. Thus you get the total advance you need - with less static advance. It's not perfect - but best you can hope to do without extensive rolling road testing.......

Edited by bmcecosse, 02 January 2012 - 11:24 PM.

[Pigeonto]

also wonder pigeonto, what carb are you using.
i have the SU2 on atm as i know the set up works.

Hello again. No,gave up on dizzys a while ago. When I gave up with the dizzy I had the mechanism all locked off and just set timing as much as possible without pinking. Megajolt all the way.It doesnt pink now!! So nice to be able to pull over when driving,tinker with the advance and drive off again.The beauty being that you can use massive idle advance but set a nice low cranking advance.Spec is in my profile but I have twin hif 38s.That hasnt made the slightest difference,the idle advance was the same with a single 38 and 44. Bythe way,get a chair. My idle advance is 33deg as it is throughout mostly--well it goes to 36 at very high revs.But drops to as low as 15 under hard acceleration. Sorry to totally kerfuffle you with these figures,they are accurate being megajolt,but thats just telling it like it is. You can probably ignore most of it whilst retaining a dizzy.

[booton]

having real problems getting it ruining nice.

it revs up and idles nice.

its just flat when i go to drive it. as i live on a very steep hill, it will not go up.

any tips.

i did advance the timing but wasn;t making much difference, untill i got to a point when it was to far advanced as it was stoping it self from turning over.

[booton]

i had it pretty close the other day, was driving around in it. should have made a mark, just can;t seem to find it again now.

i hate carbs and dizzys

i had a look at the megajolt kit, i intrested in one but not got a spare 400 quid atm.