Ignition timing. What do you run? and how it effects cars?

[boXXer]

Just reading on the internet about how ignition timing works, and was curious about some stuff.

 

1. What timing would be most common on a pinto with 190hp and 300 degree cam? (static and full advance?)

 

2. Would a lower number of advance on idle make it drive better, but lose top end power, and vice versa?

 

3. Why do cars pink at say, 3500rpm, but then dissapear after that under load?

 

Just learning really

[Toby]

boXXer this is my understanding of the subject.

 

1 Probably 12-20 static and 28-36 full. You don't need any more advance than peek power dictates. Once you have enough you are on a path to distruction!

2 The right ignition advance is best - see point 1 This is why dizzys have thier advance curves altered so you can have the right advance at both ends of the rev range.

3 The ingnition required is related to octane, and effective CR. Effective CR is what is actually created by the dynamics of the running engine ie inertial ramming. What is usually happening around 3500 (depending on engine cam / head etc) is that you are reaching peek cylinder filling - highest effective CR, and I believe peek torque. Therefore you are likely to have too much ingnition at this rev point.

 

Obviously torque will be spoilt by the ingnition being set wrong.

[boXXer]

ok cool. Sort of getting it....

 

Basically, my engine was dyno'd to run 31 degrees at full chat, and it runs on 21 degrees on idle (advances 10 degrees overall), but it does idle like a pig. So yesterday, i turned back the igntion to 16 degrees, and it ran beautifully, but obviously i wasnt getting full advance at the top end. BUT, it did pul much harder down low....

 

so in theory, if i could get my dissy to run at 16 degrees idle, and 31 top end, that would be ideal?

 

also, is there a way of detecting pinking? i.e, not just by hearing it from the engine.

[escort21]

What you need is a ignition curve that matches your engine ......phone H&H Ignition solutions

[GT_Jim]

mapped ignition

[escort21]

Don't have to be mapped...just the correct weights in the dizzy ...and thats cheaper

[boXXer]

i have a H&H igntion system in my car, and HT racing had to fiddle with the weights as they couldnt get it to advance enough.

[Guest MK1gaz]

You need some octane booster in the fuel or run about 28 degress on full advance on pump super unleaded . Pinking is very bad as it foooooooooks your pistons up . To hear pinking properly you need "Det cans" which are a headset that bolts to the engines cylinder head so the dyno operater can hear pinking at it's early stages . If you can hear it when driving in the car then you must get it sorted as it will damage your engine .

[Fiesta Steve]

i have a H&H igntion system in my car, and HT racing had to fiddle with the weights as they couldnt get it to advance enough.

 

Doesn't sound good

 

Try Bestek

[w p e]

mike put the lite on the car as i told you set 16 static then old the revs to3500rpm and check the timing by increasing the numbers on the light till the pointers meet and see what you get[ 32 ] i no ive set it and checked it

[mk14dr]

all i know is when we adjusted it, it made a massive difference to the way mine runs at all speeds

[Ratters]

what's the best timing gun to get & where from just for personal use?? i've got an old hand me down one & it has seen better days tbh.

[boXXer]

i use my dads Snap-on gun which is really nice.

 

Wayne: I havent touched it since you played with it. I will see the full advance tomorrow and see what it hits. It runs lovely now whatever ya done!

 

i just put this post up to learn about it.

[boXXer]

right, tonight i stuck the gun on again.....

 

set at 16 degrees on idle, it runs 26 degrees at 4k rpm.

 

set at 21 degrees on idle, it runs 31 degrees at 4k rpm.

 

so its only advancing 10 degrees in total.

 

Could H&H set it to run 16 @ idle, and 31 at full chat, as thats what the engine was dyno'd at with max power when i bought it, but it drives so much nicer down low when set to 16 degrees.

[Toby]

Yes.

[Guest MK1gaz]

You don't always get more power with more ignition advance . My engines got full engine management so we can add timing anywhere in the rev range but at present it gains power when we back off the timing not advance it ., strange but true .

[Toby]

I guess that means it was having a little rattle then was it? You're right no more than you need though! Just a clean smooth burn! What CR do you run?

[boXXer]

do they charge to do it?

 

I'd like to get it done, as it really does drive nicer @ 16degrees idle, but it feels quicker at 31 top end, but at the moment, i cant have both as it only winds up 10 degrees!

 

i run 12:1 compression.

[Guest MK1gaz]

I guess that means it was having a little rattle then was it? You're right no more than you need though! Just a clean smooth burn! What CR do you run?

Mine loses power before it starts pinking which is odd . My mates got Det cans on so he can hear eveything inside the engine whilst he's mapping it . The engine builder says it needs about 36 degress of advance but it pinks it's tits off with 30 . It's ok on 28 but makes more power on 25 so fooooook knows what's going on !!!!!!!!

[boXXer]

how weird is that! Mine was set at 31 degrees on HT's dyno. But the idle/town driving can be quite bad as its running 21 on idle at that setting.

[Toby]

I guess that means it was having a little rattle then was it? You're right no more than you need though! Just a clean smooth burn! What CR do you run?

Mine loses power before it starts pinking which is odd . My mates got Det cans on so he can hear eveything inside the engine whilst he's mapping it . The engine builder says it needs about 36 degress of advance but it pinks it's tits off with 30 . It's ok on 28 but makes more power on 25 so fooooook knows what's going on !!!!!!!!

 

Must be breathing well! I only run about 28 full advance. HT sorted my dizzy. Aaron knows a thing or two!

[Guest MK1gaz]

I guess that means it was having a little rattle then was it? You're right no more than you need though! Just a clean smooth burn! What CR do you run?

Mine loses power before it starts pinking which is odd . My mates got Det cans on so he can hear eveything inside the engine whilst he's mapping it . The engine builder says it needs about 36 degress of advance but it pinks it's tits off with 30 . It's ok on 28 but makes more power on 25 so fooooook knows what's going on !!!!!!!!

 

Must be breathing well! I only run about 28 full advance. HT sorted my dizzy. Aaron knows a thing or two!

More info please about the breathing so i can impress my mate at the rolling road tuesday night !!!!!!!

[w p e]

mike if the dizzys got the right advance built into it IE say 16/32 then thats all it should advance at the top no matter what you set it static. sounds like a typicle bosch dizzy with the weights sticking at high revs. get it to john at bestek he can sort it with a mod inside the housing. i just got the tango cars one set and modded to my requirements. now it dont stick

[Toby]

Gaz

 

If an engine breathes well it raises the effective CR so you need (and can only get away with) less advance. To much CR or effective CR to the point of backing timing out is not neccessarily a good thing. Back to getting all the parts to work in harmony. Good engine tuners have lots of experience, and usually specialise in one or two engines as they can get 100% out of a combination they know. Honest engine builders will tell you they can only get 90% out of engines they don't know thoroughly as they don't know the combo that works BEST.

 

[Guest MK1gaz]

Gaz

 

If an engine breathes well it raises the effective CR so you need (and can only get away with) less advance. To much CR or effective CR to the point of backing timing out is not neccessarily a good thing. Back to getting all the parts to work in harmony. Good engine tuners have lots of experience, and usually specialise in one or two engines as they can get 100% out of a combination they know. Honest engine builders will tell you they can only get 90% out of engines they don't know thoroughly as they don't know the combo that works BEST.

 

Sounds interesting , i'll ask him tomorrow