8 replies to this topic

[Max1330]

Hi everyone.

Ive looked all over for abit of guidance on setting the timing on my 1275 but i cant find anything to suit my setup.

Ive never set the ignition timing before.

Current spec is 276 cam, weber 45 dcoe, cooper s head...

What mark on the timing cover am i aiming for? I think they go up 4 degrees at a time, is this correct? Also i have no vac advance setup. and help or comments welcomed :)

Thanks, Max

[KernowCooper]

I have a similar setup are you still running the standard distributor with the vac advance disconnnected or is it a modified distributor without the vac advance unit removed? if the later is the base plate locked up? this will prevent variation in the timing throughout the rev range. I have mine (diferent state of tune) set at 12Degrees at 1000rpm But I have a Aldon Yellow Distributor. If yours is a standard distributor? if so wont have the corrct curve for a modified engine.

Also if this is a road car then it should run with vac advanve to be honest, weak mixtures on cruse need more advance to burn effieiently and this is where the vac advance comes in, if you read Vizards Book and Des Hammils book they both agree road application best on Vac Advance.

Try my setting and see how it goes if it pinks on the road back it off 2 degs and try again, the old figure they aimed at was a all out advance of 32degs and that should be all done by approx 4000rpm but with todays petrol thats not always possible without detonation (pinking)

Dont forget a engine which has a weak mixture can also cause the engine to pink!

Sorry forgot

The large pointer is 0degs TDC and going down in 4 degs so 0/4/8/12/16degs

Edited by KernowCooper, 01 March 2013 - 10:29 PM.

[tractor]

The way I understood how to set the timing was to set it around 12 degrees static as kernow says then take the car out for a spin and put it under load, if you don't hear any pinking advance the timing by 2 degrees and repeat until you hear pinking, when you do retard the timing to the previous setting.

My point is that a newly rebuilt engine will differ from a 15 year old engine and so take any figures as a guide and do what's right for your engine

I guess the best way to do it to get the car set up on a rolling road

Trac

Edit: terrible spelling and predictive text mix

Edited by tractor, 02 March 2013 - 01:06 AM.

[Max1330]

I have a similar setup are you still running the standard distributor with the vac advance disconnnected or is it a modified distributor without the vac advance unit removed? if the later is the base plate locked up? this will prevent variation in the timing throughout the rev range. I have mine (diferent state of tune) set at 12Degrees at 1000rpm But I have a Aldon Yellow Distributor. If yours is a standard distributor? if so wont have the corrct curve for a modified engine.

Also if this is a road car then it should run with vac advanve to be honest, weak mixtures on cruse need more advance to burn effieiently and this is where the vac advance comes in, if you read Vizards Book and Des Hammils book they both agree road application best on Vac Advance.

Try my setting and see how it goes if it pinks on the road back it off 2 degs and try again, the old figure they aimed at was a all out advance of 32degs and that should be all done by approx 4000rpm but with todays petrol thats not always possible without detonation (pinking)

Dont forget a engine which has a weak mixture can also cause the engine to pink!

Sorry forgot

The large pointer is 0degs TDC and going down in 4 degs so 0/4/8/12/16degs

Hi thanks for the wuick reply! Its s non srandard dizzy but its not modified. I know its the weong one for the car spec but its all i have right now until i can buy myself a new one with the correct advance curve. I jus want to try and set it up as best i can for the time being as im moving lock ups very soon. How can i check the base plate is locked?

I have also spoken to a few people about the vac advance and it seems i should go back to using it, the only reason it was removed is because it was like this when i first baught the car. I do have a vizzard book that ive just started reading!

I will try your settings today and see what it runs like. Also, how can you tell when its pinking?

Thanks alot again! Max

[Max1330]

The way I understood how to set the timing was to set it around 12 degrees static as kernow says then take the car out for a spin and put it under load, if you don't hear any pinking advance the timing by 2 degrees and repeat until you hear pinking, when you do retard the timing to the previous setting.

My point is that a newly rebuilt engine will differ from a 15 year old engine and so take any figures as a guide and do what's right for your engine

I guess the best way to do it to get the car set up on a rolling road

Trac

Edit: terrible spelling and predictive text mix

Hi, this also seems like a pretty logical way of determining the correct timing. However i dont understand how you tell if its pinking or not? Ill try setting it at 12degrees and report back as to how ot feels. Ill also try and sort the vac advance out too. Thanks alot again! Max

[KernowCooper]

Pinking is when the engine under load in say 4th gear at 40-50mph and you put your foot down you will hear a kind of a rattling noise which goes away when you lift off the throttle and comes back when you apply throttle it could be bad on light throttle which is to far advanced or may be very light pinking under full throttle which means the timing is slightly still advanced, retard the ignition as described.

You can tell if your baseplate is fixed or not by removing the distributor cap and carefully trying to rotate the baseplate where the points or trigger head is fixed it will move up/down towards where the vac advance unit was originally fixed if its free if no movement its most likely been brazed in the fixed position. If it is free and you can rotate it then its free moving and could give a error on the advance curve and the static timing, so my advice then is to obtain the correct advance unit for the distributor and refit it. The vacuum advance unit is held in place with two screws and the end of the vacuum advance arm fits on a small pin like shaft on the baseplate assembly, you'll see what I mean when you get the new vacuum advance unit.

Remember Pinking can also be caused by a weak mixture

[carbon]

Two suggestions here.

One is for static timing to use the timing marks on the flywheel, these are a lot more accurate.

Second is you should check the mechanical advance in the dizzy. If you take the baseplate out there should be a number stamped on the advance mechanism, probably something between 8 and 15. Multiply this number by 2 gives the mechanical advance.

Static timing + mech advance = total max advance. This should not be much more than about 30 if you're running standard pump fuel, but this only tells you max advance and nothing about how the advance curve works at lower rpm.

[racingbob]

i know i took mine to slarky and i had mine bit to far advanced and he knocked

it back, about 28 -30 deg if i recall at full advance 4000

[KernowCooper]

Todays fuel is poor compared to what we had in the 70s back then the parrifin had more octane rating than todays unleaded