Timing question

[Showdown]

1977 911 S non-California car with the stock dizzy.

I was looking at the workshop manuals and the technical booklet and Can’t seem to find a complete chart of the timing curve for the car.

I know the timing is +/-2 TDC at 950-1000rpm but the workshop manual only has the advance curve for the California cars which mine isn’t.

As with most things on the 1977 911 there are some strange idiosyncrasies.

Does anyone have an advance curve for a 1977 S non California, USA car?

[icarp]

Remember this info was designed for passing pollution standards not performance .
A good rule of thumb , 6* start, 4* idle 950 rpm , 12* 1200, 18* @1800, 24*@ 2400,
30* 3000rpm.....34* @ 3500 rpm ..to redline...if it is a small bore 90mm or less .

Ian

[Showdown]

Thanks Ian, off to the dyno today and though my dizzy is still controlling the timing the shop said that they may want to alter timing with the megasquirt so this is helpful!!

[icarp]

I'm sure your dyno guys know this , move your degrees of advance to max power then
back off 1-2* and call it good. A 3.0 and larger 911 engine typically have a max advance of 29*-30*
Ian
Have fun on the dyno! AFR 12.8 to max TQ then 13.4 through redline

[Showdown]

That’s exactly the plan!! Nice to know that there a commonly accepted approach!!


Sent from my iPhone using Tapatalk

[T77911S]

would love to see what you end up with.

i played around a LOT with my timing on my 77s.
most people say remove the vac retard. i liked it. the retarded timing at ide made the idle tone much deeper and sounded better. the retard is not a big deal as it is all out before 1200 RPM.

i set it as much as 15 ATDC just to see what it did.
engine temp (at idle only) would go up if it idled for a long time.
but the temp would come down after about 5 miles of driving, and that was with just a loop cooler up front.
i usually just set it for around 29 max and let the idle timing fall where it wanted, with vac retard.

[Showdown]

Right now it’s completely stock with no vacuum retard. Car runs really well but I’m hoping that there’s better on the other side of the dyno tune.




Sent from my iPhone using Tapatalk

[icarp]

Hey Julian,
Dyno results? did you have fun ? car looks great!!
Ian

[Showdown]

Hey Ian,

It wasn’t exactly the day I was hoping for- I just posted in my thread…

I did pass along your comments to the tuner and he was impressed that you got it spot on. I told him that you knew a little about 911s