Timing marks

[ngc414]

Does any one have pics of where the timing marks are on the crank pulley? I cannot find them. I want to check the timing on the car with a light. What should the timing be set at? Do you turn the distributor clockwise to advance?

[ossiblue]

Don't have a picture, but the timing mark for TDC will have a "Z" by it on the pully. Don't forget you have a bunch of notches on the pulley but only one with the "Z". Once you find it, mark the notch with some paint.

The rotor turns clockwise so advancing the timing requires a counterclockwise rotation of the distributor body.

[Por_sha911]

Do you mean this?

[ChrisBennet]

Originally Posted by ossiblue

Don't have a picture, but the timing mark for TDC will have a "Z" by it on the pully. Don't forget you have a bunch of notches on the pulley but only one with the "Z". Once you find it, mark the notch with some paint.

The rotor turns clockwise so advancing the timing requires a counterclockwise rotation of the distributor body.

On an SC, the rotor turns counter clockwise. Those SC guys just have to be "different".

That picture looks like a Carrera but no matter which 911 you have it will have at least 3 marks 120 degrees apart to mark TDC for cylinders 1&4, 2&5, 3&6.
The TDC mark for 1&4 will have a "Z1" engraved on the pulley. It may be hidden by the AC pulley.
If there are other marks near Z1 you can determine which is the "real" Z1 because it will be 120 degrees away from the TDC marks for 2&5 and 3&6.
Alternatively, you can use one of those TDC indicators they hand out at Chinese restaurants to determine when the piston is at Top Dead Center.*
Does that make sense?
-Chris

* Stick a chopstick in the spark plug hole and note when the piston is all the way up i.e. TDC.

[ossiblue]

Originally Posted by ChrisBennet

On an SC, the rotor turns counter clockwise. Those SC guys just have to be "different".

Learned something new! Thanks for the info!

[ngc414]

Should the timing be set exactly at Z1?

[rootmatt]

Originally Posted by ngc414

Should the timing be set exactly at Z1?

No.

According to Bentley, The stats for a '79 SC are
5 degrees +/- 2 BTDC @ 950 rpm w vacuum hose disconnected.
26 degrees +/- 2 BTDC @ 6000 rpm w vacuum hose disconnected.

Setting the first of these will require judgment by eye or some crafty measurement if you don't have a timing light with an advance facility. (yes, Pelican appears to sell one) Fear not, though. The second of the settings @ 26 degrees corresponds to the notch on the pulley labelled as "BTDC" in the photo kindly supplied by Por_sha911, above. As I understand it, setting the idle advance will get you in the ballpark but it is the 26 degrees @ 6000 rpm that is the important setting. Obviously the two are interdependant. Setting the max advance @ 6000 rpm will ensure that the other is correct.

Happy timing

Matt

[ngc414]

Originally Posted by rootmatt

No.

According to Bentley, The stats for a '79 SC are
5 degrees +/- 2 BTDC @ 950 rpm w vacuum hose disconnected.
26 degrees +/- 2 BTDC @ 6000 rpm w vacuum hose disconnected.

Setting the first of these will require judgment by eye or some crafty measurement if you don't have a timing light with an advance facility. (yes, Pelican appears to sell one) Fear not, though. The second of the settings @ 26 degrees corresponds to the notch on the pulley labelled as "BTDC" in the photo kindly supplied by Por_sha911, above. As I understand it, setting the idle advance will get you in the ballpark but it is the 26 degrees @ 6000 rpm that is the important setting. Obviously the two are interdependant. Setting the max advance @ 6000 rpm will ensure that the other is correct.

Happy timing

Matt

I do have a timing light with a advance dial. Does the light hook up just like a normal car? (12v power to gun and clip on the #1 plug wire). My car is idling high at around 1200-1500 rpm. Do you think it would still be ok to set the base timing with that since they reccomend it at 950rpm? When they say 26 degrees @6Krpm, do they mean to rev the car to 6k and confirm it is close to 26degrees?

[Thrlls]

On my '84 double pulley there was no Z mark, just a notch at 12, 4, 8. I have since changed it with Smart Racing's pulley.

[rootmatt]

Originally Posted by ngc414

I do have a timing light with a advance dial. Does the light hook up just like a normal car? (12v power to gun and clip on the #1 plug wire). My car is idling high at around 1200-1500 rpm. Do you think it would still be ok to set the base timing with that since they reccomend it at 950rpm? When they say 26 degrees @6Krpm, do they mean to rev the car to 6k and confirm it is close to 26degrees?

Hook up light as normal.

Setting base timing at 1200-1500 rpm will likely result in your timing being a bit retarded. Not the end of the world.

From what I have read on this very forum, that is exactly what is meant. If you go ahead and set your final timing using the 6k method, this will correct the possibly retatrded static timing from setting the base timing at a high idle.

Matt