Since timing is to be set at 5 degrees AFTER TDC the line to the left is that 5 degree timing mark and the TDC (Z1) is just to the right. The decal seems to imply otherwise. Would blow me away if I have been wrong all these years. Or am I just misreading the decal.
Z1 is TDC, the first line to the right is 5 deg. ATDC
I don't think you are correct. Timing advances to the right until it reaches 30 -35 degrees BTDC (engine turns clockwise). If the Z1 mark (left mark) is TDC then the mark to the right would be 5 degrees BTDC which makes no sense since it needs to be timed at 5 degrees ATDC. The purpose of the decal is to show correct timing. What is confusing me is it looks like TDC is represented as the left mark when it should be the right.
Chris
73 911 E
After thinking about it I think you are correct, the line 5 deg to the right is BTDC, I think the decal is marked incorrectly, does your crank pulley have the 5 degree notch to the left of TDC?
It's right. 5 degrees ATDC at 900rpm. Total is about 35 degrees BTDC at 6000rpm. I think you can see that line at about 11o'clock.
All that was fine back in the day, but you should really have your distributor remapped for modern fuel which is much more volatile. The distributor will come back with timing settings to adjust to. Makes a big difference.
John Forcier
EarlyS #1987
1968 911 Race Car "Grun Hilda"
1969 S/T interpretation "Blau Healer"
Restoration Saga
It depends what year car the pulley is for. Prior to 72 there was no vacuum retard, so there was a Z1 and 5 degree advance mark to right of Z1. In 72 and up there was vacuum retard so pulley was marked with a Z1 and a 5 degree retard to the left, and a 5 degree advance to the right.
Early S Registry member #90
R Gruppe member #138
Fort Worth Tx.
Wow, all kinds of confusion and miss information. The line at 11:00 has nothing to do with timing or advance. The timing advance indicators are the two lines at the 2:00 position.
My question remains, TDC is the line to the just to the right and the one to the left is 5 degrees ATDC. I wonder why it is labeled as showing TDC (Z1) as the left line which, again is 5 degrees ATDC, I believe.
Chris
73 911 E
This diagram was taken from PP a while back. I think Grady created it.
E911SR & RGRUPPE
'65 911 "The Ol' Gal" (long gone)
'73 S Coupe #306
So can we agree the decal is wrong or at least deceiving how it shows Z1 for a 72 and 73 911
Chris
73 911 E
From the owners manual. Glad I am correct as cam timing as well as regular timing was done from the line to the right.
Chris
73 911 E
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