Factory 3.1 SC-L cam timing help

[jimtweet]

I am wondering if someone can help me understand the cam timing on this letter for the motor I am currently working on.

In hindsight I probably should have checked it before disassembled, but both chain tensioners were collapsed and I figured it may have been thrown off

Here is the letter from the dealer/factory

[jimtweet]

[porschyard]

That technical bulletin came from my archives and i posted it in Dec. 2018 in response to questions from Pelican member Steve G about the factory 3.1 kit offered thru Porsche as an upgrade to complaining customers of the disappointing power levels at the time.

I am not sure what you are trying to understand as the timing figures are pretty self explanatory. The timing spec range is 0.9- 1.1 mm overlap @ TDC with a optimal setting of 1 mm. The 3.0 carrera, all SC's and all 3.2 carreras have the same cam specs and can be timed as far retarded as 0.9 and advanced to 1.8 mm or more depending on other engine factors.

You can time your cams anywhere in that range depending on what you are looking for (low end torque advance them - High rpm H.P retard them) Or somewhere in the middle (1.4) for a compromise.

Richard

[jimtweet]

That’s all I was trying to verify, is that it was the “same” cam timing as usual

Originally Posted by porschyard

That technical bulletin came from my archives and i posted it in Dec. 2018 in response to questions from Pelican member Steve G about the factory 3.1 kit offered thru Porsche as an upgrade to complaining customers of the disappointing power levels at the time.

I am not sure what you are trying to understand as the timing figures are pretty self explanatory. The timing spec range is 0.9- 1.1 mm overlap @ TDC with a optimal setting of 1 mm. The 3.0 carrera, all SC's and all 3.2 carreras have the same cam specs and can be timed as far retarded as 0.9 and advanced to 1.8 mm or more depending on other engine factors.

You can time your cams anywhere in that range depending on what you are looking for (low end torque advance them - High rpm H.P retard them) Or somewhere in the middle (1.4) for a compromise.

Richard

[porschyard]

Originally Posted by jimtweet

That’s all I was trying to verify, is that it was the “same” cam timing as usual

Yes, Procedurally the same as all other 911 cam timing.

Richard