Another Timing Question
 

Hello and thanks for the wealth of info on the forum. What a great source of info and opinions. I am currently in the process of resealing the cam housings on a 76 911s engine and have run across different specs for cam timing. The vintage mitchell manual has a spec of .40-.60mm which is greater lift than any other spec I have found. I understand cam timing is part of normal tuning and with performance mods different specs may be desired. My only question is.....What the heck is the stock spec!? If anyone could chime in I would greatly appreciate it. Here's some engine and cam numbers:
Engine number- 911/82 and 6462217
1-3 cam- 143.00
4-6 cam- 144.00

Also, is there a warpage limit on the housings? Using a straight edge and feeler gauge I can get .003" under it at one end. And finally, when placing a straight edge across the 1-3 cyl heads I can get a .003" feeler gauge under it right in the middle of cyl 2 head. Most cyl heads i've dealt with have a limit of .004" so i'm not all that concerned but I thought it was worth posting to get others opinions. Thanks in advance for any thoughts or specifications.

Does the cam spin smoothly by hand? If so, and the cam rack doesn't leak, you're okay.
Did you set your gauge up and check the current timing of the cams? That might give you a good idea of the ballpark of where they are now compared to what spec to use.

The cams definitely turned freely before dis-assembly. The reason for the repair is oil leaks between the cam housings and heads. I did check timing before removal of the towers and both sides were set to 0. No advancement at all. The cams were actually retarded a little(no gauge reading until after Z1). I am pretty confident the housings will seal. Just wanted to verify the .4-.6mm spec. thanks.

0.4-0.54mm at overlapping TDC with 0.1mm valve clearance.

The Cap'n

Thanks for the reply. Will set at .5mm.