Hi Folks,
Since I’m on hold waiting for parts I thought I would impose on you one more time. Im getting my 1973 S3 2+2 (pre HE) ready for spring and I decided that I would check the valve clearances (I had forgotten that I had checked them 4 years and 12K miles ago when I had the engine out replacing the slush box with a 4 speed-doh) and found them to be a little tight but essentially unchanged from 4 years ago. the tightest was B5 Intake at 11/1000. Almost all on the ‘A’ side were 13 where as the ‘B’ side were a little tighter with several 12’s and the one 11 I mentioned.
I was going to leave them alone but now I’m wondering if I should just bite the bullet and ‘pop’ the cams out and do the job. I’ve done this a couple of times on the XK engine but never on the V12, frankly the timing chain damper scares me. This would be the time given I’ve made the tools and it’s exposed except for the fragile damper.
I appreciate your thoughts.
Cheers,
Lynn
For those clearances I doubt if I’d risk the timing chain tensioner failure. I will point out, though, that Bywater taught us all that you can wring a little bit more torque out of the V12 by opening the exhaust valve clearances up a tad. Like, the spec is 0.010-0.012, but set the exhaust valves at 0.014 or so. So if you’re gonna go to the effort, you might consider that.
Also note that the clearances don’t seem to move too much with wear, but when they do move they move toward tighter. So it’s wise to aim for the wide end of the clearance spec.
Thanks Kirbert, I think I’ll wait till the next time I have the engine out 
As soon as I get the aluminum half moons I’ll seal her back up. Bought the 1/4x20 socket head ‘screws’ for the cam covers and will save the OEM thread cutting screws for the next owner. Have appreciated your book over the years, again thank you!
Kindest regards,
Lynn