piston and valve clearance help

[saxe91]

I am to the point in Wayne's book of checking number 1 and number 4 intake and exhaust valve piston clearance will rotating the crank. it turns out that I do not have what wayne write is a must have for clearance. It looks like I have about 1.15mm to 1.25mm on the intakes and 1.5mm on 4 exhaust. number 1 exhaust is above the 2mm number. This motor will not go on the track since it is a 72 t targa that is a restore putz around vehicle. I think the machine shop "fly cut the head and this is where I have come up short. the deck height looked good (Ollies machined the case and included a huge copper cylinder shim which was used).
So ... could I retard the camshaft?
or proceed on?
or break it down and add another .5mm or .75mm shims to raise the deck, and if I do that should I get new cylinder head gasket? (new currently in groove but obviously torqued down)
Thanks

[Eagledriver]

If you do have at least 1mm intake clearance and 1.5mm exhaust clearance, I'd live with it. Porsche has a hard to find spec of .8mm in the first 911 factory workshop manual for the 911S. I assume you are turning the crankshaft to do this check. If you are just dialing in the screw at TDC you won't have an acurate clearance number.

-Andy

[saxe91]

thanks for the reponse,
I did indeed move the crankshaft while having the valve in close position and no adjustment on the rocker screw. I turned the rocker screw for 1.5mm and then started to rotate the crank. Just pass Z1 I got contact. I kinda backed off until it seems the crank would rotate freely which is why how i came up with 1.25mmish I wonder about all the other piston valves. I think I am going to test all the valves.
Could you direct me to where you found the .8mm I have the manuals and have been looking for that number. Mine might not be complete, but would like to see to get a better feel of proceeding. If I DO decide to tear down, should I replace the head gasket ring? thanks

[Eagledriver]

This came up about a year ago and I went out to my garage and found the reference. I first found it when using the book for a rebuild. This afternoon, if I have time I'll look it up again to give you a page number. It's in volume 1 the big volume before all the supplements. It's also mentioned in Bruce Andersons book in the engine rebuilding or modification sections. He says he likes to use more than the Porsche spec. but he mentions the spec. I think he says to use 1.5mm but don't quote me. You'll have to decide the condition of the head gaskets for possible replacement.

-Andy

[Eagledriver]

Page E72. It's in the section on measuring valves and replacing valve guides.

-Andy