Valve adjustment

[Flieger]

I was looking at Wayne's book last night and read about adjusting the valves. He mentions ticghtening the rocker screw with a feeler gage between the rocker and valve. How thick should the feeler gage be?

[rlane]

There are excellent tech articles on both the standard method and the backside method in the tech articles section of this site but it is 0.1 mm or 0.0039", really need the special feeler gauge holder or even better the Island tool (search for this on the bulletin board)

[Flieger]

Thanks for the info.

What are the symptoms of a motor in need of a valve adjustment? Are there sounds it makes or ways it runs that show the state of tune?

[911Freak]

Poor running, popping and back-firing, and when looking directly over the engine with the engine tail open, there are tapping or slight-lite knocking noises...to name a few...

I use a very long Screw driver 18" -24" and put my ear to the handle and move the tip around each cylinder head to see who's asking for an adjustment...

[Flieger]

Thanks for the tip. :-)

[charnett]

My 911 has 99,000 miles and I'm getting close to 1000 miles after a Top End Rebuild, done by a local shop. Their recommendation is that the valves be adjusted at 1000 miles, which is something I've done before and am fully capable of.

However, the shop also tells me the rockers shafts should be re-torqued at the 1000 interval, which another mechanic says is not necessary and may be a ploy to discourage me from doing it all.

If somebody does not mind advising, I'd be deeply appreciative.

Chris

[Crashly]

I think that in Waynes book it recommend that the head studs be re-torqued at 1K. I my be wrong on the exact mileage. I have always used the tappet method to adjust my valves, until I discovered the backside method with the go no go guages. Way easier, quicker, and I felt had a lot more confidence in my work when I was finished with each valve. I didn't have to worry about that "special feel that is developed after a few hundred valve adjustments"

[charnett]

Crashly, thank you. I better read Wayne's book on this subject, and be sure I'm, not overlooking the head bolts/studs. Meanwhile, I agree on the tappet or "backside" method, which is so much easier, and more like what I did adjusting valves in the old 356's and Mercedes diesel's. Aside from the "special feel" difficulty, I kept bending and having to replace the feeler gauges, so I ended up using that method just to confirm the "backside" method, where I could actually see the elephant's foot.