bagger

Does anybody know what Porsche recommends for the torque value for the 13mm lock nut on valve adjustment screw?

I have not adjusted valves on a 911 before so I may give up on using a torque wrench due to not being able to fit the wrench and crowfoot in the space. But at minimum, I'd like to know what the right torque should feel like.

The engine is a 3.2 liter if it matters.

Art

KC911

Hi Art, maybe someone more knowledgable will chime in, but as far as I know, you can't accurately use a torque wrench on these nuts. (With a crows foot attached to the torque wrench, you're not getting an accurate torque anyways fwiw). These nuts are not prone to working loose, so just get them tight (but not 'gorilla tight') with a box wrench, and you'll be OK. Hope this helps...

Keith
'88 CE coupe

Peter Zimmermann

Art: Put the head of an 8mm bolt in a vise. Put a metal sleeve over most of the bolt threads (a short stack of steel flat washers will work), install a flat washer and a new 13mm wrench size nut on the bolt, tighten the nut against the washer, which will seat against the spacer. Torque that nut to 18 lb/ft - over and over, until you can duplicate tightness by hand. That will put you in the ballpark. As Keith stated, use a box end wrench. I'd like to take that one step further. If you are using SnapOn, Stahwille, or another high quality wrench you'll be OK. If you're using Craftsman, etc., you'll probably need to modify the wrench. Adjuster jam nuts are very thin, so you'll have to examine how deep the broached part of your wrench is. If the wrench teeth won't grip the nut tightly place it flat against a grinding wheel and remove material until its teeth can grip the nut properly. If this is not done you will round off nut corners and make a mess of the job.
Pete

r911

and keep you hand at the same point on the wrench each time - not further out or choked up/closer in

BUT.. you still haven't solved the problem of getting an accurate 18 ft-lbs - that will take a small torque wrench that most don't have

ZOANAS

If you focus too much on the tightening torque for the lock nut, you will inevitably miss the "feel" for getting the gap set correctly. You should be tightening the lock nut lightly while moving the feeler gauge, then tightening down full force when you know the gap is where you want it. Focus on the gap, not the torque of the lock nut, you'll be less likely to repeat the valve adjustment twice.

bagger

Thanks for the input everybody.

Keith, I planned to set the torque wrench to a lower torque value to correct for the increased moment arm caused by the crow foot.

Pete, Thanks for the wrench modification suggestion. Where did you get the 18 lb/ft value from?

Art

jet911

Art, Pete owned his own shop for about 30 years. I'm guessing the torque setting came from the factory service manual and experience as he has probably done more valve adjustments in a week than you and I will do in our life times....

Peter Zimmermann

Jet: I think you're right - my elbow "clicks" at 18 lb/ft! Art: 18 pounds is pretty much the standard for 8mm hardware, a rule of thumb if you will. Trying to deal with a torque wrench and crow foot while holding the adjuster screw with a screwdriver is just too much to do. You must learn to tighten those jamb nuts by hand, with a box end wrench, to their final tightness, then remove your shim stock (gauge) with drag. Then, as your double check, slide your gauge back into its adjustment position. This will require touch, if it goes in easy, with little or no drag, the valve is still too loose. If it doesn't go, you've managed to get the valve too tight.
Pete

bagger

jet911 and Pete,

Thanks for the additional posts!