What size is this nut (Valve adjustment)

[jk911]

I am getting all my tools together for my first valve adjustment !

What size is this nut ..?


Will a standard wrench lenth do the job. I imagine it would be hard to get under and around the exhaust on the lower valves !

[Paul Thomas]

Pretty sure that its 14mm. (oops, I mean 13)

[PeteT]

jk-
It is 13mm. A stubby screw driver will also be needed. There is a ton of stuff in the archieves about valve adjustments on this board. Just go slow and take your time. It is not that bad. Check your work before you button everything up.
Pete

[jk911]

Thanks for that .
I know the content of information on this topic is great !

[Sonic dB]

Pretty good illustration of a Valve adjustment there... really, better than ANY of the pictures in ANY of the Porsche books that I own. Nice work.

yes, it is 13mm

and I am having flashbacks... someone help me.

[jk911]

I should state . That is not my photo.. I haven't done it yet.

Its from this website in the 911 tech articles, its the most comprehensive description I have seen yet it makes it look extremely easy !

[targa911man]

I use a 13mm offset box wrench. I also use a screwdriver bit with a socket wrench for leverage holding the screw when tightening the nut.

[dhaines]

I second using a 13mm box wrench along with a short stubby flat head screw driver. The hardest part is geeting the feeler gauge in the gap between the top of the valve and the rocker. I pull on the rocker to make sure I have all the gap, then run the edge of the feeler gauge along the top of the valve until it falls into the gap. You can't see a damn thing, so doing it by feel works best, in my opinion. After a few times is becomes quite easy, but can be frustrating at first. Have fun!

[Wil Ferch]

I think someone said the thread pitch is 1mm, so an 1/8 of a turn from closed should give you 0.125 mm clearance...close to spec ( 0.1 mm ..or 0.004") but ever-so-slightly loose ( on the "safe" side of spec). Might want to consider this as a method to adjust valves instead of using feelers. Split a "quarter-turn" in half and go for it !

---Wil Ferch

[targa911man]

Originally posted by Wil Ferch
I think someone said the thread pitch is 1mm, so an 1/8 of a turn from closed should give you 0.125 mm clearance...close to spec ( 0.1 mm ..or 0.004") but ever-so-slightly loose ( on the "safe" side of spec). Might want to consider this as a method to adjust valves instead of using feelers. Split a "quarter-turn" in half and go for it !

---Wil Ferch

Wil--

I am trying to think of a reason why that wouldn't work but can't come up with one, except if it's that easy, why is this the first time I've heard it. Also, why didn't I think of that myself?!

[KTL]

Wil's right about the thread pitch. It's M8 x 1.

[island911]

"so an 1/8 of a turn from closed should give you 0.125 mm clearance...close to spec ( 0.1 mm ..or 0.004") "

So then how do you measure an 1/8 of a turn? BTW, wouldn't you want a 10th of a turn?

So who's going to make us all a bunch of little 36° protractors? .
. . .and will they have hard, precision ground, limit stops? (TIC)

[kstylianos]

So who's going to make us all a bunch of little 36° protractors? .
. . .and will they have hard, precision ground, limit stops?

......and a device that will beep when we have elephant foot to valve stem contact.

[Superman]

Using the special screwdriver with the spring-loaded shaft, you can just adjust them while the engine is running.

[jk911]

As a side question !

before taking the valve covers off.. do I need to drain the oil in the oil tank as well as the sump.

If I only drain the sump will I get oil all over the place when I remove the covers ?

Also last time I changed my oil I put 2 much in !

What is the correct amount of oil required for a 2.7 L engine ??

[Wil Ferch]

Yep:
You'd like to turn a 1/10th...but jeez...for a simple method that probably gets you as close as you need to...it's a very effective and cheap way to get real, real close. Depending on how far you're out to begin with, to get 0.125 aint so bad. A quarter turn can be measured easily by some visual indicator ( screwdriver handle), and splitting the difference is more accurate than you'd think. It does work.
---Wil Ferch

[targa911man]

I agree with Wil, particularly when you consider that the feeler gauge method is by definition done by "feel", which is, frankly, a matter of opinion. I think tightening the screw down and lining up the slot with the bottom of a grade school protractor, then lining the slot up with the 45 or 36 degreee mark would be relatively easy. Then tighten the nut and check the clearance with the gauge.

[island911]

Originally posted by targa911man
. . . consider that the feeler gauge method is by definition done by "feel", which is, frankly, a matter of opinion. I think tightening the screw down and . . .

whoa; isn't "tightening the screw down done" by "feel", which is, frankly, a matter of opinion? . . .just how hard do you tighten it down?

So, now, you have to have the "feel" of "tightening the screw down" PLUS calibrated eyeballs to keep track of the 36° clocking.

Personally, I would say that if you're going to stack-up that much error potential, with the adjustment, just go in there and rock them by hand. . .feel for the gap. It's surprising how close you can get. (This is what I do . . . just before I drop a feeler gage in the slot.)

OR "for a simple method that probably gets you as close as you need to" . . .just leave them alone. (considering how many posts, people have said they have made matters worse, by going in there.)

I really loath noisey valves. Noisey valves mask other potential problems. Valves too tight is a problem. YMMV

[targa911man]

". . . rock them by hand . . ." --Why didn't I think of that?