Feeler gauge for valve adjustment

[quint22cp]

Calling the UK members.

Anyone got the special feeler gauge for doing the valve adjustment or tell me where I can buy one ?

I have many jigs for machining all Porsche engine bits if you need them.

[lespaul]

I suggest you dispense with the Porsche feeler gauge and use a regular set of gauges and the "backside" method. In my opinion, it is far easier and much more accurate.

[ros74911]

please explain on backside method. i checked here for tech article on backside method. but unable to understand it. i think, i'm missing something. i'm not sure what. i've been doing the traditional valve adjustment. backside method seems and looks easy. anyone??? please. also, what happens if adjusted too tight?

[lespaul]

Read and then re-read the multiple threads on it. It will eventually sink in.

The only thing that hung me up when I read the threads was that none of them said you have to remove the tin around the valve covers to get proper access. To adjust the top set of valves, you have to approach with your feeler from underneath the car. To adjust the bottom set of valves, you have to approach with your feeler from the top. Getting the tin off will give you a chance to clean it up and paint it.

Once you do a few, you will get the hang of it. First time around, took me 3 hours. Second time - 1.5 hours.

[ros74911]

thanks, brad. o i c - so this tin is not hard or remove? now it make sense. i've been reading up on this. can't seem to recognize the pics they've shown on tech articles. yeah, i'm getting tired of doing traditional valve adjustment. thanks again.

[glenncof]

I just did my first valve adjust. I had the special tool for normal approach but could not get satisfaction (I've done valves before but not on 911.)

I used the backside method. And checked several rotations. You are working blind and the 0.0025" feeler is thin so wiggle it alot to get it in. First pass I did too loose. 2nd and 3rd made tweeks. One screw turn is 1mm (from what I read) so about 1/10th turn is all you need even if tight. There's variability as you rotate so I stopped after 3rd pass.

[ros74911]

thanks, glenn. what happens if too tight on adjust?

[lespaul]

Tin is easy to take off (about 5 screws per side) and, as I said, gives you a chance to get in there and degrease and paint the tin before putting it back on.

Get in there right up under the car to see what is going on with a good light and glasses if you need them and it will all be very clear. You will see exactly where to slip in the feeler.

Glenn is right - a 1/16 turn on the valve adjust screw makes a big difference. I slipped the feeler in, then tightened down the adjust screw until it dragged heavily - till I could just barely move it --- but still leave it in. Then tighten down the screw. If you can pull out the thin feeler but not get the thicker one in, you have it perfect.

[lespaul]

Ros, using backside, if you can still get the thin feeler out after tightening down the screw, it is impossible to be too tight.

[ros74911]

Originally posted by lespaul
Tin is easy to take off (about 5 screws per side) and, as I said, gives you a chance to get in there and degrease and paint the tin before putting it back on.

Get in there right up under the car to see what is going on with a good light and glasses if you need them and it will all be very clear. You will see exactly where to slip in the feeler.

Glenn is right - a 1/16 turn on the valve adjust screw makes a big difference. I slipped the feeler in, then tightened down the adjust screw until it dragged heavily - till I could just barely move it --- but still leave it in. Then tighten down the screw. If you can pull out the thin feeler but not get the thicker one in, you have it perfect.

ok, thanks brad. you lost me here. i use both feeler thin and thick then tighten it?

[glenncof]

Originally posted by ros74911
thanks, glenn. what happens if too tight on adjust?

Let me qualify. My exhaust mid/rears had no play what-so-ever.That qualifies as too tight.

As I understand you can "burn" the valves. Actually I think it is warping so the valve won't seat. Some expert should comment.

BTW, mine had 56K miles on the valve adjust. I had it done once before at a shop with similair miles and was told they were tight. Spec. is 15K miles I believe.

(Do as I say, Not as I do.)

[lespaul]

Sorry to be obtuse.

Slip the thin feeler in. Then tighten the adustment screw until you can barely move the feeler back and forth. It should drag heavily. Then, lock down the adjustment. Slip out the thin feeler -- it should still drag. If you can't get it out after tightening, you obviously have it too tight.

Once you have the thin feeler out, then try to slip in the thicker feeler. If you can't get it in, the adjustment is perfect.

Does that help?

[ros74911]

thanks for your input, brad and glen. appreciate it.