Emergency Valve Adjustment Advice - PLEASE

vreference · 04-16-2008, 12:37 PM

I've been putting off asking this question for as long as possible but now here I am with my valve covers off again for the 2nd time in as many weeks! I was ready to write the last attempt off as the fault of the 20 year old Feeler gauges I was using but this time, armed with a brand new crafstman set I'm running into the same issue.

Using the backside method, more often than not, when I am able to insert the .0025 gauge I am then able to sneak the .003 gauge in as well. Some times I've been able to get the .003 gauge into a gap that I couldn't, for the life of me, get the .0025 gauge into. After the .003 gauge has been there the .0025 gauge goes right in.

I take it this is an issue with oil film and I noted that people often mentioned pressing down on the tip of the rocker. I have pretty strong fingers and I've pressed the day lights out of those tips and also tried wiggling it while pressing but no joy here. What's the secret? Where am I going wrong. I cannot continue at this point - I just spent 45 minutes on #2 and I'm not so sure about 1 and 6 anymore. Backside method veterans; How do you prepare the rockers for measurement?

afterburn 549 · 04-16-2008, 12:45 PM

I think you are having too big a issue with a 1/2 a thou ! Your valve train will not care or know the diff

vreference · 04-16-2008, 12:54 PM

Perhaps I'll get them within reason but I'm half way through the cylinders and I haven't found any really obvious explanation for my clacking valve train. I used a dowel to listen and I am reasonable certain the noise is coming from the valves - the car barely smokes at all on startup so I don't think this could be a worn valve guide causeing the noise. It's a little clicky cold and a full on clack that you can hear reflecting off things as you drive by them when the engine is hot.

Fast Corners · 04-16-2008, 01:14 PM

When the valves are warm and adjusted properly you should not hear anything other than a quiet whirring sound. I listen to them with an engine stethoscope placing the end of the device on the nearest stud to the rocker I intend to listen to. With a little practice you can tell which rocker is out of adjustment.

York · 04-16-2008, 02:10 PM

Try doing the adjustment the standard way and then check to see if you can insert the 0.003 on the backside. If so, adjust the valve a bit tighter and try again. I just did this and it helped me develop a feel for the standard adjustment method, which I think is the best way to do it (just my opinion of course).

Zeke · 04-16-2008, 02:12 PM

The angle is which you insert the feeler gauge is awkward at best. Unless you can maneuver the gauge exactly square, you will get funny readings like you are getting.

I like to leave the gauge in place and let go of it. I then tighten the screw back and forth to gain a feel, then tighten the lock nut. Even when you tighten the lock nut, you get a little wider gap because the LN pulls the screw back into the rocker ever so little. This alone frustrates a lot of people, but you will learn to anticipate it and go fairly tight against the gauge when setting the screw.

coollx · 04-16-2008, 04:54 PM

I just went through my first valve adjustment and can relate to everything you are saying.

One thing I did that helped with both the backside and regular method is to dip the end of the feeler gauge in motor oil before trying to insert the gauge.

If the cam lobe and rocker arm or valve tip is fairly dry it is much harder to get the feeler gauge started which can then lead to opening the valve lash too much.

vreference · 10:30 PM

After spending a massive amount of time on each cylinder only to come back around to it to check and find it loose I decided to make an incremental change and move on to the next cylinder. Still a little time consuming but I ended up with perfection after approximately 4-6 full cycles.

Stethoscope reveals a humming valve train but I still hear a tick kind of sound coming from somewhere but I cannot locate it by probing - I wasn't able to drive it so it may very well be quieter now. I put an Allen wrench on all the lower studs and all appear to be intact - I was on the short side of the wrench so I wasn't putting a tremendous amount of force on them but I assume it was enough to reveal an issue since most people report finding them falling out if they are broken.

I'll have to get a video of it I suppose but it just seems like the car is louder than most Porsches and the high pitched sound is not coming out of the end of the pipes. Possibly the B&B Headers? I know I could always hear each cylinder fire at the H-Pipe of a 5.0 but you could only really hear it if you were under the car near the pipes.

Edit: Had to change some things that were misleading. As far as I can tell the sound isn't coming from the engine (Case, Cylinders, Valve Covers) or any part that I have probed so far. The sound is not coming out of the exhaust pipe tips. Covering the tips does not make the tick go away.

Eagledriver · 04-16-2008, 08:13 PM

911 valve trains make noise. The more wear they have the more noise they make. You can't adjust away the noise although a good valve adjustment will help. They make more noise hot than they do when cold because the clearances increase when hot. If you set the clearance when the engine is warm it will be tighter when cold and vis-versa. The noise doesn't just come from the gap between the rocker and valve. It also comes from the rockers on the shafts and the rockers against the cam housings and even the elephant feet on the adjusting screws.

-Andy

efhughes3 · efhughes3's Garage

I'm still of the opinion there is no free lunch on valve adjusts. Go with the standard method, loosen enough the get the feeler gauge in, then snug down. No muss, no fuss. What is THE deal?

RoninLB · 04-16-2008, 09:18 PM

valve train noise is a nice 911 trait imo.

T77911S · 04-17-2008, 03:33 AM

i just did my valves this past weekend and had some of the same issues. also, i was not sure if the 003 was not going in because the valve was adjusted right or i just did not have a good angle in getting it in, but just on the intakes. so in the end i set the exhaust so the 004 would go in on the front, it was very very tight, but the 003 would not go in on the back side (both of my 025's where worn out by this time anyway). by then i had a good enough "feel" for the 004 that i did the intake's with the 004. again, it was very hard to get it in and sometimes even harder to get it out. i checked a few of the exhaust with the 025 and it would go in.
what i was concerned about was that when i had the valve too tight, the 004 would go HALF way in. also some would be different when i went back through them. is this a sign the "swivel feet" on the rocker are bad?

afterburn 549 · 04-17-2008, 06:24 AM

I guess if you wanted truly reliable results the dial indicator method might be the best...........

KFC911 · 04-17-2008, 06:40 AM

Quote:

Originally Posted by efhughes3

...Go with the standard method, loosen enough the get the feeler gauge in, then snug down. No muss, no fuss. What is THE deal?

I agree...

gtc · gtc's Garage

Quote:

Originally Posted by efhughes3

... Go with the standard method ...

+1. The backside method sucks bigtime.
Get Pelican's feeler gauge and some spare tips just in case (I haven't broken any, but YMMV).

JFairman · 04-17-2008, 08:25 AM

The origonal way works fine for me too.

rusnak · 04-17-2008, 09:55 AM

the backside method is like a 9.9 on the " taint right" meter....wait, what were you guys talkin bout?

gregwils · gregwils's Garage

My first vavle job produced what sounded like Stugart's first flat-6 diesel. I repeated the process, with a better understanding of how much drag should be on the guage. I chose the standard method.

There needs to be enough drag on the feeler guage that it is not easy to insert the guage using the standard or backside method unless your approach angle is correct and the feeler guages don't have adequate sturdiness unless that angle is correct. This is my experience, but others swear by the backside.

I would suggest that if your are struggling, go with the standard method. Loosen the valve, insert the guage, tighten until it is too tight (you can't remove the gauge), then back it off enough to remove the gauge with modest effort. Not yanking, modest effort.

You will require the special Porsche feeler gauge when using the standard method. Conventional feeler gauges can't access the foot. Make sure the small bolts holding the gauge are on tight and check frequently through the process.

Zeke · 04-17-2008, 11:47 AM

Quote:

Originally Posted by T77911S

i just did my valves this past weekend and had some of the same issues. also, i was not sure if the 003 was not going in because the valve was adjusted right or i just did not have a good angle in getting it in, but just on the intakes. so in the end i set the exhaust so the 004 would go in on the front, it was very very tight, but the 003 would not go in on the back side (both of my 025's where worn out by this time anyway). by then i had a good enough "feel" for the 004 that i did the intake's with the 004. again, it was very hard to get it in and sometimes even harder to get it out. i checked a few of the exhaust with the 025 and it would go in.
what i was concerned about was that when i had the valve too tight, the 004 would go HALF way in. also some would be different when i went back through them. is this a sign the "swivel feet" on the rocker are bad?

Not necessarily a sign that they are bad, but pretty much an indication that the insert angle was off or you're "tipping" the foot.

Also, remember that a cam won't produce the same number both on the lobe and on the heel at the same time. You use one of the other of the methods. The whole point is to make sure the valve rests completely on the seat with no pressure sometime during the cycle. .004 gives you that warm when the tolerance is tighter. If you went thru this hot, you would be surprised.

vreference · 04-22-2008, 09:57 PM

Update: The passenger side of my engine has always been the worst offender. I pulled the covers for the 3rd time, adjusted with Proper tool and then verified via Backside method. I'm afraid I'm pretty darn close now and the Tick/Clack remains. I fear something more serious may be wrong here. The car still runs great; I guess the next step will be to do a compression check. I know someone has put the valve-guide theory forward. As far as I can tell the car doesn't smoke much at all (If any) on startup so I'm not so sure about a guide so worn it could make this noise and not leak a lot. After lots of poking with a Dowel I believe it's coming from the #5 - I can hear it from the Valve Cover a bit, From a cover bolt pretty well and from the Cylinder wall. There is, as far as I can tell, no sign of the sound coming out of the exhaust. Probing the case sounds perfect and I would think I would hear a bad rod or even wristpin at the case. Chain covers sound great too.

Any of you certified diagnosticians - the critical clue (That I don't know how to interpret) may be that at idle the sound will go away completely if the RPMs are just right. If the RPMs come up just a hair it will come back like someone flipped a switch. Around town the sound does not change under varying loads (Again Piston Slap, Wrist Pin, Rod, Main - All the major issues I would think would change slightly under different loads.) Idle, Off-idle, Accelerating, WOT, Closed Throttle - at all engine speeds the click does not sound any different - Only changing cadence with the engine RPMs. This screams Valve train to my mind.

I don’t really mind pulling the car apart but I really wanted to drive it for at least the season. Even assuming the issue isn’t causing any damage the clack is loud enough to make it harder to enjoy driving the car. It’s such a shame too considering it drives like new except for the cacophony that follows you around.