valve adjustment

[livi]

Thanks Doug, but isnīt that what you wrote initially too ?

0.06 mm and 0.08 mm right ?

[2.7RACER]

Markus,
I edited the post. I orginally had them at .6mm and .8mm. That wouldn't work at all.
The correct shims for GO is .06mm, which converts to 2.36 thousandths of an inch.
The NO GO .08mm converts to 3.14 thousandths of an inch.
So the metric GO is a little thinner than the 2.5 thousandths and the metric NO GO is slightly thicker than 3.0 thousandths.
Ten thousandths of an inch shouldn't be any problem.
I agree, we would all be better off with the metric system. It certainly would keep my math mistakes to a minumum.

[Brad01mc]

Hi!

Hard on myself??? Yes, I live in Redlands,but I'm not from here!!

I'm Canadian, so I understand the Metric system, plus, if these engines were designed with the metric system, then why not use the same measurement system? You wouldn't use standard sockets on your metric bolts would you??

I understand the error that we are talking about is very small, but why not be as accruate as you can. These ARE German, afterall.

Also, if the calculation for this method is 0.069mm (thanks wesayso), why do you use two different sizes? if it's 0.69mm, then it's 0.069mm, right? Why do you need a GO vs. NO GO??

I hope this comes across as more tongue and cheek than serious. I've grown up using Metric, so its harder for me to think in inches.

I just looked at my feeler guage set and I'll probably use the GO/NO GO method, but if I can find a 0.069mm gauge (probably find a 0.07mm), I'd be curious to use it.

Brad

[2.7RACER]

Brad,
No reason why you can't use a .07mm shim/feeler to set your valves.
The idea with the GO, NO GO is based upon using available inch series feeler gauges.
Use of a .07mm feeler/shim would work well, while checking with the .0025" GO and the .003" NO GO.
Actually an interesting marriage of inches and milli-meters.
Since .07mm converts to .00275 inches, it is within one ten thousandths of the calculated dimension of .00281".
Using the .06mm as a GO and the .08mm as a NO GO works, but isn't quite as close as the .0025" GO and .003" NO GO.
My view is either works well. It gives our friends in metric countries an option that is more likely available to them.
Thanks for bringing this up.

[sig_a]

Today I did it this way on all cylinders. Broke the 13mm jam nut, opened the efoot, slid in the .004" shim, tightened down the efoot to what felt right, tightened jam nut c.wise while counterturning efoot, measured rocker/cam contact point, used .003 as "no-go", used .002 as "go", recheck measurement at efoot with .004" where possible. On some cylinders, recheck measurement at efoot was not always possible. Rechecked all cylinders at rocker/cam contact point .003 no-go, .002 go. Using .003" no-go works fine, using .0025" go didn't work. Im thinking one-half of 1000th" between .003" and .002" is literally spliting hairs. Hope I'm right. The other great thing about this no-go, go procedure is you do develop a feel for how much pressure under the efoot will result in .004" measurement.
Also, most of the rocker/cam measurements work best from underneath the car. But a few worked well from above. When in doubt, I jumped on the creeper and checked from the exhaust side. My only other experience setting mechanical valves was on a Kawasaki KLX 650 single cylinder motorcycle with shim over bucket overhead cams with two exhaust and two intake. Hope this new procedure isn't too tight. I still have to reassemble before I find out. Thanks 2.7RACER.

[2.7RACER]

sig_a,
If the GO gauge won't slip in, you are tighter than 3.5 thou at the swivel foot/valve stem. If the 2 thou slips in, the gap at the swivel foot is over 2.8 thou.
So the gap at the swivel foot/valve is somewhere between .0028" and .0035". About 1 thou tight.

[sig_a]

2.7RACER:

Thanks for quick response. Now I know why my difficulty remeasuring .004" at swivel foot. Sounds like I should shoot for a loose .003" measurement at rocker/cam as "go" combined with a firm drag at .004" swivel foot. What's your advice?

[zumwoll]

Pelican sells a lot the the Tune-up DVDs. Lots of positive fb. Good video of valve adjustment.

[2.7RACER]

sig_a,
A loose .003" translates to over .0042" at the swivel foot/valve stem.
Not good. Too loose. Your valves will be noisey.
The .003" is a NO GO gauge for a reason. If it won't go, the gap at the swivel foot is less than .0042.
Pass test 1. Not too loose.
The .0025" is a GO because it will slip in as long as the gap is over .0035" at the swivel foot/valve stem.
Pass test 2, not too tight.
Remember, you are shooting for .004" at the swivel foot/valve stem gap.
Correctly set, the .0025" will slip into the rocker arm/cam lobe gap, the .003" will not.
Good luck,

[A Quiet Boom]

I love it, adjusting P-car valves has become as simple as adjusting other makes. I can't wait to try this method. I've always hated the hook gauge.

[livi]

Excellent Doug !

I think I actually understand not only how this technique works, but CRUCIALLY, WHY !! Reading up on the valve adjustment topic has enlightened me a lot on how the engine works.

Feels pretty good!

[Gunter]

Originally posted by 2.7RACER

Use a 3 thousandths (.003") feeler as a NO-GO gauge.
Use a 2.5 thousandths (.0025") feeler as a GO gauge.

Just did it with the engine out and the numbers are right on.
I used the metric 0.1 special tool and checked with the inch-blades.
Because the blades on the feeler gauge are pretty thin in that range, make sure there is a little oil between the cam and the feeler so it slides easily.
Found that going around a second time showed a few valves needing a slight re-adjustment.

[khamul02]

Originally posted by zumwoll
Pelican sells a lot the the Tune-up DVDs. Lots of positive fb. Good video of valve adjustment.

There is a vhs (which I converted to DVD) called "911 porsche tune up video". I think performance offers it. I have both the one you mentioned & this one. I think the VHS version is a lot better than the the one you mentioned. As far as the old method is concerned.

[sig_a]

Originally posted by 2.7RACER
sig_a,
A loose .003" translates to over .0042" at the swivel foot/valve stem.
Not good. Too loose. Your valves will be noisey.
The .003" is a NO GO gauge for a reason. If it won't go, the gap at the swivel foot is less than .0042.
Pass test 1. Not too loose.
The .0025" is a GO because it will slip in as long as the gap is over .0035" at the swivel foot/valve stem.
Pass test 2, not too tight.
Remember, you are shooting for .004" at the swivel foot/valve stem gap.
Correctly set, the .0025" will slip into the rocker arm/cam lobe gap, the .003" will not.
Good luck,

2.7RACER/DOUG

Reset all 12 valves with your correction procedure. First time around, I kinked the .0025" and impatience took over. My .002" GO shim did make them too tight and I suspected as much. I'm glad I checked here before I buttoned it all up. And in fact, doing the adjust over went much smoother the second time. I believe the cam/rocker measurements are more accurate and accessible when performed under the car for the intake valves and from the engine bay when doing the exhaust, No. 3 and 6 being the exception. I could do the intakes on 3 and 6 from below, but had to stay down there and feed the .003" and .0025" shims turned 180 degrees to measure the exhaust cam/rocker clearance. I cleaned up the gasket surfaces on the rocker covers and cam tower(?) and bolted it all back together, dumped the oil back in, reconnected the battery and it started up. Also replaced the sparkplugs with NGK iridium plugs (heat range 6), fitted a new rotor and cap on the distributor. So far, no leaks or excessive clicks and the engine seems to idle smoothly and lower at about 900 rpm. And it runs smoother a bit stronger throughout the RPM range. 1987 Carrera 3.2 purchased in May from the original owner with only 16800 miles. Thanks again for your interest.

[aseem]

Originally posted by Wil Ferch
Because the German mentality is..."why make it simple if we can make it complicated ? ..."

I can say that with impunity since I have a German heritage !!

- Wil

Wil, that is the French mentality. I believe that the German mentality is to do it exactly right (that is from an engineering point of view).

[aseem]

Doug, this is FANTASTIC!!!! No more doubt. I opened up to recheck all the valves I did a few days ago (engine out), and they were all loose. 0.08mm went in on all valves.

In metric measures:
-0.08mm no-go
-0.06mm go

Sometimes the 0.07mm slides in, although tight.

I will tell all my Porsche friends about this method. The best thing is that you can easily check the valves without opening the locking nut.

Thanks for sharing this with us.

[livi]

While waiting for my maintenance stuff to show up in the mail, I opened up the engine lid today to have a look see. Sniffing around in the bay to mentally prepare for the task.

O'boy, is that a close fit !! I all but lost my nerve. I canīt even begin to figure out how you guys manage to reach in to change the plugs, let alone do the adjustment. I need to fight the creeping feeling of regression back to 'clueless physician - what the hell were you thinking'.

[Wil Ferch]

The Germans search out incredilbly complicated solutions...yes, maybe because it is the "no-compromise" answer from a purely functional pespective, but I am * certain * that the pre-discussion on a new design approach NEVER goes like this..."OK, so we have this "X" design. What can we do that is 50-80% simpler or less parts...but gets us 95% of the "goodness"....

I'm sure the "practical optimization"...to include things such as maintenance access or parts complexity...never gets discussed.

Think of the diabolically complex set of levers and linkages of Mercedes-Benz' earlier wiper assemblies..the ones where the driver side sweeps 160-180 degrees, and where the passenger side sweeps only 80-90 degrees.

The reason given for this complex design is that the "wipe away" rain-fluid from the passenger side doesn't "spill" over to the important driver's side as much.

The fact that it "looks" like a malfunctioning VW-Beetel wiper assembly ( the visual-psychological effect of "seeing" an assymetrical motion in front of your eyes...as if it's always broken) or of the long term maintenance and parts/reliability aspect....probably never entered into the design-application discussion. A common linkage ( left/right) with maybe a faster high-end speed would be MUCH simpler and perhaps 95% as good.....

There are...I'm sure ...dozens of 911 examples like this. Even our vaunted "dry-sump" system has the worst features of both wet and dry sump. The utter complexity of a dry sump, and how hard it is to check oil level properly, would be OK if the darn thing functioned like a well dsigned dry sump. However, it shows oil starvation under heavy braking, much like a wet sump! Why is the rubber "S" line that feeds the engine located toward the "back" ( instead of the front) of the oil tank ??? Or..at least why isn't it baffled ????? The car can decel at much higher "G"'s than it can accelerate.

Sometimes the Germans are simply too smart for themselves....

Etc, etc....

- Wil

[GrantG]

Originally posted by Wil Ferch
There are...I'm sure ...dozens of 911 examples like this. Even our vaunted "dry-sump" system has the worst festures of both wet and dry sump. ... However, it shows oil starvation under heavy braking, much like a wet sump!

I never heard that - can you provide more info, please?

[Wil Ferch]

Some thoughts and discussions...here--->

Oil pressure drop on hard braking. My answer with Pics

- Wil