Hey, I was being kind. I usually use a phillips screwdriver. Other than using a dial guage, how is he to know that the cylinder in question is at TDC? When the piston is at the end of its travel and the distributor rotor points to that cylinder, you are in the firing position. At that point, both valves will be in the closed position, allowing OP to get his feeler guage in place.

It helped me. Obviously you guys have other methods.

I followed the "correct" procedure once, the first time I did an adjustment.

Now I just rotate the crank until the rocker is on the base circle, then adjust, don't care if its at TDC or not. Much faster.

woops thinking and typing two things, have you had someone turn it over and watch for rotation, Kevin

The fingers kick ass!

no offense but your piston is at the top of its travel when you hit Z1 ALWAYS

always.....

the difference is TDC on the power stoke (when the spark ignites the fuel) or TDC on the top of the exhaust stroke before new fuel is pulled in....

its still at TDC, just not fire stroke...so the broom handle, screwdriver, bore scope, or what ever does you no good... you have to know what the valves are doing...

the easiest way is to pull the distributor cap and look at the rotor, when it points to #1 and you are on Z1 TDC that is the power stroke (fire) start of valve adjustment point.....
the other way is to watch the valves and rotate the motor...(a little tough since 1/2 our valves are on the other side of a piece of tin...but it can be done none the less... simply go to TDC Z1 and rotate the crank while watching the intake valve of #1...if it presses IN and opens #1 intake valve you were at the Z1 360 off from the start point you need......next time Z1 comes up..start there... if the valve doesnt move you were on the power stoke....so go around 720 and you will be right back to the start point

I would never stick anything in the plug hole after just going thru a stuck open valve from debris....too risky!

Hi,
I understand completely where your coming from on this, as long as your carefull, inserting something soft like a piece of wood in the spark plug hole is the ultimate indication of the piston being at the top of the stroke, [ we run the risk of something fouling the cylinder everytime we change or remove a spark plug due to unknown dirt and debri being around the plug hole waiting to fall in] however, i would only sugest doing this if there is no other way of telling.
There are reasons why [sometimes] things dont make sense when your relying on pulley marks, dist position etc, for eg, if the key way was broken or missing on the crank shaft, that would mean that the pulley could be put on in any position hence the marks would be meaningless,as far as timing and valve checks are concerned, Also, relying on the dist for an indication of exact crank position is not ideal, anyway, i think before you go any further you need to know for sure that the cylinder you are trying to check the valves on is indeed at the top of its stroke, and on the firing cycle ie; both valves closed!
I would also like to add that i have worked on engines most of my life and even worked as an engine reconditioner/rebuilder so have seen and witnessed all kinds of strange and sometimes baffling faults.
Anthony.

I used to do base circle method on other motors but I found using the method given by the Bentley is very fast for me and I've had zero problems doing it.

Some people asked for pictures. I brushed some yellow paint on the crank pulley to improve clarity. The only thing that looks slightly suspect to me is that the rotor appears to be a couple degrees ahead of the case mark when the crank pulley is TDC - but what would that have to do with having two valves open when the engine is TDC to the corresponding cylinder? Anyway, here they are.

Distributor showing #1 Wire at top slightly to the left of noon.


http://forums.pelicanparts.com/uploa...1321021867.jpg



Advance of TDC and TDC mark


http://forums.pelicanparts.com/uploa...1321021793.jpg


Rotor location at TDC - Note that it appears to be a few degrees ahead of the TDC mark on the housing



http://forums.pelicanparts.com/uploa...1321022010.jpg


120* and 240* pulley hash marks. Not sure what these show but if I omit them someone will start talking about them.


http://forums.pelicanparts.com/uploa...1321022057.jpg


http://forums.pelicanparts.com/uploa...1321022087.jpg


Rotor location after one 360* rotation of the crank pulley. Pointing 180* opposite the TDC mark on the housing.


http://forums.pelicanparts.com/uploa...1321022170.jpg

Close up showing rotor slightly ahead of mark when crank pulley is at TDC (it's actually a bit exaggerated in this picture as the camera was slightly off center). I'd say it's two degrees ahead of the mark.


http://forums.pelicanparts.com/uploa...1321022295.jpg

Ruckus the poodle at the beach!


http://forums.pelicanparts.com/uploa...1321022592.jpg

do you have access to another set of eyes or a mirror....

place a mirror or have someone watch the #2 exhaust valve as you rotate the motor around several times and each time note when you come up on #2 TDC...the other set of eyes should see the valve move in then release....when it is released it should move...if not there is something seriously wrong....

did the car run?

what "other things" have you done in tandem with this valve adjustment?

OK so the first picture you show of the pully clearly indicates Z1. With that aligned as shown and the distributor pointing at number 1 as shown you should be ready to do number 1 cylinder on the left / rear of the engine. Both the top intake and the bottom exhaust should be loose. At least one of the rockers on the right side should unmovable at that point.

This will take a little longer but we don't know what is messed with at this point so let do just a basic adjustment. Get accurate after we know were you are. At this point just loosen the adjuster nut and turn the adjuster in/down until it has no play. Then back it off 1/8 turn. This should get close enough to make sure nothing is binding. The tighen the adjuster nut.

Next move the crank 120* to the next mark. And repeat the above process on #6 the front cylinder on the passenger side.

Next move the crank to the third 240* mark and repeat for #2 the middle on the left drivers side.

Next move the crank back to the Z1 mark. The distributor should now be pointing 180* off and both rockers should be loose on number 4 the rear right / passengers side.

repeat for #3 and last #5

If all works then repeat only use the gauge. But do not loosen the screws more than 1 turn.

jlynch,

FYI, it doesn't matter if the rotor is off a couple of degrees from #1, as long as you are at Z1. But it sounds as if you are aware of that already....just wanted to make sure you're on the right track.

The purpose of posting the pics was to show that I started on the CORRECT TDC for No. 1 (seemed to be a lot of doubt about this from several posters). Interesting that both Wayne's 101 book and Bentley's kind of gloss over this topic, although Wayne's engine rebuild covers it in one of the later chapters.

As my earlier posts stated, Nos 1 and 6 went fine, but when I got to No 2 EX, the rocker was on the lobe - lots of tension on the adjustment screw (in and out), the rocker never freed up and a gap never opened up between the valve stem and the swivel foot. I was able to rotate the crank to a random location in the cycle where the gap opened up - this is what leads me to believe the valve was partially open at TDC for No. 2 even though I could not verify this visually by observing the cam (lack of experience here). I guess what else would explain the tension on the adjustment screw or the fact that the rocker never freed up?

Same issue for No 3 IN. Every other valve went fine.

To answer some other questions posed-

Car ran fine before starting the project. No peculiar valve train noises, pulled well, etc., occasional cold start crankiness, but otherwise fine.

Only rotated crank clockwise (in neutral, sparks in).

Working alone, but I can rustle up a helper to crank while I look at the Ex cam. Put the covers back on to keep debris out in the meantime.

No other projects this go round, except sound pad insulation, draining the oil and putting on a new filter.

Seems like a cam timing problem to me, but is it even possible for the cams to get out of their correct orientation without some catastrophic timing chain event or without a likely cylinder collision given the tight tolerances here?

As I've said, I'll give it another go on Sunday; otherwise it's going off on a flatbed to a pro.

No.. the cams wont change...the way they are locked in place is virtually bullet proof

as to your comment regarding "some doubt" i just want to defend the group (and me) and say we just wanted to go over the basics...not doubting...just writing the same thing in different ways in hopes that you would see it in a way that made a light bulb come on and say..... OHHH I GET IT!!

I for one was anyhow....just covering it from the very simple.. basic...

for sure I would rotate around and watch that and #3 intake..see if they ever move....and when they move

I seriously want nothing more than your success !!

Sure is a puzzle.

Since adjustment for #1 went fine but #2 Ex did not, take out the plugs on #1 and #2 and see if they look the same at the firing end.

If the valves on #2 are mistimed for some reason, correct firing would not occur and the plug should look different?

if the valve was/is stuck it should not hold up the rocker arm...

Ivangene -

Sorry, no worries about the doubters - having plenty of doubts myself, but after I tried going through it twice more, I started to figure it was the car and not me.

I think this forum is great and I've gotten lots of help here from people who know a boatload about these cars. Didn't mean to sound cranky if it came off as such.

As to Gunter, unfortunately I just changed out the plugs a couple weeks back as part of a tune up to deal with the cold start crankiness. Not sure I've driven her enough to show a difference, but I'll give it a try anyway.

my first VA it took 40 minutes to do #1 and then I had to re-do it when I learned what I was looking for....

I get the frustration...

we gonna learn you how to set the rear swing arm angle next :p

The indication that 1 and 6 OK but 2 doesn't just compounds the confustion about what is wrong. Even if the cams were out of time 1 and 2 are on the same side. So if you do cylinder number 1 and turn the crank 240 degrees in the correct direction you have to be on #2 period. drivers side 123 passenger side 456 with one at the rear of the car.

I know you have been asked the question a million times but I do computer support on the phone and you would be suprised how many times I ask something then describe it different and get a different answer so this is not to be repeditive or make you mad but.

When turning the crank to the next position you standing at the rear of the engine, there is a socket on the crankshaft bolt. You move the handle of the wrench from left / drivers side to right / passengers side until you come to the next mark.

Please do not hate me for reasking but when something doesn't make sense start at the beginning and the only situation that describes what you are saying is that the crank is being rotated the wrong direction. Else #2 has to be 240* from number 1

If the engine ran before, forget starting from TDC. From long distance, there's too many assumptions we're making on our end. Merely rotate the engine so the distributor rotor points to the spark plug wire connector on the distributor for the cylinder to adjust; #2 in this case, then so on.

Sherwood

Yep that will work also.

I think we are all intrigued to find out what the heck is happening here now!
I realy hope you get to the bottom of this, and i [like everyone else here] will be keeping an eye on this one for updates.:)
Anthony.

Have no insight to add to this discussion, however to the fellow who posted about the dowel, I am an aircraft maintenance engineer and it is a standard practice to probe the piston with a long phillips screw driver to verify tdc on piston aircraft engines. They tend to shy away from risky practices maintaining aircraft, so for this to remain a standard practice in aviation is basically a statement that no one has ever done significant damage doing so. I do the same on my vehicles as a double check and have borescoped those same cylinders and have never seen any damage from this practice. The only thing to watch out for is dont get the dowel in the plug whole when the piston is too far down as it can cant over on the way up and jam.

I read through the thread quickly, and saw a lot of discussion about making sure you are at TDC, dowl in sparkplug hole, seeing where distributor rotor is pointed, etc.

I may be missing something, but that all seems irrelevant.

As you posted in your original post (quoted above), you can see when the cam lobe is pointed away from the rocker. For a valve adjust, that's all that matters.

If you visually confirm that the cam lobe is pointing away from the rocker on your problem valve, your problem isn't TDC, etc. All that can be eliminated.

Thank you so much. I was really getting annoyed at the messages that all but called me crazy. I have been playing with cars and motorcycles for over thirty years now, so I kinda know what works and what doesn't.

[QUOTEOriginally Posted by ivangene]
+1 for NOT sticking wood into your spark plug holes [/QUOTE]

Not sure about the aircraft combustion chamber layout and valve type you refer to, but in a 911, the poppet valves angle toward each other and become perilously close during the overlap period. Introducing another object in this region through the spark plug opening (especially a rigid steel object) while rotating the crank can create all kinds of interesting scenarios. YMMV.

This would be the safest engine format for inserting a probe:
Redirect Notice

And as described, removing one or more spark plugs to confirm piston/valve position is superfluous labor when there are simpler and less time consuming methods to do this. Again, YMMV. Several ways to skin the cat.

Sherwood

Regardless of technique, I really want to know what is going on here. Why would a valve not want to adjust?

Could be several things. Are you the orig. owner? If not, there were many chances by POs to change things up.

Post a pic of the offending valve. Maybe the audience here can observe some visual tell-tale signs. It couldn't be that you're trying to adjust when the valve is open, could it? Just checking.

Sherwood

Mystery solved - I'm a #%^&* moron!

Tried this again Sunday afternoon. Worked fine.

After wasting all this bandwidth, I think the difference came from having dabbed some paint on the pulley hash marks to take pics for this thread. Rotating the crank took some effort since the plugs were in (I had to pinch the belt hard to get it though a couple of spots) and looking at the pulley, it has some scaled/chipped paint that I can see now I could easily have mistaken for one of the marks. I'm glad the paint's there and hope it stays there for the next 15k miles.

Wow, do I feel like an idiot.

Thanks for the help and insight people offered and sorry taking up a lot of people's time on such a rookie error. My bad, as they say.

Jim

Don't worry, I'm pretty sure everyone here have done stupid misstakes at least once...

But in the future don't focus so much on the pully marks, they are quite irrelevant when doing a valve adjustment....

I for one feel great you solved it!!

like they say, you dont know what you dont know...now you know!

+1 for Perserverence!

another example of "it is usually something simple"

when I adjust valves I always look in with a flashlight to see that the rocker pad is on the low part of the cam lobe (high part pointing 180 degrees away from the pad).
Sort of a belt and suspenders approach, which I tend toward.

Another minor valve adjust item
 

One item I found happening with my valves that I didn't see mentioned in this thread as follows. During the top end part of my rebuild, I found that 3 of the 12 adjuster screws had threads that were damaged or stretched such that they would only turn a short bit before jaming in the female thread of the rocker. Made them "feel" tight to varying degrees when trying to turn with a screw driver. Because all was apart, I used a dremel and cut them off and installed new screws which moved smoothly. I could not see the issue just looking at the screw threads but they were definately bad. Maybe something happened one time in the past with the previous owner, maybe overtightened, maybe they don't last forever, who knows. The valve adjust I did just prior to the rebuild was my first and was fairly interesting as I remember, trying to get the screws to move and adjust smoothly.

An expert is someone who has made all the mistakes possible in a narrow field. You are now on your way.

congrats on solving your problem. and if i had a dollar for every time i've mumbled that exact phrase under my breath i'd be able to get my 3.2L engine professionally rebuilt with money left over :)

Yes just glad to hear you got it and nothing horrible happened in the process.

I hate so say I told you so...... :)

But I KNEW that your piston was not at TDC.

Glad to see you are now OK.