Valve Clearances, all too tight!

[Jase77]

Pelicans,

I am in the middle of a valve clearance check/adjustment and every single valve is adjusted too tight. I cannot get my feeler gauge in at all. (I have the 'special' gauge) I was going to start correcting them but then I thought it strange that all of them will need doing, hence this post here. I have never had to adjust every valve when working on other cars.

Any of you had this before or am I over thinking this?
Cheers,
Jason

[DRACO A5OG]

I would put a scope or digital scope inside the spark plug hole to see if the valves are kissing cylinders.

How long since the last adjustment?

[john walker's workshop]

Is this your first 911 valve adjust?

[Canada Kev]

Are you sure you're on the correct cylinder? What I mean is did you start out on TDC on #1? If not, that'll for make your valves tight...

And sometimes with little experience, it's tough to get the feeler in there.

[Jase77]

I haven't done them in my ownership, which is two years, and I have no documents showing when they were last done. The upper covers were stuck solid and the old gasket material is like concrete, so I will guess that it's been at least 5-10 years?

[Jase77]

This is my first adjust on the 911 but I have done them on other cars before. Yep, definitely at TDC and I agree that it is a ball ache to get the feelers in there.

[DRACO A5OG]

Well, a properly adjust valve, once the feeler is removed is very difficult to put back in.

Try a smaller feeler to test if there is a gap and that you are putting it in the proper place.

If you really want to verify, use a dial gauge. It is a hit and miss because it is dependent on the initial set up of the dial gauge.

[Jase77]

Draco, good idea. I'll give it a go in the morning. Thanks.

[DRACO A5OG]

Note, the Valve Adjuster SCREW will over time get sloppy, so it could be sitting lower than the actual gauge thickness, it may need a nudge up to get the feeler in.

[mreid]

Leave it at TDC and check all the intake valves. If you find at least one that the feeler fits under you know you are not really at TDC on cylinder 1.

[Jdub]

You may be adjusting valves that have not been adjusted in some time. If your technique is good on flat sixes, then you have to assume its tightness from worn seats, right? Otherwise, your use of the L foot valve feeler gauge just needs work.

I used to adjust valves on a Honda 400/4 inline four and you always wanted to hear that sweet even clicking across the head.

[T77911S]

you could be 180 degrees out
the valves have just gotten tight over time
you could be trying to put the feeler in the wrong place

start with #1 intake.
while rotating the crank, watch the rocker and the rotor.
after the intake closes look for the rotor to line up "close" to the mark on the dist and for TDC to line up ON the case.

wiggle the, rocker, you should feel it move a little.

I think looking in the cylinder at this time is a waste of time. you have some room for a tight valve. if a valve did hit it either bent that valve or it did not. a compression/leak down would be a better check. plus it lets you know the condition of things.

[Drisump]

I can't speak for the experience of others but I always do all of the valves because it is such APITA to slip the feeler in without loosening. The gauge sold by our host has replacement feelers for good reason....trying to get the damn things in without loosening guarantees that I (at least) will bend or break several in the course of one servicing. Other engines I have adjusted valves on use a thicker feeler and not the "tin foil" these engines require. John can probably just wiggle the rocker and determine whether it needs adjustment or not...me, not so much LOL. Cheers

[jwill911]

Originally Posted by T77911S

you could be 180 degrees out

you could be trying to put the feeler in the wrong place

start with #1 intake.
while rotating the crank, watch the rocker and the rotor.
after the intake closes look for the rotor to line up "close" to the mark on the dist and for TDC to line up ON the case.

wiggle the, rocker, you should feel it move a little.

I agree with this; once I get all set at TDC, first thing I do is wiggle the rocker to confirm I'm at the right point. It also gives you a "feel" for what is right when you check the rest of them.
I just adjusted/check my valves within the last couple of weeks. They were all but one perfect, and that one was iffy but I adjusted it any way. Last valve adjustment was maybe 10K miles ago.

[scarceller]

How tight are they? if you grab the rocker can you move it of the valve stem slightly at all?

[morrisjm1]

Sounds like they are long over due for an adjustment. As the seats and valves wear, the clearance gets tighter. I'd adjust them.

[bpu699]

Originally Posted by mreid

Leave it at TDC and check all the intake valves. If you find at least one that the feeler fits under you know you are not really at TDC on cylinder 1.

I don't think you even have to be exactly at top dead center. The clearance is the same for about 180 degrees of rotation for the cam. Then lift kicks in. As long as you are on that part of the cam, clearance is the same...

If that's wrong, let me know. But that's how cam lobes are shaped...

[Bill Douglas]

I always give my car an Italian tune the day before I do the valves. You don't want any carbon sitting on the valve seats or valves. And the engine has to be completely cold ie not started up that day.

[DRACO A5OG]

Interesting BD

[Bill Douglas]

I'm no expert. Everything I know I've learnt from you guys