Questions after valve adjustment

[markmalin]

Hi guys,

I just adjusted the valves on my 85 carrera for the first time. The car runs great, but it's noticeably more "clattery" sounding than it used to be. Is this normal? I'm dreading having to tear it all apart again to re-adjust them.

So here's what I did. Cyl. #1 seemed fine...I was able to slide the feeler gauge in just fine and there seemed to be enough of a tug that it was OK (both exhaust and intake).

Cyl #6 was another story. I couldn't get the gauge in there at all, so I loosened up the nut and turned the set screw back (backed it out). Still couldn't get my gauge in there, but noticed that if I rocked it a bit it seemed like the top of the valve stem and the little cap gizmo that goes around that ball on the top of the rocker were kind of stuck together. (the valve stem top and the part of the rocker that pushes on it). That let go finally and there was a big gap (obviously...because I had backed it out). I adjusted the set screw back down till it seemed right (could slide the gauge in and out, but could still feel a little pull ...i.e. it wasn't loose). Tightened the nut and re-checked.

From this point on, several of the valves did not need adjustment...others behaved like #6 in that it was like they didn't want to separate...eventually either I backed off the set screw and re-adjusted them, or finally was able to get my feeler gauge in there.

Anyhow, things seemed to go smoothly. 3 of the cylinders did not seem to need adjustment...the other 3 did.

I put every thing back together correctly...changed the spark plugs while I had the covers off...and changed the oil. Nothing else out of the ordinary. Thing is, it really does tick (clatter) more than it used to. Would appreciate advice. I've adjusted BMW's but never 911's.

Here's my plan - rather than pull all 4 valve covers off and drain the oil and all...I thought maybe I would NOT drain the oil and remove the top covers and do the intake side again...maybe one side at a time, put the plug wires back in and see if it quiets down. if not, drain the oil and re-do the exhaust side. I just thought that way I'd save the hassle of draining/refilling oil and doing the bottom valves if maybe the noise was coming from the intake side. Just a thought....trying to avoid completely re-doing everything

Mark.

[RSTarga]

sounds like they are too loose. Are you sure each piston was at TDC when you adjusted? That may be why you couldn't get your gauge in.

[pete3799]

You can do the valves again without draining the oil. Jack one side up, let the oil run to the other side, remove V/C and do those valves. Repeat for the other side.
Try the back side method. It will help you get a better feel for how much drag there should be on a properly adjusted valve.

[markmalin]

Originally Posted by RSTarga

sounds like they are too loose. Are you sure each piston was at TDC when you adjusted? That may be why you couldn't get your gauge in.

Yah. I started at TDC and did cylinder 1, then turned the engine 120 degrees between each (following the firing order). It's like the valve stem tops were sticking to the rocker arm or something....when they let loose the clearance looked OK.

[markmalin]

Originally Posted by pete3799

You can do the valves again without draining the oil. Jack one side up, let the oil run to the other side, remove V/C and do those valves. Repeat for the other side.
Try the back side method. It will help you get a better feel for how much drag there should be on a properly adjusted valve.

What do you mean by the "back side" method?

Thanks for the tip on lifting one side!!

[markmalin]

I guess one thing I don't understand is... do you have to loosen each one and re-tighten it down on the feeler gauge, or ... if one feels like the clearance is OK, is it OK to just leave it and move on to the next?

Mark.

[pete3799]

Pelican Technical Article: 911 Valve Adjustment - The Backside Method

[timmy2]

Originally Posted by markmalin

I guess one thing I don't understand is... do you have to loosen each one and re-tighten it down on the feeler gauge, or ... if one feels like the clearance is OK, is it OK to just leave it and move on to the next?

Mark.

It is usually quite difficult to insert the feeler gauge using the standard method as the "drag" indicates the tolerence is tight. To align the feeler and insert it easily means the adjustment is loose.

For the backside method it is a go-no go situation. It either fits or it doesn't when it is right.

[James Brown]

if you move the feeler gage after adjusting and feel a little resistance, there adjusted correctly. doesn't really matter on rotating the engine as long as the cam lobe are 180˚ from the valve, this might speed things up next time

[maui44]

+1 RSTarga Sounds like the valves are to loose. Better than to tight however, you are going to have to go through them again.

I would also use the backside method. When you have them right, then you can also check (to get the feel) the traditional way.

[markmalin]

Originally Posted by pete3799

Pelican Technical Article: 911 Valve Adjustment - The Backside Method

wow, this looks a lot easier. 2 questions.

1.) If I adjust a valve, do you adjust the valve using the "GO" gauge from the back side, or do you adjust it with the normal shim tool between the valve stem and "elephant foot"?

2.) Ok...so normally I would start at TDC and adjust cyl #1 with the normal method. With the Backside method, can I just go for any valve who's rocker is not sitting on the cam lobe (i.e. any fully closed valve)?

Thanks, guys!
Mark.

[timmy2]

Yes, yes and yes...

1. I set with normal and confirm with backside first time around.
2nd time around (Now that I'm more comfortable with the backside method,) I set them using the go gauge and making sure the no-go gauge doesn't fit.

2. If it is off cam the clearance is there.

[redstrosekNic]

It should be normal for a properly adjusted engine to be noisier than an engine with tight valves. As the valve wears away, the clearance closes. Typically, one is adjusting to compensate for the wear. I like to have a slightly noisy engine. It tells me the valves aren't too tight .

[markmalin]

Originally Posted by redstrosekNic

It should be normal for a properly adjusted engine to be noisier than an engine with tight valves. As the valve wears away, the clearance closes. Typically, one is adjusting to compensate for the wear. I like to have a slightly noisy engine. It tells me the valves aren't too tight .

I've heard older mechanics say this (i.e. guys who grew up with solid lifter engines). But how loud is too loud?

[kodioneill]

It takes lots of experience I've been adjusting valves on 911's since the early 70's several hundred at least and I still can't always get them perfect unless you use a dial indicator and that's hard to do with the engine in the car.

[redstrosekNic]

Originally Posted by markmalin

I've heard older mechanics say this (i.e. guys who grew up with solid lifter engines). But how loud is too loud?

That's the difficult part for many people. I personally like to error on the side of a bit loose. Like was stated in other threads here on Pelican, a very quiet 911 engine is not normal. Air (technically in the case of Porsche, oil) cooled engines are obviously going to be much noisier than water cooled engines.

[Reiver]

Run it by an indy shop for a quick 'listen'....too much clatter won't hurt anything, especially if it is running well....no tappet noise, too tight, can burn a valve.
thought mine were too noisy and did the above, mechanic said it sounded just right....some clatter is right.