Why does one valve adjustment go out after about 1000 miles?

robhamster · 02-01-2010, 04:25 PM

84 3.2 totally stock with 115K miles on it. I adjusted valves successfully about 200 miles ago. The intake valve for #5 was the loosest. I got it right and all was good in the universe. 1000 miles later I heard the tick-tick and narrowed it down to #5 intake. I readjusted it and checked all again and once again all was fine with the universe. It is now about 1000 miles later and I am hearing the tick-tick and it is coming from the #5 intake.

What should I be looking for as a potential problem here. (spare me the look-in-the-mirror comments)

Thanks

euro911sc · euro911sc's Garage

Look in the shiny puddle of oil on the floor

Just kidding

You may need a new elephant foot and lock nut. Perhaps it has just worn out after being loose a few times. This is a semi-educated guess.

The worst may be a warn rocker thread which would require a new rocker. That leads to wear issues as your cam and rocker wear together and now 1 will not match the other

The last thing is... and don't shoot me, are you sure you tightened it right? they move sometimes when tightening... and, if you REALLY cranked it you may have stretched it out.

Just some ideas

Best regards,

Michael

cgarr · cgarr's Garage

Sometimes the foot or valve stem can get a slight groove worn in them which make them almost impossible to adjust with a feeler gauge because of the ridge, it feels good with the gauge but you are measuring it on the high spots but it seats on the low spots. After you set it try rattling/feel it and see if it feels like the others.

Tyson Schmidt · 02-01-2010, 05:23 PM

Just want to add: make sure the oil spraybar isn't plugged for that rocker.

robhamster · 02-01-2010, 06:10 PM

Tyson,

How do I check for that?

rcaradimos · 02-01-2010, 06:25 PM

Quote:

Originally Posted by cgarr

Sometimes the foot or valve stem can get a slight groove worn in them which make them almost impossible to adjust with a feeler gauge because of the ridge, it feels good with the gauge but you are measuring it on the high spots but it seats on the low spots. After you set it try rattling/feel it and see if it feels like the others.

CCM911 · 02-02-2010, 05:04 AM

I had the same problem. Always one "tappy" valve. Mine was number three. Just replaced the shaft and rocker. Not a bad job at all. But then again, I had dropped the engine. In any case, if this turns out to be your problem, it is not an expensive fix. Just a PITA!

Good luck.

javadog · 02-02-2010, 05:32 AM

What oil are you running?

JR

robhamster · 02-02-2010, 09:57 AM

Coffeepooch,

I am running Pennzoil 10/40. I dont think this is an oil problem.

CCM911 - Thanks, I suspect I might have a worn bushing on that rocker arm. I looked at what Wayne is selling and it looks like an easy fix, even with the engine in the car.

I appreciate the help, folks. The ticking sound is driving me nuts.

javadog · 02-02-2010, 10:33 AM

It may not be an oil problem but something is wearing more than it should. Since the reformulated oils were said to be less effective in lubricating the type of rockers that are in a 911 motor, if figured that I would add it to the list. It's probably one of the things mentioned earlier but you never know.

JR

robhamster · 02-02-2010, 10:39 AM

Thanks. Someone earlier had suggested that the oil spraybar might not be working there. I am not sure where to look for that or even how to without trying to start the car with the valve cover off.

javadog · 11:14 AM

The problem occurs more frequently on the turbocharged cars, so I'd suggest looking on the 930 forum for pictures. There are some there. Here's a thread that talks about the problem:

bad rocker?

And a photo, in this thread:

spray bar orientation

There are others, as well.

JR

RetroSC · 02-02-2010, 11:20 AM

You really need to look into the oil you're using. The formulataion for almost all common motor oil's has changed in the past few years, eliminating some very important anti-wear additives for our old style motors. In essence, the main problem with these new oils on our old cam/rockers is very rapid wear, which would cause your adjustment to constantly go out as the rocker or cam lobe wears.

Lots of info out there on this, but something like Brad Penn (there's several others) oil is really critical anymore.

Bill

robhamster · 02-02-2010, 02:25 PM

RetroSC & javadog,

Thanks for the advice and the links. I am now armed with enough info to be just a little less dangerous as usual.

john walker's workshop · 02-02-2010, 06:07 PM

loose guides at that mileage, if you have not had a top end rebuild yet.