911 Valve Noise??

[adam612]

I have an '85 911, 3.2 ROW engine, steve wong, fabspeed cat bypass, 105k on the odometer, engine never apart. Engine never ran better. 2 months ago, experienced ticking noise on start-up that stopped after about a minute. Recently, while on highway going 65, heard rumble on left side of motor (under airbox) when over 2,ooo rpm. At idle no noise and purred. Parked car overnite, now noise is gone. Been driving for 3 days and car runs great, full power and no noise. I added Techron and Lucas fuel stabilizer to the fuel. Also added a 1/2 quart of Rizlone to the oil.

Does this sound like a sticking valve? Any suggestions to cure (hopefully no top-end rebuild!)

Thanks for your input!

[E Sully]

How many miles do you get before your down a quart of oil? I would pull the valve covers and check the valve clearance. There is a tendancy for the valve guides to wear on the 3.2's.

[Porsche84]

I have an 84 and had similar noise. I replaced the chain tensioners and the noise was gone. If the noise comes and goes, it can't be valve adjustment or valve guides.

[kidrock]

IIRC, worn valve guides are indicated by smoke from the tailpipe at deceleration.

If it's just tickety-ticking, I'd recommend adjusting the valves and changing the oil. You can get a decent look at your valve train / rocker assembly while you have the covers off.

Start with the easy stuff, first.

[timc]

similar issue on my 86 930, the pressure fed tensioner, dr side was starting to fail. very, very intermittent noise. Would only start making noise on long trips, after driving for over an hour or so. Never ever on short, under 1 hour drives.

edit: oh yeah, when first listening, the sound appeared to be coming from center/rear of engine, but further inspection isolated to dr side cam housing.

[adam612]

Many thanks guys! I'm going to check the chain tensioner first.