Ticking Noise, not Rythmic
 

I am picking up a ticking noise when driving my '84 Carrera that I cant pinpoint. The tick does not have a consistent rythm to it and does not do it at idle. It reminds me of the valve rattle you get in an american V8 when you run low octane gas in it. It seems to do it under moderate accleeration or constant RPMs while cruisng at about 3500 RPMs.

Any ideas?

I would get one of those auto stethoscpes and try to pinpoint the noise. Otherwise your description sounds a bit like pinging which is incorrect timing.

CJ

+1, I agree it sounds like pinging. Can possibly be fixed by using a higher octane fuel.

Not to steal the thread, but if the pinging is caused by timing, what can you do to eliminate pinging if you have a DME-equipped car?

Also, can't pinging be caused by improper air/fuel mixture (lean condition)?

I have always run the highest octane fuel available in GA and the ticking has only come on recently, so I doubt that is it. Could the ticking noise be an exhaust leak? I would think an exhaust leak would happen at all rpms and have a rythm to the ticking.

I recently had a problem with my 1988 Carrera 3.2 which was traced back to sparkplugs (specifically #6) which were improperly installed by PO to have backed up until #6 was out of the socket! I was running on 5 cylinders. When I put in new sparkplugs and did a valve adjustment check everything runs like they're suppose to.

if it is pinging or spark knock, then timing or something making it go lean. air leak?

Mileage? Visual inspection ok? Ignition tune up ruled out? When was last valve adjustment? How are the valve train components, tensioner, ramps, chains?

Regards,

Are you sure it's from the engine? How about a stone in the tire tread?

I am doing valves this weeked and am curious if I will uncover anything 'interesting'. We'll see what happens...


I would think stone in the tire would be very rythmic.

Plug wires?

is it possible a rocker adjustment bolt has backed off a bit?

Perhaps the following link can point you in the right direction.SmileWavy

http://forums.pelicanparts.com/porsche-911-technical-forum/246871-ticking-sound-dashboard.html


Regards,

John

definately not comnig from the dash, it is from the engine bay. Valves are being adjusted right now. The idea of a head stud fallibng out when the valve covers are removed is a notion that keeps entering my brain - I keep pushing that notion back - dont want to think about that right now....

Based on you initial description I suspect a broken valve spring.

thanks all for the feedback, fingers are crossed.

http://forums.pelicanparts.com/porsche-911-technical-forum/517006-85-911-strange-noise.html
Check this link. Throttle body deicing valve by the oil tank can cause a rattle when it is bad.

valves adjusted and problem solved. Thanks all. Damn she is running good!