Engine – Tick-Tick-Tick
 

Rephrasing as the sound is more like a Tap-Tap.

My 86 Carrera has an annoying ticking sound for a while now and thought it was the valve lash which was not. Double confirmed adjustment and the tick was still there.
The sound generally is more noticeable when cold, but dissipates upon warming up, but it’s still there. At times when cold, the sound is almost non-existent. It appears to be on the passenger bank side.

To make a long story short, when I installed the RSR rocker shaft seals on all shafts, I noticed that the exhaust valve on cylinder five had a slight lateral movement which all others did not and were a tight fit. The engine has approximately 220k miles on the clock with a recent rebuild at some point which I don’t have documentation for, but just the word from the PO. Oil consumption is very low (1 quart per 2,000k miles) or so.

When I replaced the engine bay fuel lines and removed the plenum, I noticed that the heads were Mr. Clean clean with very little residue which confirms a rebuild at some point.
I will be changing the oil and taking the exhaust rockers, shafts and springs to take another look.

Appreciate any and all advice.

Serge

Exhaust leak? Sometimes mistaken as a mechanical tick...

I wish it was an exhaust leak, but I can say with honesty that it isn't.

A tick tick sound is exhaust. A tap tap sound is valve train. I doubt it is your valves. 86 has cross over pipe. Cat? Or cat delete? Either way lots of joints to leak. Not to mention the six ports that always seam to come loose

I'll take a video of the exhaust valve in question once I get in there and upload it.

Wouldn't a worn guide cause the valve seat to tap?

Worn valve guides, broken valve springs sticking valves etc can certainly cause similar noise, however; I would first re-check the obvious i.e.; exhaust joints, ports etc.
Ant.

I have same in my engine. It has not been rebuilt (I will do it next year).
A bit tap tap as warming up... when totally up to temp it is less.
Valves are adjusted and even tighter than spec and it still makes the noise.

I suspect it could be either
- worn valves or guides
- lateral movement of rockers on shafts (worn out bushings?)
- the IMS gear having a bit of slop in it

Hope to find out next year!

can you make a video of the sound? up and down on the left side of the engine??
Ivan

Serge,

I dont mean to high jack your thread - but I just brought home a 1970 911E - didn't have a tick when I drove a couple weeks ago - but it did when it arrived. I think its exhaust leak tick - doesn't go away when warm though and varies with speed.

Any thoughts? Video

https://youtu.be/Dfz-nmVToNA

wild guess. Try disconnecting the AC compressor. Easy to do.

sounds like valve adjustment is off
Ivan

Ivan,

Yes, my thoughts or exhaust. Will check exhaust later today and do values next weekend. Thank you!

Marc

Have you tried turning it off, and turning it back on again?��

Seriously, have you tried using a screwdriver touching your ear touching the valve covers to see if you can isolate it to one area in particular on the Engine?
Or, if you are fancy, you can use a stethoscope

11BC2

Yes to both - your why I love these forums - :rolleyes:

SmileWavy

Valve lash ticks.

Tapping indicates otherwise. Did you post a vid or did I miss it ?

I've got to be honest guys, I think much of what your hearing with these old air cooled engines is pretty normal, we have all become so used to modern engines with tighter tolerances and water running around them to drown out [excuse the pun] every little tap, and click etc that we forget these engines are an open book, i.e.; you will hear these little noises!
But it doesn't hurt to re-check the valves and springs etc, just to make sure you haven't missed anything!
Ant...