What does the engine sound like when a valve job is needed?
 

Mine started sounding like a sewing machine, best way I can describe, from inside the cabin with the windows down and passing by an object that reflects the sound of the engine. I idled the car in the driveway and got down under to listen and it is quite noisy under there. The car had been pretty much sitting from what I can tell for the last two years. Just a couple thousand miles of driving over the last two. I noticed the increase in noise probably 300-400 miles into my 1100 mile drive home. It hasn't gotten worse just the constant since I noticed it.

Another possibility is an exhaust leak.

If it's kind of a tick-tick-tick noise, it may just be that the valves are out of adjustment.

I heard that a tick-tick-tick sound is from excess valve lash.

Mine had that noise due to worn valve guides and loose valve. It was reduced on an adjustment.

When was your last vavle adjustment?

another possibility is arcing from a spark plug wire, especially under load.

Valve job or valve adjust? If you meant valve job, it has a very distinct sound. Something like: "Ka-ching, Ka-ching" :D

BTDT, the sound is more like KA-CHING!!!!!!! :D

Mine is in for an adjustment now (12,000 miles since PO did it last).

The air cooled 911 engines are noisy to begin with, but valves in need of adjustment should sound like a constant clicking.

I think it probably needs a valve adjustment. Unfortunately the car didn't come with very good records, another reason for the good price. I am taking it in for AC work next week so I will have the valves adjusted while its in.

One last question on the subject, is it ok to drive when the engine is in need of a valve adjustment? If so for how long? Can you cause permanent damage?

As long as the valve lashes are too loose (you hear that tick-tick-tick noise), it doesn't cause any damage. It is possible to cause damage if the valve lashes are too tight, as that can result in the valves being open too far and possibly coming into contact with the pistons.

But in your situation, I wouldn't worry about it. Valves tend to get looser with age, so about the only time it's possible to have them too tight is right after an incorrectly done valve adjustment.

I must say, I have a cousin who is an extremly well known Porsche mechanic from an extremly reputable Porsche dealership who expressed that if you sound like a "Singer" sewing machine you are just fine... My 79 911 SC sounds like a "Singer" on steroids after the tweaking we have done and the stainless SSI's/Dual exhaust...

Alex