Carrera 3.2 engine sound, thoughts?

[Roger 911]

I'm getting a knocking/tapping sound that follows engine RPM (video link below). I thought it might just need a valve adjustment, so I did that. It actually DID need a valve adjustment, and the engine sounds better now. But now I can more clearly hear this additional tapping sound. It seems to be coming from the left side of the motor. FWIW, when I drained the oil yesterday, it was perfect, i.e., no metal shavings or pieces of any kind. The car does not smoke at all, on startup, when cold, hot, under load, decel, etc. Oil pressure is great.

I'd appreciate any thoughts/opinions. Thanks.

https://www.youtube.com/watch?v=FmCLpaBAlnA

[911 SLANT]

I would say a rod knock, but sounds a little high-pitched for that. I could be wrong through. I would definitely not drive.

[proporsche]

you have broken valve spring ..locate it by listening to each cyl.simply by long screwdriver to the intake and the other end to your ear in a wrist...
Ivan

[911 SLANT]

My 2.7 had a high pitched sound on passengerside. It turned out to be a broken ring in the #5 cylinder. Hopefully its only a broken valve spring. Like proporsche said.Good luck

[proporsche]

on the second thought, i did more listening....put you listening device to the left chain housing..to see if the there is not collapsed chain tensioner..
Ivan

[Roger 911]

I appreciate the comments. A couple follow up questions;

Broken valve spring - I just adjusted the valves yesterday. If a valve spring was broken, wouldn't that have been obvious as I checked each valve? Also, if the spring was broken, wouldn't that affect how it runs, i.e., the valve isn't opening and closing properly?

Chain tensioner - If a chain tensioner is failing, or has failed, does it produce a rhythmic tapping sound like mine, or is it more of a constant grind/hashing sound?

Thanks.

[Roger 911]

Also, with respect to a broken piston ring, would that cause the motor to smoke at all, or run rough? Again, I have no smoking and the engine appear to run fine.

Thanks.

[proporsche]

Roger..you would not be able to see the broken valve spring-you have to push hard on it to find out.Mechanics know how to feel it, for a regular person while adjusting the valves it would seem normal so locate the cylinder as i have suggested .Than remove the valve cover and using a little leveridge push on that valve spring...more often the large is broken

If the chain tensioner is broken it produces grinding sound l..from your video is hard to tell ..because you have stayed in one location with your camera...

ivan

[911obgyn]

Have you checked for an exhaust leak?
Doesn’t sound like a chain tensioner to me I had that and it was more constant and trash can liddy.
Do you have a long screwdriver, or a short broom handle you can localize it better by pressing it against your ear and touching the engine. Careful of the fan and belts
Automotive stethoscopes are pretty cheap and it’s fun to listen to the valvetrain, distributor,and other stuff.

[Solamar]

I screwed up a valve adjustment once, 1/8" valve lash on #3. Sounded just like your video.

[Roger 911]

I do have an electronic stethoscope, one with the metal rod, etc. I used it on the engine, but it sounded the same everywhere I placed the rod.

Yeah, I'll probably pull the valve covers again and recheck the valve clearances, and see if I can identify any broken springs. The other thought I had was a worn rocker shaft. However, I'm not sure how I'd check for that. If everything checks out OK around the valves, I'll pull the chain covers and see if anything seems amiss in there.

[proporsche]

while you have the valve covers off. set each cyl to top so the valve are loose.Then with your left hand -use it like a wedge against the sheet metal push on the valve..or use 13mm socket and ratchet and push ..if broken -i think it is one or two you`ll find it..also if you have very little mirror look from side on the springs.
Ivan
This noise is there hot or cold correct?

[Roger 911]

I took the intake cover off of the "123" side of the motor, which is where the noise appears to be coming from. I really can't get any of the valves to move with my left hand (I'm right handed). However, if I use my right hand and a stubby flat screwdriver, I can get all three to move with a lot of force. They all feel the same to me. So either all of them are broken, or none of them. I don't know what is "normal". Should a "reasonably" strong person be able to push the valve in at all by hand, using a screwdriver tip? I can't see any of the springs with the rocker shafts in place, so there is no way to inspect without rocker removal.

Thoughts?

[Flynt]

The clip on the #5 ignition wire is jumping around a bit - Have you looked in the distributor cap? Check out the advance mechanism under the dust cap.

I second the exhaust leak. And I'd double-check the valve adjustment, look at rocker shafts to make sure none are backing out, and check head studs while I'm in there..
Also - try the stethoscope on the crankcase if you haven't already.

[proporsche]

is the noise there cold and hot the same??? that was my last Q..;-)

Ivan

[Roger 911]

Originally Posted by proporsche

is the noise there cold and hot the same??? that was my last Q..;-)

Ivan

Yes, warm cold about the same. I have my "winter oil" in it now, 5w-30 (this basically just while it sits in the garage), so it is probably a bit noisier than with the normal 20w-50. But the noise is always there.

I pulled the intake valve cover on the other side, "456" and tried pushing in the valves. Seems about the same, maybe a bit harder, but it's probably just the angle that I'm pushing from. I guess I can drain the oil and check the spring tension on the exhaust valves. However, almost every post I have seen regarding broken valve springs is related to an intake valve.

[proporsche]

what would nice if you can see the springs from the side with a little mirror...that oil u r using why ?
and it is synthetic as well right?Not really good for these engines at all.
This noise just happen to be there suddenly right?Or when did you 1st noticed that?
i still think it is the broken spring-s.

Of course do take your time and remove the rocker arm one by one to inspect...

Ivan

[Roger 911]

Originally Posted by proporsche

what would nice if you can see the springs from the side with a little mirror...that oil u r using why ?
and it is synthetic as well right?Not really good for these engines at all.
This noise just happen to be there suddenly right?Or when did you 1st noticed that?
i still think it is the broken spring-s.

Of course do take your time and remove the rocker arm one by one to inspect...

Ivan

When I store the car, I put 5w-30 mineral oil in. If I have to start the car for some reason over the winter, in sub freezing temperatures, I am uncomfortable doing so with the normal 20w-50 oil. I don't drive the car with 5w-30.

As far as seeing the springs, i have a small inspection mirror on a extendable wand. But it is about 25mm in diameter. There is no room to fit this anywhere near the spring with the rocker in place. I'd need a mirror about 5mm in diameter to fit in there. I guess I'll start taking the rockers out one at a time. It would be much easier if the sound was on the other side, 456. Oh well.

Yes, this sound has been there for at least a year.

[proporsche]

that is the way to go ,take your time...one by one on that side and yes it would be strange to have it on the exhaust side but it is also possibility....start with the easiest..

Ivan

[gomezoneill]

" I put 5w-30 mineral oil in." WHAT?