Squeaking valve or valve spring or ???

Stevehose

Stevehose

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After a couple years of being very annoyed with a gremlin squeaking noise, especially when cold, I have determined today that it is coming from #1 cylinder. It's not the exhaust pipes or manifold connections, they are tight and I even loosened the down pipes to see if that changed anything which it did not.

I was about to give up when I decided to start pulling plugs on each cylinder, when I pulled #1 plug the noise stopped. It is not very perceptible when warm but quite noisy when cold. It only squeaks from idle to about 1500 rpm then goes away. The engine runs great otherwise and there is no noise when driving through the gears or under load.

Here is a video with me pulling the plug, the noise is barely loud enough to capture, but if you watch towards the end after I pull #2 plug you can hear the squeak/chirp a little better.

Any suggestions as to a fix or an I looking at major surgury? I can try a better video when the engine is cold if that is helpful.

(EDIT: I posted a better video later in this thread)

Thanks.

https://www.youtube.com/watch?v=NWghkBgIqNw&feature=youtu.be
 
Last edited:
Surely It cant be a valve or spring, because they are opening/closing just the same whether the plug lead is on or not?

What happens when you change the HT lead and/or plug?

and is the spark plug sealing properly?? thread good and not stripped?
 
Yes they are always opening/closing but maybe combustion makes a difference on the pressure on the valves or springs I don't know...

The plugs and wires are all new and the squeak has been present through several tune ups of wires, plugs, coils, caps rotors, etc. The spark waveform for the cylinder is spot on. Valve jobs have not made a difference on the noise, although in hindsight the squeal may have changed tone a little after but not sure.

Plugs seal fine, no issues there.

kasbatts said:
Surely It cant be a valve or spring, because they are opening/closing just the same whether the plug lead is on or not?

What happens when you change the HT lead and/or plug?

and is the spark plug sealing properly?? thread good and not stripped?
Click to expand...
 
Could it be the exhaust manifold gasket? It's tight and was replaced with the head a little over a year ago.
 
Mmmm???

Compression good with acceptable leak down? I.e no funny head gasket thing going on?


Quote: maybe combustion makes a difference on the pressure on the valves or springs I don't know...

Surely not? but funnier things have happened!


Can you run the engine with the valve cover off to see if its coming from the valve gear? (not sure if this is possible with the M30, oil everywhere etc?)
Maybe try and rotate the spring and valve a little if possible to see if it makes and difference?

As for the exhaust gasket, well I guess it could be, anything is possible!
I would try this before taking the head off.
 
The head was rebuilt a year and a half ago, I did a comp test a few months ago and all was good, maybe I should do another just to see.

Running with the valve cover off will blow oil everywhere (I've seen it happen) so that's a last ditch option.

Rotation idea duly noted. Thanks.


kasbatts said:
Mmmm???

Compression good with acceptable leak down? I.e no funny head gasket thing going on?


Quote: maybe combustion makes a difference on the pressure on the valves or springs I don't know...

Surely not? but funnier things have happened!


Can you run the engine with the valve cover off to see if its coming from the valve gear? (not sure if this is possible with the M30, oil everywhere etc?)
Maybe try and rotate the spring and valve a little if possible to see if it makes and difference?

As for the exhaust gasket, well I guess it could be, anything is possible!
I would try this before taking the head off.
Click to expand...
 
Just because its easy and cheap I would remove the forward manifold and smear a nice layer of grease on the #1 exhaust flange and then re-install. You will need to cycle the engine once to harden it.
If that fixes it you need to belt sand the manifold or fetch a new one.
 
What kind of grease should I use? I uploaded a better video which I will link in a new post. thanks.


sfdon said:
Just because its easy and cheap I would remove the forward manifold and smear a nice layer of grease on the #1 exhaust flange and then re-install. You will need to cycle the engine once to harden it.
If that fixes it you need to belt sand the manifold or fetch a new one.
Click to expand...
 
Well i loosened the manifold from the head a few mm and sprayed some penetrating oil between the head and gasket to try to affect change (leaving it loose) and it did not so it appears the gasket or manifold is not the issue. Damn.

So tonight i will pull the valve cover and have a look around.

Any other theories welcome.


Stevehose said:
Thanks, I think the gasket idea is worth looking into, when i had the downpipes loosened from the manifolds the chirp had a sharper more percussive tone than when tightened up so I will start by taking off the manifold and seeing if it is true as well as then greasing it up.
Click to expand...
 
You missed the point.. :]
SMEAR wheel bearing grease between the exhaust port and the exhaust manifold.
Not oil, not spray. We aren't lubricating. We are using the grease as a cheap sealant.
61porsche had a better product but that is long term.
 
One thing I am good at is missing the point!

But if it still makes the same noise without the manifold bolted on (a visible gap between the head and gasket), what would sealing it with grease or the other product (which I ordered) accomplish?

Thanks.


sfdon said:
You missed the point.. :]
SMEAR wheel bearing grease between the exhaust port and the exhaust manifold.
Not oil, not spray. We aren't lubricating. We are using the grease as a cheap sealant.
61porsche had a better product but that is long term.
Click to expand...
 
I like free answers....
I really like reductions in variables.

BTW-I was thinking of starting tonight's meal with a magnum of 2012 Domaine Rimbert.
Too soon?
 
Starting dinner with a magnum of anything is a good idea. 2012 is RTD.

I will do the gasket work and report back. thanks.



sfdon said:
BTW-I was thinking of starting tonight's meal with a magnum of 2012 Domaine Rimbert.
Too soon?
Click to expand...
 
Ok so I put the sealant that 61P suggested on the gaskets after removal and cleaning of the manifold but no luck. The manifold is in good shape and not warped or cracked. Gaskets looked almost new (they havent been on the car very long).

I pulled the valve cover to inspect but didn't find anything unusual around cylinder #1. I rotated the valve springs to see if that had any affect on noise but didn't.

I rechecked valve clearance and it is at .012.

The noise is louder when the engine is idling cold, very faint when idling warm, gets a little noticeable when pulling away from a stop (under slight load), but goes away after 1700 rpm or so. Engine runs great otherwise.

I guess I will take it in to the shop and put it on a rack and see if another set of ears can figure it out.

Any additional ideas are appreciated. It's buggin' me bad. Thanks.


sfdon said:
SMEAR wheel bearing grease between the exhaust port and the exhaust manifold.
Not oil, not spray. We aren't lubricating. We are using the grease as a cheap sealant.
61porsche had a better product but that is long term.
Click to expand...
 
Can you make up some sort of rig that you could manually operate the valves?

I.e

Engine off, cam cover off, No1 at BDC and some sort of lever system to push the valves down and release back up again under valve spring load

You would have to be very careful not to dislodge the spring retainers doing this or the valve may drop into the cylinder!
 
Ok- so I do have a ready to bolt on DOT replacement head for a carburated car in the shop.
That is a pretty rare item.... ;-]
How much wine are you ready to trade?
 
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