Mystery clutch noise

[1939mars]

I have been chasing a noise related to depressing the clutch and am basically out of ideas. Transmission has been rebuilt and new throwout bearing, pilot bushing, pressure plate and clutch disk are in. Noise persists

It makes the noise when the clutch is depressed. You can get the throwout bearing spinning a little before the clutch is in far enough for the noise to start.

Once suggestion was that the ring gear was not seated on the flywheel. An initial check did not reveal anything but I have not looked through the starter yet. No discernible axial movement of crank.

I've tried to put a link to the noise here:
https://www.scottdoudrick.com/37-noise/

-Scott

[Tim Ayers]

We need more info on clutch size, engine type etc., but that noise sounds like the end weights of the pressure plate fingers hitting the bell housing. It sounds to be like a spinning knocking noise.

If you have an early motor and used an 11" clutch & pressure plate, I believe you will get interference. If it's an 8BA style and you used the stamped steel bell housing and an 11" clutch, you definitely will get interference since they are designed for 10" clutches.

If possible, put your hand on the top of the bell housing to see if you can feel a vibration or knocking when you depress the clutch. If so, I believe that your problem.

[1939mars]

Sorry, yes. 59AB motor with 10 inch clutch. 78- case with later gears, top with 3 inch fork

[Tim Ayers]

Originally Posted by 1939mars

Sorry, yes. 59AB motor with 10 inch clutch. 78- case with later gears, top with 3 inch fork

I would still place your hand or a mechanic's stethoscope on the front mouth of the trans case or the top part of the bell housing. I don't think it's hitting the pan for that would be a tinny knock. This is a hollow, thud knock like it's hitting the thicker cast iron.

[alchemy]

Can you see the counterweights through the window? Can you see if they have a little shine on the top of them?

Is the engine fresh? Wondering if the thrust surface is gone from the main bearing?

[Tim Ayers]

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Originally Posted by alchemy

Can you see the counterweights through the window? Can you see if they have a little shine on the top of them?

Is the engine fresh? Wondering if the thrust surface is gone from the main bearing?

Interesting thought about the the thrust surface. I just assumed it was a fresh engine, but can't assume that. LOL!

[1939mars]

Not a fresh engine, but not decrepit either. No shine on the weights. Replaced the pressure plate with a known good one.

[Tim Ayers]

Originally Posted by 1939mars

Not a fresh engine, but not decrepit either. No shine on the weights. Replaced the pressure plate with a known good one.

Noise came after you replaced the pressure plate or it made no difference?

[1939mars]

Made no difference

[pistonbroke]

Simple answer is , if that noise is coming from the bellhousing pull the transmision ,clutch and flywheel. Something rotating is just lightly rubbing something stationary so look for the shiny spot and you'll have your answer. Tim

[tom1948]

just a thought; maybe the t/o bearing or arm is not seated correctly?

[1939mars]

Well, today I pulled the starter to look at the flywheel as best I could and the ring gear. There were a lot of metal shavings sticking magnetically to the starter. Nothing odd noticed about flywheel or ring gear. Reinstalled starter and started car. Noise was gone! Came back after 5 minutes. Starter only has a few hours on it but I am going to try replacing it to see if it makes a difference...
-Scott

[jimvette59]

Maybe just the Bendix ?

[Tim Ayers]

Odd that it was only happening when the clutch was depressed. Hopefully this fixed it, but curious what the clutch was hitting.

[1939mars]

Latest update. Over the weekend it started making the noise even when the clutch was out. It was worse with it in, but pretty bad either way. I changed the starter today and the noise was still there. Had some lunch, adjusted the clutch free play and went for a test drive. Noise went away and stayed gone for over 10 miles!! I am glad the noise is gone, but it is frustrating to not know why. And it will probably come back...

[cas3]

Do you have the correct arm on the throw out shaft for your frame and pedal set up?

[flatford8]

In post #12 he has metal shavings on the starter…could he have a thrust issue? The crankshaft moving when he pushes the clutch pedal….so he would need to watch the front pulley real carefully while someone pushed the clutch…. Kind of a WAG on my part but this must be frustrating…….Mark

[GB SISSON]

Were there any shiney or wear marks on the starter or bendix you pulled out? Is the flywheel the correct type for the engine ? I recall there is starter and ring gear interference when the two styles are mixed. Odd that it went away for ten miles.

[pistonbroke]

This would be a good time to remove the little tin cover and look inside the bell/clutch housing with a fiberoptic camera. Again the shiny spots will tell the story. Tim

[lonewolf]

Did you add more free play or take some away. I have the same problem

Originally Posted by 1939mars

Latest update. Over the weekend it started making the noise even when the clutch was out. It was worse with it in, but pretty bad either way. I changed the starter today and the noise was still there. Had some lunch, adjusted the clutch free play and went for a test drive. Noise went away and stayed gone for over 10 miles!! I am glad the noise is gone, but it is frustrating to not know why. And it will probably come back...