Clutch noise - still! And hoping for a miracle.

[JohninKuranda]

I first posted on this issue almost three years ago regarding my 1928 35A Phaeton. I took onboard the various comments and worked my way through the suggestions. Since that time I have dropped the rear axle and taken the transmission and clutch apart three times. I have replaced the throwout bearing twice as well as the pilot bearing. Also removed and rechecked the flywheel and pressure plate. I have dismanteld the transmission, replacing all the gears and bearings in the process. Even found a mangled split washer wedged under the reverse gear! When after replacing all the gears and still having the noise continue - I shipped the gearbox some 2,300 kilometres for an experts view.

It came back all checked out - and yes, the noise still continues - but I believe the transmission has been eliminated. Using a mechanics stethoscope, the further forward I move the probe along the transmission case the louder the noise becomes. So I am back to it being a clutch issue. Given that I have already replaced the throwout bearing and pilot bearing, I am loathe to drop the rear axle for a fourth time unless I feel that I have a reasonable chance of success. To summarize, push the clutch pedal down, noise stops. Remove my foot from the pedal, the noise returns. From the moment the outer ring of the throwout bearing starts spinning till fully engaged, the noise starts approximately one-third of the distance in pedal travel.

The link to the video below demonstrates the noise I am getting.It starts with the clutch pedal depressed and I lift my foot. The outer part of the bearing stops spinning as I believe it should.

If anyone has any more suggestions, or had experience in solving the same issue succesfully, I would love to hear about it.

https://youtube.com/shorts/nYG2MGJvGCU?feature=share

[nkaminar]

Previous text removed. It is not the throwout bearing or the pilot bearing. I cannot see how the noise could be coming from the clutch.

Update: The transmission would make a different noise. And the fact that you have rebuilt and have had the transmission checked out means that it is unlikely to be the transmission.

The only other thing I can think of is something in the engine. When you step on the clutch it forces the crankshaft against the thrust bearing. When you release the clutch it allows the crankshaft to move back. Use a lever to try to move the crankshaft fore and aft at the pulley in front. If you have movement it may be time to drop the pan and have a look inside. I have no idea what in the engine could be causing this noise but it is the only thing that I can think of.

Update: Wick, below, had the idea of the flywheel hitting a starter bolt. It could be that or something else that the flywheel is hitting. As stated in the above paragraph, when you take your foot off the clutch the crankshaft moves back. This could be a very simple fix and the miracle you are looking for.

You have several very capable experts in your country. Perhaps one of them would be willing to travel to your house to help.

[Wick]

Sounds like one of the starter bolts is too long and rubbing the flywheel.

[Will N]

Originally Posted by Wick

Sounds like one of the starter bolts is too long and rubbing the flywheel.

My thoughts too. That's a grinding noise.

[P.S.]

Originally Posted by Wick

Sounds like one of the starter bolts is too long and rubbing the flywheel.

If that were the case, it would be worse when the clutch pedal is pressed down (clutch disengaged) and forward pressure applied to the flywheel. In the video clip, the noise starts after the pedal is released (clutch engaged).

I was thinking it sure sounds like ring gear teeth brushing by something. But, what? Throwing me off is that as the clutch is released, the noise speeds up, like the transmission input shaft coming up to speed. That would point to something inside the transmission, making contact with the grooves on the input shaft or a gear inside.

Could it be the gasket folded over when the transmission was bolted to the flywheel housing?

[alexiskai]

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Originally Posted by P.S.

Could it be the gasket folded over when the transmission was bolted to the flywheel housing?

Seems unlikely it would be that loud, though, and in a contest between gasket and steel the steel is going to win pretty quickly, whereas the OP says this has been happening for three years. That seems like it could only be metal on metal.

[JohninKuranda]

Wick - Starter bolt - something I never thought of. Good call.

[Fullraceflathead]

I think wick may have figured it out it would be very easy to remove the starter bolt and check and see if there's wear marks.

[cadillac512]

It's quiet when the clutch pedal is pushed down,then starts making noise as you release pressure on the pedal. Almost sounds (in the video) like the ring gear is making contact with something. Is the starter drive (Bendix) returning properly and not sitting too close to the ring gear? Sure sounds like a ring gear contact with something.

[nkaminar]

Yeah, that could be. The crankshaft moves back when the clutch is released and the flywheel hits the bolt. Good call, Wick.

[Big hammer]

I’ve never heard a noise like that, well maybe, playing cards rubbing bicycle spokes ! How long would it take to clearance ? John it’s been 3years , you haven’t driven it much?!

[Marshall V. Daut]

Normally clutch and flywheel noises begin when the clutch pedal is depressed. You have the opposite problem. Check that the front of the engine isn't dipping too much, allowing the back of the crankshaft pulley to strike against the Y-shaped front motor mount. That will make a metallic clipping sound. Feel the back of the pulley spokes to see if you can feel divots dug into the back of them.
As you push the clutch pedal in, there is enough wear on the rear main bearing thrust surface so that the crankshaft moves forward, moving the pulley forward with it. When you release the clutch pedal, the crankshaft moves back again and the pulley comes into contact with the front motor mount. The noise that is caused by this will telegraph through the engine, clutch and transmission, making you think it's an internal problem.
To test, with the engine off and someone holding the clutch pedal down, place a piece of cardboard between the back of the pulley and the front motor mount. Start the engine with the clutch pedal still depressed. Watch the cardboard as the helper lets the clutch out. If the pulley shreds the cardboard, you have probably found the cause of the metallic buzzsaw noise.
Marshall

[Jim/GA]

Look for the ring gear walked forward. Tap it back on to flywheel all the way around.

[nkaminar]

Paul, It could be the ring gear but also could be the flywheel hitting a long bolt on the starter. As you said, when you push on the clutch pedal it pushes the throwout bearing into the clutch plate to disengage the clutch. You are pushing the crankshaft, along with the flywheel forward. When you let up on the clutch pedal you are removing the force that is pushing the crankshaft forward allowing the crankshaft to move back in the engine. The flywheel moves back too and can then rub on the long bolt (which is to the back of the flywheel) or the ring gear can rub on something. As someone pointed out it could also be the front pulley that is rubbing when the crankshaft moves back.

The thing to do is to check to see if the bolts for the starter are long and if they have witness marks. And to check that the ring gear is seated all the way forward all the way about the flywheel. And look for witness marks on the front pulley.

To me, the noise does not sound like the transmission. The transmission was rebuilt and checked out by a professional. The throwout, pilot bearing, and clutch would not make this kind of noise. Especially when the clutch is engaged.

[old ugly]

if the main bearing thrust surface has worn or is broke off the crank will move forward and back while operating the clutch.

i fixed one that sounded just like that. the rear bearing thrust surface was damage. but to compound the problem whom ever installed the ring gear did not have it on straight. so when the clutch was depressed the crank would move ahead and the warped ring gear would hit the housing.

i had to replace the ring gear. i was able to use an after market brass rear retainer on the rear main. (acts as the thrust surface). i think it came from snyders.
https://www.snydersantiqueauto.com/p...8768&cat=41685


i was hoping i would never hear that noise again. wow.

OU

[JohninKuranda]

UPDATE
I removed and checked the starter bolts. No tell-tale wear marks indicating contact with the flywheel. Replaced each one in turn with an extra washer and finger tight. There was no change in the noise. So unfortunately I do not see it as a starter bolt causation.

There have been some other good ideas, thank you all, and I will try those out this coming weekend. I will also wheel-stand the rear and just double check whether there is any difference in the noise when in first, second etc. Just to rule out the transmission entirely.

I hope to avoid removing the transmission/flywheel cover again, but it may be unavoidable. Not happy, but that's life!

John

[nkaminar]

John, As you say, there have been some good suggestions. To rule out any issues with the crankshaft moving aft, try to move it with a prybar at the front pulley. You may have to drop the pan to see if there is an issue with the thrust bearings, as Old Ugly said, see post #14. With the pan off you can see if you can move the crankshaft with the prybar.

Also, you could try turning the engine over with the hand crank and see if you can isolate the source of the noise. I don't think it is your clutch or transmission, but check the transmission as you plan.

[Benson]

Thinking outside the box ...

What if the flywheel dowel PIN retainer plate is missing or the wrong thickness?

If so, the forward ends the flywheel bolts might be hitting the rear of the main bearing cap when pressure is applied to release the clutch?

If rear crankshaft thrust is worn just enough it seems that when clutch pedal is released; the crankshaft might be moving to the rear just enough for the forward ends of flywheel bolts to stop hitting the rear main cap?

Ain't so?

UPDATE: I looked at video again. I see that the noise continues AFTER throw-out bearing stops moving. I thought that the noise was stopping when throw-out bearing stopped turning. I see that this is not true. So maybe my theory is not valid.

[Wick]

Starter bolts are ez to check, they have been ruled out now. I hate to say it but I think your clutch disc is at falt. One of the springs in the disc has broken, You wouldn't see it unless you were looking for it when everything was apart. One of the disc pads could be coming apart.
Put some duct tape on a stick and fish around inside for any kind of debris. Metal,brass,clutch material. A bore scope would come in handy.
***Also you could back off all your flywheel housing bolts 1 turn and see if the sound changes???

[Benson]

Is this engine a rebuild by H and H with the thrust bearing moved from the rear main cap to the center main bearing of the engine?