The application is a 1949 Packard. The engine and transmission were just rebuilt. The clutch/pressure plate/throwout bearing were only 3000 miles old so they were reused. No prior noises in them. The pilot bearing seemed stiff so I removed and reinstalled a new one and lubed it up according to the manual. The flywheel was resurfaced. I cleaned the clutch and pressure plate with brake cleaner and I (perhaps this is the problem) I ran some rough grit sand paper on the flywheel and pressure plate by hand to break off any glaze (I have done this with drum and disc brakes in the past with great success). I was able to upload a video with audio to YouTube at the following link: The engine is spinning at about 2000 RPM as I was still in the process of a high speed idle to keep the oil pressure up to wear in the cam shaft and new engine break in so could this be the issue as well???. A slight error in the terms I used during the video...I say the words "as the pressure plate stops" and/or "as the pressure plate begins to move" however I meant to say "driven plate (Packard speak for clutch disc)". The noise begins just as the driven plate (spinning clutch material) just starts to move and/or when the clutch material just begins to stop moving. It is quiet when the clutch is spinning with the flywheel/pressure plate. Can you all PLEASE watch the video and PLEASE help me fix this???? THANKS IN ADVANCE!!!
It sounds pretty normal to me. The through out bearing will start making noise as soon as pressure us put on it, I don't think that is the case here. The clutch disk can make quite a bit of noise when fully disengaged and the surfaces are still rough.
Is the clutch disc hitting the flywheel bolts? I assume the disc was installed with the flat side toward the flywheel. I have seen flywheels surfaced too far or the wrong bolts used to install it so the bolt heads hit the clutch disc. A throw out bearing will usually make noise when pressure is first applied to the pedal. This noise seems to start when the clutch disk and flywheel are rotating at different speeds. The disk seems to move away from the flywheel which makes me think there is interference there.
THANKS Guys...yes this is frustrating. The throwout bearing is still newish (less than 3000 miles) and it was quiet before and was not damaged as far as I can tell so I reused it. The pilot bearing did feel tight so I replaced it and the R&R was as expected with no complications. Was it wrong to "de-glaze" (scratching surfaces with some 80 grit sand paper) the surface of the flywheel and pressure plate ? Could that be the problem with the chatter??? I thought that would be a good thing as I have done this on brakes for years. The surface of the pressure plate and clutch disc were clean and in good condition prior and only had very slight wear and the flywheel was resurfaced. I cleaned everything with brake cleaner and there is no rear main seal oil leak. Naturally I do not want to break the transmission however perhaps some miles on the clutch will wear down the scratches? The clutch can only fit in one way because the springs would strike the flywheel bore if installed backwards. THANKS AGAIN!!!
While clutch discs are made to only fit one way, they have been installed wrong by mistake by people who know better and by some who didn't know better. As I said, I assume you installed it correctly. Most flywheels are recessed at the center for the bolts and use a bolt with a thinner than normal head to attach the flywheel. I have seen people replace the bolts with a standard thickness head bolts that touched the clutch disc. When the clutch is engaged, it turns with the flywheel so it won't make any noise. When you press on the pedal to disengage the clutch, the disc stops turning and the flywheel bolts rub the disc. Even with the original bolts, every time the flywheel is surfaced, the depth of the recess decreases by the amount of material removed. If it's done enough times, the recess becomes shallow enough that the bolt heads hit the disc. When we raced on dirt tracks, the rules required a ferrous [steel or cast iron] flywheel. To decrease rotating weight we would machine both sides of the flywheel as far as possible. We countersunk the bolt holes to use flat head cap screws to clear the clutch disc. To find out if your disc is rubbing on something without having the engine running, have someone hold the pedal down or use something to hold it down, put the transmission in neutral and turn the disc with your fingers or with a screwdriver if necessary to try to feel any rub. You could jack up a wheel, put the transmission in the highest gear and have someone turn the wheel with the clutch depressed while you listen at the clutch disc. Both of these methods eliminate the throw out bearing because the pressure plate isn't turning. I doubt the noise is caused by any sanding marks on the surfaces. If it is, they will wear off in a few starts and stops. Good luck.
Sure sounds like friction material of clutch disc sliding on the flywheel and pressure plate surface as it comes to a stop and start. I usually clean up the pressure plate and flywheel with a red 3M cookie wheel to knock the glaze down. I think the clutch will be little grabby until it wears in. I really don't think it will be a problem. KK
Hi Guys, I want to thank all of you for your help. I think Engine Man nailed it...your post was VERY informative and THANK YOU for your time!!! I did use regular grade 8 bolts to install the flywheel and my guess is that they are hitting the clutch hub and therefore making that zipping sound as the clutch begins to turn and then is quiet once the pressure plate locks up the clutch. !!!DANG!!! Looks like I will be pulling out the transmission...again... I will keep you all informed of my progress. I think Engine Man should be renamed Clutch Man!!! Cheers!!! Bill
I agree with KoolKat-57.. The noise is coming from the newly machined surface of the flywheel rubbing on the linings.. I've struck it before on new vehicles and overhaul jobs where the flywheel has been resurfaced.. It will disappear as the surfaces wear/bed in..
We tried a number of direct drive/parking brake rev the engine up to 2000 RPM and release the clutch pedal until the engine lugs under events and the noise did not reduce at all. Sadly...it looks like the transmission will need to come out and I will need to order new flywheel bolts.
The noise was EXACTLY like Engine Man diagnosed... the clutch disc was hitting the heads of the grade 8 bolts I used... nothing a tranny R&R did not fix. I had used red thread lock and they aren't kidding when they say high strength. THANKS Engine Man!!!
You are very welcome. It's what this site is for so us old farts can do something with the knowledge we have accumulated before old age takes it all away.
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