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In reassembling my '39 Six with the new engine, I had the 3-spd tranny rebuilt and the machine shop that did the motor, resurfaced the flywheel. I went over the clutch and pressure plate. They looked fine to me and had been working smoothly prior to disassembly. The throw-out and pilot bearing seemed within spec, so all I did was take the old clutch disc to a brake & clutch house and had them re-sinter new discs onto it and put it all together. Now I am finding a distinct chatter when engaging the clutch from a stopped position. It doesn't see to matter if I rev the car up a little bit and try and feather the engagement or use minimal feathering and let the engine torque 'grab' the drive, I am getting a chatter. Can anyone suggest anything here as a probable cause. I have driven for 50 years and many of my vehicles have been standards, so I am intimately familiar with clutch operation. I am wondering if the new disc and the fresh surface on the flywheel just need to wear in, or if this symptom portends a more serious issue. Any info or input much appreciated. Chris

Could be the new friction material was not as cushioning as the old. Perhaps wearing in will help although Packard did use different clutch discs with different characteristics for various applications and models. In addition, you might look thru the service index for 37-42 models. There are a few articles on clutch chatter and maybe one or more will suggest something that needs checking.

The snubber being in good condition and adjusted properly is one item that has affected others. First version snubber wasn't very strong and apparently the original version of the second or improved type replacement snubber which your car would have had is not too robust either. Some have mentioned the rubber in the ball joint can deteriorate without outward signs. Rods were a bit weak too and can bend or break. Flackmaster repro'd a much more robust version at one time so if yours is the original and shows signs of failing you might see if he still has the better version.

Fort Wayne Brake and Clutch in Indiana or Custom Clutch in Cleveland will use the correct materials. For awhile people were trying to use a modern Ford clutch disc that fit, but was a complete disaster.

Howard - thanks. I did not know what that 'thing' (snubber) was when I pulled the motor and tranny out. I cleaned it up, painted it and, although the rubber ball and socket joint DID appear less-than, I just put it back in as-is. This is very likely my issue. I've PM'd Mr. Flack to see if he has any of the repros you referred to. I'll report back. Chris.

Howard, I did peruse the service bulletins on clutch issues and that snubber would seem to be a common issue relating to chatter. When I had mine out, I did notice that the ball popped in and out of the socket quite easily, so I suspect it may have popped out and I have zero snubbing effect at this time. I will get under the car and check this out tomorrow, but I should think a new one would be in order. You mention adjustment, but I could not see any on mine as it just had one good-sized bolt attaching to the transmission and same thing on the frame, with the rubber ball socket as a kind of universal joint in the middle of the arm. Chris

Tim, re Fort Wayne Clutch, I appreciate the suggestion. Being up here in Canada, customs and the border can complicate business dealings which is why I went to a local clutch and brake place here to have the disc re-sintered. I was able to drop it off and pick it back up once finished, and I think the whole process was about $120 USD. which is about half of a new disc from one of our suppliers, plus freight, plus shipping the core back. If it turns out it is the disc, I will just order one off the shelf from Kanters and be done with it. I do want to follow up on the snubber issue first though, as, like I said in my previous post, I didn't even know what that contraption WAS!! I looked it over and tried to visualize it's function; couldn't, and just put it back in the same way it came out, other that when I had it apart the ball and socket DID come apart and I was suspicious that, whatever it's function was, it definitely seemed to be in somewhat compromised condition. Now I learn what it's for and, go figure, I have the condition it's supposed to prevent!!! The learning never stops!!! Chris

Newbie,
Your car uses a Long Clutch, The friction disc in a Long Clutch has a wavy thin spring plate under the friction material, called a Marcel spring.

If this is missing the clutch will chatter!! Clutch re- builders have been known to leave this out.

John

Thanks John - totally news to me??!?!? The old clutch disc just looked like regular sintered discs riveted on to the inner plate like every other clutch I've ever dealt with. Should I have been able to see this Marcel spring you are referring to?? If I order a clutch disc from, say Kanters, will it automatically include this spring??? James, from Kanters - can you weigh in here??? Wow, having to pull the transmission and replace the disc is a big job!!! Yuck! Should the clutch/brake place have known better?? Was this just corner-cutting on their part or can they be forgiven for overlooking this?? Anybody else ever have anything to do with this issue??? Chris

Got under the car today and the snubber is intact. And Howard, you are right, there is adjustment on the arm. I looked in the service index but can't find the procedure for adjusting it properly. I just put it back in the way it came out and with not changing anything other than the front motor mounts, I am guessing it should be halfway close. Is there any chance this new disc could wear in and quit chattering?? With the flywheel resurfaced, the new disc rings and I did break the glaze on the pressure plate with some really fine sandpaper before reassembling it, I guess I'm just clutching at straws here, but if there's any chance it could work itself in, I would sure give it a bit of time before tearing it all down again. I did speak with the clutch/brake outfit today, that re-sintered the clutch and they maintained that they would have relined the clutch with the same components it came to them with, that is, if it had a Marcel spring, they would have given it back to me with one. The only way I can really hold them to any account is to remove the disc and see 'what is is' and that involves a fair commitment in terms of taking the car down and disassembling everything. 'Kind of betwixt and between on this one.... anybody have any advice???? Chris.

No clue on whether the plate will wear in adequately with time but on the snubber adjustment you want there to be a slight tension on the engine and trans but not so much that the engine mounts or cushions in the snubber are squashed. Service letter 13 #1 provides some guidance.

The purpose of the snubber is to control the fore/aft movement of the engine and trans. The rubber at the ball joints in the snubber needs to be in decent condition so it can provide a constant tension yet also have a bit of cushion for when torque wants to rotate the engine.

When the car starts to move in one direction the large mass of the engine and trans will want to stay still or effectively move in the opposite direction because of inertia. Depending on how tight or good of condition the motor mounts might be determines to a great extent how much movement there is but because the mounts are rubber and flexing there will be some. As the engine moves, because of the way the clutch linkage is connected between the frame and engine that movement would almost be like letting up on the pedal thus causing a decrease in friction and slowing the car. The engine would want to move back in the opposite direction again which in turn would apply the clutch more and cause the car to move again. This movement sets up a rapid jerking or chatter condition as the engine sort of vibrates back and forth for a period until the car movement is steady. The snubber is there to provide a bit of tension to keep the fore/aft movement to a minimum without making it feel like the engine is bolted solid. As the service letters mention, there are also other things that can contribute to the problem.