Clutch Chatter & Flywheel run-out

Tom Endy said:
There are two .010 horse shoe shaped brass shims that install in the two ears of the clutch housing where it attaches to the rear of the engine block ...
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Hey Tom, I as unaware that the clutch housing attaches to the engine block. :p

Just kidding, ...I believe you are speaking of the the flywheel housing, and if you re-read my first post, we actually put an indicator on the center of the flywheel and swept it in, and it read less than 0.005" which is within spec.
 
roy green coupe said:
I think Bill is on to something here. I have also had the experience of a new disc and pressure plate needing some wear to work smoothly. It was mentioned that the flywheel had grinding marks. When a good working clutch is taken apart the surfaces will be polished smooth. Chattering is caused by the surfaces trying to grab instead of slipping until the clutch is fully engaged. Compatability of the surface finish and the lining material is critical to smooth operation much like disc brake rotors. I would try to improve the finish on the flywheel and pressure plate and clean well and break it in like Bill said.

As someone that has worked on alot of stuff over the years I have to say you can really make yourself crazy if you get too carried away with dial indicators and micrometers and such. These cars are very simple and can tolerate alot of runout or imbalance and still function pretty well. Most problems like this ultimately trace back to china and subpar aftermarket parts.
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This vehicle has about 2,000 miles since a frame-up restoration and the problem is still there, -so I'm not sure Bill's thoughts are truly applicable in this situation, as surely it has been driven enough to cure this by now. Additionally, can you imagine the response that a new Ford owner would get it they brought their new Ford automobile back due to chatter and the mechanic told them to use Bill's method to repair it?

I also want to make sure I understand what you are saying. You are saying that 'chatter' is caused by rough surfaces? I can believe that a 'grabbing' clutch would be caused by this but not one that shudders. My experiences with a shuddering or chattering clutch has been that the disc is not within the centerline of the spinning flywheel which causes the disc to momentarily spin eccentrically until it can work itself to be concentric. Generally the causes of this is any one or combination of a worn input shaft tip, a worn pilot bearing, a worn front transmission bearing, or a grossly misaligned flywheel housing, HOWEVER generally speaking, when those symptom are found, the transmission will generally jump out of 2nd or High gear on deceleration. This vehicle did not do this, which is partially why we have been puzzled. You may very well be right, but I guess I need to think on that one for a day or two.


So based on thoughts above, it seems most feel like it is the clutch disc. I will look it over on Monday to see if something is obviously wrong. I am pretty sure I do not have a copy of a print of the disc, ...and even at that I would specifically need several prints including the hub, and the plate itself. I am wondering if the repro discs that are having issues are found to have too large of tolerances in the hub area where the disc has a sloppy fit on the main gear (input) shaft splines? I am wondering exactly is different causing them to chatter?
 
I could be wrong but I thought original ford discs had solid hubs with no cushion springs. I dont think that a person should have to break in the clutch but if the surfaces are too rough it might be a solution. Bills method accelerates the process. The combination of a disc grabbing and slipping compounded by the hub springs recoiling is what I am describing. For the clutch to work properly it needs to slip smoothly at the beginning of engagement.
 
FWIW, When I was doing my fly wheel Lightening act. I tried for a 0-0 set up in a universal chuck. The chuck was worn and it required shimming (About .002 IIRC) I managed to get it pretty close. So close that it only required about a 5/16 X 5/16 hole to rebalance the fly wheel. Estimate the weight of a cast iron plug .312 X .312. It ain't much! So for me, Indicating the flywheel as closely as possible is the answer, The clutch face, I don't know! I never had the issue. Tom W. says he get good results with a palm sander. I can appreciate how Bill W's solution might seem realistic to an owner, but not really feasible for a professional restorer. Paying customers don't want to hear "Just drive it for a while and it may get better!", however well the advise may be. Good luck with it!
Terry
 
Brent, The PP I'm talking about is multi-fingered, commonly used in Chevy's for many years. Not a Borg and Beck style. They require a rounded TO bearing or the release is not constant. The first one I did made for a performance Mustang, I put it behind my 4-port Riley, which has a lot of torque. The second one was, I think, off a Ford Ranger pickup. It required less pedal effort to release although the Mustang was not bad. I understand Clutch-Masters out here now stocks a lightened, machined flywheel, PP, disc and TO brg.
 
My thinking is that the original chattering caused HIGHS & LOWS, in the disc lining. Each chattering take off makes them DEEPER. The slow, idling take off, in SECOND, doesn't chatter & helps EVEN out the HIGHS & the LOWS. That took care of Minervas' chattering, PERMANENTLY!
Bill Smooth
 
I am addressing Dick S. comment about a clutch disc being out of balance and it starting and stopping in a different position would negate balancing it. A tire wheel assembly after taking a number of right and left turns put the assemblies in different positions, but it doesn't change the fact that a tire and wheel assembly's balance has changed. Lets not forget static balance and dynamic balance.
 
KR500 said:
I am addressing Dick S. comment about a clutch disc being out of balance and it starting and stopping in a different position would negate balancing it. A tire wheel assembly after taking a number of right and left turns put the assemblies in different positions, but it doesn't change the fact that a tire and wheel assembly's balance has changed. Lets not forget static balance and dynamic balance.
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I guess there are two ways of looking at this. Balancing a disk by itself (like your tire example) or balancing the disk with the assembly (flywheel, disk, pressure plate) which I believe Dick was referring to when he stated it would do no good because the disk would likely land in a different place each time.

I just had my flywheel and pressure plate balanced and the machinist told me to leave the disk at home... They marked the two so they would always be reassembled the same way.
 
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KR500 said:
I am addressing Dick S. comment about a clutch disc being out of balance and it starting and stopping in a different position would negate balancing it. A tire wheel assembly after taking a number of right and left turns put the assemblies in different positions, but it doesn't change the fact that a tire and wheel assembly's balance has changed. Lets not forget static balance and dynamic balance.
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"A tire wheel assembly after taking a number of right and left turns put the assemblies in different positions, but it doesn't change the fact that a tire and wheel assembly's balance has changed."


I'm not sure I'm following you. I'm not seeing how making turns puts the assembly (tire/wheel) in different positions. The tire is always in the same position relative to the wheel (unlike the clutch disk relative to the flywheel/pp combo). I also don't think the wheel assembly's balance (static or dynamic) has changed by turning corners.

Flywheel/PP's are balanced dynamically...just like wheels/tires are done (currently).

I may be missing something in your explanation. It's happened before with others :)
 
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OK, a little Monday morning update. The clutch disc seems to be wearing uniformly and the edges all mic pretty close measuring about 90° apart. Unfortunately, I do not have a mic with a deep enough reach that I can measure the lining towards the center to see if it shows something different, but just based on how tight it is one the input shaft, and the wear pattern, I am not suspecting it is the disc.


Something that I have found this morning (-that is very likely the problem) is the pressure plate mounting holes are not concentric with the center pilot bearing hole. The flywheel is not reamed for shoulder bolts, and the bolt fit is pretty sloppy but when I sweep the thread holes with a longer bolt bottomed into the holes, it appears there is approximately 0.010-0.012" at the furthest point (-all bolt holes in the circumference are drilled at different locations on either side of the circumference centerline.) What I need to do next is figure out in my mind whether the offset mounting of the pressure plate is what is causing the chatter -or if it is still something else. Conventional wisdom would say that needs to be corrected however from a balance issue, the pressure plate cover already has holes drilled into the pressed steel P/P cover to compensate for the imbalance, so theoretically it being offset is not going to harm the engine. Also, it would seem the pressure plate itself while being offset is still within the centerline established by the transmission input shaft and the pilot bearing, so does it matter if it is offset??


As I mentioned above, the car owner purchased this vehicle already restored by someone else, and he does not know who actually rebuilt the engine either. Deep down, I now am suspecting the flywheel is the root of the problem, and I think we will replace the flywheel, clutch and p/p, -and then reassemble to see what that changes. My only other fear in my plan is, ...based on the craftsmanship we have seen thus far on the flywheel is, imagine if we replace his flywheel with a whole new lightened flywheel, clutch, and P/P, and assemble it only to find the engine was balanced with the crank, pressure plate, and flywheel as one unit. Imagine the feeling when we correct the chatter problem but now have a new harmonic balance issue with the engine!! Oh well, any other thoughts or suggestions are welcomed.
 
If you haven't done so already, you might want to check and see if there is a counterweighted crank in there. If so, there might be a higher probability of the crank/flywheel/pp/pulley being balanced as a unit.

I don't know if this is possible, but it would be great to learn what is causing the chatter. If you replace the disc, PP, flywheel, and correct for the slight out of concentric pp, and drill for shoulder bolts, and rebalance the rotating assembly, it probably will correct the chatter, but we can only guess at which of those factors was causing it.

Being a CAMAO (cheap *** Model A owner) and with my free labor, I'd probably start by taking a palm sander to the flywheel and pp faces and installing the best disc available and giving it a try.
 
I did this about 25 years ago. My newly purchased 29 Tudor shook like a paint mixer, and no amount of easy engagement or slipping the clutch would help. I didn't want to do the job twice, so I installed a new disc I bought at a swap meet, along with a good looking used pressure plate. I also sanded the flywheel with my 1/4 sheet palm sander and dialed in the flywheel cover. So, I don't know what fixed it, but now it's as smooth as an automatic.


The disc I removed was new, as the lining wasn't fully worn to touching yet, and the pressure plate also looked good. There was no oil on the disc or flywheel, but as I recall I found the flywheel cover was a bit off when I dialed it in.
 
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So here is what we did. We put the flywheel into the grinder and supported it off of the hub area and indicated it off of the flywheel ring gear to verify it was parallel to the stone. The face was only out by about 0.004-0.005, so it was a quick clean-up there. This was a relief to know the initial uneven reading was not due to a crankshaft flange run-out problem. :eek:

Next, we mounted the flywheel on the Bridgeport and indicated off of the pilot bearing hole to find true center. We laid out the V8 pressure plate mounting holes using the DRO, and just rotated the flywheel enough to move to an undrilled area on the flywheel. We drilled & tapped six new 5/16-18 holes and reamed the top of the holes for Mr. Gasket (Part #: 911) shouldered pressure plate bolts to properly locate the pressure plate. We then balanced the flywheel, -and then the flywheel and the customer's pressure plate as an assembly. Since there were several ½" lightening holes previously drilled into the pressure plate cover where they originally balanced it, we used a TIG to tack-weld a one inch diameter slug that we punched from some 11 gauge just to get us somewhat close(r), and from there it was balanced with the flywheel as an assembly.

The flywheel housing was left as-is and was never removed from the vehicle/engine, -and the flywheel was reinstalled along with the customer's original clutch and pressure plate. Once reassembled enough to test-drive it in and out of the shop, we found that engaging the clutch in forward and reverse revealed no more chattering. Yes, I know it was a gamble not replacing the pressure plate and disc, however if truth is told, I initially had planned to replace the disc however I got side-tracked as they were reassembling it and they already had the transmission and rear end installed by the time I handed them the disc, -and after a quick discussion whether to go on or disassemble, because we had not seen any evidence of looseness on the hub, nor unevenly worn areas on the linings, I chose to forgo pulling it apart just to change the disc simply because we felt the disc was not hurt or defective. The gamble paid off (-this time! :D ). So ultimately, it was either the poor flywheel face finish or the pressure plate being off-center that was causing the chatter issue. My opinion is the chatter was probably more likely due to the pressure plate being drilled off-center of the flywheel, but who knows. So as Paul Harvey would have said, --Now you know...…
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Patrick L. said:
How far off center was the plate ?
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Around 0.010" the best I could tell. Not sure how it was mis-drilled but I am going to guess it was done on a rotary table that was not perfectly centered.


The bottom line is whoever did this conversion was pretty sloppy/crude with their craftsmanship IMO. The scary thing about this is the engine rebuilder probably knew this was going to be installed, --or possibly it was done by the engine rebuilder. One good thing was the engine did not vibrate when we test drove it up the road, so either the crank & assy. was balanced --or at least the crank, flywheel, and P/P was not balanced as an assembly. Who knows the real story is behind all of this but if the car was mine, I'd be doing an inspection on that engine just for peace of mind.
 
Agreed! It was a pretty sloppy method! However, In a shop only dealing with a few parts, it would behoove you to machine a center pin for quick and precise locating. Just locate the center of the Flywheel and dial off the radius.
I think that this is a good example of why I want my parts balanced separately. Balancing together may be ok for some, but whatcha gonna do when the time comes that you need to change the PP? Rebalance the whole shooting match?
Terry




BRENT in 10-uh-C said:
Around 0.010" the best I could tell. Not sure how it was mis-drilled but I am going to guess it was done on a rotary table that was not perfectly centered.


The bottom line is whoever did this conversion was pretty sloppy/crude with their craftsmanship IMO. The scary thing about this is the engine rebuilder probably knew this was going to be installed, --or possibly it was done by the engine rebuilder. One good thing was the engine did not vibrate when we test drove it up the road, so either the crank & assy. was balanced --or at least the crank, flywheel, and P/P was not balanced as an assembly. Who knows the real story is behind all of this but if the car was mine, I'd be doing an inspection on that engine just for peace of mind.
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