Hey everyone. Here's the skinny on my truck's clutch history ... and I have a couple questions before I make some decisions. I bought my Y-block 292 in Summer '06, to go in my F-100. It has an 11" clutch. The engine received a full rebuild and was dropped in September 07. I had the flywheel resurfaced, and the rest of the clutch went in as is. The clutch had a pretty wicked chatter. I went to AutoZone and bought a reman. pressure plate & disc. I take 'em right out of the box and bolt them in. There's practically no chatter, the engagement is very smooth. However, it's obvious that the clutch is very unbalanced. At about 2000 RPM it's really, really bad. Shakes the steering column. So I pulled out the pressure plate and flywheel (had to grind the bellhousing a little just to get that guy out). I took them to my engine guy to balance them. He balanced them by drilling a "cone" in the back of the flywheel, and welding a big fat slug onto the pressure plate. If memory serves, I think he said the thing was 60 oz. out of balance. He marked the pressure plate and flywheel so I could install them at the proper orientation, still in balance with each other. I reinstall the freshly balanced assembly, and I'm off to the races. The vibration is (almost) gone. I'm satisfied with that, it's just a Y-block, not a Cadillac. The new problem now is that if I engage the clutch at low RPMS, it's chattering. And pretty bad too. If I rev the engine to about 1500+ RPM to engage, it doesn't chatter. As you can see by the pictures ... this is the three-finger "long" style pressure plate. I'm worried that when he welded on this thing, he pulled it out of shape, and made the pressure plate engage unevenly. Is this even sensible or possible? And if so ... can I adjust the fingers somehow to make up for this? My other idea is to s***-can the whole thing, and go with a new Hays street/strip clutch. As an additional question .... are they good clutches? Will they be in balance? I will probably get a new (or reconditioned) flywheel as well ... because this one has been around the block and is getting kinda thin. Thanks for your attention, and hopefully, for your help/advice.
Wow! 60 ounces out of balance? That's almost 4 pounds. 3-3/4 to be exact. Seems like an awful lot. Maybe he ment 60 grams. (a little over 2 ounces). Anyway, I have an 11" clutch in my 50 ford whick uses basically the same setup. My first guess to your problem would be that heat is causing your chatter, similar to what a brake rotor does after it gets hot. You mentioned that the flywheel was getting a little thin so could also contribute to your problem. Also you could check that the throwout bearing is making contact with the three clutch fingers all at the same time. They can be adjusted with the screws at the end of the fingers. I would look and see if any oil or other fluids are getting on the flywheel and lastly, most y-blocks of late 50's early 60's had anti chatter rods that went from the engine to the frame. If you know someone with a 55 up T-Bird with stick shift take a look underneath. There is one on each side at the rear of the engine. Hope this helps.
That's right, must've been 60 grams ... should've thought about that one for a second. The clutch chatters whether it's hot or cold ... it's just the low RPMS. The clutch surface is nice & dry. I guess I'll check out those fingers. There are no anti-chatter rods, though, because this truck has a hydraulic clutch and the suspended pedal setup.
Check the support bearing in the crank, can cause chatter if it's bad. Also center the clutch plate is of importance. And the fingers are important too as mentioned.
Welding the weight is no issue at all I've balanced dozens of these and it's safe, does the clutch have springs in the center plate? are they loose now? I think you need to look at throw-out bearing contact on the 3 fingers...I only use the diaphram style myself Did you resurface the flywheel. don't remember good luck!
I had the same problem with my 1950 Ford. I also had the clutch and flywheel balanced. Still had chatter, the local clutch rebuilding shop said that the long style pressure plate was prone to chatter. I switched to a Mercury clutch and flywheel which has the Borge&beck? style. While trying to solve this problem I also learned about the importance of the spring steel layer between the two clutch disc surfaces, if that is all flattened out it will also cause chatter. I think this was called the marcell layer? I did solve the problem with the clutch and disc change.
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