I recently purchased a 1969 Z/28 Camaro. It has a very smooth running 350 small block, original equipment engine in it, and a 4-speed transmission with Hurst shifter. It had the clutch replaced once awhile ago, however the car had moderate chattering in the clutch when starting from a dead stop, enough to shake the hood. I had the pressure plate, disc, and throwout bearing all replaced with new parts of good quality. The fork appears to be in good condition. I also had the flywheel resurfaced at a machine shop. The chatter was worse. I had the auto shop grind the flywheel again, and put another brand new heavy duty clutch kit in. The chatter has become even worse yet, much worse than when the old clutch was installed. It now shakes the entire car when trying to start from a dead stop in first gear or reverse, and when downshifting. I am at a standstill with this problem, I do not know where to go or what to do next. Anyone with suggestions, please feel free to e-mail me, or post a reply. Thank-you!!!!! Please help!!!

When the clutch job was done, they forgot the most important part - the pilot bushing in the back of the crank. This crummy little bronze bushing, when it wears, causes exactly the symptoms you describe. I ALWAYS remove them and replace with the Torrington needle roller bearing, available at your friendly Chevy dealer or Moroso/Summit/Jeg's for about $12.00. They last forever and solve all manner of driveline chatter and vibration problems.

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JohnZ
'69 Z28 Fathom Green

Thank-you for the quick reply. I am posting this for a friend who does not have a computer. I checked with him, and they did replace that bushing, in both clutch jobs. Would you, or anyone else have any other suggestions? Would you think perhaps replacing the flywheel might help? As mentioned before, I had it cut twice on a lathe, perhaps a replacement might recitfy the problem. Also, the both the motor mounts and the tranny mounts are fine, and all bolts are tight. The univeral joints are brand new as well. Any further info that anyone can provide me will be greatly appreciated. Thank-you.

Have your friend check the input bearing of the transmission.

Jody

Thanks for the tip, Jody, however I neglected to mention that was ok as well, there was minimal play in that shaft. Would anyone think it could be anything to do with the bellcrank, or anything? The fork itself appeared to be in good condition, so I'm inclined to believe it is not that. Any further suggestions anyone has will be greatly appreciated.

Thank-you for your time.

Didn't know the flywheel was cut on a lathe - that won't produce the correct surface for the disc. Correct surfacing procedure for a flywheel is to have it ground, preferably on a Blanchard surface grinder; this produces the correct surface pattern and roughness to be compatible with the clutch disc (similar to the smaller machine used to produce the surfaces on a brake rotor with the overlapping circular cross-hatch effect). I'd have the flywheel re-done (or replace it if it's too thin for another cut); everything else appears to have been done, assuming the bellhousing is centered within .007" or less to the crankshaft.

Thanks for the reply, Johnz. I will have him check on the bellhousing centering, that is something new to me. I also plan on replacing the flywheel as well. Thank-you to all who have taken the time to post replies, and if anyone else thinks of anything that could be causing this, please post (just in case a new flywheel does not correct the problem). Thanks!!!

One Quick question:

Is the car is a factory Z-28? If so it did not originally come with a 350...someone swapped the motor (was the DZ302). If they did not use the proper motor mounts, and several different ones will appear to bolt up properly, the drive angle can be too low or too high and cause the problem you are describing.

Just a thought...

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'68 RS, 350ZZ4

Hey Camaro 350, if you find the problem let me in on it. I've had the same problem, only not as bad as you are describing. Also went through the same steps as you, with no solution. I also had a friend that had the same problem... he got so disgusted with replacing everything and not curing the problem that he put an automatic in it. What type of 4-speed is it by the way??? Mines a p.o.s. Saginaw.

Mark

HI. Thanks for the replies. As far as the motor goes, all the numbers check out, the engine was made the 1st week of feb, in '69, and the car was made the 2nd week. The numbers on the block and tranny check with several different Chevy books I have, so I'd be inclined to think they are the proper motor mounts.

Do you know if the flywheel was replaced for the person that wrote stating they had the same problem? I am thinking of replacing it myself, however do not want to go this route if it yields no success. I'd rather put an automatic in as your friend did. Please let me know on that, and anything else you might think of. I really appreciate your time to post. Right now it is so bad the car is not driveable, it is shaking itself apart when trying to shift and pull away from a red light. Anyone else with suggestions please feel free to post, or e-mail me if you are not registered. All the info I can get is greatly appreciated. Hopefully we will be able to figure this out, and if and when I do, I will post the cause and solution prior to closing this thread.

Thanks to all who have posted so far, and to any who will post in the future!!

Oops, I forgot to mention, the tranny is also a Saginaw 4 speed, p.o.s. I'm beginning to wonder if there is a problem with the tranny itself, possibly there is a problem with the Saginaw ones. Thanks again for the replies.

Oil is your clutch's enemy. Clutch disk,pressure plate,and flywheel need to be extra clean!!!! If shop is not cleaning parts with brake clean,and then keeping their fingers off surfaces chatter will result.Also, if they are putting grease on input shaft,they may be using to much.When the input spins, there goes all that lube all over your nice cleanclutch parts WOOPS chatter time! Try cleaning the clutch with brake clean,with engine running,and buddy pushing in clutch pedal.Spray cleaner directly on both sides of clutch disk.If problem is better you know the problem is greasy parts. Be very careful when cleaning, it can be dangerous,(spinning parts,flammable chemicals) Good luck

camaro350

Have not replaced the flywheel. Resurfaced it, with a grindstone as someone stated. Replaced disc, pressure plate, pilot bushing etc. Mine just chatters a little if you take off really slow. Not bad enough to tear everything out and get an automatic yet! http://www.camaros.net/forum/biggrin.gif My friends tranny was a Saginaw too. Maybe there is something wrong with them...

Mark

The problem is in the Marceling in the driven disk. The disk has a bit of compression built into it, and the ones you are probably getting are made off-shore.

Also, there are coil springs in the spline to facing part of the disk, and if they aren't the correct tension, the clutch will chatter like a tropper.

I have heard of a few people changing just the driven disk to a dual friction Centerforce part, and that seemed to fix those chattering woes very well on vehicles that didn't have linkage, bearing/bushing or ratio issues.

Thanks to all who have replied so far. I know it is not an oil problem, as I watched the shop assemble everything, everything was kept clean. My rear engine seal is not leaking, and when the old clutches are removed they are "dry", no evidance of any types of oils or greases on them.

IgnitionMan, could you provide more detail on the ratio/bushing thing, and on what a dual friction disk is? I am about to install a new flywheel, and new Borg-Warner stock clutch, with a standard organic disk. Perhaps I should cancel this and install this dual friction disk instead. Let me know what you think on that.

Once again, thank-you for all your suggestions, hopefully we will nail this problem soon!!!!

Camaro350

One other quick thing, how am I to know if those coil springs are indeed the correct tension? The clutch chattered in all three cases, each time the disk was replaced with a new one. If there is a way to determine if I need a stronger disk, please let me know.

Thanks

Camaro350

One other quick thing, how am I to know if those coil springs are indeed the correct tension? The clutch chattered in all three cases, each time the disk was replaced with a new one. If there is a way to determine if I need a stronger disk, please let me know. Also, what do you mean by Marceling? I never heard of that before.

Thanks again for all your time,

Camaro350

Disks from the same manufacturer?? Same spring rates, maybe.

marceling is the wavy metal frame between the friction facings, in the center of the disk, flywheel side to pressure plarte side. No/wrong Marceling, the clutch won't actuate right. Engages too abruptly, not able to engage smoothly.

Ratio is the difference the pedal moves in relation to the amount of actual movement of the pressure plate.

An easy check of adjustment is to have an assistant push the clutch pedal in on a fully assembled clutch system, and check the free play between the flywheel and driven disk. A diaphragm clutch adjusted properly should give .050 to .055 clearance between the flywheel and driven disk.

Use a flat feeler guage for the check. Load the driven disk against the pressure plate for the check.

Thanks for the input I-man. Good to see you back.

Mark

Not back at all, thank Clill for that.

I'm only trying to help on something I had happen too many times to me.

Camaro350, first of all I want to commiserate with you and your buddy having to pull that pig out over and over. What a pain! On the positive side, you are probably getting pretty good at it.
Just thinking out loud, many of the things that come immediately to mind have been mentioned and you have crossed those off the list. I don't think the motor/tranny mounts would cause this problem and they would be more like a driveline type problem. We know that the problem became worse with the new parts. The clutch isn't "slipping" the tranny and engine together, it is "grabbing" them together and the new, heavy duty parts make this grabbing worse. Since the symtoms got worse with the new parts, it seems safe to guess that the problem is in the bellhousing, clutch area of the car. We assume that the new parts you are using are of good quality. We also know that if your buddy has a true z/28 car, the 302 is gone and replaced by the 350, so some alterations have been made. Here is where I need help from others. Is it possible that the bellhousing is incorrect? Was there a bellhousing for say, the Muncie vs. the Saginaw? Did the bellhousings differ by years? Were there different clutch forks? Does the tranny mount perfectly into the bellhousing with no angle? Is there something in the tranny itself, shaft/spline etc that may throw things off just enough that the clutch is not engaging smoothly? It just sounds like everthing you have done is good work with good parts and attention to the right things (no oil leak or grease on the fly wheel etc.) so I am thinking that everything looks ok and is in good or new condition, but some part is incorrect and not allowing everything to work properly. My apologies if I am way off base. Please post what you find as I would love to know what the solution ends up being.

Does it chatter going to every gear or just from a stand-still in 1st? I've got a '68 Z/28 that chatters leaving the line in 1st only (hard or soft launch), but shifting from 1st to 2nd, 2nd to 3rd and 3rd to 4th are all fine.

Anybody have any thoughts on this? Oh yeah, it has an incorrect 3.08 rear (is this the problem?).

Thanks for the info, everybody. If the new flywheel does not correct the problem, I will check out some of those other things, such as incorrect bellhousing, etc. As far as the chattering goes, it does it the worst starting out in first, but there is some while shifting. And it does it pretty badly when downshifting as well. I will let you know what finally corrects it, if the new flywheel does help or not.

Thank-you again for all your replies.

Camaro350

Guess what??? The new flywheel did not correct the problem. Does anyone know of anything else that could be causing this? I know it's probably getting on everyone's nerves, but we are at a brick wall now. Does anyone think a cracked rubber part on one motor mount could cause this? Should I replace the transmission? Anything else anyone can provide will be GREATLY appreciated, and I also appreciate everything everybody has already suggested. I am going to look into it possibly being the incorrect bellhousing, etc, however being as the car is all original, I don't see how this could be the case. Any further suggestions, please post.

THANKS!!!!!

Camaro350

Camaro350, I'm sorry to hear the problem still exists. I re-read all your posts and have a question. You say all 3 times you've changed the disk, with no change in the problem. Did you change the pressure plate also? It sounds like you have checked everything else. Just wondering about the pressure plate. And how about the throw-out bearing, is it the right size? And here's one way out in left field for the guy's with expert engine knowledge. If there was too much end play in the crank, would that contribute to the chattering problems that can't be fixed with new clutchs? Just a thought.

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Steve
67 SS 396,4-sp
67 RS 327,4-sp
72 RS 350/350
69 4X4 suburban 350,4-sp
73 3/4 ton 454/400
http://www.geocities.com/stevocamaro

Well, like I said, I'm really befuddled now. We installed a "brand new" GM factory 12 3/4" 153 tooth flywheel today with a 3rd brand new Borg-Warner 10 1/2" HD clutch kit (pressure plate; clutch disc(organic); and throw out bearing. Guess what? It "STILL CHATTERS" @$#%$#%!! We now know it wasn't chattering because the flywheel wasn't "stone ground. After installing the new clutch and flywheel, we lifted the motor and "pulled" the motor mounts off the block. They weren't dry-rotted or cracked but we decided to replace them anyway. Here's the second catch...I couldn't find replacement motor mounts anywhere, not at the GM Dealer or the aftermarket Auto Supply stores. Seems these mounts (and they are stamped with a GM Part number) are somewhat unique to 1969 Canmaros. They measure a full 1/2 inch higher (or deeper) from the flat plate that bolts to the block to the mounting hole for the bolt that goes through the frame mount. We got replacement motor mounts from 3 different parts suppliers who looked up 67-69 Camaro Small block Motor mounts and all gave us the same wrong part. These replacements measured approx. 1 5/8" from the plate to the mounting hole and the ones on my car measure almost 2 1/2" in height. No way in Hell the replacements were going to fit. Another call to the only Chevy Dealer in town who would take the time to check the old books for us did in fact come up with a GM part (#3962748) that supposedly is for a motor mount for 1969 only. Does anyone have anything on this? Did you ever hear of this? Is this a special application motor mount? When comparing the originals I took off the car to the aftermarket replacements (the ones that didn't fit), the originals are "much heavier" in construction, are about 1/2" taller, and differ from left to right. I ended up putting the old ones back on for now as I couldn't get a replacement to fit and the old ones really didn't look that bad. They are definately GM made and appear "original". I need some help here also. I don't think I'm ever going to solve the chatter and am becoming very upset over this as I already have over $1000.00 into this friggin problem and seem no closer to solving it than when I was $1000.00 richer! I also got some more info. on the cars pedigree. It is "not" nor was it ever a factory Z28. It is a 1969 Camaro Sport Coupe with the X11 option on the trim tag, 350 CI 255 HP motor w 2bbl carb, ID pad # V0201HC (matches the cars build date) of the second week in Feb.69 so I assume it to be original block; 4-speed Saginaw Transmission w/Hurst shifter (with the last 5 digits of the cars VIN stamped right in the tranny on a little machined pad), so it too is original, and a 3:73 to 1 Posi-Traction 10 bolt rear that also has the date code and ratio letter code stamped on the axle tube, passenger side. Getting back to an earlier response, I'm 99% sure the bell-housing, and all drive line components are original as all numbers match and correspond with the cars build date of the second week in February, 1969. The car is very clean underneath, doesn't appear to have been modified in any way and still contains the original reverse/ steering column locking mechanism etc. I don't think the Bellhousing or anything else was changed as everything lines up and bolts up perfectly with no visible signs of mis-alignment or damage. The car was never hit or in any kind of accident. It is a very clean "original" car. It runs great and there was no problem up-shifting or down-shifting from 2nd thru 4th until after the Metallic Disc clutch was installed so I feel this is what caused that problem. We tried the metallic disc high performance clutch in the hopes of eliminating the chatter but it only aggravated the situation and made it worse. So....as you can see, we've tried about everything I know of short of changing out the Trans. itself, and we are still right where we began.....very annoying severe chattering when starting in first and worse when backing up in reverse. Once underway, no chatter, no vibration, etc. It makes you think it's not in the driveline. I would think a crankshaft problem would have taken out the rear main seal or bearing by now but there's no evidence of that, no excessive oil leaking etc. Does anyone out there think there could be anything wrong in the rear end?? When the car is underway, putting it in neutral and free-wheeling does not produce any drag or unusual noises coming from the rear. Last week after the second clutch install. failed to rectify the problem I did several "severe burnouts" with the car out of frustation and the rear hooked up well and smoked the tires with no slippage or signs of a problem but hey, who knows, at this point i'm open to any suggestions. Please help, I'm down to my last reserves of both cash and sanity!!! Anything anyone has to offer on the clutch chatter problem "or" the strange "motor mounts" would be "Greatly Appreciated". I know you're all probably getting tired of hearing me whine about my chattering clutch but I've tried everything everyone has suggested up to and including repalcing the flywheel and "We Still Got Chatter". Please help, the car is too nice to give up on and I don't want to go the "Automatic Route" the other fellow did. Maybe it is time for a new 4-speed. Don't know if I can afford that yet after dumping a grand into the damn clutch. Thanks again for any help you can provide. And yes, we did install another new pilot bushing and used a clutch installation alignment tool so as not to warp or damage the disc during installation. Thanks again for anything you can do to help.

I was looking at another post and a thought flashed we havn't talked about in this thread. What is the story with the clutch linkage? Especially the clutch ball studs? If the ball studs or the tube-part of the linkage they fit into are severly worn, it would allow the rod-going-to-the-fork-going-to-the-throwout bearing to have alot of play meaning you don't have even pressure on the throwout bearing. Your clutch would judder like crazy! Inspect the ball studs for wear, check the Z-bar for wear and for cracking or breakage, LOOK FOR ANY PLAY IN THE CLUTCH LINKAGE AREA from the pedal up under the dash to the fork going into the bell housing. Are the holes in the Z-Bar that the rod from the pedal and the rod to the fork fit into enlarged or are the rods themselves worn down? IT HAS TO BE ROCK SOLID. I really hope this is where the problem lies, I have had problems like this that I didn't know if I should laugh/cry/beat the s@(* out of something. Good luck.

[This message has been edited by denverRS/SS (edited 10-20-2000).]

[This message has been edited by denverRS/SS (edited 10-20-2000).]

Man, I was hoping you came up with a solution. I feel for you. I know the exact chatter you're talking about. Luckily mine only does it from a standing start, and it really isn't that bad since I put lower gears in the rearend. With the 2.73 gears, it chattered so bad that the steering column shook on take off. It never did it in any other gear though. I was going to suggest that the rearend isn't at the proper angle and putting a bind on the u-joints under stress... just as a last resort. Checking out all the linkage for play sounded like a good plan also. I'm stumped. Wish I had an easy solution for you. Good luck.

Mark

I know your frustration, but had to laugh at you dumping the clutch and frying them out of anger. I do the excact same thing. I wish I had the answer. I hope you can find problem. I'll keep reading, let us know what happens. Good luck.

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Steve
67 SS 396,4-sp
67 RS 327,4-sp
72 RS 350/350
69 4X4 suburban 350,4-sp
73 3/4 ton 454/400
http://www.geocities.com/stevocamaro

Hello out there again on the chattering clutch. I will double check "all" the clutch linkage very closely tomorrow but when everything was out of the car it looked ok. The fork was checked closely and appears true. I lubed the Bellcrank (Z arm?) assembly and didn't notice any excessive play in it. The ball stud is secure in the block. The adjusting arm is a two-piece affair and looks straight and works ok as far as adjusting the clutch goes. It's just a threaded rod into a sleeve so I really don't know what else to look for here. all return springs etc. are there. As for the rear end, the 3:73 gear seems tight. The rear doesn't seem to be "dog tracking" as all the spring shackles are intact and the multi-leafs (4) are all in alignment on each side. The spring mounts up under the trunk floor are cherry, no rust, one of the main reasons I bought this car(sure as hell didn't buy it for the clutch!!!). The front mounts look original but I see no evidence of the rear having shifted. I've seen some camaros and Novas going down the road that looked like the ass-end was going to pass the front end but this car is really original and really straight, you've got to take my word on that. I will take the car to a 4-wheel alignment shop next week just to make sure though. I plan on cabling the block to the frame tomorrow (like we used to do in the old days to prevent breaking the motor mounts) to see if that helps any and check out a few other things. Please keep thinking and advise if anymore suggestions come to mind. Believe me, they are all appreciated no matter how far off the wall they may seem. I really feel this is going to be something really unusual or so far un-removed from the obvious that I'll probably cry when it's finally found. I'm firmly starting to believe it can't possibly be in the clutch/flywheel assembly anymore. It's all been replaced too many times. It Has to be something else. Thanks again for all the help, I'll keep you posted and please keep the suggestions coming.

Camaro350

Check this link for engine mount info....
http://www.camaros.org/engine.shtml#EngineMounting

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'68 RS, 350ZZ4

I looked at the past posts, did you check the bellhousing centering by putting a dial indicator anchored to the flywheel and dial indicating the bellhousing bore where the trans centers?
If the trans is positioned off center by the bellhousing, it will make it chatter.
You can buy offset bellhousing centering dowells to fix it. I think Lakewood sells them.
If you find it off center the problem may be in either the block or the bellhousing.

If the trans was hammered hard the trans input shaft could be bent too.
David

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Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer

That's what I was thinking also dave, especially after he said it also does it down shifting. He did say the front trans bearing was O.K. but the shaft could be bent. Like the muncie I have that was in the car when it was hit. I had it rebuilt, and it bench shifts perfectly, but get it in the car and it won't shift right. We're thinking the main shaft is probably, ever so slightly, bent.

camaro350, do you have another trans you could try?

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Steve
67 SS 396,4-sp
67 RS 327,4-sp
72 RS 350/350
69 4X4 suburban 350,4-sp
73 3/4 ton 454/400
http://www.geocities.com/stevocamaro

Yes, my cousin runs a auto shop and has another Saginaw that I can try. I will do that, and let you know if it fixes or helps the problem.

Thanks again for all your replies and thoughts up to this point.

Camaro350

I guess one more post on this one can't hurt; only two thoughts remain....1) Are you absolutely sure your rear trans mount is OK? You can't really tell by looking at it. They're cheap, easy to install, and a bad one can cause precisely your symptoms. 2) I'm not familiar with the Borg-Warner clutch you mention, don't know if it's a Borg & Beck coil-spring type or a diaphragm type; all I can conribute is that I've used Centerforce II's (NOT Dual-Friction) on at least six cars over the last five years, and all have been smooth as silk and trouble-free in spite of hard use. Just a thought.

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JohnZ
'69 Z28 Fathom Green

Well, I just wanted to say we finally cured the chattering clutch. It turned out to be the mechanic at the shop didn't know his transmissions well enough. I swapped the tranny with another Saginaw my cousins had, and the chatter is totally gone. It starts out smooth as glass now. I took the original to a guy that specializes in rebuilding old trannys, and he said the input shaft had way too much play in it, that there must be some bearings shot someplace. He is going to re-build it, and then hopefully we will re-install it back into the car, and it will be chatter-free.

I want to thank all of you for taking the time to think and post suggestions on this problem. I will look to do the same and help out others on here, if I am knowledegable on the topic being discussed. I also want to compliment the administrative ppl of this bulletin board. It is a very valuable asset, and popular, to many camaro owners.

Once again, thank-you to all who took the time to read this thread, and post suggestions. I hope that my solution will possibly help someone else in the future that may have or does have this annoying problem.

Thanks again,

Camaro350

Glad to hear you cured the problem!

Mark