Muncie 4 speed

[GPster]

[CQQL33]

Yeah, I know............Yellow Book dot commmmmmmmmmmmmmm

My question is related to the clutch chatter concern at the beginning of this post..................

[zzebby]

No solution yet. I'm saving my $ and hope to be able to tear it open in about 2 weeks. I'll get the muncie redone while it is apart if I can find a local shop that has parts and know what they're doing. While it is out I'll measure where the pilot is and how much the input shaft sticks out. I'm hoping to reuse the clutch and PP as it has only been in there about 6 months. $$$ you know.

[zzebby]

Wow it has been 5 yrs since I posted this. I don't drive it much, but the last few weeks I've driven it daily. Backing up, the chatter shakes the whole car.....bad. I took it to a local shop that does mostly muscle cars (friend) and they took it all apart, dial indicator to the flywheel and no runout in any plane. Everything looked perfect. Hays flywheel, Luk clutch, new pilot bearing. You could see from marks on the input shaft that it was riding fully in the pilot bearing. On leaving that shop there was no chatter, nice and smooth. BUT 100 miles later it is chattering again. I kept driving it and noticed that the chatter would come and go, most of the time it would chatter, but maybe 1 time out of 20 it would be smooth. Then I noticed that the speed vibration, about 65 mph, would also come and go. Usually at speed you could see the hood vibrate and feel it thru the whole car, it would harmonic, about a 4 sec period. Once in a while there would be no vib.....nice and smooth all the way up to 75 mph. Realized that the clutch chatter and speed vibration must have the same cause ....and it comes and goes. Something is floating off center .....must be the pilot bearing. Tore it all apart last night and pilot looks fine and marks on the input shaft show that it is fully in the pilot. Only though is that there was the slightest indication of oil on the flywheel surface near the center. Oil can cause clutch chatter, but not speed vib and if that was the cause then it would always be there. engine does leak a little oil but not much, bottom of the oil filter (spin on conversion kit) is wet.
Ideas ? 66 chevelle, stock 396, 4 speed all original stuff, no wear in the clutch linkage, rebuilt several times. Same proble for 5 yrs now and maybe 3000 miles.

[Pete]

You mentioned changing bell housings but did you dial it in??
I have seen stock ones off as much as .018 and that can sure cause the problem you have.

[jaybee]

The idea that the input shaft isn't properly centered on the crankshaft centerline has some merit, though your comments about checking runout hopefully eliminated that question.

Now, here's one that's out of left field. Your speed-related vibration...is it strictly road speed, or is it possible it's engine speed? Some BBC's are externally balanced, yours is internal. Possible there's a parts mismatch?

[Carnut]

Ok, can I go way out on left field?

Any chance you have a grabbing brake shoe on the rear axle? I've seen folks have chatter problems and thinking it was the clutch when it turned out to be a rear brake hanging up.

but on forward vibration at speed I'd go up front and check for a bad or rotated harmonic balancer.

[reborn55]

have you checked the motor mounts---maybe one of the bolts worked loose or even bell housing bolts or trans bolts.

[GPster]

[wayne petty]

this is just my fingers rambling around the keyboard..

lets talk about the OIL LEAK...

you might also want to verify the oil leak is NOT coming from the FUEL PUMP GASKET... my 396/402 that i had in my 66 GTO had a weird oil leak.. rev it up and oil would be all over the bottom of the motor.. i had to bring the rpms up over 4000 RPMs sitting still to actually find it.. super weather strip adhesive on both sides of the fuel pump gasket solved the problem.. i never figured out why that actually leaked there.. but thats how i got the motor.. it always leaked oil..


spin on oil filter adaptors.. a question.. what brand oil filter adaptor are you using??? there are several out there... some are KNOWN oil leaks just waiting to happen..

in the short run... do you you have room to reinstall the canister filter assembly .. or can you select a different brand of spin on adaptor???

some engines had the oil filter area machined for the factory spin on but still got the canister... are the sides of the machined area stepped where its all 90 degree angles..
like this.. --|______|-- or this style that will not accept the later adaptor.. --\______/-- where the sides are as cast and at an angle..

the leak is usually the oring or seal between the adaptor flange and the block.. so its hard to see.. and hard to fix.. without a newer better o ring or seal..

how much oil pressure do you have??? excessive amounts can blow out almost any of these seals..


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almost any oil mist on the clutch will make it chatter when its chattering as you get it to finally engage... its a small chance that it could be ever so slightly off center.. when you get to the 65 and the vibration starts.. stomp on the clutch and release it.. see if the vibration vanishes after you reengage the clutch..


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brake shoe issues have also caused weird things.. but are easy to check.. if you need more info on this.. i can supply it..

i also have a neat way to check the brakes adjustment . when there is a hole in the backing plate..

with a flash light and a screw driver.. stick it through the slot in the backing plate.. shove the star wheel forward then shove it backwards.. if you get more than about 1/16 of an inch.. that brake might be out of adjustment..

[GPster]

[zzebby]

Hey guys, thanks, lots of good ideas. Not brake shoe problem, it is the clutch shaking the whole car and not a little. Motor mounts are good, replaced and checked. Linkage is solid.
This past weekend I pulled it all apart and looked at all the marks and checked and measured. The input shaft is a perfect fit. Only .002 of clearance and fully into the pilot. Dead on. I did not see much oil, but maybe ....hard to say. So I washed everything in simple green and then with brake clean. Sanded the flywheel with 180 and washed again. Put it all together and backed it out.....silky smooth....no chatter at all. Drove it to work, 8 miles and parked it. At the end of the day backed it out and sure enough it was starting to chatter just a little in reverse. OK in first. I think it is an oil contamination....but really. 8 miles and enough oil gets on the flywheel to make it chatter. Not bad but it is starting. Does this sound possible ? I'm thinking that spin on oil filter adapter is causing it. Yes I did have a poor adapter at first and it did puke big time. Switched to another one with a Ford filter and all is dry. Yes it does have way too much oil pressure, 80 lbs on the highway and 60 at idle.
Also I think I need one of those shields for the lower part of the bell that keeps the oil mist off the flywheel. Still don't get it, the engine doesn't leak much.

[Bruce Dorsi]

A friend went through the same clutch chatter last year.

He completely re-did a 1965 442 and the clutch, pressure plate, throw-out bearing, fork, linkage, etc was all new.

Clutch chatter in reverse, sometimes violent, other times not as bad.

He pulled everything apart and checked all that was mentioned in this thread, and several other things. ....No tell-tale signs of a problem. ....Put it all back together and same clutch chatter.

In disgust and desperation, he pulled it apart and removed the fairly-new Hays clutch disc and replaced it with a different brand. ....No more chatter.

We still don't know what made the Hays clutch chatter, but not the replacement. ....Possibly different friction material?

He also had a minor driveline vibration at certain speeds. ....He adjusted the pinion angle slightly, and that cured his vibration.

[bowtietillidie]

I believe Bruce Dorsi had came close to your problem . I tried to explain this problem in an earlier post. I am not good at communicataion using a typing keyboard Enjenio and Wayne Petty are very good at putting thoughts into words using a keyboard they may be able to make this more clear for you Here are my thoughts on your clutch problem . You have a clutch MARCEL problem
the MARCEL is what makes your clutch engage somthly { NO CHATTER}

This can only be checked out of the car . I take the clutch disk and an old Trans in put shaft Clamp the input shaft in a vise then I slide the clutch disk on to the trans input shaft then try to rotate it is a CC and CCW direction . If I feel any movement at all I change out the disk This problem seems to show it's ugly head around engines that produce lots of torque.
I first learned about clutch MARCEL from Drag racing 409's and trying to ease into the stage lights . it has become standard procedure around my shop to check clutch MARCEL on every clutch job PS: try goggling clutch MARCEL The clutch disk is more complatcated then you might think

[enjenjo]

Bowtietillidie may be on to something. I had a Rambler one time that would do this.

There are two things they do to clutch discs to make them engage smoothly. One is Marcel, which is a Marcel spring installed between the friction faces of the clutch disc, which soften the shock of engagement by cushioning the apply when letting out the clutch. The other is a set of springs in the hub, that under pressure allow the disc to move radially slightly, but don't come into play under normal circumatances.

On my Rambler, for some reason, in a few hundred miles the radial springs in the hub would get loose, allowing the clutch to chatter, and for the disc itself to get off center, even though the hub was centered, causing a vibration that would come and go. On my car stabbing the clutch while going down the road would usually center the disc, stopping the vibration, but not always.

I cured the vubration with a solid hub racing clutch disc, but it would still chatter from time to time.

[GPster]

Which Rambler? The one that Shelby drove on Prom night, the one that you had when you first started driving or the one that the old timers talk about that has the keys laying on the table for anybody that needs something to drive? GPster

[enjenjo]

[zzebby]

Wow, have not heard of Marcel, I'll google it. Still suspicious as to why today and yesterday it is OK, not quite silky smooth but not objectionable. All I did was wash everthing down clean. Bottom of engine was clean and just orange paint. I did look at the clutch springs and they all appeared normal. And this is the 9th or 10th clutch that I've put in it of various makes, always diaphram type. The LUK in it now still had some of the silkscreen marking on it....very few miles. Still need the stamped steel cover plate and I doubt if they are repo yet.

[GPster]

I do not remember the particulars but in '69 when I changed the clutch in my Nova there were two types of diaphram pressure plates. One was the regular one and there was one called " Bent Finger ". The bent finger was for High Horse-power applications because it seemed that high RPMs had enough centrifugal force to hold the pressure plate disengaged. This was part of a set and required a matching clutch disc and throw-out bearing. It was confussimg because there were sets for 10 1/2" and 11". Do yo have mis-matched sets? GPster

[wayne petty]

a few more thoughts... and expansion of tips on others..


the marcel is the spring steel pads that the rivets go through to hold the clutch facings on.. they are bent...-------\______ if you look at them from the outer edge of the disc... each clutch facing is attached to the highest side of the bent marcel..

when you are engaging the clutch.. it acts like a cushion as the pressure place squeezes the disc into the flywheel ... this gives you a moderated engagement.. so its not all the way on.. instantly.. friction increases as the marcel flattens out ...

this moderated engagement also relies.. on a flat surface for the clutch linings ... if your clutch cover is slightly glazed.. or has a slight wear pattern.. or if the flywheel needs to be resurfaced.. you can have issues with chattering.. as one side tries to grip before the other side.. one side grabs.. then breaks away , then grabs again..


glazed friction surfaces can also have an effect..

oil mist can also play a roll in clutch chatter.. as it changes the friction of the disc as the pressure plate is starting to apply.. grip, slip, grip, slip

i have had people bring back cars that would chatter.. i take it out for a 5 mile test drive.. by the time i am done.. it does not chatter any more.. i give it to them.. it lasts a few days.. and they return.. what do i do to stop it from chattering.. i have never figured out how i drive it slightly differently.. or how to explain it..



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the damper springs on the hub absorb the power impulses from the firing of the individual cylinders..

yes.. the cranks shaft is twisting slightly do to the power impulses.. diesels are really bad at this and require a DUAL MASS flywheel.. that has additional springs and devices to absorb the impulses... and once in a while.. actually way too often.. the dual mass flywheel will be worn to a point where the engine torque is more than the flywheel can handle so it starts to slip.. not the clutch.. the flywheel... but this is NOT your problem.. this is just info..


on some brands of clutches.. you may notice that the spring hub springs are different sizes.. this is to absorb the different input frequency better..

some springs are also designed for stock horsepower motors.. when this gets exceeded.. the springs get mashes and loose tension. remember.. we are dealing with profit statements when it comes to buying components.. so save a few bucks on lessor quality steel springs.. only a few will notice...

the hub springs can also be selected for increased horsepower engines..


this is just some of the theory i have picked up along the way...

out here in the los angeles area.. there is a clutch company called A.I.T.A clutch.. i have sent a few people to them for special discs and covers when stock versions just would NOT cut it.. i used to deal with a small parts store who actually had a clutch rebuilding shop in it.. i learned a great deal from him..

i do know that with a solid hub.. that the transmission gears take a much bigger hit when street driven..

i have never seen anything in writing.. on hub spring tension.. but i would expect that more tension would be needed with increased horsepower and increased compression ratio...

they do use 6 springs in some discs...

even inside torque converters.. some of the torque converter clutch hubs have springs to stop from shattering the sun gears as the engine goes through its harmonic /torsional motions..

that does also before i end this session.. and its a way off thought.. how big a harmonic damper do you have on the front of the motor??? 6, 7, 8"?? probably has NO EFFECT on chatter issues on engagement..

wait.. engagement.. oh i guess that is the proper word as we are almost all married to our cars..

i guess i will chatter at you later..