CLUTCH GRINDING NOISE / BH MISALIGNMENT

[Franko]

This is a long and complicated question. So for intrepid Mopar problem solvers, get your reading glasses and here goes:
Last summer I ordered a 10 1/2” McLeod Borg and Beck clutch and pressure plate for my stock ‘69 Swinger 340. I received the scalloped 10.95” PP, an 11”clutch disc (sizes as stated on the packing slip) and the bolts with smaller heads.
After 600 miles, the clutch made a loud grinding noise when the pedal was fully depressed. It turns out that the clutch disc was hitting the bolt heads and that the clutch material and the metal disk in the center were damaged. Also the pilot bushing end of the input shaft was slightly grooved even though the transmission had been recently rebuilt. So I had a new input shaft installed.
When I had the 340 short block rebuilt (the block was from a ‘71 Duster and was recently purchased), I was told by the engine builder that he aligned the stock BH, as I requested. Apparently, he didn’t. So I bought a dial indicator, removed 2 flywheel bolts and checked the BH alignment. It was -.019 off at 4:00 so it needed to move in the 10:00 direction. I ordered RobbMC .007 offset dowels (adjustable with an Allen Screw) because .019 / 2 = .0095.
When I installed these offset dowels, I tried dozens of times to align the BH to within the .004 spec. But I couldn’t get it within -.010 in the 4:00 direction. Next I had the BH dowel holes miked. These holes should measure 1/2”, but were .505. The dowels are .496. So there was .009 slop. I had the BH re-bushed, which changed it to -.022 off at 4:00.
For some reason, the .007 offset dowels still wouldn’t align the BH. This should have gotten it to the .004 spec (.022 / 2 = .011 - .007), but I still showed -.010 at 4:00. I don’t know why.
So I ordered .014 offset dowels. I finally got the alignment to .004. The strange thing is that it should have yielded +.003 at 10:00. But I ended up being -.004 still at 4:00, which doesn’t make any sense, if I understand this correctly.
NOW THE TRANSMISSION WON’T GO ALL THE WAY IN
But at least the BH was within the .004 spec. I installed a Centerforce II 10 1/2” clutch and PP but when I tried to install the transmission many times, it wouldn’t go all the way in by 1/4", which is the thickness of the bearing retainer. In fact, each time the trans was stuck so hard that I had to pound in some shims to separate the BH and the trans. I had the input shaft shortened by 3/8” in case something wasn’t right with the taper in the crank. I reinstalled the Centerforce with the same result. So then I reinstalled the previous McLeod clutch and PP, but the trans still wouldn’t go in all the way.
It appears that the BH is so far out of alignment that the bearing retainer is hitting the BH hole. I don’t know how this is possible, since the dial indicator (verified with a second DI) shows that the BH was aligned.
Now I am wondering if there is something that has caused the BH to appear to be aligned when it is, in fact, way off…. such as something wrong with the stock flywheel or the stock BH that could cause this effect. The BH was obviously way out of alignment to start with, to have damaged the McLeod clutch and the input shaft and caused the grinding noise.

Does anybody have any possible solutions to this mechanical problem?
Sorry I had to write a book to state all the facts that I think may be pertinent.

 

[toolmanmike]

You might have to contact Brewers Perfoemance. Is it possible you have the wrong bearing retainer? Just thinking outloud.

 

[KosmicKuda]

I really don't know much but because the trans is 1/4" short of seating, that's the interference. So the pilot diameter may not be concentric with the input shaft end.

It seems every manual transmission I've played with has "slop" at the input shaft. In other words, the tip will move up and down snd side to side. I've been told this is normal and not to worry. Does your input shaft have slop or is it tight?

When the input shaft was replaced, was the bearing retainer replaced as well? In today's world with just about everything being sourced from overseas, I wouldn't be surprised if the various diameters of your new bearing retainer are not concentric. QC can be foreign to those people sometimes. I'll admit I've never removed an 833 front retainer but I have done design work on industrial gear boxes. Just fishing here on what may be causing the problem.

Or the pilot diameters of the bellhousing and bearing retainers have an interference fit, not line to line or slightly clearanced. Make sure those diameters are clean and in good shape.

One more thing...because you have shortened your input shaft you may as well replace the bronze bushing in the crank with the needle bearing style.

You could try calling Wayne Brewer or Jamie Passon if you keep hitting a dead end. Or go to the Mopar Nats thus week and ask them in person.

 

[Franko]

I talked with Wayne at Chryslers at Carlisle a few weeks back. He suggested shortening the pilot bushing end of the input shaft. The input shaft appears to have the usual amount of slop. The bearing retainer is the original one that fit in the BH while running the 600 miles on the McLeod clutch.

I believe the BH is out of alignment because even though it is hard to see, it looks like one bolt holding the bearing retainer has almost no clearance to the BH opening, while another has clearance.

 

[67Dart273]

Is it possible that say, ...........the bell hole is not entirely "round?" This might lead you astray. I'm assuming you aligned it using a dial on the crank, rotating in the bell hole. Is it possible the pilot is out of center (not concentric) with the crank/ flywheel mount?

Also did you check it for the transmission face being parallel to the rear of the block? This will "tip" the gearbox off one direction or 't other regardless of center.

By the way I DO NOT LIKE scalloped clutch setups. I had "continuous" trouble "back in the day" with my '70 RR 440-6. It would run fine for a few hundred miles, but a few hard shifts would generate "fuzz" on the outside of the disk, which would drag on the pp bolt bosses, and inhibit clean release.

At the time I put the 340 in the car, (same 18 spline 833) I used the factory 340 clutch, and later, changed to a Corvette 10.5 diaphragm in the car. Either clutch INSTANTLY caused cleaner, easier shifts with the gearbox.

 

[AJ/FormS]

Just to be clear, we are talking about an A-833 here right?
#1, is ;are the retainer bolts the correct ones.Integral Washer-head with no extra washers, The underside of the washerhead is serrated to prevent backing out.
#2 is; Has the retainer been machined down from a different diameter? And is it still round, and concentric to the bearing, and was the entry bevel remachined onto it?
#3 is; The snap ring on the input bearing; is it the original one to the tranny? The snap ring that comes on the replacement bearing is always wrong, without exception.
#4, remove the retainer and pop it into the BH opening. Does it fit?
#5, Are you absolutely sure the flywheel is fully seated on the crank? If it was off, just a wee tiny bit, then the flywheel would wobble, sending your indicator into fits, just as you describe. And making it possible that all your efforts in centering it were for naught.It would then also hold the disc at an angle, and probably prevent the input from fully engaging.The same can be found on a flywheel that has been ground crooked, where the front and rear surfaces are not parallel.
#6 As to moving the BH around, don't forget, it can only move as far as the bolts allow it to. Sometimes you have to clearance the bolt-holes to make things happen.Furthermore the dowels are there to provide repeatability. They don't actually have to be there. There is nothing stopping you from leaving them out, which can make dialing it in so much easier. But you will have to re-dial it every time the BH comes off, or is loosened.. No biggie to me. You can weld up the aluminum holes, and drill through from the starter side, and put the original dowels back in.
#7, Are the two surfaces of the BH parallel?
#8, does the disc slide nicely on the input splines?
#9, Did you use a pilot tool to align the disc prior to sliding the tranny in.The plastic ones are notoriously poor fitting, requiring the installer to fudge the disc somewhat in the vertical direction.And if the pilot bearing is bad, the fudging gets fudged. I highly recommend the Magnum BB replacement pilot bearing,that registers into the Convertor hole. You can leave the old bushing in the crank, I did,with no problems.
#10, With a scalloped clutch it might be a good idea to install the PP and disc, except leave the PP bolts loose enough to to shift the disc around while the tranny slides in. Then tighten those PP bolts in the usual way.

And that's all I can think of for now.Good hunting!

 

[toolmanmike]

I was just thinking, is it possible to install the trans. without the clutch assembly so you can see where the problem is? Maybe even leave the retainer bolts loose, install the trans. (if it will) and then snug the bolts. Just thinking out loud here.

 

[Franko]

* My transmission is an original A-833. The BH is the original 482.
* I used an old input shaft purchased from Brewer's, as an alignment tool. I found out the hard way last summer about the inaccuracy of the plastic alignment tool.
* I'm sure the bearing retainer and bolts are original. I don't know if the rebuilder (Liberty's Gears) used the original snap ring on the input bearing. I'll have to check on that. Could the replacement snap ring cause any problems?
* Flywheel fully seated - I think so. I scuffed the crank flange and the flywheel with a pad on a die grinder before installation.
* I don't know how to check if the transmission face is parallel to the rear of the block.
* Both clutch discs seemed to slide fine on the input shaft.
* I don't know if the 2 faces of the BH are parallel or if the hole is concentric. I don't know how to determine this. I had the BH bushed at Brewer's, but I doubt if they checked those surfaces. Speaking of which I suppose the block surface doesn't necessarily have to be square, does it.
* I called Wayne Brewer yesterday to order a new flywheel. He wanted me to use the dial indicator on the surface of the flywheel that the clutch rides, instead of removing 2 bolts and installing the DI in that recessed flange. I haven't yet been able to get the DI I ordered from Summit to fit on the clutch surface and clear the underside of the BH, even though I've been cutting the rods.
* I'll try to install the transmission with no clutch and PP soon. When I remove the BH I'll also make sure it fit's on the bearing retainer.
* That's a good point about clearancing the BH bolt holes...for future reference.

Thank you gentlemen for your sage advice. Let me know if you have anymore pearls of wisdom. When I get this resolved, I'll post what the solution was.

 

[AJ/FormS]

* My transmission is an original A-833. The BH is the original 482.
* I used an old input shaft purchased from Brewer's, as an alignment tool. I found out the hard way last summer about the inaccuracy of the plastic alignment tool.
* I'm sure the bearing retainer and bolts are original.Do you know what the originals looked like? I don't know if the rebuilder (Liberty's Gears) used the original snap ring on the input bearing. I'll have to check on that. Could the replacement snap ring cause any problems? Yes,Absolutely for sure, I have never seen the replacement snap ring fit into the retainer. It is too thick and too large on the OD
* Flywheel fully seated - I think so. I scuffed the crank flange and the flywheel with a pad on a die grinder before installation.I think so is not good enough. Put a dial indicator on it.
* I don't know how to check if the transmission face is parallel to the rear of the block.That is not what I asked

#7, Are the two surfaces of the BH parallel?

* Both clutch discs seemed to slide fine on the input shaft.Both?
* I don't know if the 2 faces of the BH are parallel or if the hole is concentric. I don't know how to determine this.To check the BH for parallelism, stuff it between to sheets of glass and measure it's height in several different axises.The surfaces will, of course need to be touched up with a lathe-file prior.As to concentricity that is what you were originally trying to do. I had the BH bushed at Brewer's,OH! but I doubt if they checked those surfaces. Speaking of which I suppose the block surface doesn't necessarily have to be square, does it.The back of the block and the front of the tranny have to be parrallel. If they are not, then the tranny will try to go into the pilot at an angle. Of course while trying to get in there it will be fighting the disc. If you manage to get it in there,the disc hub will flex with every crank revolution, and eventually the hub will fail, And shifting will be difficult cuz getting adequate clutch departure will be nearly impossible, without which the disc will be dragged along by the PP. And no A833 synchro can deal with that. So parallelism is paramount.And the flywheel has to run parallel to the block face too. But it is assumed to be doing so, in a virgin, un line-honed/un line-bored block. It is very difficult to check
* I called Wayne Brewer yesterday to order a new flywheel.WHY? He wanted me to use the dial indicator on the surface of the flywheel that the clutch rides,And so do I instead of removing 2 bolts and installing the DI in that recessed flange.Get a magnetic base and a flexible arm. Remove the BH , stick the DI to the block, indicate the face of the flywheel, looking for ZERO runout, or very near to zero. I haven't yet been able to get the DI I ordered from Summit to fit on the clutch surface and clear the underside of the BH, even though I've been cutting the rods.That's right it won't work with just the one rod. It needs a second knuckle at least.
* I'll try to install the transmission with no clutch and PP soon. When I remove the BH I'll also make sure it fit's on the bearing retainer.Yeah, this is real important. But it is a lot easier to unbolt the retainer and fit it into the hole than vise-versa.
* That's a good point about clearancing the BH bolt holes...for future reference.

Thank you gentlemen for your sage advice. Let me know if you have anymore pearls of wisdom. When I get this resolved, I'll post what the solution was.

 

[67Dart273]

* I don't know how to check if the transmission face is parallel to the rear of the block.
* I don't know if the 2 faces of the BH are parallel or if the hole is concentric. I don't know how to determine this.

.

You do both the same way, in a matter of speaking. This is best done at assembly, with the engine vertical. The thing is CRANK END PLAY (thrust bearing) will affect your readings---so far as transmission face parallel to the block.

Basically you fasten the indicator device to the crank or flywheel, so it rotates the feeler / indicator on the bell face, so that as you turn the crank, the indicator rotates around the mating face area of the bell.

Another way would be to assume that the block is OK, and set the bell up in a mill or some other setup where you can establish precision. Basically all you need here is to see if the transmission face is parallel to the block face. You could put it bell down on a mill, attach an indicator to the spindle, and move everything around to determine the "4 corners" of the transmission face are at same height from the table.

Same thing "concentric hole" You simply indicate on the inside bore of the bell hole, and rotate the crank to see what happens at the indicator.




By the way if the block has been line bored (align bored) the centerline could very well be off. I am CONVINCED after all these years, that my old 70 440-6 car was misaligned......it was fairly hard shifting and "used up" pilot bushings.