I've tried searching past threads but have not found any answers.

I'm restoring a 69 vert, 4 speed M21 with a newly remanufactured 383 stroker. Engine runs great but I can't get it into any gear and think (AKA hope) it's just some kind of adjustment (and not a screwup on how I put the clutch, pressure plate, throwout bearing, etc. together). I have about 1.5" of free play at the top of the clutch pedal but even all the way to the floor, can't get it into any gear. Clutch rod at end of pedal is adjusted all the way to the end. I can get it into all gears when it's not running, albeit still in need of adjustment as it's difficult. When it's running and I'm trying to get it into a gear, it does put a load on the engine a little (you can hear it). Grinds big time trying to get it into reverse, even after putting it in 3rd first.

I'd realllllly appreciate some suggestions as I'm just about done with the resto and haven't driven it in 21 years! Thanks in advance for whatever advise you can provide!

 

Did you have the shifter out? Do you have the stock shifter?
Hopefully its only a shifter rod adjustment but that can be a PITA with it in the car. You may need to rebuild your shifter too.
I suggest you check the adjustment. Make the alignment tool to see how far out the shifter rods are.


I don't have the dimensions for the tool but I know other members do.
Put the tool in the shifter with the rods disconnected then adjust the rods so the insert into the holes with little to no force. Also you'll notice there are two sets of holes in your transmission arms where the rods connect. The other set of holes are for short throw. I recommend you do that. It make shifting a lot more fun (and fast).
Good luck and hopefully that's all it is.

 

Thanks for the quick response! I do have the original stock shifter and I did have it out and did clean, lube, etc. I TRIED to create a tool that I could get in the slot (I think I read it's .060) but could not make it work. Guess I'll drop the exhaust again and go at it!

 

Based on your description, I don't think its a shifter problem. If it only happens when the engine is running, I think its safe to assume that your clutch is not releasing fully. Beyond that its hard to say exactly what the problem is, other than its likely some sort of geometry problem. Make sure you have the right throwout bearing. GM made a bunch of them in different dimensions. Same goes for the fork pivot. Is the clutch and pressure plate a high quality unit from a reputable manufacturer?

 

A rebuild would be a good idea. My shifter was fine when I had it out but I rebuilt it anyway, a "while your in there" project. It made a huge difference.

 

The # 1 cause Ive seen is the disc is in backwards, did you follow the label on the disc
flywheel side?

 

Also did you set the old throwout bearing next to the new one to make sure it was the same.Like drwet said they come in many different heights.I would say that the clutch is not adjusted right and if the clutch adjuster is as far out as it can be than I would bet that the throwout bearing is the wrong one there should be only about a 1/2 to 1 inch of free pedal on the top of the clutch peddle.

 

YEP...I doubt it is in the shifter. Even though I ahve serviced countless clutches...and check the parts to make sure all is good. I always take the clutch fork and manually move it with my hand and make sure that when I feel the throw out bearing contact the pressure plate fingers...the clutch fork is basically in the CENTER of the square opening of the bellhousing where the rubber boot is installed. IF THAT is correct...than I can get the linkage to do what I need to make the clutch work.

DUB

 

Think maybe clutch plates frozen together?
I had this happen in New Orleans after one of its many floods.

 

If you start the car in gear with foot on clutch, does it try to move? If it wants to creep but you can hold it on the brake, clutch in, then the clutch isn't releasing properly (most likely an alignment/adjustment issue) - this is what I'd expect from your description so far. If it won't hold on the brake and/or won't start because it wants to drive forward, the clutch isn't releasing much, if at all (and it becomes more likely the clutch is stuck, or incorrectly assembled such that it won't release).

 

If the flywheel on the 383 is not as thick as the factory flywheel, the clutch pivot may not be far enough forward to allow the clutch to release.

 

From your description the problem is clearly not with the shifter. It is the clutch that isn't releasing fully.

Are you sure the clutch is correct type for a Corvette? Some clutches need a longer travel in order to release than is available with the Corvette clutch linkage.
I had a Sachs clutch once with that problem and the same symptom as you have.

It could also be a geometry problem (wrong clutch pivot stud, worn clutch linkage, flywheel, ...)

/Karsten

 

Thanks to all for some great suggestions. Here are some answers to some of your questions:

- There is an external balance plate mounted between the crankshaft end and the flywheel, provided by the engine remanufacturer; it’s about 1/8” thick, so that might be taking away some normal clutch travel. Given that it’s a must for the engine's rotating assembly itself, I will have to compensate for it in some other fashion, I would think. Will a shorter pivot ball help that problem? Can I compensate using a shorter throwout bearing?

- Clutch disc, pressure plate and flywheel came from Jeg’s and, while not top of the line, appeared to be high quality and appeared to match the original flywheel, throwout bearing, clutch disc and PP.

- I’m 99.9% sure that I mounted the clutch disc with the correct side facing the flywheel. Obviously if other efforts fail, I’ll have to take the trans and bellhousing off and make sure.

- The clutch pivot ball is original and feels like it’s screwed in as far as it’ll go; the clutch fork is original, albeit cleaned up, lubricated, etc. Both appeared to be in good condition and reusable.

- If I start the car with it in first gear and clutch depressed to the floor, it does not creep forward but there is some slight grinding from either popping out of first or never quite being in first.

- I don’t think the plates are frozen together. These were all new parts and installed late last year or January but …?

- As Dub suggested, I will try moving the clutch fork and see where it is at the point of touching the pressure plate fingers. I assume this is where the real resistance would be felt (?).

- While it’s been several months since I put this together, I’m pretty sure I compared the new throwout bearing to the old one and it appeared to be exactly the same. Of course, I don’t guarantee any memory-based items anymore.

- I will recheck my free pedal distance, but I’m pretty sure it’s still more than .5 – 1.0”

- While I agree that it’s likely not my primary problem, a shifter rebuild may be in order to make life a bit easier.

Any other thoughts will be highly welcomed! Thanks a million for the guidance so far. Sounds like I have some work cut out for me. Ugh.

 

I would guess that the external balance plates are messing everything up. Clutch manufacturers have a spec that specifies the distance from the clutch pivot ball to the back of the block. Flywheel thickness enters into the equation. You have moved the flywheel, the thickness of the balance plate, away from its original position.

 

I have put together a similar 383 combo with Muncie and external balance plate in the past, and no such issue. Check to make sure your throw-out bearing is installed correctly (clip on the fork riding in the wide space on the bearing, not the lip locked into the clip). If you put in a heavier-than-stock pressure plate (heavy pedal pressure), look closely at your bell-crank (pipe & arm mounted to the pivot ball on DS of the block) and make sure you didn't bend/flex that clutch linkage, losing your adjustment. The latter happened to me, so I had to remove & straighten the bell-crank and had a gusset welded in to stiffen it up. No problems after that.

 

You've installed the wrong clutch release bearing. You have the short one and it should be the long one. That accounts for you having to run your adjustment all the way out. i know because it's happened to me before. Experience speaking..........

 

Not knowing if you are going in with ALL NEW clutch linkage rods, etc. I can 'say'...that if your rods and or 'Z'bar has wear in them where instead of an exact perfect hole for teh rod to fit ...you have a slot or wear on the shaft or swivel..I would advise you replacing them..because it may not seem like a lot...but it DOES make a huge difference if all your linkages are perfect..and the ONLY place that you should have a slot...is the rod that goes into your clutch fork where the clevis pin goes into the clutch fork.

DUB

 

I'm not sure of the crossover linkage on a Vette but I had a problem on my 66 SS 396 that was very much like what you're having it turned out to be a crack in the crossover bar between the frame and the block.Every time I would step on the clutch it would flex just a little and would not fully release the clutch,I bought a new one and welded a gusset in the corners so it would not happen again.My 77 Vette is a auto so I don't know what you're s looks like.

 

My 383 is externally balanced and has the same weight installed between the crank and the flywheel. It doesn't make enough difference to cause the problem you are having.

 

Thanks yet again for all the great suggestions. Here are some responses and additional thoughts:

- The shifter, clutch crossover bar and all the linkage is original. I restored all these parts and did use a crossover bar rebuild kit to replace the felts, and other parts on each end of the bar itself, new springs, etc. While I was not specifically looking for it, there did not seem to be any cracks in the bar or otherwise but I’ll take another look.

- As far as I know, the plate between the crank and flywheel is solely to externally balance the rotating assembly. I’m 95% sure that at the time of assembly, I did compare the old and new flywheel and they appeared to be identical, including width.

- The shifter and linkage, while taken apart and cleaned up, are original and are, probably, pretty sloppy on a good day. I don’t know that it’ll cure my problem but it sounds like a rebuild kit is a good investment of time and money.

- Assuming other efforts do not provide a solution, I will have to take the trans, bell housing, etc. out and check the position and size of the throwout bearing and ensure that the disc is installed properly.

- I have not done “Dub’s test” yet but will do so tomorrow!

I greatly appreciate everyone’s feedback and suggestions!! Now cross those fingers for me as I realllllllly don’t want to have to take it apart! Thanks again.

Jack