[Lidpainter]

I have been messing with my clutch since June or July and I am finally throwing in the towel. Need some help to figure out what the issue is instead of continuing to throw money and parts at it.
I am finishing up a 69 Firebird project that I bought a few years back. M20 was just rebuilt, clutch, (RAM, diaphragm), pressure plate were new, 0-miles when I got the car. Belhousing is stock. Flywheel was resurfaced and balanced with pressure plate.
The issue is that the clutch will not fully disengage unless I reduce the pedal free-pay to almost nothing. Doing this makes the throwout bearing ride the diaphragm fingers constantly. I have used 3 different clutch forks ( just replaced again today), multiple different brands and sizes of throwout bearings, different pivot balls, stock and adjustable heim joint "aviation style" rods. Problems persist.
At this point I am wondering if maybe the clutch disc is warped. Before I go and peel off another couple hundred bucks on parts that won't change anything, I was hoping for some insight for anyone who may have experienced this before.

[chuckies76ta]

Just a thought, Check to see where the push-rod is connected to the pedal. Seeing that all this mechanical clutch stuff works on a fulcrum principal sort off. Your clutch fork has to be at a certain angle also. I know when done the throw out bearing rides very close to the pressure plate fingers. Might be an issue with the pressure plate. I guess you could start the engine up with the tranny out and very carefully check it for straightness. Another issue that sometimes happens is the flywheel bolts interfere with the clutch hub. I've had that happen. Also make sure the spring on the clutch fork is strong enough to pull it away from the pressure plate. Some of these after market clutch forks aren't as good as the stock ones. Just some thoughts. Good luck

[Half-Inch Stud]

Hmmm, sounds like Flywheel bolt heads a bit proud. Too unlikely to have a flipped clutch.

[Jay S]

I had a similar problem, I swapped in a heavier duty pressure plate and had to lengthen the clutch linkage a lot of make it work, then it barely worked kind of like what was described here. I drove it like that, but I could tell something was not right, later I installed a blow proof bell housing and could not make the clutch adjust up at all. One of the guys on here said they installed a Mcleod 16908 adjustable pivot ball on a similar set up. That is what I end up doing, it made the throw out arm pivot further forward, better geometry, and the throw out arm didn’t hit on the bell housing.

I think when I had the stock bell housing it could have used an adjustable pivot ball to correct the problem. I had to use a McLeod on the Lakewood I have now. I think I could have used this to fix it when I had the stock bell housing, probably fix yours also.

https://www.speedwaymotors.com/Adjus...SABEgIvUPD_BwE

[track73]

I had the same problem. The flywheel bolt heads are too thick. Use Mr. Gasket part number 914. I have a picture but don't seem to know how to put a picture on this website.

[Jay S]

I over looked that big list of things that was already tried. Appears like something is either hitting or warped.

[Singleton]

Have seen a similar situation a few years ago with a friends 1971 GTO. His problem turned out to be interference between the exhaust manifold and the lower arm of the countershaft. He was using the wrong Ram Air exhaust manifolds (64-67) on his later car, and the manifold prevented the countershaft from extending all the way forward, effectively shortening the stroke of the clutch pedal. I ended up grinding a small relief in the manifold to allow slightly more travel. So make sure that nothing is preventing the full forward pivot, (or starting point of clutch travel). You have a completely different car and exhaust, but thought I would throw this example out there.

[Lidpainter]

Thank you for all the suggestions. Lots to think about. Definitely never thought about the flywheel bolts. I'll need to check those out. Wanted to say how much i appreciate the input. Posted this issue elsewhere last week and all I got was "Maybe you should drive an automatic" and "Hire a pro as you have no idea what you're doing", etc.

[BB70]

I wander if you have looked under the dash to see if anything is flexing, kinda a 2 person deal or maybe easier to watch the rod coming thru the firewall to see if you're loosing travel.

[turbo69bird]

Originally Posted by Lidpainter

Thank you for all the suggestions. Lots to think about. Definitely never thought about the flywheel bolts. I'll need to check those out. Wanted to say how much i appreciate the input. Posted this issue elsewhere last week and all I got was "Maybe you should drive an automatic" and "Hire a pro as you have no idea what you're doing", etc.

What site was that on? That way we all know never to waste a moment on that loser site. What morons you’re among better people now who will try to help as best we can .

Everyone has to learn and even those of us who’ve done this forever still run. Into issues.

By the way I’m betting it’s the flywheel bolts I raced since 1987 and been bit by that one using stock bolts . I also put my disc in backwards once when throwing it together before a big race rushing to make it. Id I’ve had it in and out probably 100 times through the years racing. It happens .

[lust4speed]

Years ago I had a McLeod clutch that simply refused to fully release. Finally pulled it out and sent it back to McLeod for warranty. They returned it to me saying it checked out good. Put it back in and still didn't release properly. Probably had it in and out over a dozen times. Ordered out and installed a new clutch from a different manufacturer and all problems disappeared. Sometimes no matter how good it looks and how good it checks out, it can be garbage.

[Tom Vaught]

I am a big fan of LUK clutch parts, standard 11" diaphragm stuff with a known "no stress cracks" flywheel.

I also used the Chevrolet #3729000 which is correct for my application at 1-1/2" long.
The other one which you will sometimes see, GM #3887159, 1-3/8" long, was released in error for '66, and after hundreds of field failure reports, was cancelled and replaced in production by the good old #3729000 stud on April 4, 1966, which remained in production through the mid-80's. Check and verify that you have the correct length ball stud. Chevrolet makes 3 different lengths.

https://fortesparts.com/product/clut...pivot-ball-gm/

Notice the difference in the pivot ball height.

Tom V.

[Tom Vaught]

I am a big fan of LUK clutch parts, standard 11" diaphragm stuff with a known "no stress cracks" flywheel.

I also used the Chevrolet #3729000 which is correct for my application at 1-1/2" long.
The other one which you will sometimes see, GM #3887159, 1-3/8" long, was released in error for '66, and after hundreds of field failure reports, was cancelled and replaced in production by the good old #3729000 stud on April 4, 1966, which remained in production through the mid-80's. Check and verify that you have the correct length ball stud. Chevrolet makes 3 different lengths.

https://fortesparts.com/product/clut...pivot-ball-gm/

Notice the difference in the pivot ball height.

Tom V.

[70L34]

Where are you in Michigan? I have a couple new old stock clutches I'm never going to use - one is a McLeod and the other a Luk.

[MatthewKlein]

Originally Posted by Lidpainter

I have been messing with my clutch since June or July and I am finally throwing in the towel. Need some help to figure out what the issue is instead of continuing to throw money and parts at it.
I am finishing up a 69 Firebird project that I bought a few years back. M20 was just rebuilt, clutch, (RAM, diaphragm), pressure plate were new, 0-miles when I got the car. Belhousing is stock. Flywheel was resurfaced and balanced with pressure plate.
The issue is that the clutch will not fully disengage unless I reduce the pedal free-pay to almost nothing. Doing this makes the throwout bearing ride the diaphragm fingers constantly. I have used 3 different clutch forks ( just replaced again today), multiple different brands and sizes of throwout bearings, different pivot balls, stock and adjustable heim joint "aviation style" rods. Problems persist.
At this point I am wondering if maybe the clutch disc is warped. Before I go and peel off another couple hundred bucks on parts that won't change anything, I was hoping for some insight for anyone who may have experienced this before.

If you are able to post pictures it could help. It's possible something is installed wrong and it would jump out in a picture.

[geeteeohguy]

X3 or 4 on the flywheel bolt heads being too thick. BTDT, with aftermarket bolts.

[Lidpainter]

Looks like I found the issue. Those who said bolt heads too tall probably nailed it. New bolt up top, old bolt on bottom.

[Tom Vaught]

Glad you will be able to get on the road.

Tom V.

[Skip Fix]

Yep had too thick bolts and in high school my buddy put the disk in backwards on my car while I was at college.

[GtoFM]

OK, who's the sadistic ba$turd that designed this? "Yeah, I know we can engineer the flywheel and flexplate to use a standard bolt, but let's have some fun".
So, tell this ignorant, backyard mechanic, what's the reason for the special bolts? There's gotta be a reason.