Hot Rods Clutch pressure plate issues

That was a very comprehensive reply of answers. Bravo!
Knowing frustration builds in doing what your doing, I offered up the improper installation of the clutch as a possibility.


Not say it is the problem, just that sometimes mistakes happen.















Pictures are worth a whole lot of typing, but at the end of the day, a clutch shouldn't be hard to push, should push smoothly, and shouldn't be a pain to keep depressed in traffic.

Maybe step back, take a breath and give some additional thought to how it works and plays together. The problem child may then become apparent and easily corrected.

 

I think @Fordors is on the right track.

 

Okay, I read all of your replies at work today and when I got home I pulled my motor/trans again. Its the 6th time and it only took an hour, so I'm getting pretty good at it!
I'll just jump into what I found this time rather than answer everyone because I think I may have found the culprit. (maybe)
I wanted to see if I remembered correctly how the clutch fork pulled back with a 5' exhaust pipe, if it oil canned like I remember. Well, this time I couldn't even budge it! I almost tipped over the engine stand trying to make it move just a hair! So I was really eager to see what was going on inside. I pulled the trans off and looked at the clutch fork and throw out bearing and found something intersting.

I'm going to try post pics. I haven't tried in years, so I hope this works.
First pics are of my '48, my 250 and the Saginaw 4 speed and Hurst shifter

 

Here's a shot of what it looked like right after sliding off the trans

 

First thing I noticed is that the clutch fork was not seated in the pocket with the ball.
The way I installed it looked like the following pics. Ball in the pocket, but the fork wasnt snug up against the throw out bearing like the previous pics

 

The other thing I noticed, is when the T.O.B. is centered, the clutch fork actually touches the bottom of the bellhousing hole

 

Some of you may be wondering what is going on with the end of my clutch fork. Well, years ago I had a clutch linkage retainer spring break and the linkage fell away from the clutch fork. Back then, after getting a tow, I solved the problem with this method. A mechanical connection using a heim joint.
I measured the length of the original clutch fork and noted the location of the pocket so my pivot would be the same and welded it up. It worked beautifully for 6+ years

 

Sorry for all the posts. If someone could explain how to slide photos into a post along with text, I'd be thankful.

I'm hoping someone can tell me if I'm using the wrong clutch fork?
Is the clutch fork suppose to snug up close to the TOB like in the first pictures? If so, the pocket on this fork isn't lining up with the ball.

 

I can't tell if it's camera distorting the image. Are the fingers on the pressure plate sunk in over center? Has your flywheel been step cut?

 

This is the proper fit of Bearing on the Fork.


What I don't like is this fit. Notice the 2 ware marks in the opening probably caused by the Fork fitting correctly.

The change in the Fork placement I can't explain.

 

That would be what’s causing Monsters “oil canning” per his opening question and why it takes more pressure to operate clutch.

 

I like the way you lined up all the responses and addressed them.

Sometimes the fork/fingers have an interference issue and a different throwout bearing or pressure plate is needed. Sometimes it can be as simple as shortening (or lengthening) the pivot ball. Lots of frustration I'm sure, but I think your statement above tells you its not in the pedal linkage.

I think the one thing you might take as a general experience is trying to isolate components within a system and testing them rather than having all the components involved in a test.

 

For sure. This moved the Fulcrum point way out of position to work correctly.

 

First, I want to go back and address some people's statements and questions.

Wanderlust- sorry you did not have a good experience with this product. So far, all the components appear to be made well, I'm just not sure yet if I ordered the correct parts

Pist-n-broke- do you happen to know the part numbers of the three different clutch forks that I could be using? Or do you have a picture or description of the three different styles? Thank you

ClayMart- with your explanation and looking at the photos I provided, would you suggest that my p.p. is low cone? Also, does it appear to be the correct height throw out bearing? The pressure plate and throw out bearing came together in the same box so I'm assuming they are a match but anything's possible.

SS327- I'm not familiar with center force. Who is a distributor for that brand? Can you pick their stuff up at summit?
Also, what is a backwards disc? Are you referring to installing the clutch disc in the wrong way? I installed the clutch disc with the flat side to the flywheel and the spring side to the pressure plate.

Mr48chev- both my brother and I have taken turns pushing the clutch pedal and inspecting all of the linkage and the Z bar. None of that seems to be binding or flexing at all. Except for the undue strain of how much pressure is required to push the clutch pedal until it oil cans. I'm fairly certain that the problem I'm having has to do with either the wrong bell housing or the wrong clutch fork. It's possible that I also have the wrong pressure plate and wrong throw out bearing.

Brando1956- thank you for the explanation of the pressure plate varieties. I haven't done a search on Google yet but I will do that once I'm done posting this. Tonight I'm going to remove my bell housing and inspect the pressure plate and clutch more thoroughly and compare it to what I find online. I never had an original flywheel, clutch disc, pressure plate or any of it. I'm building this from scratch.
The where marks that I see on the pressure plate fingers looks like two different sized radiuses, or two different wear locations. I think this is due to the oil canning. It rides on one location until it pops to the next? I'll look into that further tonight.
It's very possible and almost likely that I have the wrong clutch fork. I need to do some more homework

SS327- do you happen to know the part numbers for the three different throw out bearings that Chevy used? Or do you have images or a website that describes the three and how to tell them apart, measurements? Thank you

Pist-n-broke- you are correct, I'm building this from scratch. I have no reference to what the original flywheel or clutch pack look like or should look like. I'm going off of pictures that I have found through RockAuto and summit and Napa. Along the way, one of these components does not work with the other and I'm not sure which one it is yet.
I definitely do not have any idea if the clutch fork was the original mate to the bell housing I have. I think I picked them both up at a swap meet years ago. I have two other Bell housings just like this one, the fork ball is in the same location on all of them and they are all aluminum.
I think you're right, I need to find an exploded view of a parts list for the drivetrain of whatever this motor transmission combination would have been found in production. I need to run the casting numbers on the block to find out what year it is but I think that the 250 inline 6 started life sometime in the early 60s and went through the 90s. They were put in cars and trucks and vans and possibly commercial vehicles. With all of those different applications, there was a wide variety of transmissions. Powerglide, other automatics and manual transmissions.
The bellhousing flange surface on the 250 is the same as a V8. The crank position and pilot bushing are the same for an inline 6 and a V8. I don't believe it matters what kind of manual transmission you have bolted to the other side of the bell housing for this problem. I feel the Bella housing and clutch fork need to be a match and the pressure plate and throw out bearing need to be a match. Somewhere along the line I'm thinking I have a mismatch.

Fordors- that's a great question! When I pull my bell housing off tonight I will inspect the throw out bearing and put my dial Caliper on a lot of different components.

NoelC- thank you for all those excellent pictures! By the way, how can I insert a picture along with the body of text like you did in your post?
After I disassemble everything tonight, I will put my calipers on the thickness of my clutch disc and see if it's the same as the one you have there.

427 Sleeper- he definitely has a good suggestion

Johnny Gee- I think maybe the lighting is making it look as if the fingers are concave. Once I take the bell housing off tonight I will be able to take much better pictures. As far as the flywheel being step cut, I don't believe it is but I will take a picture of it tonight and you can be the judge

Pist-n-broke- thank you for clarifying the proper location of the clutch fork on the throwout bearing!
I'm not too thrilled about the clutch fork position coming out of the bell housing hole either. When the throw out bearing is completely centered, the clutch fork makes physical contact with the bell housing shown in the photo. I'm thinking at this point that the clutch fork is the wrong one. When I pulled the transmission off the back of the bell housing, the clutch fork was snug up against the throw out bearing and the ball was not nestled into the clutch fork pocket. Tonight when I take everything apart, I will try and show the excessive wear on the edge of the clutch fork pocket. I'm wondering if this is the oil can that I'm experiencing? The clutch fork ball being outside of the pocket, and then as the clutch fork is pulled back, it pops into the pocket?

Johnny Gee- I'm leaning towards that as well

Ekimneirbo- do you know how many different lengths of clutch fork balls there are? Do you have a diagram or image displaying the different sizes or lengths of them? I would be curious to know which length is used for what application and what combination of clutch components.

Thank you all for your input, questions and suggestions up to this point. It's very helpful and I appreciate it!

For the sake of this drivetrain, let's forget that it's in a 1948 Chevy truck. This drivetrain would have been found in a 1972 Nova for instance.
Regardless if it had a muncie, Borg Warner or Saginaw, would I be correct in thinking they would all still use the same bell housing, clutch fork, pressure plate and throw out bearing? The following pictures are a bellhousing and clutch fork listed on RockAuto for a 1972 Nova with a manual transmission.

 

Would anyone recommend this?

 

I Googled just Chevrolet Clutch fork and on the Danchuck sight it shows 5 different forks of different shapes that anyone could go in your bellhousing. They all have just small variations of shape. It looks like things change from the Ball outboard.
Here's a Ball that might cure this issue for you. it's adjustable in height. Something else you might want to consider. Put the motor back in your Truck less Trans. Remove your front bearing retainer. Install your clutch alignment tool. Would be good if it were a stock input shaft with the Bearing retainer and T.H.B. Now work yourself through this issue being able to see what happens and get to the ball and fork without tearing the Truck back apart.

 

Great minds think alike! I just found that adjustable clutch fork ball as well. Taking the trans off the bell housing and putting it back in the truck is a great idea. Right now it's perched on a very Stout engine stand with locking casters. I think with the correct clutch components, I should be able to maneuver the clutch fork with a little bit of leverage. We'll see

 

NoelC- thank you for all those excellent pictures! By the way, how can I insert a picture along with the body of text like you did in your post?

Well T_M, I'm on a desk top computer. I up load the pictures after signing in, then I start adding text. I hit return to start a new line
(then hit full image next to the picture to insert)

Hit return again and hit full image



Hitting return once leaves a space, hit again you can fill with text, hit return leaves a space then hit full image for another picture.





Any chance the clutch just wasn't centered when it was tighten down? It happens. Sounds to me like it's a simple issue, but simple is being over looked.
I robbed a few 4 speed parts from Nova's and the odd Camaro over the years. What you have should work? That said, It could just be as mentioned, a simple mismatch and all it would take is a wrong clutch fork for the bellhousing. I'd say "NO" on replacing the ball stud.
While not much help, I'm cheering for you from the side lines.

 

I'm kind of thinking the Fork may have been knocked off the Ball while installing the Gear Box. It just didn't get back in place properly thus causing all of your issue. I'd probably reinstall everything you have as is being very careful and cycle it through several times, see what you come up with.

 

Thank you so much NoelC for the picture tutorial!!!
Okay, I took the bell housing off and have a show and tell. First one here shows the pressure plate. Looks to be a "low cone" to me? The pLUK part number is stamped into it




Here is the thickness of the clutch disc. I will put my calipers on it later


Here is the throw out bearing. I'll put calipers on this as well to find out if its short, medium or tall. The original part number is stamped into the clutch fork




Here is the fulcrum clutch fork ball. You can see the marks from the original shift fork hitting the bell housing more clearly here. Also, I noticed the female threaded hole just above the dowel pin hole. Could this I.D. this bellhousing? My other bellhousing doesn't have this female threaded hole





Thanks!

 

More info to chew on!
Here's the clutch disc I'm using and the caliper measurement



Here is the flywheel I'm using



Here is the pressure plate removed. You can see what the fingers look like now. A slight cone. I would call that a low cone and when it's installed, I'd call it flat.




Here is the caliper reading on the throw out bearing


Here is my other bellhousing. I almost forgot where it was, and remembered its latest job is a computer monitor base! ha! The reason I didn't use this one is because someone made a really poor window and then changed their mind and did a cover up(?)





Here you can see the two bellhousings I have compared to each other. The black one has the female threaded hole I was talking about earlier and the silver one doesn't




And there are the bellhousing numbers. Kinda hard to see the black one



Does this info help out at all? Does anything jump out at you?
Thanks again for everyone's comments and suggestions!

 

Your flywheel looks like the 15# L-88
‘wheel but being a new one it’s likely aftermarket. If it is GM it will have a 3856579 casting number on the back but somebody (Pioneer?) makes a copy but theirs might only be cast iron and not the stronger and safer nodular iron. The ‘403 bell housing is for a 10.5” clutch and works with all of the typical GM stick transmissions. All the fork ball positions are the same so the Chevy forks interchange. The threaded hole above the dowel hole is for a ball that the z-bar rides on. Some are on the bell and some screw into the block depending on the vehicle.
The pp is the low performance, flat finger type. GM went to the bent finger pp’s because the flat fingers would “fly out” at high RPM and effectively disengage the clutch.
I forgot to mention that your long throw out bearing is correct for the flat finger pp, the short t/o bearing is around 1 1/4”.

 

Fordors - Thank you for the detailed reply! Unfortunately, that means that everything I'm using is fine and there is no smoking gun. I'm not sure why I'm having the problems I am with this set up(?)

 

I think the fork just got knocked off the Ball on first install and didn't get caught. I believe I would be putting everything back together making positive sure the Fork and Ball are together correctly. If after working the Clutch several times if the Fork ends up off the Ball again, I'd shift to finding out what is causing that to happen. I don't think you have a parts issue.

 

@Pist-n-Broke hit on something on his last post. I’ve had trouble myself with that style fork retainer popping off so easily at the ball stud. Before stabbing trans try using what ever you have on hand to put pressure on the fork to pressure plate so ball stud will all ways be in the forks socket.

 

Centerforce clutch kits are available through Summit. The Hayes that started Hayes clutches got bored after selling the company and started Centerforce clutches. I have had excellent luck with them. I have bought a few from them.

The different throw out bearing lengths I have found are bigger (C40 & up) older trucks with cast iron bells, early 60s 3 speed transmission and older and 4 speeds early 60s and up. Sorry I don’t have pictures or measurements.

 

Lol. I think it's the clutch...made in Korea. It's for a foreign car.


Just kidding. I'm sure it's a common disc.

But good job on adding the pictures. I have it down to a quick science to blow them up to see details if the quality is there. Yours were.
Yea the window was a bit poorly hacked, but it was a popular thing for a "hot rodder" to do. One of a 50 tips issue I'm sure. I'd clean it up some and who knows, a new window cover and call you handy and it improved upon.

As far as the the back of the crank, is that a pilot bushing or bearing.

Looks bushing. everything ok there? Could be throwing off where the input shaft enters causing some binding???
They do say bearing is better but that was a different tip of the previously mentioned 50.

Thinking out loud, I think the disc was off center after the pressure plate was tightened down and you'll bolt it back together and it'll all be fine.



Anyhow, you'll figure it out I'm sure.

 

I looked at Pioneer’s listings and they do make some of their flywheels from nodular iron. IIRC the GM L-88 ‘wheel in my coupe is 15 #, Pioneer lists yours as 17.2 #.

 

Pist-n-broke- thank you for your helpful comments and suggestions. I hope the ball misalignment was all that happened. I will definitely be paying close attention to everything when I put it all back together. Thanks!

Johnny Gee- I think you're right. If the clutch fork feels a little loosey goosey as I'm trying to install everything, I may try to bend the spring down a little bit to capture the ball in the pocket a little more snugly. If that doesn't work, I may purchase a new clutch fork. When I was looking on a website called 4speedconversions.com, or something like that, I counted 54 different clutch forks for classic Chevrolets!!
There were a number of them that were made from the factory to accept a heim joint. Their design is far superior to mine. They drilled holes on the top and the bottom of the C channel clutch fork arm. This way you can have the heim joint in between the C channel and have the bolt go all the way through. Super strong design!


SS327- thanks for the info on center Force and Hayes clutches. I've always felt like Hayes offered quality parts.
I'm learning more about the different size throw out bearings as well. Thanks!

NoelC- thanks again for the picture help. That's a good idea regarding the bell housing window. Maybe I will clean it up and make a new cover for it. Do you think having a window in that location will affect the strength of the bell housing at all?
I installed a new pilot bushing. I've heard some negative things about pilot bearings having failures. I don't believe there are any misalignment issues with my pilot pushing, it went in really nicely.
I had an alignment tool installed during the pressure plate torque down, and I will do the same thing when I put it back together this time to make sure that everything stays aligned. Thanks!

Fordors- thank you for looking up that information. If my information is correct, a lighter flywheel will allow quick revs but a heavier flywheel will help with continued momentum and less likely to stall. Will 2.2 lb make a difference? Maybe, maybe not. Hopefully this one will be durable enough to withstand the tremendous horsepower coming out of this stock 250! Haha! Thanks!

I'll bolt everything back up tonight and try to operate the clutch fork while the engine is still on the stand.
When I pulled the motor out this last time, before disassembling everything, I put a 5' pipe over the clutch fork and tried to move it. Not only did it not budge one hair, I almost tipped over the engine stand trying.
I'll report back if I was able to move it or not tonight once everything is back together.
Thanks again everyone!

 

Bushings will wear, if a pilot bearing fails it can ruin your input shaft. When installing the pressure plate I will just tighten the bolts sequentially until the disc is barely captured then I check how easily I can slide the alignment tool out and back in, if it slides in and out without any drag I finish bolt up or make adjustments till it’s good. If the alignment tool is the generic type with interchangeable pilot bushes and the cone on a shaft, well I have one and am not so fond of it, not very accurate.