Clutch Question

[Hondo]

Like the pdf, very informative. Apparently you can mix and match. Mine has the top bork and beck three finger pressure plate with a rockford clutch disc. Had the disc and pressure plate that came out rebuilt at ba friction materials in san jose CA. They turned them around in a day, even replaced the fingers. Has about 10k miles on it now. Wondering if the clutch and pressure plate you put in matched what you took out? When I took mine out, the clutch disc was installed backwards, and those raised bumps on the disc were half way through the flywheel bolts, wouldn't that have been fun.

 

[harrywt]

My 1970 mach I had a cleveland...

Getting the names of the parts right saves time. It's not so bad now with the internet so you can compare pictures to your existing parts. Back in the day you had to wait until it arrived in the mail

like the pdf, very informative. Apparently you can mix and match. Mine has the top bork and beck three finger pressure plate with a rockford clutch disc. Had the disc and pressure plate that came out rebuilt at ba friction materials in san jose CA. They turned them around in a day, even replaced the fingers. Has about 10k miles on it now. Wondering if the clutch and pressure plate you put in matched what you took out? When I took mine out, the clutch disc was installed backwards, and those raised bumps on the disc were half way through the flywheel bolts, wouldn't that have been fun.

 

[harrywt]

Flywheel out.











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some crazing seen here (below), higher heat? It's hard to see. I cleaned the flywheel and took more photos. Shown in next post

 

[harrywt]

Cleaned flywheel with kerosene and steel wool.



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next two are same picture, added arrows tothe second one. This is the crazing I spoke of earlier. There is a slight ridge where the perimeter of the friction plate met the flywheel. It is barely to be felt with a fingernail and not seen with the straightedge. I estimate it to be no more than 2-3 thousandths of an inch.

 

[FDChappie]

That looks a lot better than I thought it did in the first set of photos. Just have it resurfaced and you'll be good to go.

 

[Greg R]

what I need are dimensions a & b that you see on page two. Page three is a list of specs for various clutches. Maybe someone can find the clutch I have in another service manual and send me the specs?

Hope you find your specifications. You do realize those dimensions are set with setup blocks? They're called "spacer blocks" on page 3 of the pdf you posted. The dimensions are set under compression of the clutch plate on the setup blocks so you have the proper pressure on the disc and the right amount of travel in the linkage to release it once it's installed on the flywheel.

 

[harrywt]

Yup, dimensions a & b

hope you find your specifications. You do realize those dimensions are set with setup blocks? They're called "spacer blocks" on page 3 of the pdf you posted. The dimensions are set under compression of the clutch plate on the setup blocks so you have the proper pressure on the disc and the right amount of travel in the linkage to release it once it's installed on the flywheel.

 

[harrywt]

Yes, my thoughts as well. It always looked better with Mark 1 eyeball than the previous pics. Tried a little harder with these last pics

that looks a lot better than I thought it did in the first set of photos. Just have it resurfaced and you'll be good to go.

 

[harrywt]

Back from machine shop. Little miscommunication..

It seems that the clutch is not affected

 

[ihpartsjeff]

You need to send that flywheel back harry and have it completely surfaced. How it is now is wrong and throws the overall clutch adjustment off. IH's do not run a stepped flywheel like other cars/trucks so your machinist might be thinking that's the way it needs to be but he is wrong.

 

[FDChappie]

What Jeff said and tell the machinist to use a sharp bit in the lathe this time. :-]

 

[harrywt]

Is it bad to not be mirror smooth? I would think that one likes the extra friction of a surface that is not mirror smooth.

I looks like they cut it like a brake rotor instead of using a fly cutter. I brought it to a general shop that I do a lot of business with through my job. I will see if they can use a fly cutter this time. I was so surprised when they delivered like this, never seen a flywheel cut like this before

what Jeff said and tell the machinist to use a sharp bit in the lathe this time. :-]

 

[FDChappie]

It only needs to be rough enough to allow the new disk to seat, to rough and you'll wear a lot more clutch material off than necessary. It will eventually be mirror smooth, but to start with a surface that looks like it was sanded with 80 grit will do. The step Jeff pointed out is a bigger issue though as it will change the amount of pressure applied to the disk.

 

[harrywt]

It is pretty smooth, hard to get a good representative picture, dog thinks everything is ok

 

[harrywt]

What do we think of this throw out bearing body? Iu am surprised that I didn't notice the wear two years ago, I was sure in a hurry at the time.

I realized that the only place the bearing has an interference fit is in the red area so the wear in the other areas shouldn't affect the bearing as the parts of the bearing that match the "non-red" areas are moving, so you don't want them to touch

 

[harrywt]

I am thinking about having the heads of standard 5/16-24 hex bolts ground down to imitate the stock clutch adjustment bolts.

However, the stock bolts have larger heads.

I could also ask my machinist if he could duplicate the stock bolt or at least one with an m8-1 thread which is closest to 5/6-24

View attachment gap adjuster_hex.pdf

 

[harrywt]

Got the flywheel back. I had them make me adjusting bolts. They look great but they made them m8x1 instead of 5/16-24, little communication mix up. They made me four of these and heat treated them, $20! I do a lot of business with them through work. They are making me a new set now

 

[harrywt]

New friction plate came from IHPA, you can see that it was a good investment, mine was worn down considerably with at most 10 000 miles, more like 5 000

the last picture shows the new clutch next to the spacer I had made. The spacer is 8mm thick, the manual calls for 8.13, the millimeter equivalent to the english unit quoted. That makes for a 0.005" difference which I think I can ignore.

The interesting thing is that the spacer is thinner than the new friction plate and thicker than the old one which had a shiny rivet and therefore worn out. This makes sense, when I set it all up I'll bet that with the spacer in the adjuster bolts will be perpendicular to the spacer so that they'll start at an angle greater than 90 with the new friction plate, be at 90 at about the half life of the friction plate and a little less than 90 at the end of the friction plate life.

I'll report all of the measurements when I am done

 

[Robert Kenney]

Remember the disk will compress quite a bit when under the load of the pp.
The spacer spec is closer to the compressed thickness.

 

[harrywt]

So I now have my custom made clutch arm adjustment screws cut the right size of 5/16-24. I bolted up the pressure plate to the flywheel with the spacer. I started installing the new screws when I began to suspect that they wouldn't go in enough.

So I put in one of the old ones that I knew had the lock nut in the original position. Lo and behold the original will never work either if I go with 50.8mm specified for 11" clutches in the service manual. 52.37mm might work but I doubt it. Also the 1 15/16" for the 10.5" clutch wont work either. (see the pdf for these numbers) and yes, I know that I am measuring from the flywheel bolt surface and not the flywheel face, I added the difference to 50.8 to make the measurement you see in the picture

View attachment 07031601.PDF

My clutch is not a bork & beck as it is listed at IHPA. It is a rockford clutch. I really need help finding out the settings of the adjuster screws