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Beer is not just for breakfast anymore... tranny is going back in right now, and I'm shooting photos... Barring any further challenges and discoveries, this could be done today.
The job is now complete, and the original post has been updated with the assembly sequence and warp-up. The clutch system is working perfectly, and has a very nice "feel" to it. Another Vette back on the road!
Beer is not just for breakfast anymore... tranny is going back in right now, and I'm shooting photos... Barring any further challenges and discoveries, this could be done today.
Lars
Sounds great Lars, I excited to get behind the wheel. We might have to have a dram of Scotch to go with that Beer!
The entire C1 Clutch Replacement article has been edited, cleaned up, and made into an MSWord document. It is available, with all photos and information, by dropping me an e-mail request. I have not had a chance to reduce the photo sizes, so the article is 9MB large - make sure your e-mail can receive and open a file of this size. I'll work on reducing the size for easier e-mail transmission.
The article has now been cleaned up and compressed in size, and can be transmitted via e-mail a bit easier (2MB). Just drop me an e-mail request for an MSWord copy.
I have received several e-mail questions about the rationale for switching the car over to a diaphragm clutch. Forum member Reed sums up the questions:
"Lars,
Any reason to replace the pressure plate with a diaphragm unit over a good aftermarket Borg and Beck 3 finger, like from Ram Automotive? Is there a downside to a ‘good’ Borg & Beck? Just wondering what the rationale is...Thanks, Reed"
My personal rationale is that I've never tested a 3-finger Borg & Beck that would fully release with the clutch travel available in a Vette. I've even had trouble with them in GTOs. I'm sure there are some good ones out there, but I've never seen one. I've experienced many bad ones (the "exact reproduction" one seen in this thread is a perfect example), so I don't use them any more. I have even had 3-finger pressure plates that will stay depressed (clutch pedal goes to the floor and will not come back up) at elevated rpm due to the geometry of the finger mechanism inside the pressure plate - this is frightening... GM supposedly solved this problem on the Corvette-unique 3-finger pressure plate, but I still don't trust it. When I'm working on somebody else's car, I need parts that will be right the first time and meet spec, so I go with what I know will work. I've never tested the Ram Borg & Beck, so this is not a slam to that manufacturer. You can use either pressure plate system, but the point of this article is to show how important it is to test everything before, and during, installation. If any of you buy a Ram, or any other brand, 3-finger pressure plate, I would be very interested in seeing actual test data and measurements for the pressure plate disengagement travel distance, and which parts you used to create the correct clutch fork geometry. And I'd like to hear verification that the clutch pedal did not stay on the floor during a 1-2 shift above 6000 rpm...
Lars, thanks so much for that very helpful analysis. In assembling my 1960 corvette, with a Hays B&B style pressure plate, I have encountered the same problem with the throw-out fork misalignment. After I saw your article, I pulled everything out and did some checking. First issue... the aluminum flywheel is thinner than the factory flywheel. This moved the Pressure plate 0.130" closer to the engine (and farther from the pivot. The factory pivot is 4.75" from the face of the bell housing, but now to compensate for the thinner flywheel, I believe that distance should be reduced by 0.130"; i.e. the pivot should now be 4.62" from the bell housing face. This will require and adjustable pivot. That is ordered. I also measured the pressure plate as you described. It is a new Hayes 85-101 borg and beck style unit. It appears to be OK. At 0.500" of deflection of the fingers, it opens a gap of 0.065" from the disk, and actually generated the 0.050" gap at about 0.440" of deflection. This appears to be well within the specs. Another consideration I am unsure of is that even with the taller pivot, not sure the factory style throw-out bearing (1.225") will be long enough. The longer factory style bearing you used has a rounded face, which as I understand is OK for the diaphragm style clutches, but not the B&B style (I believe these require a flat face on the throw-out bearing). So is the only option to get an adjustable length bearing? (e.g. the McLeod 16505). Not sure how these hold up, would be interested if anyone has experience with this.
While the pressure place is advertised as a factory replacement, I assume things have gone amiss due to the non-factory (and thinner) aluminum flywheel. Will see when all the parts arrive how it all fits up.
jon
clutch arm alignment wrong B&B style PP installed on aluminum flywheel
Allmoro-- you said your flywheel is .130" thinner- One thing that is very important. look and see on the back side of the flywheel that the flywheel bolts aren't protruding through. If they are, they will catch on the back of the block and destroy your rear main bearing at the least, and possibly break the block. If the bolts are too long, you will have to have them machined shorter, they only come in one length. Is that picture with the clutch at rest? If so, you need both the taller clutch pivot ball and the adjustable TO bearing. I have used the Mcleod 16505. They are good.
01-31-2019, 10:56 AM
Way to go. I'm sure this thread will be frequently referenced over the years to help other members with clutch issues.
