Hey guys I just put in a 4 speed Muncie in my ‘63 Impala with a resurfaced flywheel, new clutch ***embly & later 64+ bell housing. This is where the old clutch rod was :
The clutch is stock new 10.5”, the fork is original’63, the bell has the larger hole for the Muncie M20. What the hell?
I'm starting to want to see photos of that "Muncie 4 speed" it's starting to sound like his Muncie is an SM465 with the oversize bearing collar and other issues.
I think all @Eth727 is saying is that he changed bell housings from his small register hole 3788421 bell to a ‘64 and up bell to fit his 1964 and later Muncie. I haven’t reviewed all the threads he’s posted, but he may have used a flat finger diaphragm pressure plate with the wrong length throw out bearing causing the adjustment issue.
I seem to recall that Chevys of this era and somewhat newer had different length clutch rods for 6 cyl. and 8 cyl. applications. Some also used a clevis, like yours has, to connect to the Z-arm and others had a 90° bend on the end to make that connection. Maybe too many mix-and-match parts you're trying to use? Did you change from a low-cone diaphragm pressure plate to a high-cone or B&B style clutch? Do you have the short or long style T.O. bearing?
I’m not sure which Muncie other than it’s a M20 that originally came out of a Pontiac. The bell is a “383” that has the bigger hole for Muncies . The original 63 one has the small bearing retainer hole. It was converted from short shaft 3 speed ******. I had another post on here when the ****** had hard time getting in until I hooked up the clutch pedal and pushed it in. T/O bearing is the short one.
That’s a good question. I thought it looked the same as the other one . It didn’t occur to check the height. People just said yeah just put a Muncie it’s really easy.
All chevy V8 bellhousings are the same depth [so if your trans fits it isn't the issue] The variation is in the type of clutch pressure plate you are using You have the wrong length throwout bearing [there is 3 different lengths] for your clutch Back off the adjuster to the center somewhere, and pull the fork back [shine a flashlight into the bell and have a look] You will probably need the medium length bearing [this allows some adjustment when the clutch wears] Also If you pull the transmission out, don't touch the clutch. Then it will install again a lot easier. You are only playing with the clutch fork and throwout bearing [not the actual clutch]
I don't understand why the bellhousing needed to be changed in the first place. Didn't the Muncie 3 speed's, like the car originally came with, and the 64 and later Muncie 4 speed's all have the same diameter bearing retainer?
Also said the flywheel was machined. They make thin spacers to put between the crank and flywheel. I DOES make a difference
I googled this issue and others have been in this situation. I’d like to extend the lower and upper rods somehow
It’s been a while since I messed with my old ‘63 Belair, but I recall making / modifying the lower arm from a different car, like a Chevelle??? A longer lower arm will put your upper adjustable arm in the right spot. Summit lists the length, I just bought one long enough and cut (rounded) the end off. Here’s a link that at least might get you on the right track…. I realize it says “upper arm” but it doesn’t matter if you’re going to cut it to fit. https://www.summitracing.com/parts/...HhB_sNhfr-z-8LljdKLjfdh0wbAaIgggaAqrTEALw_wcB
There are different length pivot balls, different length throwout bearings, and different offset forks. All have to be matched to be correct. The pivot balls can often make the biggest change if not the same. Bellhousings are usually the same depth or they'd have to make different input shafts for different trans.
That is a Corvette trap! Before you consider that , get somebody to push the clutch in, crawl under and see if the fork has plenty of clearance around the opening in the bell. In this example a longer ball stud would be the remedy [it pushes the whole fork forward, requiring the rod adjustment to be backed off] Also while checking this clearance ,check the working angle of the clutch fork / push rod. If the angle is too acute the clutch feels weird [soft when fully engaged] You might need a medium length throwout bearing.
No, the 4 speed bearing retainer is larger. Learned that lesson the hard way myself on my 63 Bel-Air.
I’m thinking a longer lower clutch fork linkage and or upper clutch rod would fix my situation? It’s 9 1/4 for the lower one. Can I cut and weld to add another 1/2” or so. The photos below are is clutch neutral and all in.
this photo looks pretty good [just pull the boot/gaitor back and check the clearance that I mentioned previously] With the clutch pedal fully engaged Yes you can absolutely lengthen the rod . But there is a lot of compression load on it ,so it can bend easily. The best method is a piece of tubing with the ID the same size as the rod. [slip this over the rod when cut] Drill the tube for a couple of plug welds as well as fully welding the ends. The best thing about using tube is you can set up one half, then back off the adjuster to get the ideal position then scribe a mark then final weld. I've done this a few times on race cars.[it is an acceptable method]
While you have the welder out make some corner braces for the cross shaft, the factory welds break loose after many years. One example (not mine), Mine
Go on something like the LMC truck site to see if they have a longer rod. In the past I have seen some cobbled up homegrown gems that were brazed and have held up.
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