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#1
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Clutch set up is making me crazy. Advice needed.
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.
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#2
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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
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68 Firebird. IA2 block, 505 cu in, SD Performance E-head, Solid roller 3600 weight. Reid TH400 4:11 gear. 29" slick. Best so far 9.95@134 mph. 1.43 60 ft. 76 Trans am, TKX .81 o/d, 3.73 Moser rearend, 468 with KRE D-ports, Doug headers, 3" Exh. |
#3
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Hmmm, sounds like Flywheel bolt heads a bit proud. Too unlikely to have a flipped clutch.
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#4
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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 Last edited by Jay S; 09-17-2023 at 08:44 AM. |
#5
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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.
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1979 Trans Am WS-6 .030 455 zero decked flat pistons 96 heads with SS valves 041 cam with Rhoads lifters 1.65 rockers RPM rods 800 Cliffs Q Jet on Holley Street Dominator ST-10 4 speed (3.42 first) w 2.73 rear gear __________________________________________________ _______________________________ 469th TFS Korat Thailand 1968-69 F-4E Muzzle 2 |
#6
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I over looked that big list of things that was already tried. Appears like something is either hitting or warped.
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#7
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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.
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66 GTO, 495, M22, Strange S-60 w/4.10 Sold new at Royal Pontiac. 70 Formula |
#8
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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.
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The Following 3 Users Say Thank You to Lidpainter For This Useful Post: | ||
#9
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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.
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#10
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Quote:
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 .
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Happiness is just a turbocharger away! 960 HP @ 11 psi, 9.70 at 146. Iron heads, iron stock 2 bolt block , stock crank, 9 years haven't even changed a spark plug! selling turbos and turbo related parts since 2005! |
The Following User Says Thank You to turbo69bird For This Useful Post: | ||
#11
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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.
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Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon. |
#12
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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.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#13
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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.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#14
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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.
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#15
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Quote:
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#16
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X3 or 4 on the flywheel bolt heads being too thick. BTDT, with aftermarket bolts.
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Jeff |
#17
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Looks like I found the issue. Those who said bolt heads too tall probably nailed it. New bolt up top, old bolt on bottom.
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Last edited by Lidpainter; 09-20-2023 at 06:21 PM. Reason: Corre |
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#18
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Glad you will be able to get on the road.
Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#19
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Yep had too thick bolts and in high school my buddy put the disk in backwards on my car while I was at college.
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#20
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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. |
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