Jumpy Clutch

[409 cu.425hp.]

Hi All! I'v been a member since 2009 but not been very active. You know, work and all the stuff that gets in the way of the fun stuff. Now retired . Anyway my name is Dave Raska I live in Radcliffe, Iowa. I live and breath Route 66 and Chevrolet wedge motors. Now for my problem. The clutch in my 63 SS 409/340 is very jumpy. I have tried everything I can think of. Maybe someone out there will have a idea. So far I have changed the clutch and flywheel many times, new trans ( 2:56 low) Different drive shaft, Different rear end 3:71 ratio. Had rear main seal leaking so overhauled the engine, checked motor and trans mounts while motor was out. Also have changed clutch linkage. The clutch will jump when moving from a standing stop, will not jump when leaving from a rolling stop. Also will not jump if I put the E-brake on just a little then move. If anyone has any ideas I'm willing to try it. Thanks Dave

 

[Iowa 409 Guy]

Welcome Dave. I know oil will make a clutch jumpy, but if you are sure there is no oil after you changed it, i'm not sure what is going on. Someone here will have an answer I am sure. I know where Radcliff is located. We do some work for a contractor south of Eldora.

About Route 66, my wife and I rode that on our Harleys from Chi town to the Sana Monica Pier a few years ago.

Also on a different note, look for the post in the "event section" for 348-409 National Convention #2. It will be held in Great Bend, Ks late summer and will be THE biggest race/car show ever held................don't miss it................

 

[blkblk63ss]

Back when i had my new 64 ss 409 ----, out of warranty ----, mine would chatter when backing out a diagonal sloped parking stall. I pulled flywheel and had it resurfaced and it was smooth as could be. Have you ever resurfaced flywheel rather than replace, i would think this would be better . New don't always cure the problem. Example --- on one of my pickup's year's ago i replaced all my brake drum's with new. Put all new brake's shoe's and drove it and it would pulsate when stopping in town . Went back to store where purchased drum's and the sale's man grumpy older guy told me i did not do something right. i told him it was smooth before but he refused to do anything about it. Being a wrench for a living i knew better, I went back to the service department and told the shop foremen . He told me to bring them all in and he would resurface all at no charge . All were out of round and it corrected the problem. So new is not always better. Hope this help's.

 

[Fathead Racing]

Hi All! I'v been a member since 2009 but not been very active. You know, work and all the stuff that gets in the way of the fun stuff. Now retired . Anyway my name is Dave Raska I live in Radcliffe, Iowa. I live and breath Route 66 and Chevrolet wedge motors. Now for my problem. The clutch in my 63 SS 409/340 is very jumpy. I have tried everything I can think of. Maybe someone out there will have a idea. So far I have changed the clutch and flywheel many times, new trans ( 2:56 low) Different drive shaft, Different rear end 3:71 ratio. Had rear main seal leaking so overhauled the engine, checked motor and trans mounts while motor was out. Also have changed clutch linkage. The clutch will jump when moving from a standing stop, will not jump when leaving from a rolling stop. Also will not jump if I put the E-brake on just a little then move. If anyone has any ideas I'm willing to try it. Thanks Dave

I would look at the engine mounts again. May be worth the money to try solid engine mounts.

 

[PAINTJOHN1]

Dave: What you didn't tell us and we need to know : Is the car an original 409 car? Or was it a small block or 6 cyl. car? : When you changed the linkage did you also change the "z bar cross shaft" ?. Both 63 and 64 Chevrolets cross shafts for 409 's are different than small block and 6 cylinder cross shafts.The levers are at different angles then the small block. If the car was a small block or 6 cyl. buy the correct cross shafts.It will make a difference..This could cause your jerking or shutter when pulling out from a stop,but you will not noticew it shifting gears.

 

[Dick MacKenzie]

John is right about the "z" bar, also known as a Bell crank. This Diagram From the Show Cars web sideshows the difference in different "z" bars.

Holy Cow!! Big picture!! You're interested in the two at the bottom. Notice that the vertical arm on the left is shorter on the 409 bar.

 

[blkblk63ss]

ok guy's not disputing your z bar suggestion's but i see the angle's are the same on non 409 to 409 car's at 150 degree's . The lever is shorter by 1/2 inch on the 409 z bar is the only difference. So could he get enough adjustment to set correct clutch free play,by not changing lenght of rod's, or modifying any thing with an incorrect z bar???? Just the shorter lever changes the ratio of clutch release. Don't think he could be using a z bar from 1958--- 1960 with off set lever's and a fixed pin on lever for 1961 . I had a incorrect z bar that came with car when i bought my 63 as it had no motor in it , nothing lined up {still don't know what it fit , i think 1965 } I bought a correct z bar for a 327 engine from a member here and everything worked fine. Feel free to tell me if i'm full of $hit , but just curious as to what dave's problem might be .

 

[Dick MacKenzie]

Ok, you're full of $hit! No, really, just having fun. No offense meant. I didn't read John's post closely enough to notice he said the angle is different. As for getting enough adjustment, I can't answer that either. I do have a friend who had the problem with a jumpy clutch and changing to the correct Z bar solved his problem. Of course that assumes he is using a small block Z bar and there's not another problem.

 

[blkblk63ss]

Ok, I can take it ,Apparently the ratio of the shorter lever is the factor!!!!! Might be a lot of other different component's on 409 car's , clutch fork, linkage rod's ect, to match the shorter lever.

 

[409 cu.425hp.]

Dave: What you didn't tell us and we need to know : Is the car an original 409 car? Or was it a small block or 6 cyl. car? : When you changed the linkage did you also change the "z bar cross shaft" ?. Both 63 and 64 Chevrolets cross shafts for 409 's are different than small block and 6 cylinder cross shafts.The levers are at different angles then the small block. If the car was a small block or 6 cyl. buy the correct cross shafts.It will make a difference..This could cause your jerking or shutter when pulling out from a stop,but you will not noticew it shifting gears.

Th

Dave: What you didn't tell us and we need to know : Is the car an original 409 car? Or was it a small block or 6 cyl. car? : When you changed the linkage did you also change the "z bar cross shaft" ?. Both 63 and 64 Chevrolets cross shafts for 409 's are different than small block and 6 cylinder cross shafts.The levers are at different angles then the small block. If the car was a small block or 6 cyl. buy the correct cross shafts.It will make a difference..This could cause your jerking or shutter when pulling out from a stop,but you will not noticew it shifting gears.

John, Yes the car was originally a 327 car. I did get the right z bar and all the right clutch linkage from Show Cars. Also I did change from the alum. 621 full bell housing to the correct alum. half bell housing. Thanks for the reply! Dave

 

[PAINTJOHN1]

All I can say!! If there was not a need for a different cross bar,why then would GM make a small block, and a seperate big block cross bar??? I was wrong in saying angle,but does the other lever for the 409 being a longer lever change the ratio or the pitch or whatever.THERE MUST BE A REASON!!!!

 

[409 cu.425hp.]

Back when i had my new 64 ss 409 ----, out of warranty ----, mine would chatter when backing out a diagonal sloped parking stall. I pulled flywheel and had it resurfaced and it was smooth as could be. Have you ever resurfaced flywheel rather than replace, i would think this would be better . New don't always cure the problem. Example --- on one of my pickup's year's ago i replaced all my brake drum's with new. Put all new brake's shoe's and drove it and it would pulsate when stopping in town . Went back to store where purchased drum's and the sale's man grumpy older guy told me i did not do something right. i told him it was smooth before but he refused to do anything about it. Being a wrench for a living i knew better, I went back to the service department and told the shop foremen . He told me to bring them all in and he would resurface all at no charge . All were out of round and it corrected the problem. So new is not always better. Hope this help's.

Yes I did have two different flywheels resurfaced before installing a new one. Thanks and keep the ideas coming,maybe we will hit on something. I'm beginning to think maybe aftermarket clutch may be the problem. Seems that thay are all made in China or somewhere across the pond. Let me know what you think. Dave

 

[blkblk63ss]

All I can say!! If there was not a need for a different cross bar,why then would GM make a small block, and a seperate big block cross bar??? I was wrong in saying angle,but does the other lever for the 409 being a longer lever change the ratio or the pitch or whatever.THERE MUST BE A REASON!!!!

409 is shorter lever john,the picture's are misleading if you don't watch it close, no offense. I agree on different z bar's.

 

[blkblk63ss]

Yes I did have two different flywheels resurfaced before installing a new one. Thanks and keep the ideas coming,maybe we will hit on something. I'm beginning to think maybe aftermarket clutch may be the problem. Seems that thay are all made in China or somewhere across the pond. Let me know what you think. Dave

Yeah ,that clutch might be the problem . Do you have the correct free play when clutch is released????

 

[62impala409]

OK Dave. Two things come to mind. Are you using the '63 transmission with the oddball, (one year only) small bearing retainer on the front of the transmission that requires the '63 only matching bell housing. The trans would not be centered on the clutch plate if you are using the small bearing retainer trans and the bigger hole bell used in all of the other bellhousings. Another question is the input shaft. Is it pretty tight or flop around like some I have seen. That would allow the disc to fall off center slightly especially if the pilot bearing is a poor fit Leo

 

[PAINTJOHN1]

Did You install a new pilot bearing?? Possibly its binding with the tranny head shaft.My free play on my 64 impala is about 3/4 to 1 inch.No throw out bearing spin at all.I also had heard that flywheels can develope hard spots in the surface,it was suggested to me that this could cause a problem like what you are describing as well.The problem with alot of the parts is like you mentioned is, that they are made in China and I really believe it is really inferrior metal to what was always produced in the USA. Hope we all have been of some help.Clutches can be a problem with light vibrations also. Good way of checking it is to start the car leave it in neutral and rev engine slightly ,hold the door open and feel the door for vibrations.If you do get vibration in the door,clutch could be out of balance,or possibly a weak spring.

 

[409 cu.425hp.]

OK Dave. Two things come to mind. Are you using the '63 transmission with the oddball, (one year only) small bearing retainer on the front of the transmission that requires the '63 only matching bell housing. The trans would not be centered on the clutch plate if you are using the small bearing retainer trans and the bigger hole bell used in all of the other bellhousings. Another question is the input shaft. Is it pretty tight or flop around like some I have seen. That would allow the disc to fall off center slightly especially if the pilot bearing is a poor fit Leo, This is something I do not know for sure. I know that the trans I am using is not the original trans. Year ago I bought a new Borg-Warner. As for the pilot bearing I have put in a roller bearing pilot bearing as I also thought that might be the problem. Keep the ideas coming. Dave

 

[blkblk63ss]

More thought's , hard petal or soft petal???? Does clutch disc slide on tran's shaft easily??? Does your bell housing have the dowel's all in place, and no slop on bell housing to engine????

 

[Don Jacks]

I suspect the clutch disc.I used to run into a problem with the lack of dampening material,commonly referred to as "marcel" as a possible cause oof your problem.Sometimes folks will say"I've got a high performance engine here,therefore I need a racing clutch on the street".Racing clutches operate under different enviornments than a street clutch,and ften times arent as comfortable[smooth] as a street oriented clutch.What kind of disc are you using?

 

[409 cu.425hp.]

Did You install a new pilot bearing?? Possibly its binding with the tranny head shaft.My free play on my 64 impala is about 3/4 to 1 inch.No throw out bearing spin at all.I also had heard that flywheels can develope hard spots in the surface,it was suggested to me that this could cause a problem like what you are describing as well.The problem with alot of the parts is like you mentioned is, that they are made in China and I really believe it is really inferrior metal to what was always produced in the USA. Hope we all have been of some help.Clutches can be a problem with light vibrations also. Good way of checking it is to start the car leave it in neutral and rev engine slightly ,hold the door open and feel the door for vibrations.If you do get vibration in the door,clutch could be out of balance,or possibly a weak spring.

John, Yes I have installed a new roller pilot bearing thinking that would be better, no difference. I check on your other suggestions, I think I'm OK with this but not sure. I'm really thinking about getting a Ram or Hays clutch instead of a NAPA or other parts house clutch. What do you think about trying that. Thanks again, Dave