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my new clutch slips! 1 Attachment(s)
beautiful day here yesterday so i thought i could finally put some real miles on my 34 jalopy. its been around the neighborhood a few times, but the first time out on the pavement with insurance. i put about 50 miles on, around the big block i call it, for the most part all good. temp stayed at 180, subaru thermostats, oil pressure a little lower than i expected, but still 30, hot, cruising. columbia works fine, trans is smooth shifting, motor runs perfect, but the fire breathin monster has enough power to break the clutch loose in overdrive/high. a 59ab with merc innards, new fort wayne 9"clutch and pp, early flywheel with the blob cut off, balanced and surfaced. all smooth but if i floor it at highway speed i can get it to break loose. this project has been going on for two years, so at this point i will hope its just some surface rust that will fix itself, time will tell. old photo, she's a little more dressed up now!
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Re: my new clutch slips! "old photo, she's a little more dressed up now"
https://www.fordbarn.com/forum/attac...6&d=1587697124 |
Re: my new clutch slips! thanks pete, can you erase some of the junk in the back ground?
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Re: my new clutch slips! Quote:
No, but I'm sure 51 MERC-CT should be able to do it for you.... |
Re: my new clutch slips! If its new just check your adjustment again , dont panic yet it might just take a few miles to settle down. Its happened a few times to me .
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Re: my new clutch slips! When you say Merc innards ,do you mean a 4in crank,If so the 9in will be no good, the engine will make too much torque for it.I know from experience.
Lawrie |
Re: my new clutch slips! 9" usually have 6 springs in them...but if i remember right you can put in 3 more.
Or just stick in heavier springs. You have 2 options if all is working as it should and it slips...heavier springs or a softer clutchplate with higher friction. |
Re: my new clutch slips! I've been thinking about this overnite and it seems to me that an extra 16 ci is not going to able to make even a 9" clutch slip under all but the most extreme circumstances. Are you sure everything is releasing properly? I'd check everything out to make sure there is no binding or hanging up before I did anything else. (Unless, of course, you have upgraded the powerplant shown a significant amount.)
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Re: my new clutch slips! "I've been thinking about this overnite and it seems to me that an extra 16 ci is not going to able to make even a 9" clutch slip under all but the most extreme circumstances. Are you sure everything is releasing properly? I'd check everything out to make sure there is no binding or hanging up before I did anything else. (Unless, of course, you have upgraded the powerplant shown a significant amount.)"
Tubman, just had an almost exact case here. Period correct rod with hot flathead. Rebuilt 9" pressure plate from on-line (not Ft Wayne.) 2 PP levers severely binding ... one not releasing at all. You'd think a lot of chatter, but not really. Slipped under power in 3rd. Fix: Polish and lube levers. Problem gone. Can only guess that PP was rebuilt and sat on the shelve at the rebuilders. It did not sit here. |
Re: my new clutch slips! merc crank, and merc cam, bored 80 over. no other mods than that. adjustment was done before the body drop using a straight edge off the number pad on the tranny which got me close but too much free play, about 2" so that is not the problem. my flywheel grinder guy always sprays with wd40 when done to stop flash rust, i cleaned that off, and the surface of the pp with starter fluid, my favorite cheap cleaner. i would think a 9" would hold my mild motor, but its hard to argue with lawrie if he's been there done that. i had the pp levers start to seize at the pivot point one time, but you could feel that on the stroke (different project). so, thanks for all the ideas, i will run it for a while and see what happens. guess i cant sign up for the truck pull at the fair just yet!
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Re: my new clutch slips! Couple years ago at the NHRA nationals in Brainerd MN I watched John Force burn his new clutch several times .
I was curious and asked a crewman what he was doing and got this response . They rebuild the computer controlled slipper clutch every round and he was " seating the discs " . Did your new disc have a rough surface ? |
Re: my new clutch slips! I thought Ford began using a 10" c&pp with the beginning of 59 series engines, but a new 9" c&pp should not be slipping as op is experiencing. Ft. Wayne can do heavier/higher force spings, if/ when requested.
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Re: my new clutch slips! 1 Attachment(s)
Dealt with Fort-Wayne one time for a members build here.
First and last time for me, they had to take the pressure-plate back, visibly defective! Thanks, Gary in N.Y. P.S. Am still keeping my posts a bit short due to some recent health issues! |
Re: my new clutch slips! david j, gosh, that was two years ago, i cant remember yesterday! now, what was i saying? oh, jm, yes i believe the 10" came on the 59 series, i went this route as its the lightest "ford" clutch you can build. i cut the blob off myself, so it was cheap too. gary go fast...wow! hard to believe ft wayne let that out the door. they usually have a pretty decent reputation from what i know. thanks all
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Re: my new clutch slips! WOW! That's surprising (and disappointing). From reading your post, they did take it back, which is encouraging.
I hope this is a one-time occurrence, I'd hate to see another usually good vendor start having problems. I hope you feel better soon. When you do, I would like to see more information on that cap girdle; initially, does the pan need to be extensively modified? |
Re: my new clutch slips! Suggestion... go back and read rumbleseats notes.... 9-in should work fine, and Ft Wayne seems to have the reputation to build whatever is necessary. There was a reason that Paul (rumbleseat) chose the 9-in, and as I recall, he had a pretty strong motor. JMO
(my personal experience with the 9-in has been very favorable, as well.) |
Re: my new clutch slips! Quote:
(Add) For any clutch/pressure plate work we use Falcon clutch over here in Deer Park! Thanks, Gary in N.Y. P.S. Am still keeping my posts a bit short due to some recent health issues! |
Re: my new clutch slips! A Rumble Seat post:
INCREASING CLUTCH ENGAGEMENT PRESSURE: Changing the springs in the clutch cover to stronger springs will result in increased engagement tension with a resultant decrease in slippage. Although installing a larger clutch will produce the same result along with the added benefit of more friction material, the larger clutch will also increase the mass of the flywheel/clutch assembly considerably (didn’t you just go to a lot of trouble and expense to reduce your flywheel weight?). This is the same as adding weight to the flywheel which will decrease acceleration. Clutch rebuilders stock different strength springs and will replace stock springs with stouter ones during rebuild.... just ask. However, this can be done at home with the help of friends, a long pry bar, and using basic hotrodder ingenuity. It’s a fairly simple process, but BE CAREFUL.... those springs do fly around at about Mach 7 or so..... and have been known to take out windows while in flight! Or you could just take it to a rebuilder and have him change springs for some minor compensation. Well worth the expense, and you won’t have to organize a search party to locate the springs and nuts that flew (including out the window and into the vacant lot next door). Don’t forget the engagement effort (pushing down the clutch pedal) increases dramatically and stock linkage (as well as your clutch leg) may need beefing up (I beefed up my linkage after it bent... I never learn easily!). Don’t forget to check the height of the three fingers anytime you’ve been messing with the springs etc. |
Re: my new clutch slips! With respect to the pressure plate I would probably opt for a "diaphragm" type plate with a "centrifugal-assist".
The "diaphragm" design takes care of excess pedal pressure and the "centrifugal" grabs much tighter the faster it's spun up! Thanks, Gary in N.Y. P.S. Am still keeping my posts short due to some recent health issues! |
Re: my new clutch slips! Quote:
On a 39 style transmission - due to the width of the flat surface of a standard 32-48 style throw-out bearing - there can be issues with trying to use a diaphragm clutch (the throw-out bearing surface contacts the clutch teeth in an incorrect manner when the clutch is depressed). Who here knows of a good GM style 10.5" clutch manufacturer that is KNOWN to correctly work with our big, fat and flat throw-out bearings??? |
Re: my new clutch slips! "Hoop", I do remember that when I measured the height of the fingers from the surface of the flywheel on the new clutch in my car, it varied by as much as .060" (that may not sound like much, but it's damn near 1/16"). I spent a bunch of time shimming the fingers so they all came out within .007 of each other. Granted, that was on my '51, but it's about the same as the earlier cars, except for the size of the hub on the pressure plate.
I gotta believe it's something like that. |
Re: my new clutch slips! I tried a 9" from Ft Wayne and it slipped as soon as I went into 2nd gear. It was on a 59A with merc crank. Had to go to a 10" and works great. Need to check clearance of
flywheel bolts to the springs on the clutch disc. I have taken the clutch apart after barely worn and they were hitting the bolt heads. Went to ARP Bolts with a lower head. |
Re: my new clutch slips! well thats interesting. if i have to change anything i will go to a 10" as my tired old knees would not like stiffer springs on the 9"
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Re: my new clutch slips! Who here knows of a good GM style 10.5" clutch manufacturer that is KNOWN to correctly work with our big, fat and flat throw-out bearings???[/QUOTE]
This is the $64 question. I'm patiently waiting and hoping to see a response. John |
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Re: my new clutch slips! good info Jerry, thanks for that
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Re: my new clutch slips! Never looked into it but a slightly longer throwout arm would make a big difference on pedal pressure .
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Re: my new clutch slips! cas3, how did the pressure plate saga turn out?? If you went to a 10" pressure plate, you would have an extra 3 springs that are stiffer tham that of the 9" design. Probable not good on your knee. But, 6 springs from a 10" pp swapped into your 9" wouldn't be as much force to activate, but stronger that what the 9" already has?
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Re: my new clutch slips! Deuce, I've not done anything about it. Only slips at low RPM if you floor it, quite usable as is. I intend to someday pull it apart, check spring tension and replace with something slightly stiffer. I'm guessing one phone call to "the clutch doctor" in minnesota would tell me what spring to use, and I hope to redo it myself. Never had a PP apart before, but its just parts and bolts aint It?
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Re: my new clutch slips! Load it up in a bearing press, compress the springs with a 1" square steel bar across the top. Remove the 3 bolts, and release the pressure, wah-lay. It's safely apart. Remember to stamp the orintation of how it came apart, and it needs to go back together the same way.
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Re: my new clutch slips! cas3,
I'm running a 9 inch clutch with a warmed up 8ba without any problems or slippage. Is it possible you have some contaminants on the surfaces? |
Re: my new clutch slips! Possible, but not likely. Everything was new and clean. You're not the first I heard of with no problems, but others say it may not work. Even the old Rumbleseat data he says to use bigger springs. It could be the lightened flywheel wants to rev up so quick. Just cutting the big blob off the 9" Ford flywheel makes a big difference...I like it.
We'll know when I someday take it apart and measure the springs. |
Re: my new clutch slips! I'm always careful not to over grease my throw-out bearing. I also lightened and balanced my flywheel, so I don't think that's your problem.
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Re: my new clutch slips! well im assuming that you cut the flywheel and pressure plate if you didnt replace it and you didnt over lube the input shaft [ive seen it done and they tried to claim warranty] so being under clutched is most likely cause unfortunately only one way to fix thats remove and replace or rebuild to bigger spec [heavier springs] this is actualy a common problem in transport where generic 15x2 clutches are common and one size dosent fit all
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Re: my new clutch slips! I have a merc 276 in my 35 with the original merc flywheel and 10 in disc, couldn't be better.
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Re: my new clutch slips! aussie,
Did you mean balance the flywheel and pressure plate? |
Re: my new clutch slips! no cutting is deglazing/ balancing is totally different a new clutch plate wont grip into a polished surface [worn] its even as simple as a quick rub by hand with some 80 grit emery tape just get rid of that shine on the surface and then chamfer the square edge off the disc inner and outer edges [ yeh rough but works for all you purist's]
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