never had a clutch do this before !
08-04-11, 03:51 AM
#1
rotory chicken
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never had a clutch do this before !
Ok to start It's a 87 tii over 300 rwhp had act lightwieght flywheel 6 puck disk not sure what pressureplate well 1st and second shift fine all the way through then 3rd to 5th slip after about 4k rpm unless I barely feather the gas I've never had one slip only in select gears like this much less at select rmp in select gears any ideas before I pull her apart ?
08-05-11, 01:35 AM
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rotory chicken
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Well car was bought from another menu if you search perfect lucky 7 you will find it along with a vid of it on the dyno clearly states rwhp but nothing about torque I am still trying to track down dyno sheets
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08-05-11, 02:42 AM
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"thats a space peanut"
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some one on this forum said this and i cant for the life of me remember who but i do remember the information that was said...
get where you have some road room to "test" and get it into third, then as your keeping a steady speed and a steady rpm use your left foot and press the brake and see if you can get your clutch to slip just by trying to use your brakes.... and i do believe that if you can controll your RPM using your left foot while everything else hasnt changed then its time for clutch maintenence....
Now im pretty sure thats the basics of it, if someone else could correct me if i am wrong but its a cheep test...
get where you have some road room to "test" and get it into third, then as your keeping a steady speed and a steady rpm use your left foot and press the brake and see if you can get your clutch to slip just by trying to use your brakes.... and i do believe that if you can controll your RPM using your left foot while everything else hasnt changed then its time for clutch maintenence....
Now im pretty sure thats the basics of it, if someone else could correct me if i am wrong but its a cheep test...
08-05-11, 06:29 AM
#12
talking head
either the clutch fork is riding
,, or the pressure plate straps have bent
,, or a combo of disc wear,, plate wear,, and flywheel stepped wear has opened up tolerances so there is not enough clamping pressure
if the clutch does not have a little bit of dead play at the fork,, and 1 inch drop at the peddle
then it is riding
if not,, you have to pull it down,, inspect disc, flywheel and pressure plate
if the disk is not down to the rivets,, and the pressure plate fixing straps look good
( the fingers will all pull nearly flat and even when tightened down if good )
then the issue is in the stepped wear on the pressure plate
- common enough on light steel flywheels
you need the friction surface machined flat and past the hot spots,, the the outer flange rim machined down to re-adjust the stepped difference
else it will slip when the clutch disk is only partly worn
FC turbo clutch has the inner friction surface as very slightly higher than the flange face
old school 8.5 inch clutch has the inner several mm lower than the outer flange face
83-85 and FC NA 9.0 clutch flywheel has a large difference between the mounting lug height,, and a much lower friction face
,, or the pressure plate straps have bent
,, or a combo of disc wear,, plate wear,, and flywheel stepped wear has opened up tolerances so there is not enough clamping pressure
if the clutch does not have a little bit of dead play at the fork,, and 1 inch drop at the peddle
then it is riding
if not,, you have to pull it down,, inspect disc, flywheel and pressure plate
if the disk is not down to the rivets,, and the pressure plate fixing straps look good
( the fingers will all pull nearly flat and even when tightened down if good )
then the issue is in the stepped wear on the pressure plate
- common enough on light steel flywheels
you need the friction surface machined flat and past the hot spots,, the the outer flange rim machined down to re-adjust the stepped difference
else it will slip when the clutch disk is only partly worn
FC turbo clutch has the inner friction surface as very slightly higher than the flange face
old school 8.5 inch clutch has the inner several mm lower than the outer flange face
83-85 and FC NA 9.0 clutch flywheel has a large difference between the mounting lug height,, and a much lower friction face
08-05-11, 10:42 AM
#14
I'm guessing straps = fingers? As in the inner portion of the p-plate that the throwout bearing presses against.
No luck finding your dyno video. Posting a link would be a better idea than giving some search terms.
You can calculate torque from HP if you know the corresponding RPM.
Torque = 5252 * HP / RPM
So if you made 339 whp, and we take a guess that it was at 6500 RPM, that's 273 wtq. But that also says nothing about mid-range peak torque, which could very well be over 300 wtq depending on the turbo and boost level.
No luck finding your dyno video. Posting a link would be a better idea than giving some search terms.
You can calculate torque from HP if you know the corresponding RPM.
Torque = 5252 * HP / RPM
So if you made 339 whp, and we take a guess that it was at 6500 RPM, that's 273 wtq. But that also says nothing about mid-range peak torque, which could very well be over 300 wtq depending on the turbo and boost level.
08-05-11, 11:38 AM
#15
talking head
strap is the 3 or 4 straps around the edge of the pressure plate that join the friction surface plate with the tension fingers cover
when you badly buzz the gearbox with a miss-selection on the overun
,, and also sometimes in a violent tug start ,, you can badly flex these straps
- even bending them
when done thus ,,and looking at the assembled clutch on the back of the engine
you can usually see the fingers on the plate no longer all lay flat
- a VERY bad sign-
- tension is lost,, and if the straps fail completely it will launch the heavy friction surface through the bell housing ,, hopefully not at your legs
when you badly buzz the gearbox with a miss-selection on the overun
,, and also sometimes in a violent tug start ,, you can badly flex these straps
- even bending them
when done thus ,,and looking at the assembled clutch on the back of the engine
you can usually see the fingers on the plate no longer all lay flat
- a VERY bad sign-
- tension is lost,, and if the straps fail completely it will launch the heavy friction surface through the bell housing ,, hopefully not at your legs
08-05-11, 11:55 AM
#16
talking head
here are a few pics,, note this is a 8.5 inch clutch
,, it is more open around the 3 straps than the 9.5 incher and so serves the demonstration a little better
this is all assembled onto the flywheel tight ,, note the fingers are not as even as they should be
and this is the reason,,, you may be able to note a slight z profile on what should be a straight strap
worse examples may split between the strap leaves ,, with visible air gap between the two leaves
if you see any of this with your pressure plate,, it needs to be rebuilt or thrown far away for a new one
,, it is more open around the 3 straps than the 9.5 incher and so serves the demonstration a little better
this is all assembled onto the flywheel tight ,, note the fingers are not as even as they should be
and this is the reason,,, you may be able to note a slight z profile on what should be a straight strap
worse examples may split between the strap leaves ,, with visible air gap between the two leaves
if you see any of this with your pressure plate,, it needs to be rebuilt or thrown far away for a new one
08-06-11, 10:25 AM
#17
rotory chicken
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https://www.rx7club.com/showthread.p...=perfect+lucky the vid link is at the top sorry for not posting sooner
08-06-11, 10:29 AM
#18
rotory chicken
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ok so i orderd a 420lb p plate and the ss blade from act found a good deal on the kit too oh and i am now slipping in all gears i can put it in gear and hold the brake to the floor and my rpms will still go up so yeah deffinitly time
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