Old school 4 speed Trans to LS question
#1
Old school 4 speed Trans to LS question
As some of you might know I'm building an LS swap 81 camaro with a super t10 4 speed.....now I got the Sachs truck flywheel and an 11" clutch kit, but I'm using a mechanical clutch linkage, my question is for guys who have done this, but did you use the short (~1.25") or long (~1.7xx") throwout bearing? It seems as though I have to adjust the linkage all the way out to even get near the clutch pressure plate fingers...
Also worth adding I had to reclock the zbar ear to accommodate the exhaust manifolds I'm using...I'm know this is part of the issue but would like some input...and yes I should of done the hydrualic clutch I know! Dollar for dollar and time for time I should of ponied up the few xtra dollars for hydro unit, but I've never owned an old school 4 speed car and wanted to retai. The mech linkage for nostalgia...
Also worth adding I had to reclock the zbar ear to accommodate the exhaust manifolds I'm using...I'm know this is part of the issue but would like some input...and yes I should of done the hydrualic clutch I know! Dollar for dollar and time for time I should of ponied up the few xtra dollars for hydro unit, but I've never owned an old school 4 speed car and wanted to retai. The mech linkage for nostalgia...
#2
TECH Junkie
iTrader: (1)
I used the 1.25" for the Sachs flywheel/11" BBC clutch and used an adjustable pivot. I used the 1 3/4" with the LS1 flywheel/clutch.
Check out the Novak link in the 1st post for correct clutch fork geometry and throwout bearing length.
https://ls1tech.com/forums/conversio...-ls-motor.html
Check out the Novak link in the 1st post for correct clutch fork geometry and throwout bearing length.
https://ls1tech.com/forums/conversio...-ls-motor.html
#3
The pressure plate finger design typically calls for which bearing to use. Does your pressure plate have raised fingers or flat? I also concur that an adjustable pivot is essential to get get proper geometry.
I just looked at the link above. BE CAUTIOUS with what pilot bearing you install. I used the normal pilot bearing with my set-up. I have a TKO 600 and a Quicktime LS Bellhousing. That LS7 bearing would not have worked for me!
I suggest you mock it up first.
BTW FWIW...$600 for a hydraulic clutch set-up for the 70-81 Camaro...I doubt you have wasted that much on the mechanical linkage.
I just looked at the link above. BE CAUTIOUS with what pilot bearing you install. I used the normal pilot bearing with my set-up. I have a TKO 600 and a Quicktime LS Bellhousing. That LS7 bearing would not have worked for me!
I suggest you mock it up first.
BTW FWIW...$600 for a hydraulic clutch set-up for the 70-81 Camaro...I doubt you have wasted that much on the mechanical linkage.
Last edited by badazz81z28; 12-27-2012 at 03:41 PM.
#4
TECH Senior Member
iTrader: (12)
Yes the adjustable Pivot Ball is a good idea.. as with the different fly wheels, crank flange, bell housing.. the Pivot Ball might need to be adjusted for the different leghten that might be needed to the parts being used.
Found this on another site.. but this being a Gen III or IV block. .all might be different.
There are a lot of variables. 4.750 is the proper theoretic measurement from the face of the stud to the bellhousing flange (contact surface with the back of the block). If you are using a block plate between the bellhousing and block you have to figure this into the depth of the bellhousing (add .132" and adjust the stud accordingly outward towards the block .132"). Flywheel thickness will also effect your geometry. A thinner flywheel moves the pressure plate away from the ideal contact point, as it moves forward the bearing and arm move forward, causing the outboard end of the fork to move rearward and cause increased pedal travel and effort. So the 4.750 measures to the back of the block because it is a constant measurement that never changes. It assumes you have a stock thickness flywheel. If the flywheel is thicker or thinner than stock you must also disl in the correct amount on the stud for this dimension. GM considers .960" as the "standard" flywheel thickness. So if your flywheel is .860 thick you need to move the stud forward another .100". Hopefully you are using a factory bellhousing, because I don't know about McLeods, but Lakewood are almost impossible to get the geometry correct even with the adjustable stud.
GM has two stud lengths, 1.78 for the long throw out bearing and 1.48 for the short bearing which is what you should have. The Lakewood adjustable stud only provides up to 1.58 length. Barely enough to correct for the block plate and a resurfaced flywheel. The last Lakewood I worked with had .120 deeper than the stock bellhousing to begin with, so proper geometry could never be achieved. If you get it correct with the clutch pedal pressed to the floor, the lower arm of your z bar that goes to the clutch will be pointing straight down. You never want it to go further rearward than that or you start stressing things with it going overcenter. It is okay for it to be slightly short of straight down towards the front of the car.
BC
Last edited by bczee; 12-27-2012 at 05:14 PM.