Dual Mass Installation / Clutch Advice Needed
 

Hello - looking for some advice on clutch and flywheel replacement on my 90 Z. My current pilot bearing began making noise last week and has gotten worse, so I'm now forced to take everything apart. Car currently has a Carolina Clutch single mass flywheel/pressure plate combo. I have parts for converting back to a dual mass setup (flywheel and oem lt5 pressure plate). Going off of Marc's article for clutch replacement with a dual mass, I've purchased the centerforce clutch disc (with shims) he recommends as well as the Acdelco roller pilot bearing.

So questions I'm trying to get answered before taking everything apart:

1. Is there a recommended throwout bearing for an oem setup? I've found this - does anyone have experience using?2. Does anyone know the exact specs for pressure plate bolts for the LT5 OEM Valeo pressure plate? Are they 3/8-16 x 2.125"? I'm not sure what the current carolina pp uses.
3. Current parts list: dm flywheel, oem pp, clutch disc, shims for centerforce disc, pilot bearing, slave cylinder, new fluid, TO bearing (above), pp bolts (above). Am I missing anything?
4. Plan on installing the rear diff drain plug (& fluid swap) while exhaust is off as well as replacing the clutch slave cylinder. Any other things to check/change while everything is apart?
5. Any other tips/tricks I should keep in mind or know for making this swap?

Thanks in advance!

Re: Dual Mass Installation / Clutch Advice Needed
 

Best thing to do is contact zfdoc . He is awesome at figuring clutch problems out 602 319 6575

Re: Dual Mass Installation / Clutch Advice Needed
 

Short answer, NO, they are not just a 3/8-16 x 2.125" bolt, regardless of the grade. They are a special bolt, designed for a specific purpose. The bolt is not designed just for axial clamping force, but also to resist shear force against the pressure plate when the clutch is engaged.

The following photos show how the OE Pressure Plate bolts engage the flywheel to provide maximum shear resistance and whereas a typical bolt does not.

Photo 01
https://cdn10.bigcommerce.com/s-nkg9...0.1280.jpg?c=2
Note the full diameter shank extends below the pressure plate and ultimately into a close tolerance counterbore in the flywheel.

Photo 02
https://cdn10.bigcommerce.com/s-nkg9...0.1280.jpg?c=2
The counterbore in the flywheel is abt 0.150" deep, which receives the 0.375" diameter x 0.088" bolt shank. The purpose is to provide maximum shear resistance, which a standard bolt will not do.

Photo 03
https://cdn10.bigcommerce.com/s-nkg9...0.1280.jpg?c=2
Correct Pressure Plate bolt installed in the flywheel to demonstrate correct fitment.

Photo 04
https://cdn10.bigcommerce.com/s-nkg9...0.1280.jpg?c=2
Demonstrates how a standard bolt cannot provide equal shear resistance, due to two, primary reasons.
(1) the root of a typical 60 deg, V thread is 22% less in diameter and 38.5% less cross sectional area than the 0.375" OE bolt
(2) A typical bolt thread will have a sharp bottom at the thread root, i.e. a stress riser, the origin point of breaks.

Photo 05
https://cdn10.bigcommerce.com/s-nkg9...s/photo-07.jpg
Comparison of the OE Pressure Plate Bolt to a standard bolt. The grade of the bolt, 3, 5, or 8, all have the same thread form. The critical dimensions are the shank diameter & length, both lacking in the standard bolt. Cutting the bolt off to the proper length, still leaves exposed threads above the surface of the flywheel.

Re: Dual Mass Installation / Clutch Advice Needed
 

Re: Dual Mass Installation / Clutch Advice Needed
 

Quote----I've found this - does anyone have experience using?

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https://www.summitracing.com/parts/ctf-n1400/all

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2.
Thanks in advance![/QUOTE]




Just put that TB from Summit in my Z. Good product, it will make a noise just spinning it by hand and the center will look not centric. This is normal and it functions perfect. I use Power torque brand from Oreily's (Master and Slave unit) with good results. Good construction.