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Z-Pak Clearance help

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Old Jan 4, 2019 | 10:48 AM
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Default Z-Pak Clearance help

I’m installing a Z-pak in a 99 4L60E. With all the Z-pak plates installed, my clearance is .023. If I remove the shim plate below the pressure plate it is .070. I plan to drive moderately. No dragging. Just an occasional burnout. I have been reading around the forum but still can’t decide on whether to go tight or loose. What’ are your thoughts on clearances? I don’t want the thread to spin off on brands or quality or anything else. Just clearances please.

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Deuce

Last edited by DeuceW; Jan 4, 2019 at 03:48 PM.
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Old Jan 4, 2019 | 10:59 AM
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My thoughts are don't use the Z-Pak. In my opinion Borg Warner high-energy clutches are way better.

Last edited by bbond105; Jan 4, 2019 at 04:07 PM.
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Old Jan 4, 2019 | 01:45 PM
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Bbond
aside from brands what do you think about clearances?
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Old Jan 4, 2019 | 04:16 PM
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I think.023 is a little tight. I would set it at not less than .040. What do the instructions call for? Not many people on here would use the Z-Pak clutches even if they were given to them. There is more to it than a brand name, it's the design of the clutches. They are too thin and don't hold very much oil in them for cooling.
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Old Jan 4, 2019 | 07:39 PM
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Thanks bbond
The specifications call for .050 - .070. I can remove the shim plate and the clearance is .070. I just didn’t know if I wanted to start out on the far end of the specifications. I’m not sure if that would lead to premature slipping.
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Old Jan 5, 2019 | 12:44 AM
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If you are using the Corvette servo, then .023" is ok. How much horsepower? What hole size in the separator plate for the 2-3 shift? Any Shift kit installed?
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Old Jan 7, 2019 | 06:58 AM
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I also strongly reccommend the Borg Warner High Energy clutches. Set up at .0035-.0045 per clutch

I would leave the z pak tight at .023 rather than open it up past .050
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Old Jan 7, 2019 | 09:25 AM
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You have a shim UNDER the pressure plate? as in the bottom plate? I hope not, that is supposed tp go under the top plate with the groove. You can selective thickness apply plates to set your clearance.

I dont like the z pack either. Theres not enough steel to dissipate the heat. However, the clutch material is excellent. The new GPZ raybestos has the same clutch material and is the best clutch plate you can buy. The high energy clutches are good, but they are not as good as the GPZ. I have gps in my turbo car. Probably 650-700hp at the flywheel. I Do not even have a smart drum, just a reinforced stock drum, Kolene steels and 8 clutches. Never skips a beat and ive been hammering on it for about 2 years now.

Last edited by Kfxguy; Jan 7, 2019 at 09:51 AM.
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Old Jan 7, 2019 | 01:35 PM
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KfxGuy
i have the shim in the right place. What are your thoughts on the clearance? .023 with the shim.... .070 without the shim. Or buy a thinner shim and split the difference?
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Old Jan 7, 2019 | 01:49 PM
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Originally Posted by DeuceW
KfxGuy
i have the shim in the right place. What are your thoughts on the clearance? .023 with the shim.... .070 without the shim. Or buy a thinner shim and split the difference?
man .023 is kinda tight. My suggestion is to air Check it a couple times to make sure it’s all seated. Then Check again. I like no less than .030-.035 on mine. When the clutches seat in, they will loosen, which you already know. I wouldn’t set it at .070. That’s way too loose. If you air Check it, and it doesn’t loosen past .030 measure your bottom plate. Then get one from the dealer or your local shop or parts supply. If you can’t find it, let me know. I have a supply place in town that stocks almost everything is ever need.
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Old Jan 10, 2019 | 10:18 AM
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We usually set dry about .020 this after application opens up a bit to around .025 to .030 as for the zpack While we do not presently use it we have in the past with good results , The trick to it is quick apply application so I suggest using .100 inch feed hole and corvette or sonnax 2nd apply servo. It cannot release heat quickly so minimal apply slippage very important .
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