SBC Clutch too thick?

[lil corb]

So I have been having clutch drag issue with my SBC TZ-B clutch kit and Act Flywheel. So I finally got around to removing it as SBC said to send them the kit to see the issue.

I snapped some pics after removing the trans.

Based on what I have researched so far, it seems the thickness of the SBC is more than a regular standard aftermarket disk. From what I gather .315-320 seems to be the preferred disk thickness to pair with an oem spec .610 flywheel surface.

Here are some pics of the disk thickness in various spots and a pic of the pressure plate with it looks like heat marks?? (clutch drag anyone?) Mind you this set up was only installed for 1500 miles before I realized I didn't want to take the risk of damaging my synchros on my 2000 mile shep stage 3 trans.

I am going to send the clutch kit and flywheel and see about them either fixing the issue (probably with increase step height of flywheel) or getting a refund. I don't see anyway there could of been any install error based on the pics (maybe a wisemen can tell me otherwise)

Could someone tell me if the TOB looks ok to be re used (again 1500 miles) but I don't want risk any issue if the TOB might of been damaged based on dragging clutch.

This isn't a bash on SBC at all and before anyone asked I have exhausted all options other than shimming pivot or extended slave which I don't want to do. New pedal welded assembly, master and slave cylinder and bled routinely. Clutch is smooth after a few minutes of driving then gets notchy after car warms up and because a real issue to get into first or second. Clutch also disengages about 1 inch off the floor. Master cylinder was adjusted various ways and finally set on no threads left (extended all the way while still being able to push slave in)

Now, I did not check the act flywheel step prior to use but based on the measurements of the clutch and research I have done on here and other sites it seems to be a common problem with SBC clutches.

I have heard great things about SBC, especially from Tim Zimmer who has been nothing but helpful through this ordeal, about it holding good power while maintaining a decent pedal stiffness, and that's probably because of the thickness and material of the clutch but a disclaimer of "Warning SBC Disk are thick please step flywheel to xxx amount" Would of been great rather then me and other people having to pull out trans again after install smh

I am contemplating have them re step flywheel so I won't have problems or getting refund and going ACT 2600 and re surfacing flywheel. I finally want a clutch that I can drive without worrying about anything and will be able to hold 500whp in the future.

We shall see what Jon at SBC says first.


Based on the pictures any info on the situation?

Thanks everyone

*Update*

 

[Ghost_92TSi]

I always heard you needed to step the flywheel on these, I read somewhere about the xx amount, I'll search and post, Said to do that or use a slightly worn down flywheel for clearance.

Here read through this:

http://www.dsmtuners.com/forums/drivetrain-tech/418989-clutch-engagement-issues-southbend.html

 

[BoostedBeaver]

I have been running the TZ-FE disk with an ACT 2900 pressure plate and streetlight flywheel.

I will check the step height (maybe I wrote it down.)

I have adjusted the clutch according to Jacks video with no engagement issues. I also put the car on jackstands, pushed in the clutch, put the car in 1st gear and reved to 7200RPM with no wheel movement.

I never thought to measure the disk when I installed the clutch 3 years ago, so we can't compare.

Hopefully some more info will come out and keep us posted on the findings.

Robert

 

[T is for TURBO]

Where was your clutch for sitting in the "window"? If your flywheel has been machined more than once, the geometry is going to be off by putting the whole clutch assembly closer to the engine block (further away from the clutch for and TOB) and you will either need to shim the pivot ball to get the fork and TOB to sit closer to the clutch assembly, or shim the flywheel to get the clutch assembly to sit closer to the fork and TOB. If you don't the, the clutch will likely not fully disengage. I'm running the southbend clutch and Kevlar disk. It does not drag, and feels great. My flywheel was machined at least twice resulting in me having to shim the pivot ball

 

[lil corb]

I have heard that its possibly just a clutch disk issue and regardless of the step height there is an issue based on my symptoms. being that the disk is wearing uneven in addition to clutch thickness it's causing a dragging issue. I will def keep everyone updated as I'm sending the kit tmw to sbc.

Robert, is yours or has ever disengaged close to bottom and not top or middle?

Where was your clutch for sitting in the "window"? If your flywheel has been machined more than once, the geometry is going to be off by putting the whole clutch assembly closer to the engine block (further away from the clutch for and TOB) and you will either need to shim the pivot ball to get the fork and TOB to sit closer to the clutch assembly, or shim the flywheel to get the clutch assembly to sit closer to the fork and TOB. If you don't the, the clutch will likely not fully disengage. I'm running the southbend clutch and Kevlar disk. It does not drag, and feels great. My flywheel was machined at least twice resulting in me having to shim the pivot ball

The fork sat dead center in the window and the flywheel was never machined before. It was bought brand new from act. It sounds like because you did shim flywheel prior that you possibly avoided this issue. I am thinking how would it be if you never shimmed it to begin with. Was or is yours disengage close to ground?
Does anyone know if these measurements are too thick for spec?

Thanks

 

[T is for TURBO]

I have heard that its possibly just a clutch disk issue and regardless of the step height there is an issue based on my symptoms. being that the disk is wearing uneven in addition to clutch thickness it's causing a dragging issue. I will def keep everyone updated as I'm sending the kit tmw to sbc.

Robert, is yours or has ever disengaged close to bottom and not top or middle?



The fork sat dead center in the window and the flywheel was never machined before. It was bought brand new from act. It sounds like because you did shim flywheel prior that you possibly avoided this issue. I am thinking how would it be if you never shimmed it to begin with. Was or is yours disengage close to ground?
Does anyone know if these measurements are too thick for spec?

Thanks

The disk is thicker, but the pressure plate is designed to work with the thicker disk. I too had clutch issues and I asked Tim about about the thickness issue.

His response:

"The pressure plate is designed to work with the slightly thicker kevlar disk..."


Did you verify step height before installing the flywheel? Just because it is brand new does not mean the step height is correct. Also, I did install it with out a shim. The fork sat dead nuts in the middle, but I still didn't get full disengagement do to so much material being removed from the flywheel. I then had to pull the trans off again to shim the pivot ball.

 

[lil corb]

The disk is thicker, but the pressure plate is designed to work with the thicker disk. I too had clutch issues and I asked Tim about about the thickness issue.

His response:

"The pressure plate is designed to work with the slightly thicker kevlar disk..."


Did you verify step height before installing the flywheel? Just because it is brand new does not mean the step height is correct. Also, I did install it with out a shim. The fork sat dead nuts in the middle, but I still didn't get full disengagement do to so much material being removed from the flywheel. I then had to pull the trans off again to shim the pivot ball.

I didn't verify the flywheel step, I will take the hit on that one. But if the flywheel step being that bad to cause it disengage off the floor and drag then I would be happy if it's just that and not a bad disk. I don't know how bad a brand new act flywheel could be out of spec but I guess it's a possiblity.

Does your still engage off the floor to this day?

Thanks again for you help

 

[T is for TURBO]

I didn't verify the flywheel step, I will take the hit on that one. But if the flywheel step being that bad to cause it disengage off the floor and drag then I would be happy if it's just that and not a bad disk. I don't know how bad a brand new act flywheel could be out of spec but I guess it's a possiblity.

Does your still engage off the floor to this day?

Thanks again for you help

Step height does not need to be off by much to cause problems.

It still engages pretty low off the floor (starts to grab about 1" to 1-1/2" off the floor, and probably fully engaged by maybe 2ish inches? However, it does not drag, and it shifts butter smooth all the way up to my rev limit of 7500. I absolutely love this combo. Launches are but smooth but it has a ton of bite, and still drives like stock.

I expect the engagement point to rise once I get a few miles on her. It only has maybe 500 miles on it.

 

[lil corb]

Step height does not need to be off by much to cause problems.

It still engages pretty low off the floor (starts to grab about 1" to 1-1/2" off the floor, and probably fully engaged by maybe 2ish inches? However, it does not drag, and it shifts butter smooth all the way up to my rev limit of 7500. I absolutely love this combo. Launches are but smooth but it has a ton of bite, and still drives like stock.

I expect the engagement point to rise once I get a few miles on her. It only has maybe 500 miles on it.

I am hoping it could be just that. It does shift like butter while car is warming up and at the beginning of the operating temp but then gets notchy especially 1st and 2nd after a while of driving.

We shall see and I'll keep everyone updated. The marks on pressure plate look normal to you? and also what about TOB?

 

[DROPthatCLUTCH]

Sbc ssx pp, tz series disc, fidanza lightweight flywheel here, engages less than 1" off the floor with no drag issues. Shimmed pivot.

 

[T is for TURBO]

I am hoping it could be just that. It does shift like butter while car is warming up and at the beginning of the operating temp but then gets notchy especially 1st and 2nd after a while of driving.

We shall see and I'll keep everyone updated. The marks on pressure plate look normal to you? and also what about TOB?

That sounds like your master cylinder is over extended. Did you follow this method?

Proper Clutch Adjustment

 

[lil corb]

That sounds like your master cylinder is over extended. Did you follow this method?

Proper Clutch Adjustment

I have tried that method but it was the only way to get it to even enter a gear. Lowering the pedal height would make it notchier to go into gear even when the car not at operating temp. Where I am at I can push the fork back in to the slave but I was still getting clutch drag.

 

[twicks69]

The disk looks great, but it definitely looks like a pressure plate that was not disengsging enough and warped. You had those cover bolts torqued to 22-24ft/lbs correct?

 

[lil corb]

The disk looks great, but it definitely looks like a pressure plate that was not disengsging enough and warped. You had those cover bolts torqued to 22-24ft/lbs correct?

Hey Tim,

Yes sir, Double checked the torque wrench it was set at 22lbs and bolted on in a criss cross pattern then torqued to spec in a criss cross pattern. When unbolting the the pressure plate bolts, the bolts were not either overtightened or too loose while putting effort to remove them.

Any ideas on why it could of warped? is the pressure plate salvagable?

 

[twicks69]

Hey Tim,

Yes sir, Double checked the torque wrench it was set at 22lbs and bolted on in a criss cross pattern then torqued to spec in a criss cross pattern. When unbolting the the pressure plate bolts, the bolts were not either overtightened or too loose while putting effort to remove them.

Any ideas on why it could of warped? is the pressure plate salvagable?

Could have been over-disengaging it causing the damage to the pressure plate, or it was potentially defective.

I have been touch with Greg @ SBC regarding your clutch so far as well and they are going to figure something out for yours which may be a step height variation as well as we will look at the design and placement of the diaphragm pivot spring to see if we can open up the engagement window a bit so it is not a floor-presser, but the drawback is going to be a stiffer pedal feel because we are modifying the fulcrum placement. As well we discussed modifying disk thicknesses and marcel design to hopefully make it an even better clutch disk that will work for our community.

 

[BoostedBeaver]

Robert, is yours or has ever disengaged close to bottom and not top or middle?
Thanks

I replaced the pivot ball and clutch fork and never had any issues. It engauges about halfway through my pedal travel and it always has.

Robert

 

[bastarddsm]

Could have been over-disengaging it causing the damage to the pressure plate, or it was potentially defective.

I have been touch with Greg @ SBC regarding your clutch so far as well and they are going to figure something out for yours which may be a step height variation as well as we will look at the design and placement of the diaphragm pivot spring to see if we can open up the engagement window a bit so it is not a floor-presser, but the drawback is going to be a stiffer pedal feel because we are modifying the fulcrum placement. As well we discussed modifying disk thicknesses and marcel design to hopefully make it an even better clutch disk that will work for our community.

No Marcel at all, that's what causes all the disenagment issues.

 

[lil corb]

Could have been over-disengaging it causing the damage to the pressure plate, or it was potentially defective.

I have been touch with Greg @ SBC regarding your clutch so far as well and they are going to figure something out for yours which may be a step height variation as well as we will look at the design and placement of the diaphragm pivot spring to see if we can open up the engagement window a bit so it is not a floor-presser, but the drawback is going to be a stiffer pedal feel because we are modifying the fulcrum placement. As well we discussed modifying disk thicknesses and marcel design to hopefully make it an even better clutch disk that will work for our community.

Excellent! Thanks Tim, I am very interested in seeing what you, Jon and Greg can come up with. I'll be sending the kit and flywheel tomorrow morning. I don't mind the stiffer pedal as long as everything works correctly and no damage can occur. Yea, hopefully some more R&D can be made to have less issues for us dsm'ers.

Appreciate all your help and I will keep everyone updated.

 

[donniekak]

No Marcel at all, that's what causes all the disenagment issues.

I agree. People want 600hp dsm's to drive around like a 2013 stock family car. I've never put any disk in my Dsm with marcel springs, I don't even really like them to have a sprung hub. The lighter, and thinner the disk, the faster it shifts.

 

[lil corb]

Update:

So I spoke to SBC about the Clutch issue. They apparently did in fact found that the disk was not fully disengaging. They advised me that Jon milled the pressure plate slightly for an even, lighter surface, changed the fulcrom point of the pressure plate to give it more movement for disengagement. Thinned out the marcel springs to make them flater thus making the disk thinner (Interesting enough when I removed disk I could hear like a metal ping sound everytime I flipped the disk upside dow) They verified the step height on the flyhweel and told me it was perfectly stepped and no unusual wear at all. They advised me the pedal should now disengage a lot higher and I should have no issues of clutch drag ( I hoping or else I will )

I received everything and bolted everything back up using proper torque #s (even bought a brand new torque wrench) red locktite on new flywheel bolts 100lbs and torqued pressure plate bolts 22lbs, greased up all the essential parts, verified TOB, fork and pivot ball were in great shape. Did not let the input shaft hang from the clutch pack using a jack underneath. Torqued trans bolts and mount bolts to proper #s. I use brake cleaner on the pressure plate and the flywheel side and used latex gloves during the install.

I was not able to snap any pics of everything upon return but the disk is physically thinner and I could see where the pressure plate was milled.

I did take a pic of the clutch fork after everything was bolted together and you can see the fork now sits more towards to the driver side (which is what I want for more throw) I assume it sits more towards that way because the pressure plate fingers stick out more (changing the fulcrum point) Maybe a wisemen can school some knowledge on that.

Going to finish the rest of install this weekend and will update everyone.

Thanks

(picture is upside down )

 

[kchaazz]

Did you ever get her up and running??

 

[lil corb]

Did you ever get her up and running??

I did!! Haven't been able to update. System was re bleed and adjusted accordingly. Clutch engages perfectly, about 2-3" from the floor, maybe a little too high but a little adjustent will fix it. I don't hear any weird whirring or any noise anymore. You can see the difference in how thin the disk is now. Pedal pressure feels a tiny tiny bit stiffer but Car feels like A LOT better now and I def don't have any worries about clutch drag. SBC did a great job fixing the issue but unfortuately I had to tell them after the first purchase to fix rather it being from the factory.



Overall very happy!

 

[lil corb]

An update and more of a question. I had some wiring issues from my ect sensor that I fixed and I go for a drive. All of a sudden now I'm getting that shhh noise again upon disengagement in first and reverse. The clutch isn't dragging at any high rpm and I torqued everything down so it can't be over torqued pressure plate. It still dis engages higher than before around 2.5" from ground but now that noise (shhh) is back. Is possible that it's normal Kevlar/ ceramic noise? It's the ss pressure plate and act flywheel. A friend of mine told me he has heard that noise in anothe before and it's pretty common with aftermarket flywheels. I don't hear that in my evo clutch flywheel set up.

Any ideas?

 

[lil corb]

Spoke to Jon at sbc and he said noise is perfectly normal. Sound of disk engaging flywheel for those who might have same question about noise.

 

[Artago]

My SBC SS-TZ also drags. Does anyone know the correct step height?