philistine

iTrader: (2)

My guess is that the factory hydraulics are/were insufficient to extend the slave the distance required on the pressure plate. So I suppose some have shimmed the slave to become closer - so close that there is preload on the pressure plate.

I believe "clutch drag" is another term for partial disengagement (or not fully disengaged) - where the slave cannot either put enough force on the pressure plate or cannot extend to the proper displacement WITH enough force.

The problem I see with preload is that it defeats the clutch disc from doing its job - run the risk of the clutch disc slipping on the flywheel (clutch slipping).

rob Peter to pay Paul kind of deal - but it sounds like doing this corrects the clutch drag.

wes8398

iTrader: (2)

You got 'er! Thanks for adding the explaination. I'm sure someone in the future will find it helpful. And I agree, Philistine's master would probably be the best way to fix the problem I was having. Unfortunately I didn't do this myself, and pulling the trans again to remove the shim that's currently there will cost me another $400, on top of the new master. After already paying to have the trans dropped for a 2nd time (after realizing the drag issue) to have the shim installed, paying for a trans removal a 3rd time really isn't tickling my ***** right now...


Thanks for adding further clarification to the thread.

69stangscj

iTrader: (3)

So what was Tick's explanations of how they came to their tolerance numbers, and why RAM's may be different?

wes8398

iTrader: (2)

In brief, there are different part dimensions between GM (LUK) FWs and RAM FWs. Tick's tolerances are specific to the parts that the instruction sheet says they're for.

AAIIIC

iTrader: (19)

Just trying to visualize things here, so correct me if I'm wrong...

Using the Tick or RAM measurements and shims, the goal is to have the slave/TOB be close to, but not making contact with, the fingers on the pressure plate when your foot is off the clutch pedal, right? If there's no contact, then the TOB should not be spinning. When you push down on the clutch pedal, the slave pushes against the pressure plate and the TOB starts spinning.

If you shim the slave to the point that it's always making contact, then the TOB is always spinning.

I've never taken apart the slave/TOB, but the shop that replaced mine last time said that there's a plastic cage/sleeve thing in there, and that plastic part melts due to heat, and then the whole thing ***** itself. They said that riding the clutch (as in, sitting at a long stoplight with your foot on the clutch pedal, or in stop-and-go traffic) would accelerate the failure of that plastic part.

That makes me wonder how wes8398's situation is going to work out, since (again, if I'm visualizing this right) his TOB is spinning all the time.

isis

iTrader: (1)

I think you have it right. I'd have the same concerns I think. Which is why I'd do the MC at the same time as the clutch/slave. Too bad Wes didn't have all that info up front, so I understand his 'get it done' situation and thank him for finishing this thread out so the rest of us can learn from it.

philistine

iTrader: (2)

Here is a factory slave that I disassembled a long time ago - still had it in my junk parts box.

wes8398

iTrader: (2)

I'm baaaaaaaaaaack!!! Bit of a thread resurrection here, but Philistine's master cylinder has got me re-reading all this stuff from months ago because I'm trying to decide whether I should have the trans dropped again in order to UNinstall the slave shim I had put in before I install the PMC. Re-reading all this and looking at my measurement numbers again, I'm feeling confused and wanted to see if anyone was still interested in commenting on this. Now, assuming the measurements were done correctly and the numbers are accurate, here's another recap of what we did...

"A" measurement was 2.4475"
"B" measurement was 2.4235"
Difference/gap was 0.0024"
Tick suggested gap is 0.125" to 0.200"

I was getting clutch drag (which we now all know was very likely to be due to weak OEM hydraulics), so I installed a 0.113" shim to the slave, therefor making my "new B" measurement 2.5365" and my "gap" now NEGATIVE 0.089" (IE no more gap, rather 0.089" of pre-load).

This seems to be working out fine up to this point, but I'm afraid of that plastic sleeve on the slave melting to oblivion and messing things up because of the preload. My shifting could also be smoother. So I wanted to try the PMC out, which is what's got me back here reading these threads all over again.

The question I have right now is this. If my original "gap" was 0.024" and shims only make that gap smaller, how would I have gotten to Tick's suggested gap range of 0.125" to 0.200"?? And if I had done that, WOW, wouldn't my clutch drag have been far worse? I don't even think I would have been able to drive my car, would I?

lt1fbody355

WoW! Just read this entire thing very interesting..

So! My Conclusion.

1. ctsv master doesnt push ls7 slave far enough.

2. ctsv master is a POS my 06 has always had low pedal engagement!

I cant stand the clutch engaging at the bottom or before halfway.

assuming you measured and have the correct gap.

So what the fix? Aftermarket MASTER!

Who makes one?

wes8398

iTrader: (2)

One of the members here does. See: Philistine's Master Cylinder. AKA the "PMC".

bmylez

iTrader: (3)

He is two posts up from you, with a link in his signature.

duckmanjbr

I don't mean to bring up old threads but I thought my info could help others. I have an 06 V w/ LS7 clutch, flywheel, and slave. All factory GM items! After install I measured the diff and I was way off! Almost an 1/8 of an inch. So I shimmed w/ .118 from Tick and still don't have complete release of clutch (hard shifting in gears and no reverse unless I turn the car off). I knew the .118 shim was on the small side of my measured numbers but I wanted to try it at least. With it shifting is better but reverse is still difficult. Plan is to pull the trans back out and put in the larger shim this weekend.

FuzzyLog1c

iTrader: (4)

That's not the problem. You're already way past the recommended gap (you actually have preload) with no shim. Although this may blow your mind, the most likely reason why you're having troubles getting into reverse is that you're over traveling the pressure plate, slamming the casting against the PP shell. This causes the clutch to re-engage, making it harder to shift.

Recommend pulling the shim out and replacing the stock plumbing with a McLeod quick disconnect clutch line. If you still have problems, check back in. You're probably dealing with a shot clutch MC seals or a bad bleeding procedure.

ls1247

iTrader: (2)

Does this replace the factory clutch line connector all together or simply just mate up to it?

duckmanjbr

@Fuzzy- My original install with all stock parts (ls7 clutch, pressure plate, slave) didn't work. I thought the same thing so I replaced the MC. Still had same problem so I pulled the trans again and measured the gap. That's when I saw I was 1/8 off. Where did you pull your statement of "recomended gap"? These are all parts that don't go together from factory so you have to make it work. Without measuring it you have no idea what the issue is! Anyway, I installed the .114 shim along w/ speed bleeder and Tick CTS-V LS7 adapter just to make life easy. (At this point the entire system is new. Clutch, slave, MC, lines, etc.). I still had the shifting issue although it was easier to get into forward gears and you could force reverse. Today I pulled trans again and installed the .180 shim. Life is now great. Easy shifting and reverse is a breeze. Almost everyone on this forum says you don't need a shim w/ factory ls7 parts but I promise you I did! Measure it out when changing the clutch and if you're off shim it! I agree it's a little strange that some people have no issue and I need a huge shim. I guess I'm just the lucky one. At least the car runs smooth now!

FuzzyLog1c

iTrader: (4)

Yep. The stock system is completely gone, including the stupid flow restriction device.

At the end of the day, here's the thing that people aren't understanding: the Corvette LS7 clutch kit is not appropriate for front-engined Gen III/Gen IV cars because it was sized for the front mid-engined Corvette bellhousing. The length of the C5/C6 Corvette bellhousing is 5.786". By contrast, the front-engined Gen III/Gen IV bellhousing is 5.500". Therefore, when you install a Corvette clutch kit that was designed for that 0.286" longer bellhousing, you're going to have insufficient gap or preload.

I've done 14 clutch installations/modifications on the V1. I've done a lot of measurements. I've talked to a lot of vendors. Most of my installations (11 of them) were done when I was new to cars and following the bad advice on LS1Tech and CadillacForums. I don't regret the amount of time I spent on it, because it was clear that at the time, nobody in the community knew anything about clutches and few were willing to spend the time to try and come to grips with the issues. So I feel like I'm providing a service, even when people bring a collection of the forum posts they Googled to the table and tell me I don't know what I'm talking about.

Anyway, on a self-adjusting clutch (all street clutches are self-adjusting), a significant amount of gap is required for two reasons:

1. To allow the clutch to compensate for friction surface wear. While the recommended minimum gap varies by manufacturer (i.e.: based on the pressure plate lever arm ratio and the total friction material thickness) most clutches require a gap of at least 100-150 thousandths of an inch to guarantee 25-30 thousand mile life. To get a full 40-60 thousand mile lifetime, you need to provide 200-250 thousandths gap.
2. To prevent the slave throwout bearing from being damaged by being continuously forced against the clutch fingers. Slave cylinders (and in particular, the throwout bearing and seals) are designed for short, intermittent operation. So when you see someone complaining that he melted his slave, you know he's got preload on the clutch. Riding the clutch at stoplights is another bad idea that will reduce the life of your slave, but that amount of heat won't melt it like some of the pictures I've seen.

Before I go do more productive things, I have to say--your setup is fucked up. Consider yourself warned in advance. If your system is bled properly, when you put the pedal down, the clutch fingers are overtraveling and transitioning from Class 1 to Class 2 levers, which is putting them at risk of snapping (you should feel the increased pedal effort, by the way). The only way you'll avoid doing damage to the clutch is if your bleeding technique is terrible (and most people are terrible at this), because you won't get the full range of motion on the slave. But even if you dodge that bullet, the preload on the clutch will prevent it from adjusting and it'll start slipping within several thousand miles. Ask me how I know. I've been there.

If you're still scratching your head and want a second opinion, to the best of my knowledge, the only people that have more technical or practical V1 experience are Lee and his team @ McLeod Racing in southern California. That's because customers around that area bring V1s to McLeod to have their entire systems (clutch, flywheel, master, slave, and hydraulic plumbing) replaced/upgraded. Why? Because McLeod has a reputation for doing the job right the first time. Why haven't you heard of these people on LS1Tech? Because there's a big population of V1 owners that don't like participating in these forums--I get emails and PMs from them occasionally.

In talking with Lee, it sounds like their installations almost always involve a 0.750" bore clutch MC, which makes sense because that bore's displacement will fully disengage most GM-reference clutch designs. Since I wanted to be able to max out the travel on my clutch with everything super hot, old fluid, and a mediocre bleeding job, I'm running a 13/16" bore. Lee and I argued about that since, technically, you can overtravel the clutch if the MC seals are in excellent condition, the hydraulics are in perfect condition (no bubbles in the plumbing or moisture in the fluid), and you plant the pedal on the floor. Ultimately, he either caved or agreed with me--I'm not sure which.

ls1247

iTrader: (2)

I've got an LS7 in mine and its OK but not as refined as I would like it to be. I'd almost be happy if I could convince myself this was the case as there would be some hope for improvement.

But, I checked GM part numbers for a clutch assembly for a 2001 Z/28 and a 2001 C5 Corvette and it's showing them as being the same part numbers. The Z06 numbers are inconclusive as they aren't listed as complete matched set, they're listed individually.

http://www.wholesalegmpartsonline.co...rimLevel=15623

http://www.wholesalegmpartsonline.co...riveLine=11463

FuzzyLog1c

iTrader: (4)

Aren't you forgetting the slave?

ls1247

iTrader: (2)

The GM numbers for the fbody and vette slave are different.

I don't have the time, the resources or the desire to investigate this much further than what I read on this screen because I have more important things to do, its working reasonably well, it's a wear item and I know I'll be back in there soon enough. As is often the case, the longer a platform stays in service, the more options we eventually get and that's what I'm hoping for here.

Until then, I depend on the more successful suppliers for information, information like this that clearly states that they recognize no difference in the various slaves available for the LS platform.

http://www.tickperformance.com/gm-sl...-firebird-ls1/

If you know something they don't, just spit it out.

InfrareV

A lot of information there, but the CTS-V bellhousing is the same depth as the corvette bellhousing...