[travislambert]

I'm working to install a Monster LT1-S Triple Disc clutch on my ZL1. Unfortunately, the instructions for shimming the slave cylinder leave some unanswered questions when using an OEM style slave cylinder (with an integrated spring).

Normally, the slave cylinder is installed with the spring compressed about 1/2" which allows plenty of travel to fully disengage the clutch. Monster is saying I need to fully compress the spring to measure and leave at most a 0.2" gap. That seems way too tight.

Here's what a stock clutch and slave cylinder looks like. Notice the compression of the green boot.


Here's about that would look like with the slave cylinder out of the car.


Here's what Monster's recommendation would look like. (Note, the spring pressure is so tight I could barely hold it to take a picture.)


On Monster's site, they have universal instructions for shimming the slave cylinder. I just don't know if I can trust these instructions given that it's so much different from what GM does. The clutch may feel great, but it seems to me this puts way too much unnecessary pressure on the throwout bearing.

I've reached out to Monster multiple times, and they have been less than helpful. I guess somehow a person is just supposed to innately know why Monster clutches need the slave cylinder spring compressed so much in spite of the pressure plate being a stock GM pressure plate. The slave cylinder only needs to travel so far to fully release the clutch, so I don't know what the extra compression of the slave cylinder spring is buying them.

Anyway, does anyone have experience installing one of these? If so, maybe you can help me understand what I'm missing here.

Does it hurt anything for the slave cylinder spring to stay almost fully compressed?

Can the slave cylinder apply enough force to the clutch to damage it? It seems there is far more travel available in the bearing then there is the clutch fingers with the positioning they want to use.

Is the shim that comes with the kit normally all that's needed with a stock transmission, stock slave cylinder, stock crank, etc?

[Root]

I’d assume you got this installed and working correctly but never saw any other comments or updates. Did the install go as planned.

[travislambert]

It's installed per Monster's instructions, but the clutch release point isn't correct. It release point is much too close to the floor. Drivability is great like this, but it will also wear the synchronizers out on the transmission. That's why these cars come from the factory with a very high release point.

I'm going to try a different clutch master cylinder (new OEM) and see if that helps. If not, I'll be looking for another clutch option. If I do it over, I'm going to avoid the triple disc and find a high-quality dual disc.

[He11bent]

Originally Posted by travislambert

It's installed per Monster's instructions, but the clutch release point isn't correct. It release point is much too close to the floor. Drivability is great like this, but it will also wear the synchronizers out on the transmission. That's why these cars come from the factory with a very high release point.

I'm going to try a different clutch master cylinder (new OEM) and see if that helps. If not, I'll be looking for another clutch option. If I do it over, I'm going to avoid the triple disc and find a high-quality dual disc.

I haven't installed a monster clutch before but it shouldn't release close to the floor. I have always changed the clutch, bearing, and pressure plate as a set. Is there a reason your are trying to mix and match?

[travislambert]

Originally Posted by He11bent

I haven't installed a monster clutch before but it shouldn't release close to the floor. I have always changed the clutch, bearing, and pressure plate as a set. Is there a reason your are trying to mix and match?

Everything from the flywheel to the pressure plate comes as a complete balanced assembly. The OEM slave cylinder is what Monster recommends for this clutch. Nothing is mixed.

If I change the clutch, I will install a complete balanced set once again.

We'll see if the new clutch master cylinder helps. If I put a vacuum on the clutch/brake fluid reservoir, bubbles come up from the clutch line anytime the clutch is fully depressed. It seems to be an infinite supply of air, so I know it's somehow making its way into the system. There are no fluid leaks, so this seems strange to me. Maybe it's just how the seals are in the clutch master cylinder, and this is normal when a strong vacuum is applied. Regardless, I'm going to replace it and go from there. My car has about 8,000 track miles on it, so it's possible the seals are worn.

[Jonru]

Did you ever figured out your issue?

[travislambert]

Originally Posted by Jonru

Did you ever figured out your issue?

Through a friend of a friend I spoke to one of the GM clutch engineers. We came to the conclusion it's just an issue with Monster's triple-disc design. Most people don't notice because it'd be fine for the street and maybe even the drag strip. For road course, with fast upshifts AND downshifts, sometimes downshifting 2 gears at a time, it's problematic.

I went back to an OEM clutch and it shifts perfectly with the proper clutch engagement location. I'm running ~1,000 crank horsepower and it has been holding without issue while being thrashed at the road course for over a year.

[Jonru]

Originally Posted by travislambert

Through a friend of a friend I spoke to one of the GM clutch engineers. We came to the conclusion it's just an issue with Monster's triple-disc design. Most people don't notice because it'd be fine for the street and maybe even the drag strip. For road course, with fast upshifts AND downshifts, sometimes downshifting 2 gears at a time, it's problematic.

I went back to an OEM clutch and it shifts perfectly with the proper clutch engagement location. I'm running ~1,000 crank horsepower and it has been holding without issue while being thrashed at the road course for over a year.

That sucks. I have a monster tripple Lt1-s and I have been having some issues with it, anytime I do some WOT pills then I come to a stop and it gets hard to get it to go into 1st gear. If I bleed the clutch seems to be ok until I do another pull . There are no leaks anywhere it’s just weird . I spoke to two other guys that have the same clutch and they have similar issues as mine . When I installed the clutch I went back and forth with monster clutch tech support about the shimming. One guy said one thing and another guy said something different. I ended measuring it and came up with a number that was on part with the shim they send you to install. The other thing I was thinking is if the speed bleeder I have could cause an issue but it’s too bad I can’t remove to test that theory unless I pull the transmission out. The stock clutch it’s not an option I know at 850 whp the clutch would slip in 3rd gear at the drag strip. My car has heads, cam and a magnuson 2650 making a little over 1k whp. I’m going to call or email monster and see what they say .

[travislambert]

Originally Posted by Jonru

That sucks. I have a monster tripple Lt1-s and I have been having some issues with it, anytime I do some WOT pills then I come to a stop and it gets hard to get it to go into 1st gear. If I bleed the clutch seems to be ok until I do another pull . There are no leaks anywhere it’s just weird . I spoke to two other guys that have the same clutch and they have similar issues as mine . When I installed the clutch I went back and forth with monster clutch tech support about the shimming. One guy said one thing and another guy said something different. I ended measuring it and came up with a number that was on part with the shim they send you to install. The other thing I was thinking is if the speed bleeder I have could cause an issue but it’s too bad I can’t remove to test that theory unless I pull the transmission out. The stock clutch it’s not an option I know at 850 whp the clutch would slip in 3rd gear at the drag strip. My car has heads, cam and a magnuson 2650 making a little over 1k whp. I’m going to call or email monster and see what they say .

My best guess is that your synchronizers are worn due to the improper disengagement of the clutch. With the clutch not disengaging as soon as you touch the clutch pedal, it puts a lot of extra stress on the synchronizers.

Monster likes to make a big deal out of the shimming, while that is important, with our style slave cylinder, it's not as important as they make it sound. For what it's worth, I had the same experience with that.

I can tell you for certain though, after talking with the GM clutch engineer, I won't ever run a monster triple again. He recommended if I absolutely had to go aftermarket to look at the tilton clutches.

Are you certain that bleeding the clutch makes a difference or is it possibly a cool down period, or something like that?

[Jonru]

So I drove it Saturday after two WOT pulls it was getting hard to get it into gear again. Drove back home and parked it. I did not bleed the clutch . About an hour ago I took the car out for a quick wot pull to data log the car and this time was fine not issues. The difference between Saturday and today is I drove the car for 10 miles Vs today about 3 miles so it looks like it start acting up when it gets hot .