Do you need to shim or use a spacer when installing a LS7 clutch on a LS1?

 

I didnt when I installed mine on my 02 SS, The petal was extremly low for about two day's and then it came up, still kinda low for my taste but not bad.

 

If your pedal is low, bleed your hydraulics again...there has gotta be air in there, or you have a problem with the hydraulics.

I installed all OEM LS7 parts (flywheel, disc and pressure plate) as well as a brand new OEM slave and OEM master...the only aftermarket part I used is a Tick remote bleeder.

Bolted it together in my 2000 Z28 with no shims or spacers or anything...spent 15 minutes bleeding the clutch with a friend, and the pedal feels essentially EXACTLY the same as the stock clutch in the car felt 130K miles ago...pedal feel is almost identical, clutch grabs at a very very normal height (just about half travel, which I find perfect)...drives as smooth as glass, and hits much harder than the stock clutch did when I let the pedal fly.

 

The LS7 is made to be used with the LS7 slave so that is why the pedal is low. Also, the adjusters create room for error. These adjusters are worthless IMO. The Diamond Stage 1 uses a much better pressure plate than the LS7, but with a similar disc. Guaranteed to have a good pedal. I sell it for $369.
To answer your question, Yes shim the slave out if you want a good pedal. I sell 1/8in shims for $10ea if you decide to go this route. I havent measured so I don't know for sure how much to shim it out, but my best guess is 1/4in. So you would need 2 shims

 

Thats what I figured but wasn't sure.... I will just have to measure it to see how much shim I may need.

 

NO. The ls7 clutch is self adjusting it will work its way to the top after its broke in. I was the 2nd person to the the swap on ls1 and i have over 40k hard miles on it!

 

Like I said, I put an LS7 flywheel, disc and pressure plate in my car, with brand new stock f-body hydraulics, bled my system THOROUGHLY, and my clutch is perfect. The very first time I drove it, the pedal was exactly where it should be, and exactly where it still is.

The LS7 clutch does not need a spacer, or an adjuster, or a special slave cylinder. If the pedal is low when it's installed, and winds up coming up, it means there's air in the hydraulics, that is eventially working it's way to the resevoir.

 

I don't like the adjusters on the LS7 pressure plate. I've seen them mess up way more times that not. That design leaves too much room for error. It's just a glorified stock clutch.

 

lol! Every clutch install is different so to say NO to a question like this is wrong. You should do a search on how many people have to use spacers on these ls7 clutches. There is no way of saying if it needs shims or not until it is measured. Any clutch install should get measured in order to have a long lasting clutch. Wrong info will waste the o.p time... ALWAYS measure.. one persons luck isn't yours.

 

I used a spacer. the PP wasn't designed to have used 50% of its ratcheted travel on day one. its supposed to be used over the life of the disc. Being that the LS7 slave is longer, I would be prepared to shim to get it close to where GM intended it to be when specifying the PP.

I chose the LS7 because it has the adjustable PP as it will probably last 100k miles in my car. I DD and rarely beat it.

 

Do you understand how a hydraulic spring loaded slave cylinder works?...you should see how many OTHER LS7 clutches I've installed...that have also ALL been perfect on the first try...EVERY F-Body LS1 T56 bellhousing is going to be the same within a few thousandths of an inch, and EVERY LS1 crank flange projection relative to the bellhousing...is also going to be the same within a few thousandths of an inch...as well as the height of EVERY LS7 flywheel...and unless you can remove your parts and put them in a CMM...or work somewhere with a surface plate...you can't measure ANY of those components with ANYTHING accurate enough to even pretend that you know what you're talking about...and your shims are a total waste, that if anything, might be causing the slave cylinder to not be able to fully retract and this always leaving pressure on the throwout bearing/pressure plate...similar to "riding the clutch"...it's not rocket science, it's a clutch, and it's a LOT of people who don't know how to bleed their hydraulics properly.

If you understood how the hydraulics worked, you'd realize that if a spacer was NECESSARY, then without one, the clutch pedal would bind up before it gets to the floor, and pressing it the rest of the way, would break something (a seal in a master or slave cylinder)...if you're lucky enough to install one where you shouldn't, and have the slave still be able to retract fully without binding at the base of it's travel, then your clutch won't be destroyed...however I repeat, when using ALL UNMODIFIED OEM PARTS (LS7 flywheel/disc/pressure plate, and 2002 F-Body slave/master, and 1998-2002 LS1 bellhousing/T56, there is NO NEED to install a spacer in there, the only thing you MIGHT do with one, is cause problems. If you use all the parts I specified, and bleed ALL of the air out of the system appropriately, you will have absolutely NO issues, your clutch will fully release, and it will "grab" at an appropriate pedal height (it's actually closer to the top than it is to the floor).

...who's post is a waste of time again?

 

thats what i did like 4 years ago and still haven't had to bleed it. installed over 40k miles ago bled once like old school brakes and that was it! shifts like a auto when u want it to

 

Installed two LS7 kits and no spacers used. First one finally let go after 6,000 rpm plus launches on slicks and many extreme passes on the street. Very good clutch for the money...

 

Kind sounds like yours again because you made several errors. The main one I will point out is the fact that you said if you need a spacer and dont use one it will bind and break something. This is incorrect. It will simply not disengage. If you use a spacer when one is not needed, you run the risk of over extending the slave and tearing up the pressure plate. It is in no way bad advise to tell someone to measure their clutch package before installation. Somebody posted that between three different OEM type slaves they came up with three different dimensions. I would error on the side of caution and always measure regardless if you think it needs one or not. Cause if your wrong, the only way to fix it is pull the trans back out.

 

Quote:

Originally Posted by raven154

Kind sounds like yours again

Thank you! Someone understands!

 

I'm not even going to bother reading the nonsense arguments as they are not worth dignifying with a response I've installed a good amount of LS7 clutches, and it's hit or miss as to whether or not they will work, and I'll explain why. Out of the many LS7 clutch installs that I've done, roughly 30-40% of them had engagement issues, the other 60-70% worked fine. I use a pressure bleeder which is the most efficient way to bleed a clutch system. So air in the system is not an issue. Go do some searches and you'll see that a lot of people have a low pedal with this setup. Some are so low the clutch won't even completely dis-engage even with the pedal all the way down to the floor. Just because your LS7 worked fine with no shim, doesn't mean that every one will be like that.

BTW, have you ever measured the height and throw of an LS7 slave then compared it to an LS6 slave? There is a big difference. That is the reason that I shim it out.
With that said, I contribute most of the problems with the LS7 to the overly-sensitive adjusters. By process of elimination, it has to be the reason for the intermittent engagement issues. A few scenarios which I'm telling you from experience that did cause problems due to the adjusters: (1) Replaced the master/slave + the LS7 clutch/fly on an f-body. This car had a lot of air in the system. It would not disengage at all, even with the pedal all the way down to the floor. It was completely power-bled out so the hydraulics were good. Ended up getting another LS7 clutch kit and swapped it out, then it worked perfectly.
The pressure plate had apparently adjusted to compensate for the air in the hydraulic system. So once it was bled out, it still wouldn't disengage. When it adjusts, it won't go back (one-way adjusters), therefore the pressure plate is ruined.
Another scenario: (2) Another f-body LS7 install. The box that the clutch came in looked tattered/beat up a bit. I checked every square inch of the clutch over and it looked perfect. So I went ahead and installed it. It would not disengage, and didn't even have much air in the system (didn't replace the master on this one). Went ahead and power-bled it a few times, and still wouldn't work. Swapped it out with another new LS7 clutch, and it worked perfectly. It was obvious that the clutch was jarred/dropped during shipping. This had to have knocked the adjusters out of whack, so once again....ruined pressure plate. Just think about it....the clutch kit goes through a lot from the manufacturing facility until it shows up to your front door.

These are just a few cases that I remember off the top of my head. There were a lot of the LS7 Clutches that worked fine, but engaged low. Once again, this is due to the difference in the slave cylinder height/throw. Put a shim under the LS6 slave and chances are it will work just how you want.
Most people don't realize all the problems that can arise from an adjustable pressure plate. It's a stupid design and always has been. Even the LS1/LS6 clutches had these adjusters, but they were not nearly as sensitive as the LS7.

At any rate, this is enough for me to not want to even install any more LS7 clutches. I don't want to risk having to pull the tranny again then wait on a replacement clutch to come in the mail. When I do an LS7 install, I always shim it, and have had better success.
I'm not trying to just be a salesman and just promote the Diamond Clutch line, but the failure rate is almost non-existent. So I normally turn people to my Stage 1 kit. I use a non-adjustable pressure plate, and the engagement point is at the 40-50% mark of the travel. Plus its cheaper than the LS7 at $369, and you can use the stock flywheel once its resurfaced.

 

It is possible to put the pressure plate in a press to release pressure and move the adjustment ring back to a stock location. I had to do it to one that the slave failed on. When I bolted the unit back together it was way out and the pressure plate fingers were way to far down.

 

With that said, I will never use another clutch with a SAC pressure plate. I have had problems with both of the clutches I bought that had them.

 

No, the plate has to be disassembled and reset. At least this is what a local knowledgeable clutch rebuild shop told me. I've never bothered to have it done, though. I think they wanted $50 to put it back where its supposed to be.

 

There are a few threads in here detailing the operation and several have been successful.

https://ls1tech.com/forums/manual-tr...ure-plate.html

https://ls1tech.com/forums/manual-tr...djustment.html