Anyone installed Philistine's MC along with a slave spacer?
12-12-2014, 10:58 AM
#21
So if I'm reading and interpreting this correctly, the PMC will allow a properly shimmed clutch slave assemble to fully disengage the clutch because the factory master just doesn't have enough *** to do it but the PMC won't compensate for a slave cylinder that isn't shimmed correctly?
When I say properly installed clutch - it means AS DESIGNED. No goofing with the adjustments and augmenting the stack-up. It's purely mechanical. Some have installed a spacer that preloads the pressure plate and void of a gap. My guess is that was to assist with poor displacement of the slave cylinder due to weak hydraulics. Preload on a pressure plate can heat up and wear out your throw-out bearing. In severe cases, reduce the clamping force of the clutch disc and possibly cause slippage - that would be an extreme case and probably pretty rare. The spacers are intended to achieve the proper gap for installation - if they are from Tick, then it is explicitly stated on their website and instructions and is littered all over LS1tech with very detailed explanation. Spacers are available for aftermarket clutch combinations that are intended to give PROPER STACK-UP.
The PMC will cause the slave cylinder to extend to the displacement required to disengage the clutch and proper stack-up is important. It will not over-extend the slave cylinder. If the gap is excessively large there is no opposing force and it will continue until it reaches the pressure plate and give a displacement. The limit of the displacement depends on the opposing force of the pressure plate - it's a catcher's mitt. There are a variety of pressure plates from clutch manufacturers with a variance of the spring force. The PMC provides more hydraulic force safely to overcome the opposing force of the pressure plate - actually it's force/area so it's actually pressure.
For example, if the preload of a spacer yields 25-50psi on the pressure plate then that is insignificant in regards to slave displacement when the PMC is stroked. If the preload yields 100-125psi then that will have a significant affect when the PMC is stroked. The PMC does not require or need any preload assistance to perform the task of disengagement.
So if the gap is small or large (within specified tolerance), it has no affect on the performance of the PMC. If there is preload and it is a very small amount (25-50psi) it will not affect the performance of the PMC. Small amount of preload affects the throw out bearing and the PMC cannot help that - that is separate and falls into installation practices of the clutch.
Hope that explains it more clearly.
12-12-2014, 12:00 PM
#25
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It is designed to work with a properly installed clutch. There are a lot of factors. If you torque the pressure plate less or too much that affects stack up. If you use a spacer that is too thin or thick that affects your gap and stack up. If you choose an adjustable slave cylinder and the displacement is too short or long that affects disengagement/engagement.
When I say properly installed clutch - it means AS DESIGNED. No goofing with the adjustments and augmenting the stack-up. It's purely mechanical. Some have installed a spacer that preloads the pressure plate and void of a gap. My guess is that was to assist with poor displacement of the slave cylinder due to weak hydraulics. Preload on a pressure plate can heat up and wear out your throw-out bearing. In severe cases, reduce the clamping force of the clutch disc and possibly cause slippage - that would be an extreme case and probably pretty rare. The spacers are intended to achieve the proper gap for installation - if they are from Tick, then it is explicitly stated on their website and instructions and is littered all over LS1tech with very detailed explanation. Spacers are available for aftermarket clutch combinations that are intended to give PROPER STACK-UP.
The PMC will cause the slave cylinder to extend to the displacement required to disengage the clutch and proper stack-up is important. It will not over-extend the slave cylinder. If the gap is excessively large there is no opposing force and it will continue until it reaches the pressure plate and give a displacement. The limit of the displacement depends on the opposing force of the pressure plate - it's a catcher's mitt. There are a variety of pressure plates from clutch manufacturers with a variance of the spring force. The PMC provides more hydraulic force safely to overcome the opposing force of the pressure plate - actually it's force/area so it's actually pressure.
For example, if the preload of a spacer yields 25-50psi on the pressure plate then that is insignificant in regards to slave displacement when the PMC is stroked. If the preload yields 100-125psi then that will have a significant affect when the PMC is stroked. The PMC does not require or need any preload assistance to perform the task of disengagement.
So if the gap is small or large (within specified tolerance), it has no affect on the performance of the PMC. If there is preload and it is a very small amount (25-50psi) it will not affect the performance of the PMC. Small amount of preload affects the throw out bearing and the PMC cannot help that - that is separate and falls into installation practices of the clutch.
Hope that explains it more clearly.
When I say properly installed clutch - it means AS DESIGNED. No goofing with the adjustments and augmenting the stack-up. It's purely mechanical. Some have installed a spacer that preloads the pressure plate and void of a gap. My guess is that was to assist with poor displacement of the slave cylinder due to weak hydraulics. Preload on a pressure plate can heat up and wear out your throw-out bearing. In severe cases, reduce the clamping force of the clutch disc and possibly cause slippage - that would be an extreme case and probably pretty rare. The spacers are intended to achieve the proper gap for installation - if they are from Tick, then it is explicitly stated on their website and instructions and is littered all over LS1tech with very detailed explanation. Spacers are available for aftermarket clutch combinations that are intended to give PROPER STACK-UP.
The PMC will cause the slave cylinder to extend to the displacement required to disengage the clutch and proper stack-up is important. It will not over-extend the slave cylinder. If the gap is excessively large there is no opposing force and it will continue until it reaches the pressure plate and give a displacement. The limit of the displacement depends on the opposing force of the pressure plate - it's a catcher's mitt. There are a variety of pressure plates from clutch manufacturers with a variance of the spring force. The PMC provides more hydraulic force safely to overcome the opposing force of the pressure plate - actually it's force/area so it's actually pressure.
For example, if the preload of a spacer yields 25-50psi on the pressure plate then that is insignificant in regards to slave displacement when the PMC is stroked. If the preload yields 100-125psi then that will have a significant affect when the PMC is stroked. The PMC does not require or need any preload assistance to perform the task of disengagement.
So if the gap is small or large (within specified tolerance), it has no affect on the performance of the PMC. If there is preload and it is a very small amount (25-50psi) it will not affect the performance of the PMC. Small amount of preload affects the throw out bearing and the PMC cannot help that - that is separate and falls into installation practices of the clutch.
Hope that explains it more clearly.
For example my transmission is always quiet, shifter is good. I don't get fully locked out of gears, but it can be very tough to get into 1st or R, sometimes 2nd is tough to shift into. Clutch is bit heavier than normal and it engages fairly low to the floor. But not right off the floor...
are these symptoms of a weak master or a clutch which isn't fully disengaging? It sounds like your product is right up my alley, but just want to confirm these are the symptoms expected with the stock Master and ls7 clutch with no shim.
12-12-2014, 12:43 PM
#26
@philistine i have a thread going about a potentially bad mstr clutch cyl. I'm really thinking about buying yours - especially since i have the ls7 clutch. It only has a few thousand miles on it. New release bearing too.
For example my transmission is always quiet, shifter is good. I don't get fully locked out of gears, but it can be very tough to get into 1st or R, sometimes 2nd is tough to shift into. Clutch is bit heavier than normal and it engages fairly low to the floor. But not right off the floor...
are these symptoms of a weak master or a clutch which isn't fully disengaging? It sounds like your product is right up my alley, but just want to confirm these are the symptoms expected with the stock Master and ls7 clutch with no shim.
For example my transmission is always quiet, shifter is good. I don't get fully locked out of gears, but it can be very tough to get into 1st or R, sometimes 2nd is tough to shift into. Clutch is bit heavier than normal and it engages fairly low to the floor. But not right off the floor...
are these symptoms of a weak master or a clutch which isn't fully disengaging? It sounds like your product is right up my alley, but just want to confirm these are the symptoms expected with the stock Master and ls7 clutch with no shim.
Thanks!
12-12-2014, 12:47 PM
#27
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The master cylinder kit I sell is aftermarket and high performance. It has helped several with the symptoms you have described when the problem was hydraulic related. No need to drop the transmission and monkey with the slave if the stack-up is correct. The engagement will be higher off the floor and 1st and reverse should be silky smooth. There are varying levels of clutch hydraulic degradation, aggressive aftermarket clutches, and some greatly benefit over others with this kit. Regardless, the kit will outlast the factory and perform much better. The Tilton uses much better internal materials and seals over factory. In the event the seals should ever go bad, rebuild kits are available for ~$20.
Thanks!
Thanks!
Im not mechanically stupid, but more info the better
12-12-2014, 01:54 PM
#28
I believe a detailed write-up is in the works by one of the members here and should bear some fruit on the install process. If/when that happens, IDK. Many complete the job in 2hrs and others up to 3-4hrs. During testing I installed a proto-type and my times varied anywhere from 2-5hrs. By the time I installed a production unit, I submitted to the tip/trick for installing the clutch pedal switch - I was at my boiling point and happy that all it took was 5 minutes for that part. There are good days and bad days for turning a wrench, haha.
12-12-2014, 02:08 PM
#29
Detailed instructions with color pics are included with every kit. I also provide supplemental guidelines via email. It includes tip/trick submitted by some members, clutch bleed, and simplified process for removing the factory master cylinder.
I believe a detailed write-up is in the works by one of the members here and should bear some fruit on the install process. If/when that happens, IDK. Many complete the job in 2hrs and others up to 3-4hrs. During testing I installed a proto-type and my times varied anywhere from 2-5hrs. By the time I installed a production unit, I submitted to the tip/trick for installing the clutch pedal switch - I was at my boiling point and happy that all it took was 5 minutes for that part. There are good days and bad days for turning a wrench, haha.
I believe a detailed write-up is in the works by one of the members here and should bear some fruit on the install process. If/when that happens, IDK. Many complete the job in 2hrs and others up to 3-4hrs. During testing I installed a proto-type and my times varied anywhere from 2-5hrs. By the time I installed a production unit, I submitted to the tip/trick for installing the clutch pedal switch - I was at my boiling point and happy that all it took was 5 minutes for that part. There are good days and bad days for turning a wrench, haha.
12-12-2014, 02:24 PM
#30
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Philistine, thanks a lot for all the input. Everyone else as well. My case is definitely an example of one of the downfalls of having someone else do the work for you. I say this because I can't say for sure whether my pressure plate is preloaded or not. I know my intention was to have my mechanic install the slave shim to yield a proper gap between the slave and PP because the clutch was dragging without the shim. Unfortunately I didn't personally do the measuring, and I didn't button things back up together, so I don't know if it's preloaded or if it just has a gap within specs now. I'm going to have to re-read through a bunch of my posts/threads here to refresh my memory about what exactly went on, and what all the measurement numbers were when they installed the shim. At least I gathered that info from the shop, so that should help.
So relative to my OP, what I gather from the info you provided us here is that even if I have a bit of preload, the PMC isn't going to hurt anything because it wont cause the slave to "over extend", right? And if I'm anywhere in that prescribed range for gap (0.125" to 0.200" by Tick's numbers), I'm also good-to-go with the PMC. If either of these 2 situations are the case, then I think I'm safe to install the PMC without having to have the trans dropped to UNintall the spacer. Right? Sorry if I'm making you want to bang your head off a wall, but I'm just trying to make sure I make the best decision here.
Time to do some reading of my old posts...
EDIT: Didn't take me long to find my measurements. Looks like we installed approximately 0.089" of preload with the slave shim we installed (which was 0.113" thick). Before the shim (when I was experiencing clutch drag) it looks like I had about 0.024" of gap.
Philistine, does this change your recommendation at all?
Edit 2: Looking at these numbers again has got me all F'd up over here. If my original gap measurement was only 0.024", and a shim "shrinks" that number, then how would I have gotten to the suggested gap range of 0.125" to 0.200"? As Philistine pointed out to me many PM's ago, shims REDUCE the gap, they don't increase it. But in my case - if the measuring was done correctly - I needed to increase the gap, not decrease it. At the same time, increasing the gap wouldn't have done me any favours in terms of the clutch drag I was getting (it would have made it worse, actually), but.... wow.... I feel like I've just regressed 4 months and now I'm back to having no F'n idea. lol
So relative to my OP, what I gather from the info you provided us here is that even if I have a bit of preload, the PMC isn't going to hurt anything because it wont cause the slave to "over extend", right? And if I'm anywhere in that prescribed range for gap (0.125" to 0.200" by Tick's numbers), I'm also good-to-go with the PMC. If either of these 2 situations are the case, then I think I'm safe to install the PMC without having to have the trans dropped to UNintall the spacer. Right? Sorry if I'm making you want to bang your head off a wall, but I'm just trying to make sure I make the best decision here.
Time to do some reading of my old posts...
EDIT: Didn't take me long to find my measurements. Looks like we installed approximately 0.089" of preload with the slave shim we installed (which was 0.113" thick). Before the shim (when I was experiencing clutch drag) it looks like I had about 0.024" of gap.
Philistine, does this change your recommendation at all?
Edit 2: Looking at these numbers again has got me all F'd up over here. If my original gap measurement was only 0.024", and a shim "shrinks" that number, then how would I have gotten to the suggested gap range of 0.125" to 0.200"? As Philistine pointed out to me many PM's ago, shims REDUCE the gap, they don't increase it. But in my case - if the measuring was done correctly - I needed to increase the gap, not decrease it. At the same time, increasing the gap wouldn't have done me any favours in terms of the clutch drag I was getting (it would have made it worse, actually), but.... wow.... I feel like I've just regressed 4 months and now I'm back to having no F'n idea. lol
Last edited by wes8398; 12-12-2014 at 03:23 PM.
12-12-2014, 02:57 PM
#32
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The way I'm interpreting this is that the pmc pushes more fluid and does it better than the factory one. It sounds like it does not push the slave any farther or beyond OEM specs, so a proper shim is still required. But it fixes the problem of the OEM master not getting full reach due to weak hypdrallics or something along those lines.
I just bought one, and ill let you know how it holds out. I'm convinced my master is shot. It feels like im not fully dis-engaged and it's hard to get into gears sometimes. Add to the fact that my clutch engages really close to the floor.
I'm guessing the internal seals got messed up due to the fluid getting way too hot from the headers and the fluid was not changed often enough. My clutch is pretty new, and only has a few thousand on it. Also have a new slave. The MC is the only thing which hasn't been touched yet.
I just bought one, and ill let you know how it holds out. I'm convinced my master is shot. It feels like im not fully dis-engaged and it's hard to get into gears sometimes. Add to the fact that my clutch engages really close to the floor.
I'm guessing the internal seals got messed up due to the fluid getting way too hot from the headers and the fluid was not changed often enough. My clutch is pretty new, and only has a few thousand on it. Also have a new slave. The MC is the only thing which hasn't been touched yet.
12-12-2014, 03:21 PM
#33
So relative to my OP, what I gather from the info you provided us here is that even if I have a bit of preload, the PMC isn't going to hurt anything because it wont cause the slave to "over extend", right? And if I'm anywhere in that prescribed range for gap (0.125" to 0.200" by Tick's numbers), I'm also good-to-go with the PMC. If either of these 2 situations are the case, then I think I'm safe to install the PMC without having to have the trans dropped to UNintall the spacer. Right? Sorry if I'm making you want to bang your head off a wall, but I'm just trying to make sure I make the best decision here.
Time to do some reading of my old posts...
EDIT: Didn't take me long to find my measurements. Looks like we installed approximately 0.089" of preload with the slave shim we installed (which was 0.113" thick). Before the shim (when I was experiencing clutch drag) it looks like I had about 0.024" of gap.
Philistine, does this change your recommendation at all?
Time to do some reading of my old posts...
EDIT: Didn't take me long to find my measurements. Looks like we installed approximately 0.089" of preload with the slave shim we installed (which was 0.113" thick). Before the shim (when I was experiencing clutch drag) it looks like I had about 0.024" of gap.
Philistine, does this change your recommendation at all?
The way I'm interpreting this is that the pmc pushes more fluid and does it better than the factory one. It sounds like it does not push the slave any farther or beyond OEM specs, so a proper shim is still required. But it fixes the problem of the OEM master not getting full reach due to weak hypdrallics or something along those lines.
I just bought one, and ill let you know how it holds out. I'm convinced my master is shot. It feels like im not fully dis-engaged and it's hard to get into gears sometimes. Add to the fact that my clutch engages really close to the floor.
I'm guessing the internal seals got messed up due to the fluid getting way too hot from the headers and the fluid was not changed often enough. My clutch is pretty new, and only has a few thousand on it. Also have a new slave. The MC is the only thing which hasn't been touched yet.
I just bought one, and ill let you know how it holds out. I'm convinced my master is shot. It feels like im not fully dis-engaged and it's hard to get into gears sometimes. Add to the fact that my clutch engages really close to the floor.
I'm guessing the internal seals got messed up due to the fluid getting way too hot from the headers and the fluid was not changed often enough. My clutch is pretty new, and only has a few thousand on it. Also have a new slave. The MC is the only thing which hasn't been touched yet.
I use Motul RBF 600 but any DOT 4 should be good.
12-12-2014, 03:27 PM
#34
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10-4, thanks guys. One more question. How likely is it that the plastic sleeve on the throw out bearing will melt and seriously F things up because of the preload situation I now have myself in? Is that enough of a factor to consider having the shim un-installed once the PMC is in there?
12-12-2014, 03:51 PM
#35
FWIW, I run lower boiling temp brake fluid (cheap stuff) in my clutch because it absorbs less water. Regardless, our clutch hydraulic system is easily contaminated and flushing the fluid, or at the very least exchanging fluid in the reservoir, should become part of your routine maintenance schedule. 
I refill washer fluid, and turkey baster the power steering and clutch reservoirs probably once every two months.
I refill washer fluid, and turkey baster the power steering and clutch reservoirs probably once every two months. 
12-12-2014, 04:35 PM
#37
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IMHO if you are preloading the slave with a shim, I wouldn't worry about adding the master cylinder. The slave will only extend to the end of travel, and the preload doesn't extend the slave... It just puts the slave closer to the pressure plate so it can more adequately disengage the friction material from the flywheel. The clutch spring (fingers) aren't going to care. They have Chuck Norris levels of strength.
12-12-2014, 04:50 PM
#38
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The PMC could still very likely increase the slave's effectiveness... no? The preload I have is very minimal, and who knows how inadequate my hydraulic system is. The preload solved the "drag" I was getting, but shifting is still pretty notchy, and it's always a PITA to downshift to 2nd around town... takes far too much f'n around...
12-12-2014, 05:52 PM
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I know its tough to know on the forums but I'm not new to driving. Been doing it for 15 years or so now...I know how to drive. ;-) I'm not too familiar with transmission work but from what I've read in the past, I'm not inclined to think my shifting issues are synchro related. I guess the PMC will tell! I just need to decide if I want to keep that preload there (and apparently risk melting the plastic sleeve on the slave), or just pay to have the preload (shim) removed. As I said above tho, even if I remove the shim/preloaded, I still wouldn't have the proper gap as Philistine suggests his MC is designed to work with...