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Pressure Plate Question

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Old 10-16-2007, 06:21 PM
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Question Pressure Plate Question

Hey guys,

I have done a bit of reading and found a bunch of comments that the pressure plates for the LT1 t56 are all the same from any aftermarket clutch and are all made by valeo. I also read that many people buy a clutch kit for cheap from a auto parts store etc.. and just toss the disc from it out and get whatever disc they want and use that to make their complete kit, rather then spending a lot more money for the more expensive kit.

My question: with all these comments I haven't had it verified for sure if this is true, so is it? I want to know because I ordered a McLeod clutch to replace the one in my car (same one currently in there) and need a new pressure plate as well, but don't want to spend the $300+ for the "McLeod" one, as I was told it is the same thing as one you would get in a kit at say Oriely's etc for way cheaper, just painted a different color. I ordered the Clutch Kit from Oriely's auto parts for $200, and just plan on using the McLeod disc with the kit, but before I put it in I want to verify that the pressure plate is indeed the same. I mean they look identical, but is there any differences internally or anything that I don't know about?


Can someone verify this for me and assure me this is true?


Thanks guys.
Old 10-16-2007, 07:30 PM
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The pressure plate is a vital part of the clutch assy, i wouldnt even try being cheap with it. Aftermarket plates are stronger than stock pieces. The fingers on them and spring pressures are a lot greater than a stocklike plate.
Old 10-16-2007, 09:06 PM
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what is different? I have read there is no posible way to make a stock LT4 Valeo Pressure plate any stronger than it already is. And I know aftermarket is stronger than stock, but have heard all the aftermarket plates are the same for the LT1..in which they all use the LT4 style plate..If they are different, how come no one can tell me what Specifically and exactly is different?

I am just trying to learn as much as possible, thats why I ask so many questions

Thanks
Old 10-16-2007, 09:56 PM
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I told you what is different in PP's, the fingers and springs are usually much stronger in aftermarket plates, this will aid greatly in high rpm shifting. I find it very hard to believe that a stock pressure plate is going to be as strong as a good aftermarket one.

You can put your $$ on what everyone else says but I would personally put my $$ in with a nice name brand aftertmarket plate. Thats just my opinion.
Old 10-17-2007, 06:47 AM
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Originally Posted by brad8266
I told you what is different in PP's, the fingers and springs are usually much stronger in aftermarket plates, this will aid greatly in high rpm shifting. I find it very hard to believe that a stock pressure plate is going to be as strong as a good aftermarket one.
Please provide rock solid proof to validate this statement.

This may be true with the LS1 clutch but not the LT1 pull type clutch. The plates are all exactly the same, they are the LT4 pressure plate with the NON-ribbed fingers. I had an Autozone, stock LT4, SLP and Spec pressure plate pressure tested at a clutch shop, all the same. Check out this link for a second opinion:
http://www.bfranker.badz28.com/fbody/clutch.htm

The diaphragm springs in these clutches are the same. I have even called Spec and asked them what they do if anything to improve them. The guy told me that they don't even start with the Valeo piece. He just kinda beat around the bush and only told me that they are supposed to be stronger. Obviously he does not know his product. The only possible mod I can think of that can be done is to further heat treat the diaphragm spring, until someone shows me proof of this with actual numbers I wont believe it.

You can not adjust the fulcrum points in these pressure plates like 3 finger plates either. I remain convinced that pressure plate in the aftermarket clutch kits is the exact same pressure plate as the one from Autozone for less than $200 with a lifetime warranty. I have measured and compared many pressure plates and been through the clutch dance too many times with my LT1 Camaro, I have even talked to online retailers and they all agree that the LTx pressure plates for all makers are the same.

Obviously everyone makes their disks differently based on ones needs. A lot of guys are buying a good disk and then go to the parts house for a clutch set, its cheaper that way. I just got a Spec stage 3+ disk and I am resurfacing my SLP pressure plate, I plan on putting it back together this weekend.

Last edited by wrd1972; 10-18-2007 at 06:37 PM.
Old 10-17-2007, 10:47 AM
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^^ THANK YOU Wrd1972, that is exactly what I was looking for!
Old 10-17-2007, 03:42 PM
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I am again amazed at the absolute lack of reality that is presented in posts by folks that "heard something from someone that heard something." I can't speak for every manufacture but I will be happy to provide a glimpse at the what goes into making an aftermarket clutch.

To begin, most manufactures do start with a stock-style plate (Valeo or otherwise). Our covers are actually stamped for us specifically giving us complete control of their build and potential. From that point clamp-load is increased by changing leverage points and methods. WRD, leverage points can in fact be changed on clutches...this has been done for years and as such increased clamp load is gained. Remember, clamp-load is only part of the equation. Friction coeffecient is also a great part of the capacity of clutches as well. Let me know if you have any further questions. Thanks!!!
Old 10-17-2007, 07:11 PM
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Originally Posted by SPEC-01
I am again amazed at the absolute lack of reality that is presented in posts by folks that "heard something from someone that heard something." I can't speak for every manufacture but I will be happy to provide a glimpse at the what goes into making an aftermarket clutch.

To begin, most manufactures do start with a stock-style plate (Valeo or otherwise). Our covers are actually stamped for us specifically giving us complete control of their build and potential. From that point clamp-load is increased by changing leverage points and methods. WRD, leverage points can in fact be changed on clutches...this has been done for years and as such increased clamp load is gained. Remember, clamp-load is only part of the equation. Friction coeffecient is also a great part of the capacity of clutches as well. Let me know if you have any further questions. Thanks!!!

I guess the scales were reading "fuzzy" the day we checked the Spec PP against the stock LT4 and SLP and all were within 5% of each other with the SLP being the strongest. If the leverage points (fulcrums) on the Valeo pull type pressure plate can be altereed then please post pics and end the pissing contest once and for all.

Last edited by wrd1972; 10-17-2007 at 07:30 PM.
Old 10-17-2007, 07:14 PM
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^^ You are using internet hearsay to argue with a clutch manufactuer.
Old 10-17-2007, 07:24 PM
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Originally Posted by brad8266
^^ You are using internet hearsay to argue with a clutch manufactuer.
Yes I am, I guess that the internet hearsay regarding Comp beehive springs was BS too. I don't consider the people on the board to be morons. PLus this is not an arguement, its a discussion that has sadly been going on for way too many years. Time for someone to settle it once and for all. This is why I am calling out Spec.

Originally Posted by SPEC-01
To begin, most manufactures do start with a stock-style plate (Valeo or otherwise). Our covers are actually stamped for us specifically giving us complete control of their build and potential. ks!!!
I want to respectfully challenge this statement. If you guys are stamping a custom designed LTx pressure plate cover then why do they still say Valeo and show the 382109-D0 P on the cover. I will assume what you are referring to as "cover" is the aluminum housing, not to be confused with the diaphragm spring or friction surface (plate).

Do you guys imprint the Valeo logo and casting number for your custom designed LTx pull type pressure plate covers?

Here is a pic of a new spec clutch showing the Valeo logo and casting number on the cover:
http://cgi.ebay.com/ebaymotors/SPEC-...spagenameZWDVW


If he is affiliated with Spec then I challenge him to post results of the Stock Valeos PP pressure vs. the Spec PP pressure. I am sick of manufactures promising products "much stronger" without backing it up with actual proof. Again I had my Spec pressure tested and it was not "much stronger". Posting the proof can only increase sales since many share my opinion.

I just bought a new Spec stage 3+ disk for $300, the complete stage 3+ clutch set goes for almost $700.00. That means if I had spent nearly $700 I would have a new pressure plate similar to the Spec PP I already have. I have talked to Spec and they told me that all the StageX PP's were all the same.

The Valeo pull clutch has been around since 1992, you would think that after 15 years this issue would be put to rest with for good with rock solid proof from maybe an after market manufacturer or performance magazine review. I completely understand that leverage points can be tweaked on 3 finger clutches and some pusher clutches, I am skeptical on the Valeo pull type just like many many others on the boards.

If the Valeo pull type PP can be made stronger, then someone provide proof.

Last edited by wrd1972; 10-18-2007 at 10:11 AM.
Old 10-17-2007, 09:30 PM
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You must have some excellent eyes because I couldnt read anything on that PP. All I saw was the SPEC logo in white on the bottom of it. I did see some imprint but couldnt read it.
Old 10-18-2007, 07:05 AM
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Originally Posted by brad8266
You must have some excellent eyes because I couldnt read anything on that PP. All I saw was the SPEC logo in white on the bottom of it. I did see some imprint but couldnt read it.
The imprint you are seeing is the Logo and casting number I stated above on each side of the Spec sticker. Yes I have good eyes, high dollar imaging software and a Valeo pressure plate siting right in front of me.

Have you ever seen the Valeo LTx pressure plate up close, if you have you would clearly recognize the logo and casting number? I am not at all commenting on the LS1 PP.

Last edited by wrd1972; 10-18-2007 at 07:19 AM.
Old 10-18-2007, 09:16 AM
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WRD, I am not arguing that we have never used Valeo style covers in the past (in fact on occasions when we have delays in getting the plate that we have made we may still use the Valeo style cover--this is not the norm for us but again remember, all we are talking about is the cover, not the entire plate assmebly). I don't view this as a pissing match or an argument. Though I do feel that you are misguided in your understanding of the workings of clutches and the potential for increased clamp-load. As for taking pictures of what makes our clutches our clutches...this request is like asking the Colonel whats in the secret recipe. Every manufacture has their own methods for increasing clamp-load and most are guarded about the specifics of their modifications.

With this in mind, I am unsure what plate you tested and how you tested it. We use Shepard-Thomason Load Cell machines that are calibrated regularly. Considering you indicate that you have "tested" a number of plates I assume that you know what the stock style assemblies are able to produce in terms of clamp-load. For those of you that do not know this, the stock plate produces ~2600psi. Our assemblies pruduce considerably more. After reading your post I thought..."why not just go put an LT1 plate on the tester and take a picture for the skeptics." That is exactly what I have done.





The plate pictured is no different than any other that we manufacture for the LT1. Nothing "special" or "different" was done to up the numbers. This is what you can expect from our LT1 plate (enough said)!
Let me know if you have any further questions. Thanks!
Attached Thumbnails Pressure Plate Question-28098770008_medium.jpg   Pressure Plate Question-28098770009_medium.jpg  

Last edited by SPEC-01; 03-04-2010 at 11:34 AM.
Old 10-18-2007, 10:01 AM
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I do agree with you on the "secret recipe" comment to a point, however I believe that the consumer would not be able to duplicate your efforts and I can assure you the competition has already reverse engineered them. I am content with your statement on the leverage points.

Thank you for you for posting this information. This is the first concrete proof that I have ever run across that confirms Specs claim. It is information like this that could have settled the dispute a very long time ago. This is the first time I have seen someone take the interest to help the consumer with respect to this issue.

I think it is perfectly reasonable to be skeptical of "much stronger" until a responsible and concerned manufacturer like Spec proves otherwise by posting stock pressure specs vs.their upgraded pressure specs. In todays world we want to see actual numbers, hard to believe it has taken this long to put it to bed. Another example, how many people would buy aftermarket heads if those heads showing the CFM gains were never published. This would lead to endless speculation.

The machine we used is primarily designed for a push type clutch, he could not get an actual poundage rating but he could use the two numbers as a point of reference for comparison and we came up with the 5% number. We agreed that for comparison purposes and not actaul rating purposes it would do fine.

Again I applaud Spec for posting this information. I truly hope that everyone that has ever questioned the pull type LTx pressure plates see this thread. This would have made one hell of a magazine tech article back in the LT1 days.
Great discussion none the less.

Last edited by wrd1972; 10-18-2007 at 10:47 AM.
Old 10-18-2007, 10:29 AM
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WRD, I am glad that I can be of assistance. As a side note the Shepard-Thomason machines that we use can be configured in a way that allows for the testing of both push and pull type assemblies (perhaps the machines that you were referencing were different, perhaps the opperator didn't really know how to use it--no insult intended by these statements). As a point of reference, Load Cells have not really changed much since their inception...they have gotten to be more accurate but the function itself is the same. In the future, I ask that you provide the complete story in regards to your testing procedures as the information you initially provided was simply incorrect and as such was misleading to those that don't know any better. Please let me know if you have any further questions. Thanks and have a great afternoon!
Old 10-18-2007, 12:45 PM
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To put those numbers into relative strength terms, that SPEC plate is %29 stronger then a stock plate.

Jeremy, thanks for taking your time and posting that information, I am sure it will be very informative to anyone else that has this similar idea concerning stock vs aftermarket plates.
Old 10-18-2007, 01:05 PM
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No problem at all! As you know, I am here to help. Let me know if you all need anything else.



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