Clutch Master Cylinder Specs for Viper CSC??? & Mcleod Clutch PP Travel?

[Socrates]

Howdy,



Does anyone know the 2004-2006 Dodge Viper clutch master cylinder bore and stroke specs? Best I can tell from google and rockauto is that the stock bore is 7/8" but no info on the stroke length (and I'm not 100% confident the 7/8" spec, either, given the reference...).

What I'm ultimately trying to figure out is if the LS1 (3/4) or LT1 (7/8) MC is compatible with the physically larger/longer Viper concentric slave cylinder, providing enough stroke/fluid displacement to fully extend the slave, and doing so with moderate to light foot pressure. I know the GM and Viper parts will mate, I've done it, though am unclear on the critical fluid dynamic parameters here. I've been searching for hours to no avail. I can't find this info anywhere, so thanks much for any help on any part of it!

Lastly, does anyone know the minimum amount of travel required for McLeod Super StreetPro (diaphragm) pressure plate for full actuation/release, and also the max travel specs for the fingers? The Viper CSC I'm using has a ton of travel, 1.5" by my caliper, and I should have a good 0.900" of it available with the spacing I used on my setup with the trans installed (which incidentally I believe is the travel length of the LS1 CSC, at ~0.950", correct?).

This custom clutch install stuff is a major PITA!

[andrewb70]

Most OEM MCs will have about 1" of travel. A 7/8" bore MC will move enough fluid to disengage just about any clutch when using the LS1 style hydraulic TOB. I assume the Viper TOB is very similar to the one used in LSx cars. As for the travel required for full release, McLeod should know that spec.

What exactly are you trying to do? I might have some other suggestions if you tell me more info.

Andrew

[Socrates]

Hi Andrew,

I am installing a 2006 Viper T56 behind a 428 Pontiac in a 66 GTO. I'm using a 2004 Viper hydraulic throwout bearing/concentric slave cylinder (hTOB/CSC). I have the trans bolted to the engine in the car, using a 1.125" scalloped spacer required to make the viper input and viper slave fit in the McLeod modular bell. What I need now is a suitable OEM clutch master cylinder (MC) to actuate the hTOB/CSC.

The viper CSC has 1.5" of max travel. About 0.600" of the travel is not used in my custom setup, that is, for the bearing to touch the clutch pressure plate (PP) fingers it is sitting about 0.600" from fully stacked, thus there should be about 0.900" of travel still left in the slave, I just need to find a suitable master to get the needed half inch or so (or whatever a McLeod PP needs for full release) from the Viper slave as it sits in my car to actuate the pressure plate. Any ideas? I'll call McLeod on Mon for the release specs, though I assume a half in would be plenty.

I have the common clutch MC adapter/mounting bracket that mounts to the brake booster bolts and accommodates the LS1 or LT1 MCs, which would be ideal for me to use if they will work, though I'd gladly entertain suggestions for universal MC or a MC from another make. The original Viper clutch MC's have a funky mounting scheme, nixing the obvious solution of just using the Viper MC. Though, again, it would still be awesome to know the factor Viper MC bore x stroke specs here! Any ideas?

[andrewb70]

Hi Andrew,

I am installing a 2006 Viper T56 behind a 428 Pontiac in a 66 GTO. I'm using a 2004 Viper hydraulic throwout bearing/concentric slave cylinder (hTOB/CSC). I have the trans bolted to the engine in the car, using a 1.125" scalloped spacer required to make the viper input and viper slave fit in the McLeod modular bell. What I need now is a suitable OEM clutch master cylinder (MC) to actuate the hTOB/CSC.

The viper CSC has 1.5" of max travel. About 0.600" of the travel is not used in my custom setup, that is, for the bearing to touch the clutch pressure plate (PP) fingers it is sitting about 0.600" from fully stacked, thus there should be about 0.900" of travel still left in the slave, I just need to find a suitable master to get the needed half inch or so (or whatever a McLeod PP needs for full release) from the Viper slave as it sits in my car to actuate the pressure plate. Any ideas? I'll call McLeod on Mon for the release specs, though I assume a half in would be plenty.

I have the common clutch MC adapter/mounting bracket that mounts to the brake booster bolts and accommodates the LS1 or LT1 MCs, which would be ideal for me to use if they will work, though I'd gladly entertain suggestions for universal MC or a MC from another make. The original Viper clutch MC's have a funky mounting scheme, nixing the obvious solution of just using the Viper MC. Though, again, it would still be awesome to know the factor Viper MC bore x stroke specs here! Any ideas?

How are you coming up with the 1.5" of total travel for the Viper CSC? 1.5" of travel is A LOT. Is the Viper CSC of similar design to the 4th gen f-body? The f-body design us spring loaded so that the bearing is always riding on the spring fingers.

You can actually test to see how much the spring fingers need to travel in order to fully release, if you have a press, a used mechanical TOB, a spare flywheel and a dial indicator. I won't go into details here unless you have all those things available to you. Hopefully McLeod knows the spec for their clutch.

I am using parts from Keisler to mount a Wilwood, Girling style MC on my firewall. This particular style of MC has a very long stroke, about 1.4". This gives a great deal of flexibility when mixing and matching pedal ratios, MC bore size, CSCs, and various clutch types.

I know my thoughts aren't answering your questions directly, but its something :-) You can check out the details of my hydraulic clutch conversion in my build thread. Link in sig. It might help.

Andrew

[Socrates]

Thanks for the ideas, Andrew. I though 1.5" was a ton, too, though I checked it 4x and came up with 1.5" or just a hair under with my caliper. The Viper CSC is quite long, though it is very similar in design to the 4th gen F-body slave. The Viper CSC is longer with a much beefier actual bearing assembly relative to the F-body piece, with better designed bleeder valve and larger orifices in the quick disconnect feed line. How do you post pictures here and what web photo hosting do you use? I'll post a pic of the LS1 and Viper slaves together.

I have all the tools to calculate the PP throw, though the assembly is in the car now with the T56 bolted up, so that's not going to help! I'm sure someone at McLeod has this answer, though.

Do you have the part number on the Wilwood MC you're using? It's 0.750" bore by 1.4" stroke? The LS1 F-body stuff is 0.750 x 1.0", right? The LS1 factory MC can be modified for more stroke by cutting the internal stop in half, for about 1.5" of stroke (assuming it's 1.0" to begin with).

[Socrates]

Just spoke with McLeod tech: They suggest 0.450" for full PP engagement/clutch release. They couldn't offer a maximal travel spec though suggested at least up to 0.550-.600" would be ok...

With those specs at hand, I'm still searching to find the right clutch MC to tie it all together. Any additional suggestions?

[andrewb70]

The MC that I am using is Wilwood PN 260-6088.

Details here:

http://www.wilwood.com/MasterCylinderList.aspx

0.450" seems very reasonable to achieve full release. I am using the LS7 clutch and it needs a little less, around 0.350". I actually started with a 0.750" bore MC and later switched to a 0.700" bore MC because I wanted to limit CSC travel and get a lighter pedal as a side benefit.

The only suggestion that I have is to test everything before bolting it up inside the car. If the engine and trans are out, this should be simple. Install the MC in the car and then run a 6' hard line up over the fender. Attach the line to the CSC and determine if your clutch is fully releasing or maybe if you are over-traveling the bearing. Doing it this way is much easier than when the engine and trans are in the car. Let us know how it goes.

Andrew

[Socrates]

The Wilwood stuff looks great. Would you happen to know if there is an easy way to adapt the factory LS1 type braided hose and quick connect to the Wilwood masters? Maybe I could find a local shop to modify the factory LS1 line for an AN fitting to match the Wilwood if I go that route, or v.v., to attach the quick connect to the standard wilwood line if a pre-made line isn't available? Thanks for the ideas...

[andrewb70]

The Wilwood stuff looks great. Would you happen to know if there is an easy way to adapt the factory LS1 type braided hose and quick connect to the Wilwood masters? Maybe I could find a local shop to modify the factory LS1 line for an AN fitting to match the Wilwood if I go that route, or v.v., to attach the quick connect to the standard wilwood line if a pre-made line isn't available? Thanks for the ideas...

The RX7 LS1 swap guys have been tackling this issue for years. It used to require modifying a stock line, but now you can just buy a line:

http://www.speedwaymotors.com/T56-Hy...Body,9086.html

Good luck!

Andrew

[Socrates]

Perfect! Thanks for the link!

So, I tried a stock LS1 MC last night. It did not produce enough travel at the Viper slave to release the clutch in stock form (this makes me think the Viper CSC is at least 7/8" bore). However, I was able to modify the ls1 MC, cutting the internal stop down by 0.600 inches, yielding a new total stroke close to 1.50" vs. the factory stroke of a little under 1.00". The modified LS1 MC will produce enough travel at the slave and release the clutch with a wee bit more travel to spare after full release! I verified release by turning yoke in the trans with one hand while pushing the clutch pedal in with the other, made possible by having a BFHole in the trans tunnel floor . The clutch pedal is light though firm, not mushy, and returns quickly. I just need to install a pedal stop and then should be good to go here.

If the LS1 MC has issues on the street or track the Wilwood or Tilton with the speedwaymotors adapter line are going right in. I already found a spot to mount them. Now that I know the MC parameters needed for my setup it will make ordering an aftermarket MC much easier. Thanks again for the help, Andrew.

...

.

[andrewb70]

Glat to be of service. If you need more volume in a 4th gen style MC, then you can get the LT1 MC. It had a 7/8" bore.

Andrew

[John Wright]

So which MC did you end up with? I'm watching this thread, because I have a Viper T56 and I'm trying to use the Viper T/O bearing...I'm still undecided as to what will work so I haven't purchased the quick disconect fluid lines or the M/C yet.

[Socrates]

John Wright:

I used a 2002 LS1 MC with a 2004 Viper slave on a 2006 Viper T56. The Viper slave, as I'm sure you know, is really long with lots of travel. I am also using a 0.700" McLeod scalloped spacer (MCL 8703-13) to make the slave work with the McLeod modular bell and McLeod clutch. Without a spacer you'll bind up the slave and will effectively be constantly riding the clutch, and further you need the spacer to accommodate for the length of the Viper input shaft (0.75" longer then the LS1 T56 input shaft).

The LS1 master absolutely required cutting down the piston stop to get enough travel for the Viper slave, though it's not big deal, a 10min job with just a small pick. I'm using the LS1 quick connect fitting in the Viper slave to mate with the LS1 MC. The Viper female quick connect is too big for the LS1 male fitting so you'll have to pirate a LS1 quick connect fitting from a junk LS1 slave or use aftermarket lines to connect everything. The Corvette female fitting I have works with the LS1 MC, too, fwiw.

Is that all clear? If you're ever near Richmond you're welcome to stop by and check out my setup in person to get a better idea of how things fit together. The T56 swap isn't rocket surgery but it is a lot of trials and errors to get everything in sync.

[John Wright]

John Wright:

If you're ever near Richmond you're welcome to stop by and check out my setup in person to get a better idea of how things fit together.

Sweet!...I didn't realize that you were just a few hours East of me.

Here are a few pics of the T/O bearing that came on this tranny(1998 Viper):











I used the McLeod Modular bell and a 95' HD GM truck 11" flywheel(for 1pc rear seal), clutch and pressure plate. I had to trim a little off the end of the input shaft because it bottomed out inside the pilot bushing end of the crank.

Thanks for all of the above info...this helps narrow down the possibilities while looking through parts catalogs.

[John Wright]

whoa...I didn't realize the pics were so large...sorry about that.

[Socrates]

I'm using the same slave. I think they are the same from the 90's to 2004 and changed in '05, although the actual bearing on the 2004 is a bit more modern and heavy duty looking then the 98. I'll post some pics later.