Twin disc issues

[Slowdr1v3r]

Whats up guys. Have a bit of a dilemma so sorry for the long post.

So ill start way back to try to give as much info as possible to hopefully get pointed in the right direction because im having a few issues that I need resolved before I do damage to the transmission.

So when I first got the car at 28k miles I noticed every time the tires would break loose car would wheel hop and get a nasty knock in the back. Took it back to Bmw as it was still under warranty and they did the big diff bushing in the subframe and helped but issue didn't fully go away. Swapped out diff(for other reason) drive shaft and axle no more knock.

When tuning my car recently clutch started to slip bad(45k miles) fbo e85 f80 paul tune. Street tune so not sure of the numbers power wise. So swapped it out for a clutch masters FX850 with their aluminum flywheel etc. Never messed with a twin disc so sent it to a local performance shop that has good reviews. Clutch master sent the wrong throw out bearing with the first kit and broke my slave cylinder. Shop got the new bearing and replaced slave.

So when I got the car back from the shop I noticed from neutral and idle its very hard going into gears most of the time. 1st and Reverse especially. I took the vehicle back to the shop and guy said its normal for a twin disc. That they are just harder to go into gear. He said finish breaking it in and go back to him if the issue persisted.

Current issues---
Now that the clutch is fully broken in I finally got to actually beat on the car and shifting at higher rpms is a little tougher than before but works(not a fan). Cant shift as fast with this setup as I could before the stock one gave out but there is a loud knock when I shift quick. I believe it is the clutch because if I press in the clutch and let it out quick I hear the knock. Dont hear it at any other time. And still very hard going into first and reverse. Also when going into gear from neutral the car will actually creep forward or back as if the clutch is still engaged. But when I let off the pedal it has still has plenty of room before the car will start to go which is what im confused about. Anyone have any insight on these issues or setup? Thanks in advance

**Solved**
So after talking to clutch masters again, they said the CDV needed to be removed. After removing it and bleeding the system the car feels 1000 times better. Still slight notch after a lot of local driving but tolerable.

[Ca_m4mike]

was the clutch adjusted when installed ?

[Ca_m4mike]

from the sound of it, it doesnt seem like it was adjusted properly

[Slowdr1v3r]

Originally Posted by Ca_m4mike

was the clutch adjusted when installed ?

I don't know to be honest. Its the most reputable shop I found in the area and they do a lot of Porsche race cars so I'd hope they did. But when I called clutch masters to see if they had heard of this issue I did ask about any clutch adjustment and they said if I did not get a hydro slave cylinder from them there is no adjustment needed except the high or low setting on the throw out bearing, and I did ask the shop and they said they called clutch masters to verify the right setting but im honestly just working off their word at this point.

[Slowdr1v3r]

Originally Posted by Ca_m4mike

from the sound of it, it doesnt seem like it was adjusted properly

If it was a clutch adjustment issue wouldn't it happen in all gears? Especially at the higher rpms and quick shifts? A friend of mine did mention that his friends shop car has the same clutch and has similar issues and they were thinking of removing the clutch and widening the beginning of the splines to give the input shaft a little extra space to go in smoother but they haven't done it yet so I dont think thats something I would want to do.

[1000hp]

Originally Posted by Slowdr1v3r

If it was a clutch adjustment issue wouldn't it happen in all gears?

Sounds like it is happening to him in all gears when shifting quickly.
The notchy shifting into gear from idle and the car creeping when going into gear at idle are also things that happen when a clutch isn't fully disengaging, or not disengaging quickly enough.

Sounds like an adjustment issue. I hope it's not just "the way they all are" as the shop stated to him.

[Ca_m4mike]

Originally Posted by Slowdr1v3r

If it was a clutch adjustment issue wouldn't it happen in all gears? Especially at the higher rpms and quick shifts? A friend of mine did mention that his friends shop car has the same clutch and has similar issues and they were thinking of removing the clutch and widening the beginning of the splines to give the input shaft a little extra space to go in smoother but they haven't done it yet so I dont think thats something I would want to do.

What you are describing is clutch drag . I had a twin disc from competition clutch on my evo 9 and it had to be shimmed and adjusted to make sure if fully disengaged . Your clutch needs adjustment I would do it before it causes damage to your transmission. Contact the manufacturer and get info for yourself and go from there

[Slowdr1v3r]

Originally Posted by Ca_m4mike

What you are describing is clutch drag . I had a twin disc from competition clutch on my evo 9 and it had to be shimmed and adjusted to make sure if fully disengaged . Your clutch needs adjustment I would do it before it causes damage to your transmission. Contact the manufacturer and get info for yourself and go from there

Just got off the phone with Clutch Masters. Informed them of the situation and they said "you would need to ship us the complete setup for us to test it to see if there is anything wrong with it or if its defective."

They said if I did not upgrade to there slave cylinder there is no other adjustment for the clutch. No shims or anything and the guy sounded like he just did not know what to say at that point. What they did tell me the first time was to add a bigger bump stop because the pedal was maybe going too far and I did try that but no luck.

[Slowdr1v3r]

So I called clutch masters again and spoke to a manager and he said it may be the clutch delay valve that is restricting the fluid and not giving it enough pressure for the clutch. And yesterday on the way home the car was giving me a lot of trouble going into any gear but now coming to a stop the car was jerking as if I was not pressing the clutch even though it was fully pressed and hard to come out of gear. Felt like I was going to break somethin going into gear. When I finally got it into gear I was able to baby it to get home and parked it up.

The issue is now worse and pointing more a hydraulic issue in my opinion. I did just see a thread about drilling the little plate on the slave as a CDV mod pretty much. So ill try that and see if it helps at all. Any one have any other suggestions?

[Ca_m4mike]

yea sounds like maybe air in the system. As far as the delay valve some vehicles have it inline before the slave to protect against people dumping the clutch. That would give inconsistent engagement from take off or launching but not every gear like how your experiencing

[TopJimmy]

The description of clutch drag sounds like it may be the issue. If your stock clutch was engaging and disengaging properly before the CM install then it's unlikely the slave or CDV or a bubble.

MJ6 any insight here. You've done a ton of playing with ClutchMasters.

[MJ6]

Originally Posted by TopJimmy

The description of clutch drag sounds like it may be the issue. If your stock clutch was engaging and disengaging properly before the CM install then it's unlikely the slave or CDV or a bubble.

MJ6 any insight here. You've done a ton of playing with ClutchMasters.

I've definitely had a fair share of experience with them, both an FX1000 and FX250.

As long as the system was bled properly, everything should be working as it was before. If it's not disengaging fully, short of there actually being something physically wrong via manufacturing defect, I'd be thinking along the lines of a hydraulics issue (master or slave not holding pressure) or a throwout bearing issue. The TOB's that are sent out have both "high" and "low" settings, and depending on how it's set on the clutch fork could absolutely impact engagement. From what I was informed by both CM and SPEC was that the TOB needs to be installed at the "high" setting, basically the setting that pushes the bearing closer to the clutch disk. I'd imaging at the lower setting (what with the increased clamp load) there might not be enough leverage to fully disengage.

This is the TOB at the "high" setting for reference.

[Slowdr1v3r]

Originally Posted by Ca_m4mike

yea sounds like maybe air in the system. As far as the delay valve some vehicles have it inline before the slave to protect against people dumping the clutch. That would give inconsistent engagement from take off or launching but not every gear like how your experiencing

I did try bleeding it when I first got the car back from the shop but I am definitely going to try again as I saw some other guy was having issues bleeding it the normal way and had to reverse bleed it so I did want to give that procedure a try.

[Slowdr1v3r]

Originally Posted by TopJimmy

The description of clutch drag sounds like it may be the issue. If your stock clutch was engaging and disengaging properly before the CM install then it's unlikely the slave or CDV or a bubble.

MJ6 any insight here. You've done a ton of playing with ClutchMasters.

It was working perfect before but when the shop installed clutch the first time they did not know clutch masters sent the wrong throwout bearing the first time and broke the slave cylinder. So they did swap it out with a new oem one and bled it but do wanna try the reverse bleeding method to see if maybe theres some air in there that does not want to come out.

[TopJimmy]

So if the TOB is on the Low setting it may not push enough to fully disengage. That sounds like it could cause the clutch drag.

I'd get the car back in the shop ASAP since you could be cooking the clutch with not engaging fully. First ask if they're SURE the TOB is on the High setting so it pushes further. If it is set right then remove the CDV from the slave (it's not a fix, but since you're in there), and then fully bleed the system. If the bleed doesn't fix it I'd try the CM adjustable hydraulic slave. If this doesn't fix the problem I'd send everything back to CM (since it doesn't work with their recommended solution).

Last resort would be to go back to an OEM clutch and DMF. My F80 was FBO (stock turbos) on Paul's full-race E85 (actually a hotter race mix of pail fuels) and I raced at the dragstrip regularly without any clutch problems. The only mods to my gearbox are Rogue mounts, a $10 clutch stop, and Motul HT-DCTF oil.

[Slowdr1v3r]

Originally Posted by MJ6

I've definitely had a fair share of experience with them, both an FX1000 and FX250.

As long as the system was bled properly, everything should be working as it was before. If it's not disengaging fully, short of there actually being something physically wrong via manufacturing defect, I'd be thinking along the lines of a hydraulics issue (master or slave not holding pressure) or a throwout bearing issue. The TOB's that are sent out have both "high" and "low" settings, and depending on how it's set on the clutch fork could absolutely impact engagement. From what I was informed by both CM and SPEC was that the TOB needs to be installed at the "high" setting, basically the setting that pushes the bearing closer to the clutch disk. I'd imaging at the lower setting (what with the increased clamp load) there might not be enough leverage to fully disengage.

This is the TOB at the "high" setting for reference.

I remember when the shop got in contact with clutch masters they told the shop which setting to put it on. I do not recall which one they did but I can ask(doubt theyll remember. )
I was thinking its hydraulic as well. Did not see any leaks and the fluid level was correct. If there was an issue with the master would I have brake issues as well? Because everything with the brakes feel fine. Or if there is a way for me to check the master I would definitely like to do that before going with another clutch.

I did notice something though from the little driving I have been doing that the first few shifts when I get into the car are butter. With every shift it starts getting a little harder. Shop also said it may be the fluid inside the transmission but I got it done with a friend at the dealer maybe 1000 miles ago with oem fluid. And since the issue starts after just a couple of shifts it doesnt seem like its a fluid issue but I could be wrong.

If it was an issue with the bearing being on the wrong setting would I still have the play I do before the car taking off when driving?

[Slowdr1v3r]

Originally Posted by TopJimmy

So if the TOB is on the Low setting it may not push enough to fully disengage. That sounds like it could cause the clutch drag.

I'd get the car back in the shop ASAP since you could be cooking the clutch with not engaging fully. First ask if they're SURE the TOB is on the High setting so it pushes further. If it is set right then remove the CDV from the slave (it's not a fix, but since you're in there), and then fully bleed the system. If the bleed doesn't fix it I'd try the CM adjustable hydraulic slave. If this doesn't fix the problem I'd send everything back to CM (since it doesn't work with their recommended solution).

Last resort would be to go back to an OEM clutch and DMF. My F80 was FBO (stock turbos) on Paul's full-race E85 (actually a hotter race mix of pail fuels) and I raced at the dragstrip regularly without any clutch problems. The only mods to my gearbox are Rogue mounts, a $10 clutch stop, and Motul HT-DCTF oil.

I have an appointment Monday but the last time I brought it in he was already a little defensive. But Ill see what he says. In the mean time Ill try the delete and the bleeding. Lets see how it goes.

And thats pretty much the same setup. Fbo full e85 with a paul tune but do plan on going single turbo next year so they advised me to go this route.

[TopJimmy]

Originally Posted by Slowdr1v3r

I have an appointment Monday but the last time I brought it in he was already a little defensive. But Ill see what he says. In the mean time Ill try the delete and the bleeding. Lets see how it goes.

And thats pretty much the same setup. Fbo full e85 with a paul tune but do plan on going single turbo next year so they advised me to go this route.

For a manual trans and "street use" you want the torque to come in as early as possible, so I suggest fast-spool twins like regular Pures or Vargas GCs, but not the pluses. If you're going "full drag" then the pluses or a big single will give you a really strong top end, but your engine better be built to handle redline all day. Our S55 does have the 7.5K redline but it's sure not meant to go there frequently.

To go full drag I switched from a FBO manual F80 into a DCT F82 with built motor, trans and driveline, and Kratos EVOs. It's still freezing here but I'm looking for Nines this race season.

[MJ6]

Originally Posted by Slowdr1v3r

They said if I did not upgrade to there slave cylinder there is no other adjustment for the clutch.

Out of morbid curiosity, did CM happen to mention what slave cylinder they offer for our platform? I've been scouring high and low for a beefier clutch slave, but no one seems to make one for the F8X.

[Slowdr1v3r]

Originally Posted by MJ6

Out of morbid curiosity, did CM happen to mention what slave cylinder they offer for our platform? I've been scouring high and low for a beefier clutch slave, but no one seems to make one for the F8X.

I think he said it more in passing than something that actually applies to our cars. I can call and find out if you'd like.

[Slowdr1v3r]

So update on this. Tried the CDV delete and fixed the problem. Every gear is smooth. After a little while of local driving first and reverse get a little notchy again and start to creep but not much. The worst of it now is still smoother than the best days before getting rid of the valve. Also helped a lot with taking off and shifting through the gears. Gonna drive it some more and give it more time to wear a little but still may change the setup as its still pretty aggressive for the driving I do now. Now the only thing left to tackle is the knock/thumping noise when shifting quick but I honestly think I just need to upgrade the trans mounts because even just driving if I press in the clutch and release it quick I hear it.

Anyone in here with a twin upgraded trans mounts?

[1000hp]

Originally Posted by Slowdr1v3r

So update on this. Tried the CDV delete and fixed the problem. Every gear is smooth. After a little while of local driving first and reverse get a little notchy again and start to creep but not much. The worst of it now is still smoother than the best days before getting rid of the valve. Also helped a lot with taking off and shifting through the gears. Gonna drive it some more and give it more time to wear a little but still may change the setup as its still pretty aggressive for the driving I do now. Now the only thing left to tackle is the knock/thumping noise when shifting quick but I honestly think I just need to upgrade the trans mounts because even just driving if I press in the clutch and release it quick I hear it.

Anyone in here with a twin upgraded trans mounts?

Interesting.

Sounds like it might be worth trying their slave cylinder then.