05 EVO 8 MR
Recently 5 speed converted (new BR Bushwhacker - stage 2 ult)

I recently had my ACT 6 puck unsprung clutch give up the ghost. So I bought and had my friend help install a Quartermaster Twin Disc STREET (new version) with a HTOB. It is our first time installing a twin disc so we don't know too much about them. We studied up on forums and carefully followed the provided QM instructions for installation, vacuum bled the HTOB/CMC and started testing it out. We are aware of the fact that we need a pedal stop to eliminate about 1 - 2 inches of pedal travel from the floor, so we were careful on how much we pushed in the pedal.

Upon initial start-up, the moment the clutch pedal was depressed even a little, there was a squealing similar to belt slippage. Completely unaware of what that was, we initially disregarded it with the knowledge of twin-discs not being the quietest clutches).

I installed a homemade pedal stop and began attempting to adjust it. (Engine off, 1st gear, friends pushing the car, pushing the pedal in until the car moves) It would not disengage with the stoppers length. When tested with engine on, all gears grinded and refused to budge. I removed the stop and slowly tested little by little...still didn't disengage. We adjusted the clutch pedal rod all the way out so that it'll push the most fluid into the HTOB, and eventually got the VERY BOTTOM of the pedal to disengage the clutch...kind of. Reverse grinds like a muthaf, and all of my gears are now hard to get into, like the feeling of being locked out and having to force it in. The grinding is gone. If I sat there with the pedal in, trying to put it into first, I can feel the car trying to drag forward while the shifter is leaning against the "wall" that's stopping me from getting into first.

NOTE: the only reason we pushed the pedal all the way in is cuz we were under the impression that the HTOB isn't actually over extending the PP fingers due to the engagement point being at the floor, nearly PAST the floor. I hope we weren't wrong haha.

After adjusting the clutch pedal rod, we noticed that pressing the pedal doesn't make the belt squealing noise anymore. Just the usual chatter. We rotated the crank, peeked at the clutch PP fingers and they all appeared to be okay and the HTOB is making contact (no gap) with the PP.

Today my friend removed the trans and took apart the clutch and everything looked okay, no damage. It's at this time that we need some suggestions from people who know this stuff from experience. Are we adjusting incorrectly? Did we bleed it wrong? What can we do? It appears that the disengagement point is just out of reach. Bad CMC? Bad trans? (explain?)

Thanks in advance! Sorry, tried to be detailed.

* Worth noting I had to drive it home. We did it at his workplace (Nissan) on lifts over the weekend. So Sunday, I drove it home like that. Other than disengagement issues, the grab was beautifully forgiving yet strong, and the pedal feel is rather similar to an exedy stage 2? Possibly softer. If that sounds wrong, let me know. Cuz it could help us lol. I won't be driving it anymore until we figure this out.

 

did you measure the distance from the push type slave cylinder to the face of the tranny?

sounds like it needs to be shimmed.

Mine was perfect when i installed mine and didnt need any shimming but it sounds like yours does.

cause it seems your HRB is to far away from the clutch.... thats why you had to mess with your clutch lever.

alot of post about it... and the instructions have the measurement details

 

The more I thought about it, the more I believe it. I guess we failed to see that it may need to be shimmed due to even certified dealers posting on forums that they swear by it being a drop-in fit and that shims were only for adjustment and rebuilds.

In hindsight, I’m not sure if measurements were taken. As I wasn’t there while that part of the install happened. But I know what you mean, I did see something that looked somewhat like a workbook on the instructions for you to scribble you measurements on.

I dont have the instructions with me, they are with my friend. But the shims go on the HTOB right? Damn we need to drop the trans for a third time, this is...less than fun hahaha.

 

Okay, update.

For some reason the measurements were coming out with negative clearances. We tried both the formula on the instructions and alternative formulas we read on here where the OP's were saying that they were getting negative values too. We ended up having to "guesstimate".

We took a mic and measured the acceptable clearance, then pretty much shimmed, re-assembled and eyeball-compared the mic clearance with the gap between the HTOB and the PP fingers. It took a few tries. After that, the clutch engagement came off the floor about an inch. Knowing that the CMC rod is still adjusted fully outwards, I still feel that it either needs to be shimmed more or that we need to bleed it better. Either way, it fully disengages at a stop now...at pretty much the bottom of the pedal throw. But when the car is moving, if I clutch in, it's rather difficult to pull it out of gear. As if it isn't disengaging fully. What's the deal with that? I couldn't wrap my head around it. I did find that I'm missing two transfer case bolts and one trans to engine bolt. Is that where my fluctuating engagement point is coming from?

Thanks guys.

 

uhhhhh....
not sure how you could get negative numbers unless the HRB was already pushing into the clutch when you bolt it up.
the instructions posted here:
https://www.evolutionm.net/forums/ev...t-version.html

measure the distance from the face of the transmission to the face of the TOB.

then measure the face of the block (where the tranny meets up) to the spring fingers on the clutch.

I just used a straight edge and a ruler.
only tricky part was measuring the distance to the spring fingers... had to measure from my straight edge i had setting on the clutch face to the spring fingers and then add that to the full distance for the clutch.

it sounds like your HRB is still too far from the clutch.

you need to replace the bolts... but as long as the tranny is pulled up correctly to the block, this would not affect your measurements.

 

For the most part you dont want a huge gap as you could potentially push the tob piston out of the housing. Ive been running that clutch for over 3 years and never used a stop. In my experience i have to adjust the rod on occasion. You could potentially over extend the fingers and mess up the Pressure plate. Also this clutch will kill synchros if you do not have it adjusted right. Should be able to flat foot the crap out of it if it is adjusted right. Any clutch drag will eat up synchros.

 

never used a stop? on what? the pedal?
what rod are you adjusting?

 

as far as measurements go, it’s beyond me why we can’t get the formulas to work. Regardless, through trial and error we got a clearance estimatethat I’m comfortable with.


Got it. Approximately, how many inches from the bottom of the pedal have you adjusted it to engage at?


I believe he means pedal stop, yes. And I think the adjustment rod of the CMC is what he is referring to.

 

UPDATE:

My orders of all of my OEM transmission-block & transfercase bolts came in. Even a bolt that was missing for the rear end of my front crossmember. Installed all bolts and the car shifts like a dream! I suppose missing one transmission bolt and two transfercase bolts is definitely enough to make engagement really wonky
Most unpleasant noises have also subsided. The squealing and scratching sounds have turned into a common clutch chatter. My engagement point feels very high up in comparison to before. Keeping in mind that my CMC rod is still adjusted all the way outwards, (idk how to describe the orientation of this adjustment), I feel I can safely adjust the rod back inwards to bring the engagement point down enough to not need a pedal stop.

I found why that rear bolt for the front crossmember was missing, as well. Started that new 17mm bolt in the rear and then went to tighten the 2x 12mm’s up front and witnessed the crossmember slingshot the 17mm into the pavement LOL. The threads in that bolt hole are done deals already. It looks like I’m going to have to thread it a size bigger and find a new bolt to match.

Also, I rubbed a hole in my driver’s side brake line while test driving last night. Never ending, I tell you lol.

on the side, I’ll probably keep searching about why the measurements we took kept returning negative values when plugged into the formulas for clearance. It bothers me. Would it have to do with having a Buschur Racing trans?

 

tranny must not have been fully pulled up to the blocks.

glad you got it figured out.