Can I adjust my Clutch Pedal safely on this 2008 350Z after this work has been done?

[Chromatic]

Car: 2008 350Z

 

I just had a JWT HD Clutch package, Zspeed CSC Slave, Wilwood HD Master, OEM Flywheel, with all Stainless steel braided lines installed to fix some issues.

 

Everything is great.

 

Except the pedal with the new JWT clutch and HD master/slaves engages almost near the top of the pedal travel. Further up than it even did from the factory stock on this 2008 350Z.

 

I really would like to lower it any safe amount closer to the floor for engagement.

 

After all these expensive parts I don't want to jeopardize damaging the Master/Slave and so on.

 

So I snapped two pictures of the adjustment rod as it is right now to see if you guys think I have room to safely turn it counterclockwise to lower the engagement/pedal closer to the floor.

 

 

 

 

I've read that adjusting this (which I've done before on the old clutch) (but the Nissan mechanic adjusted this one with this new install) -- Can cause premature master/slave cylinder failure.

 

Room to turn there?

 

The pedal is VERY stiff with the JWT HD clutch package (I like it).. and returns up to the top very strong. But it literally engages at the very end of letting the clutch pedal out (maybe 1" or so from the top).

 

I thought new clutches were supposed to be really close to the floor if anything,.. so this is why I'm also asking your opinions before I adjust that rod any.

 

Thanks for any advice and if you need more information just let me know.

 

Thanks,

[Tricky-Ricky]

Yes you can adjust it, it wont cause wear etc, you will probably find it will also make the clutch pedal feel less stiff/hard because the helper spring is designed to work best over a certain angle, and the current adjustment is making it worse, however if this is not the case, you can also remove this, some find its better without.

[Chromatic]

Yes you can adjust it, it wont cause wear etc, you will probably find it will also make the clutch pedal feel less stiff/hard because the helper spring is designed to work best over a certain angle, and the current adjustment is making it worse, however if this is not the case, you can also remove this, some find its better without.

 

Thanks Ricky.

 

I'm just super cautious because of the money I put into parts and the time that it ultimately took to get this all done the right way. (It was a headache) So now that it's all in, and done "right".. I don't want to be the moron who goes and causes it to wear out and go bad by adjusting a rod a few turns.

 

I've read and been told that if you adjust too much (even if it sound fine (ie: You hear throwout with pedal out, and it stop with pedal in) -- That you can still cause binding and the Mastercylinder not to get it's full "action" if you will, which keeps some pressure on the hydraulic system even if slight,.. which causes premature failure, and wear the whole time.

 

The only key thing I've been able to hone in one so far from reading and asking questions is that if the clevis/pin (near where you adjust the bolt/rod) can still move freely AFTER the adjustment it's OK. If it cannot move freely by wiggling it after adjustment, you've gone too far and it's keeping pressure on the system.

 

The Rod is longer on this HD Wilwood Master Cylinder than the Stock MC rod was -- (I was told this by another person who has this system in their vehicle today).. So that makes me feel a little better about the way it looks right now.

 

I see it already screwed into / past the fork 4-5 threads which on a stock rod would be / should be close to the floor (or maybe even too far) -- But, since this rod is longer that makes sense now.

 

If anyone else would like to chime in on the safety of the adjustment here,.. and what to check post adjustment to ensure nothing is under pressure or wearing improperly -- I'm very open to it. I am not rushing to make this adjustment as the clutch needs it's break in time.

[Tricky-Ricky]

Basically if you over adjust the master cylinder rod at the clevis pin so there is no free play before the clutch pedal is depressed you can risk the clutch slipping at high load because some of the clutch spring pressure is negated by the adjustment.

 

Conversely if you over do it the other way IE too much free play before the clutch disengages the MC rod could bind on the clevis, but this would also cause the clutch to feel heavy and possibly not disengage properly.

 

But these are extremes and with a bit of common sense most people Wong get it that wrong.

 

As I mentioned the main reason is to get the adjustment within a window that allows the pedal to function properly and feel reasonably easy, the spring is meant to help with this providing that the general adjustment is within the window I mentioned, however, IMO the spring wouldn't be needed if they had the fulcrum design correct.

 

If you adjust the MC rod so that there is from between 1.5 to 1/2" of free play depending on personal taste, you wont go far wrong, and the switches will still work, although I would advocate by passing the start switch, as this is not good for the crankshaft thrust bearings on cold start.

 

Edit, if to me it actually looks like the clevis itself is shorter than stock rather than the MC rod being longer, if you run into problems you could always re fit the stock clevis if the threads are the same.

Edited February 13, 2015 by Tricky-Ricky

[Chromatic]

From the best of my knowledge/what I've been told...the rod is longer,.. I have been told this by the manufacturer and it is designed for the particular 350 model years .. But they do have mention of shortening (sawing) the rod shorter in some applications, but it's not standard.

 

Another person who is knowledgeable and has this same Master Cylinder and Slave (for that matter) from both companies has commented that he actually had to learn from this.. and had his bind due to his actions (I forget precisely what he did initially) - and had to replace the Wilwood with another Wilwood MC due to this. His advice was essentially to adjust as I wanted to my preference but to simply ensure the clevis could move when pedal was not engaged (ie: get under there and wiggle it) and if it had room to move a little (this doesn't move much on it's own for obvious reasons when just wiggling it with the clutch pedal against the cruise switch/stop) -- I was ok.

 

What is interesting to me as every different car is , well, different -- but our Z's , esp if you have a DE clutch system and all that goes with it vs another DE or an HR compared to HR -- That the stock components will be roughly the same on engagement/disengagement (Given clutch wear is the same, and components aren't failing). -- But interestingly to me,.. Is I had stock everything in it.. with 39k miles -- And the engagement point was high as it is with them all stock from factory,.. but as I went through the gears the engagement point was not as high as it was in First gear.

 

With this new setup (Which is rock solid.. I love it) the engagement point is identical from 1st gear to 6th gear -- And the engagement point makes the car quite tricky to start from a standstill ,esp. stopped on a hill for example, in 1st gear with the engagement being literally 0.25-1" from when the pedal hits the stop (fully out). Just about anyone who would get in this car right now who was adept with a manual transmission would likely stall the car the first time in first gear like this.

 

I guess the point is .. it's so high that it needs to come down even if just a half inch.

 

Testing when the throw out bearing actually starts spinng (making even the smallest amount of noise) at Idle, in neutral, with clutch pedal FULLY down and slowly mm by mm letting it out -- It has about minimum 2" maybe 2-3 inches (hard to gauge how far the pedal is moving by feel without looking at the same time from the side) before that throwout even begins to spin.

 

I'm not sure if this tells you anything about "room for adjustment" as this is on the other end of the pedal from floor to a few inches off the floor -- But hopefully that indicates that there is a bit of room to pull the pedal downwards.

 

I do know that with this JWT HD package.. the pressure plate is 2600+ lbs of force (1200KG of clamping force) -- and that due to it's ability to handle a much higher horsepower load the pedal travel is longer to engage the pressure plate.

 

(The first mechanic who screwed up my shifter then had to go out of town suddenly (long story)) -- Actually told me that with my JWT HD kit, stainless steel lines and HD Master and Concentric Slave Cylinder(s) that my engagement point would be almost right off the floor. He couldn't have been MORE wrong.

Edited February 13, 2015 by Chromatic

[Tricky-Ricky]

Sounds like its just badly adjusted, in order to get the engagement/disengagement point lower you will need to adjust the rod so as more of it protrudes through the clevis, so I suspect if the rod is longer than std, you will need to cut this shorter, that is obviously the reason for it bad adjustment, whoever fitted it did not know it was longer and had to adjust the pedal rod to get clearance not to bind.

Edited February 14, 2015 by Tricky-Ricky

[Chromatic]

Rickey.. I'm waiting until I finish my 500 mile "Break in" period of granny driving before I adjust it.. and I'm at 110 miles .. so it'l be a little bit before I do it. That said,.. would a short quick video of the pedal and master cylinder rod.. and me pushing pedal in while videoing give you any better idea? I make videos and throw em on youtube a few times a week.. so it's not a huge effort/time thing for me.

[Tricky-Ricky]

You can if you want, but by what you describe its definitely down to the rod being longer, therefor it couldn't be adjusted effectively due to the fact that it would bind on the pedal before there was enough adjustment to make much difference,

 

IF there is not enough free play between the resting point of the pedal and the point at which it starts to disengage you risk clutch slip, so you could end up damaging your nice new clutch plate due to slip...the choice is yours.

 

The clutch/start switch does act as a pedal stop so you may be able to gain a few MM by adjusting this in the short term.

[Chromatic]

You can if you want, but by what you describe its definitely down to the rod being longer, therefor it couldn't be adjusted effectively due to the fact that it would bind on the pedal before there was enough adjustment to make much difference,

 

IF there is not enough free play between the resting point of the pedal and the point at which it starts to disengage you risk clutch slip, so you could end up damaging your nice new clutch plate due to slip...the choice is yours.

 

The clutch/start switch does act as a pedal stop so you may be able to gain a few MM by adjusting this in the short term.

 

Hrmm.. Well, you see in the pics there is at least a little room to turn the rod before it will bind in the clevis fork... A few turns on the old rod made a BIG difference, not sure if it's the same with this one..

 

The pedal does have some play (as I think it should) at the top. like, you can press down on the pedal with your hand or foot and it will give like half an inch (I haven't measured) without any pressure. You know that free slack at the top of the pedal? I think it's recommended to have X amount of free play here by Nissan specs?

 

The point at which the pedal disengages the clutch is waaaay down .. probably 3" ish off the floor (This is the same point I can first hear the slightest signs of the throw out bearing noise, and as I continue to let the pedal out that noise gets louder to a certain point.. quite a long travel here -- but it still doesn't GRIP till right at the end of the pedal.)

 

I guess this is why video sort of makes this easier to show.. putting it in words is very visual. I may do a quick video since it's not late over there in the UK to see what you think. Again, I'm not making any adjustments for at least 4-5 days.

[Tricky-Ricky]

Now I get your point! so long travel before proper disengagement, despite the fact its moving the master cylinder from 1/2"-1" onward, its now sounding like there is either air in the system, or the master cylinder or slave cylinder is either to small or too big, now as you mention that this particular combination has been used by others, it seems most likely to me that there is air in the system.

 

 

One further thought, there is a damper on some models, between the MC and SC, and I wonder if this is having more effect (if fitted) than it would with the std MC/SC combination.

[Chromatic]

Heya Ricky,..

 

I made a 5-6 minute video trying to show the pedal movement --

 

 

The pedal doesn't really show any signs of air in the lines. It isn't spongy, isn't falling, grips hard,.. etc -- Just engages too far out.. Simple as that.

 

The Master and Slave are engineered for this exact make/model/year -- So it's not really possible to be too small or too big.

 

I mean, is it not likely just the turning of the rod will alleviate this?

 

The guy who did the work has done probably a few thousand clutch jobs on Nissans in his 25 years as a Master Mechanic solely for Nissan.. So, I am inclined to think he bled it out well/proper. Air in the line is not the first thing I would have thought of though.

Edited February 14, 2015 by Chromatic

[Chromatic]

*Delete*

Edited February 14, 2015 by Chromatic

[Tricky-Ricky]

I suspect what what your noticing is the quite pronounced difference between the original MC/SC combination, which gives a very short engagement /disengagement period,(lack of feel) a lot of people complain about the std setup because of this, the side effect is that its also very stiff.

 

The MC/SC combo you have fitted is obviously designed to prolong this action, with the intent on giving it more feel, as I said before this is down to the differential in the size of the MC in relation to the SC, I think there is probably very little you can do other than try and adjust the beginning and end point of the process by adjusting the MC rod, but the actual point between the is not adjustable.

[Chromatic]

I suspect what what your noticing is the quite pronounced difference between the original MC/SC combination, which gives a very short engagement /disengagement period,(lack of feel) a lot of people complain about the std setup because of this, the side effect is that its also very stiff.

 

The MC/SC combo you have fitted is obviously designed to prolong this action, with the intent on giving it more feel, as I said before this is down to the differential in the size of the MC in relation to the SC, I think there is probably very little you can do other than try and adjust the beginning and end point of the process by adjusting the MC rod, but the actual point between the is not adjustable.

 

Yeah I've adjusted for hours.. Then went back and spent more hours putting it back to full pedal range (at least as it was when I picked it up a few days ago).

 

The bottom line is you really can't do anything about it with the 350/370/G35/G37 platform. Short of taking it out and modifying it.

 

As such,.. I think my best option (and I don't want to spend any more money lol) -- is to go ahead and pre-order an RJM AFP Clutch Pedal System to replace the OEM Nissan Clutch pedal assembly entirely to get a smooth friction zone that isn't just on/off.. no bite/bite -- With full adjust-ability

 

I am surprised that it isn't talked about more as a "Must have" mod for the Z and G platforms with manual transmissions more given how much it improves the drivability of our cars. Even guys with Race style Puck,.. multi disc, setups that are incredibly hard to drive can apparently go from a difficult car to drive in traffic/stop and go etc.. To a very easy one with this design by the Mech. Engineer who has designed these.

 

So.. that's next.

 

I'm also inclined to go this route because I think adjusting the rod into the clevis is asking for Slave cylinder failures,.. possible master cylinder damage,.. excess clutch wear, and so on.

 

When I adjusted the pedal, from very slight change to more significant change it did nothing but pull the top down (to shorten the pedal travel) -- Not helping any of the issues.. even with a shorter travel it still was a no bite then sudden bite at the very end of the pedal travel which doesn't alleviate my particular dislikes.

 

Have you considered an RJM Clutch pedal assembly?

[Tricky-Ricky]

If the RMJ clutch pedal is the same as this..http://www.350z-uk.com/topic/50287-how-to-adjust-clutch-pedal/page__st__40#entry1163127.I did it years ago the big problem IMO with the Z and G clutch assembly is that the designers got the fulcrum point wrong, so the result is that the pedal will always be heavy, it could be alleviated buy using different combinations of master and slave cylinders, however as you have already found out, the selection is VERY critical.

The only other option bar the pedal is to extend the clutch actuator arm so its longer and the slave has less work to do and there is more range of movement, in some ways I wish I had also tried this route as it would be less of a pain to do IMO.

 

As for your worrying about MC rod misalignment...don't as the MC rod actually has a ball at the end and is designed to cope with a fair bit of misalignment, in fact my mod and the RMJ setup relies on this also.

Edited February 15, 2015 by Tricky-Ricky

[Chromatic]

You were/are on the right track that is for sure. But, no it is not what you fabricated (but very smart).

 

It IS based on the Fulcrum.. but since it's been designed and uses the best parts possible (laser cut, etc) -- and has dozens of other improvements to the original stock pedal.. it's not the same.

 

But,.. no offense to you,.. but this was done by a Mechanical Engineer (so it falls right in his ballpark) as a solution to his own distaste for the clutch response of the G35, 350Z, G37, 370Z etc..

 

Then he was asked to replicate another for someone else and it turned into a small side business.. He is still a mechanical engineer by day

 

Anyhow.. This is what it does:

 

- Smoother Launches with more Control, Lower Friction Point and Predictable Engagement!

- Much Smoother 1-2 & 2-3 Upshifts Shifts!

- Smoother and easier 4-3 & 3-2 Downshifts!

- Improvement in Pedal Feel & Clutch Control for all clutches OEM to Extreme Multi-plate and Heavy Puck clutches.

- Adjustable for Stroke Length, Pedal Angle/Height, Friction Point & Pedal Pressure!

- Now features a Single Acting Torsion Return Spring & Eliminates the Terrible Factory "Assist Spring Mechanism".

- Rev 3.3 Features increased adjustment capabilities over older versions for more setup flexibility.

- ZERO Pedal sticking to the floor after Hard Driving, Track Days or Events

- Reduces or Eliminates chance of CSC failures on 07-08 HR 350Z.

- AFP Adjustment Mechanism featuring a simple dial adjustment for fine tuning.

- Altering the pedals fulcrum point widens the narrow factory engagement window.

- Adjustable Catch/Friction Point

- Adjustable Modulation Area and Pedal Height.

- Significantly Smoother Shifting with much less jerking in lower gears!

- Makes once rough 1-2 shifts much faster & smoother.

- Works to improve ANY clutch from bone stock to heavy single's, puck types and even twin/triple disks.

- All clutch types see a huge improvement in drivability and ease of use.

- Increases your ability to modulate even the most aggressive on/off type clutches.

- Smoother launches with better control and less shudder!

- Makes heavy stop-n-go traffic a breeze without needing to rev before letting the clutch out!

- Much easier hill starts without bucking or jerking.

 

The list goes on.. the engineer , Ryan, is a super nice guy.. will always take the time to help you.

 

He built a MUCH better mousetrap due to Nissan's utter failure in their clutch system in the G and Z series of 2003+ --

 

This is a CAD (I believe) representation of it:

 

 

Here is it.. looks like a Version 3 model at first glance:

 

 

I know initially he removed the spring(s) entirely.. (or rather didn't put any springs into his design) -- But in the later version(s) he has put a single light spring to merely ensure the pedal returns to the top (stop).

 

The inside of the OEM pedals is like a compound bow sort of.. It goes against you.. and switches to "assist". Which some people remove the spring from the stock to get a "feel" .. cause the stock spring system keeps a very "NUMB" clutch feeling.

 

Anyhow.. I assume you know all about it. Your self modification is smart,.. but I appreciate this guy using his professional talents to design a part we can all use that is made about as well as things can be.

 

If you have not read up on it that much.. Go google RJM Pedal Review - or something similar. I have yet to see one person speak negative about it.

 

The RJM pedal is THE fix all for our clutch issues. He was willing to develop a Right Hand drive version (as RHD's are very different under the dash where the Clutch is) if 20 people wanted one.. But no one organized it .. so he only has the LHD products.

 

From the billion reviews out there.. I have zero doubt this is what I'm after (and it's fully adjustable in half a dozen different ways on the fly.. )

 

Speaking of the Slave. His design here.. actually reduces wear and tear on many things.. including the Slave -- The stock setup will often push the slave further than it needs to go to perform the "task" if you will.. that coupled with some pressure (trapt fluid and heat issues) will pop seals, and cause CSC/Slave failure. This design actually reduces wear and tear on everything..

 

Since you won't ever do the incline, stopped, 1st gear start (rough start) as is common.. it saves on the entire drivetrain, ujoints, etc..

 

Given how it keeps the actuator of hydraulic fluid only working as much as it needs to be by "design",.. it technically can extend the life of the Clutch disk, MC, SC, FLywheel, etc etc..

 

He can go into ridiculous detail on what it does/how it's beneficial beyond just being a way to turn Manual Z's into what they should have been.

 

Not looking forward to hours under the dash.. but it's a one time deal for a HUGE payoff.

[Tricky-Ricky]

The principal is the same, he has just taken it further and has the machinery to make everything required, I saw the first version, he has obviously refined it and made the whole thing more complicated, which figures as he obviously wants to make some money, so nobody is going to pay big money for the simple option that can be achieved DIY.

 

I am sure the design is good but I was quite happy with the results I got from mine for the work involved, I too have an engineering background, just not the tools these days.

[Chromatic]

The principal is the same, he has just taken it further and has the machinery to make everything required, I saw the first version, he has obviously refined it and made the whole thing more complicated, which figures as he obviously wants to make some money, so nobody is going to pay big money for the simple option that can be achieved DIY.

 

I am sure the design is good but I was quite happy with the results I got from mine for the work involved, I too have an engineering background, just not the tools these days.

 

I do think you are underestimating and assuming here (Just as I did a few weeks ago). No offense,.. he has the parts laser cut,.. He's one of the nicest guys you'll ever meet and this is a side thing for him.. he does batches of 20 at a time and they sell out and then he has more parts laser cut, etc.. And he hand paints and assembles them all.

 

He prices them at $249 and his costs are close to $200. He doesn't make much money from this,.. this is genuinely a case of providing a solution that beats any other hands down with a little profit. He could easily sell these things for $499 and they would sell out.

 

This pedal assembly and adjustments (done with the turn of a knob as you drive if you want) are light years better than anything I've seen others do on their own. Again, no offense, quite awesome of you to do modify your own pedal the way you did,.. however I suppose you have to do some reading on just what this thing does and more specifically why it is designed the way it is and how it changes dozens of things rather than just one.

 

His revisions are him taking in customer feedback and putting it into the product to make it better, and easier to install. He doesn't increase the price when he adds more features, makes a feature better, etc. The original models had no spring whatsoever -- The newer ones do have a single spring, as I mentioned, only to ensure full pedal return every time (no more pedal drop period).. It's a very light spring which has no effect on the feel this product gives the 350Z's clutch that is not there with the factory pedal.

 

You are happy with the way your modification performs and , for you, that is all that matters. That said, I'd be willing to bet if you had one of these just put in your car you would see what all the "fuss" is about, so to speak. Though there is no RHD model at the moment because he had a request for one and it's a major redesign and he is already a very small operation.. but he said sure, he would put in the R&D to basically create a new product for RHD if the forum where the guy asked could get 10-20 people interested in buying it. I believe 2 people responded,.. so , so far it hasn't been done.

 

I'm not certain just how many 350's, 370's, G35's and G37's are in the UK -- but I bet on the right forum (maybe this one) 15-20+ would be willing to spend the £160 to have their clutch feel radically better and eliminate the 1st gear starts, 1st to 2nd issues some have.. actually put back in the feel of a clutch in the car,.. and the other 28 features this thing adds

 

To me,.. this should be the FIRST modification anyone with a 350/370/G35/G37 manual should do/add to their vehicle.. hands down. You don't get more benefit than altering the way your car drives via the clutch if you think about it.

 

I'm not selling you on it.. lol.. I talked to this guy a year ago and he went back and forth with me knowing I wasn't buying anything for a week..

 

The only reason I'm now finally buying it is because of the new improved products I put into my Zed and them making the friction zone (or lack thereof) SO apparent that I have been researching for days on solutions and the answer I kept coming across was this RJM Pedal. Every single person who bought it and installed raves about it like it's a miracle worker. So we'll see.

 

I'm just this positive about it because the guy who makes it is so giving of his time and .. rather unclassically, .. not in this for the money. Which is very apparent when you see his communication between all the people who ask about the product, etc .. or if you just send him a random email or PM.

 

Thanks Ricky for your help here though -- Your advice is part of the reason I ended up just going with this pedal to just fix the problem once and for all.

Edited February 16, 2015 by Chromatic