S13 Chassis, SR20DET Swap (Redtop) - Clutch Disengagement/Engagement Issues

[zaneithan]

UPDATES IN ANOTHER POST BELOW

Reposting in a more appropriate section.

Background: I've had this swap in multiple S13 chassis and it always seemed to have issues with the clutch disengagement/engagement. For the longest time it was just an issue where, as the car warmed up, the engagement point would change (usually creeping up from the bottom to the top of the clutch pedal swing). From there it got worse to the point where once warmed up, no matter what, the car would stay "stuck" in gear or give resistance (like the clutch wasn't fully disengaged) when trying to put it in gear. At this point the car was parked to start digging in and try to solve the issue.

New Parts:

1. OEM Master Cylinder
2. Nismo Slave Cylinder
3. New Fluid

Additional parts of note:

1. SS Clutch Line
2. Exedy Hyper Single Clutch (w/ Flywheel)

Where it currently stands: The clutch damper has already been bypassed.
I've also got the new master and slave cylinders installed and bled the hell out of the system. The slave clearly extends and presses on the fork as shown in the pictures below. This is with the clutch pedal adjusted to push the master cylinder piston as far as possible.

I'm not sure where to go from here but think that the next step is to drop the transmission. Prior to doing that I wanted to post here to get advice to see if there's anything I might be missing. I searched old threads and didn't find this exact issue but from what I could gather together this could be a pivot ball issue, bent clutch fork issue, or something else behind the bell housing.

Pictures:




Thanks for your time.

[Ilya]

That clutch fort to pivot ball joint looks toast. When you have the transmission off next time, verify that you have all the parts at the clutch fork like it shows in the diagram of the s13 KA24DE FSM (SR and ka are same enoughdown in that department). Looks like you are missing a clutchfork retaining clip that makes sure the clutch fork only stays on the pivot ball or your pivot ball is toast.

[Agamemnon]

I'm also interested in thoughts about this as I am having the same issues with my KA. I should drop the trans and look into it but its been too hot here lately.

[Bnr32gtr]

Do u guys have proper free play in the linkage from the pedal to master? It should have play/slack in the linkage before the rod itself moves. I like it's like 1/8-1/4" but looks it up in the fms it tells u Exact range.

[zaneithan]

Originally Posted by Bnr32gtr

Do u guys have proper free play in the linkage from the pedal to master? It should have play/slack in the linkage before the rod itself moves. I like it's like 1/8-1/4" but looks it up in the fms it tells u Exact range.

Thanks for the reply. I’m not following however on how this would affect the ability of the system to disengage the clutch. Can you elaborate further?

[Kodiak303]

So aaah... how do I post a new thread?

[derass]

Originally Posted by zaneithan

Thanks for the reply. I’m not following however on how this would affect the ability of the system to disengage the clutch. Can you elaborate further?

If there's too much free play, the pedal isn't able to fully depress the piston in the master cylinder. As a result, the slave cylinder doesn't fully extend.

Originally Posted by Kodiak303

So aaah... how do I post a new thread?

As a new member, you have to wait 30 days to create a thread. You can read the rules here:

http://zilvia.net/f/showthread.php?t=326097

[zaneithan]

Originally Posted by derass

If there's too much free play, the pedal isn't able to fully depress the piston in the master cylinder. As a result, the slave cylinder doesn't fully extend.


http://zilvia.net/f/showthread.php?t=326097

Ah, I see what you guys mean now. I was thinking the other way (i.e. having no play). It's certainly not too loose in my case at least.

[spooled240]

I had clutch disengagement issues with my KA for years and finally fixed it recently when I upgraded to a white bunny setup. What I believe fixed the issue was replacing the clutch fork and pivot ball. They were probably original and looked pretty worn.

If you do end up dropping the trans I strongly recommend you change these parts. It's not even that expensive for new replacements. Also apply a light amount of grease on the input shaft splines so the clutch disc can move freely without binding.

[Bnr32gtr]

I have seen a few pivot ball be worn out so that could be a thing but if u have been fooling around with the linkage or if it's not a factory five speed id be adjusting the linkage to spec. If u been riding around with no free play it makes clutch slip. It should have a good bit of slop before the rod moves.

[Agamemnon]

But look at the pic of the slave cylinder. It’s clearly extended. It looks like the clutch fingers aren’t forcing the release bearing back. That’s not really an indicator of a bad maladjusted clutch rod.

[zaneithan]

First, let me apologize for the lack of updates on this. I was finally able to get the transmission off to inspect everything. What I found was that there appears to be excessive wear on the fingers of the clutch diaphragm (see below pictures 1 thru 3). These wear marks appear to be caused by the throw out bearing but I'm not sure how.

According to Exedy's troubleshooting guide there are four potential causes for this.

1. Eccentricity between the axis of rotation of the clutch cover pressure plate assembly and that of the clutch thrust bearing.
2. Inferior clutch thrust bearing (not self centering type).
3. Worn release bearing sleeve carrier or clutch fork.
4. Lack of free travel.

Based off of the fact the groove worn into the diaphragm fingers is even all the way around I believe #1 can be ruled out. The install manual (and research done here) indicates that no special throw out bearing needs to be used, just a standard OEM one. I confirmed this was replaced with a brand new OEM one and installed when the clutch was put in (see picture 4 below). #3 seems the most likely since those parts were never replaced but they don't appear to be in too bad of shape (see picture 4,5 below). #4 was debunked with the original post showing the slave/fork have plenty of free travel.

I don't want to just replace parts and throw this back together only to be in the same situation which is why I'm posting to get everyone's opinion. Other questions beyond the wear on the clutch are:

1. There appears to be excessive free play in the fork (see below video). The pivot ball is not broken (see below picture #5) but the fork does not sit on it like a ball in socket. I'm not sure if this is normal.
2. The clutch alignment tool I got with the clutch was for a Subaru. The part numbers between the one I ordered and a Subaru GC8 clutch only differ by one letter (NH01SD1 vs. FH01SD1). It's a long shot but I'm curious if I got a clutch for a Subaru. I have the serial number off of mine and will be sending to Exedy for comment on this.

Pictures:







Video:

https://youtu.be/7xutxHHcwiE

[Kingtal0n]

My 1 suggestion is to clean everything spotless while you have it off. That dust contaminates every part and a clutch spends its life throwing that stuff off just to have it gradually creep back in and muddle things up nearing/accentuating the end of its life. I usually pressure wash then take a rag with brake cleaner to really get in there, especially the input shaft grooves go through them with a sharp pick.

When everything is clean go back over it with a coat of Molybdenum sulfide lubricant (the FSM will say to use this) on parts, especially input shaft where clutch slides, pivot ball and anywhere you could get rust (steel exposed parts)

I especially coat the throwout bearing where it contacts the pressure plate.


2. Comments
Exedy was a great help when I was having similar issues (had multiple clutch plates and diaphgrams and didn't know what to use or which one was good) they had me send the plate in for a pressure test etc... and recommended the correct parts to buy that would work with their setups. The guy knew some very interesting details about the sr20det configurations, for example some years got thicker discs or something. He was able to tell just from a picture which one I had too. Its all very confusing to me but they seemed to know exactly what I needed so I have a feeling they will set you right.

[zaneithan]

Originally Posted by Kingtal0n

My 1 suggestion is to clean everything spotless while you have it off. That dust contaminates every part and a clutch spends its life throwing that stuff off just to have it gradually creep back in and muddle things up nearing/accentuating the end of its life. I usually pressure wash then take a rag with brake cleaner to really get in there, especially the input shaft grooves go through them with a sharp pick.

When everything is clean go back over it with a coat of Molybdenum sulfide lubricant (the FSM will say to use this) on parts, especially input shaft where clutch slides, pivot ball and anywhere you could get rust (steel exposed parts)

I especially coat the throwout bearing where it contacts the pressure plate.


2. Comments
Exedy was a great help when I was having similar issues (had multiple clutch plates and diaphgrams and didn't know what to use or which one was good) they had me send the plate in for a pressure test etc... and recommended the correct parts to buy that would work with their setups. The guy knew some very interesting details about the sr20det configurations, for example some years got thicker discs or something. He was able to tell just from a picture which one I had too. Its all very confusing to me but they seemed to know exactly what I needed so I have a feeling they will set you right.

Thanks for the tips. Everything will be cleaned/greased and I'll also be replacing some of the components with brand new OEM while I'm at it (TOB, Fork, pivot ball (going Nismo), sleeve). I'd like to avoid dropping the transmission again in the near future so might as well take care of all when i have it off and am diagnosing/taking care of this problem.

[zaneithan]

Update #2 - I spoke to Exedy and they are unable to determine the fault based off of the information I have. The throw out bearing model number used was correct and the pictures don't definitively point to anything. Next step is to send the clutch out to them for testing.

[dorkidori_s13]

i would highly recommend switching to the solid face type TOB as well as replacing all of your hydraulic based parts while you have the tranny off (new carrier unit, pins, clips, pivot ball etc).

ive had nothing but issues with the open face type (ACT and Exedy supply these in the box). i have been using the solid face type TOB religiously now for almost 10 years with ZERO issues (ran into a lot of engagement and catching issue with the open face type a while back ACT supplied me, swapped back OE to solid face and all problems went bye bye)

EDIT: one other thing to check is the threads of both the input shaft and the clutch itself... it MAY be catching due to improperly finished surfaces. take some 200 grit sandpaper to both and clean them up.