DIY: clutch adjustment for second gear grind

[vtackk]

I've seen posts about this before but never any pics. This has been such a heated topic on these boards, I think a disclaimer is needed:

1. I don't claim that this is a legitimate fix for second gear grind, its only an adjustment that (in theory) may help reduce it.

2. I realize the clutch itself is hydraulic and self-adjusting, this post is about adjusting the point of engagement along the clutch pedal's travel.

3. I don't reccommend this for someone who hasn't already taken their car to a dealer to try to get the issue resolved, or at least tried a different trans fluid. Those things are MUCH more likely to have a positive effect on the problem.

4. If you aren't mechanically inclined, or if you don't have a decent understanding about what you're trying to adjust for, DO NOT ATTEMPT THIS. You could end up with a clutch that doesn't fully engage or disengage, resulting in mechanical damage or personal injury.

To repeat myself, this isn't a true "fix" for anything. The theory I'm working off of is if the point of engagement is higher in the pedal's travel (it happens sooner when you press the clutch), the clutch will be disengaged for a longer period of time between shifts, giving the synchros longer to do thier job. We're talking fractions of a second, but I have to think every little bit helps. You could get the same effect by adjusting your driving habits (pressing clutch sooner, keeping it in longer) but like everyone else, I'd like to be able to drive this car like every other car I've driven in my life that had a standard trans. Instead of adjusting myself to the car, this is an attempt to adjust the car to myself. Here we go:

First, you have to take off the plastic trim piece above the pedals, just twist the knob in the middle and pull down on it, it unsnaps pretty easily.



This is a pic of where the clutch master cylinder attaches to the clutch pedal. Right where I'm pointing there's a jam nut on the master cylinder shaft (can't actually see it in pic, its on the backside). Break it loose by using a 12mm wrench, you'll need to turn it clockwise as you're facing it. Now, to raise the point of engagement in the pedal travel, turn the master cylinder shaft clockwise (once again, clockwise relative to how you're facing it). This will unscrew the shaft from where it attaches to to pedal, essentially making the shaft longer. Theres not a whole lot to play with, go slow, maybe one turn or less at a time, give it a try, then adjust it some more if needed. Re-tighten the jam nut when you're done (this will be counter-clockwise).



If the engagement feels too close to the top of the pedal travel, you can extend its travel a wee bit by adjusting this, its a switch that also acts as a stop for the pedal's uptravel. Unplug the wires from the top, loosen the jam nut (I'm pointing to it), and then unscrew the whole thing. Once again, go a little bit at a time, one full turn or less. When you're satisfied, plug the wires back in and tighten the jam nut.

I haven't had much time to drive since I've made these adjustments, and in all likelyhood it won't do much, but in theory it should help a little. Let me know what you guys think.

[MacMan]

I think another option for a fix is the aluminum shifter cable bushings to help eliminate slack/give while shifting, and maybe even a short shifter (less distance to throw stick = less time to throw stick, though as OP said it would be fractions of a second).

TBH, when I read this post, all I could think was 'full time clutch slip'. I'd guess that since the 2nd gear problem (at least in my car - '09 RR Si Sedan) is 6k+ RPM's that the people doing this mod would eat up their clutches quickly if this wasn't adjusted perfectly. Clutch 'feel' would not be a sufficient gauge of measurement for *my* car. I'm not that interested in buying a new clutch. Definitely try the trans fluid swap, then go for trying to get the dealership to fix it.

This seems like an interesting idea, I'd be interested if you kept us up to date if it helps and how long your clutch lasts, if the life is at shortened.

[vtackk]

Its possible to adjust the engagement point in the pedal travel and still have full engagement and disengagement. This is where it gets hard to explain and if you don't have a good understanding of what you're adjusting and what to look for, you should stick to the more common fixes like trans fluid, etc. Anyway, after driving the car for a day I ended up adjusting it back closer to the factory setting. Whether or not it helped with the grind, I dunno, but I figured out I like the engagement better in the middle than near the top. But still, every car isn't going to be exactly the same, so looking into this may pay off for someone else...

[CaptainSmokeSi]

adjusting definitely helps the grinds. so does changing the clutch hose to a braided stainless one. Amsoil works wonders too