1991 NSX Clutch Replacement and Other Projects

[Nukem]

This Thread is to document and get feedback on my next project. Some history, I was driving my car in the mountains and on the way home the clutch pedal only came half way out. However pushing it in again it acted like normal until an hour later. I was at a light, 5 minutes from home, and the clutch felt like there was no pressure, but would go in and out the full range, however it felt as if the car had no power with vibration as the pedal was let out. I was able to limp the car home. I inspected the clutch fluid and it was full, slightly greyish. My first thought and many others agreeing the Clutch Master Cylinder. Now for a while I always wanted the NSX Type R gear set with the 4.23 Final. I have given a lot of thought on replacing my clutch, which may or may not be going bad. So below are my plans for what I would like to get done to my car since it will be done. I will update this post as I decide or get more feedback on what I should do. Please feel free to give me your input on parts, or other items I should tackle.

DRIVETRAIN:
- OEM Clutch - Not ordered yet
- Lightweight Flywheel - Not ordered yet
- NSX Type R gearset for 5 speed manual - Not ordered yet
- 4.23 Final Drive - Not ordered yet
- Clutch Master Cylinder - 46920-SL0-A01 $189.47
- Clutch Slave Cylinder - 46930-SL0-003 $148.15
- Clutch Release Fork - Not ordered yet, Are there any other parts I need that should be ordered to replace this part?
Should I replace the Pilot Bearing? What else should I give some TLC towards

ENGINE BAY:
- Timing Belt/Water Pump - Accomplished in March 2022
- Coolant Hoses - Not Ordered yet
- Motor Mounts - Not Ordered yet, Should I stick to OEM?
- Test Pipes? - Currently running custom Pride High Flow Cats that bolt from 2002 headers to 1991 Pride V2 Exhaust.
- Oil Pan - slight leak from the gasket,

ScienceofSpeed Stainless Steel Oil Pan Baffle - NSX, 1991-05

ScienceofSpeed Stainless Steel Oil Pan Baffle - NSX, 1991-05 Oil starvation is the number one cause of engine damage that we see for the NSX. During high speed cornering, braking, and acceleration experienced under high performance driving, oil sloshes aw

www.scienceofspeed.com

$522

MISC:
- Short Throw Shifter adapter - I think I purchased the SOS version a few years ago so it is sitting in a box.
- Tighten up all chassis, and suspension

 

[TANTO]

I don't know how to reference legacy threads, but you should find them under the DIY that are VERY extensive and are going to include about every piece of rubber on the car. I suggest you inspect your various exposed rubbers like your CV boots from the bottom of your car as much of my 92 stuff is holding up very well, but our 09 RDX has all it's rubbers rotting out fast. Of course do all your coolant hoses for sure. On the clutch actuation i would suggest to simply flush out the system very well and it might be fine. Flush the heck out of your brake system. You always want to replace the "throw-out"(pilot) bearing whenever you do a clutch and simply inspect the fork for excessive wear. I think most will recommend replacing the fork outright. If you are going to replace a good clutch -you at least are going to go out and tear it up first, right? he-he as replaceing a non-slipping clutch is not a "maintenance" item. With the OE clutch you have to buy it with a flywheel that you won't need, so the parts will run you about $2500 (just did what you are proposing), but clutches will likely always be available so there is no hurry on that. I would get that R ring and pinion ordered right away. Ditto for the "non-US" tranny gears (what you are calling R), you may find that with the R R&P you will be happy with the US tranny gears. Oil pan seepage may be something to let go as some of us have replaced it and we still get some seepage (the pan oil may be coming from the cam seals/valve covers - very hard to tell). I think we will all agree on your proposed plans, except for the test pipes. Have fun with your "restoration" he-he.

 

[Nukem]

I don't know how to reference legacy threads, but you should find them under the DIY that are VERY extensive and are going to include about every piece of rubber on the car. I suggest you inspect your various exposed rubbers like your CV boots from the bottom of your car as much of my 92 stuff is holding up very well, but our 09 RDX has all it's rubbers rotting out fast. Of course do all your coolant hoses for sure. On the clutch actuation i would suggest to simply flush out the system very well and it might be fine. Flush the heck out of your brake system. You always want to replace the "throw-out"(pilot) bearing whenever you do a clutch and simply inspect the fork for excessive wear. I think most will recommend replacing the fork outright. If you are going to replace a good clutch -you at least are going to go out and tear it up first, right? he-he as replaceing a non-slipping clutch is not a "maintenance" item. With the OE clutch you have to buy it with a flywheel that you won't need, so the parts will run you about $2500 (just did what you are proposing), but clutches will likely always be available so there is no hurry on that. I would get that R ring and pinion ordered right away. Ditto for the "non-US" tranny gears (what you are calling R), you may find that with the R R&P you will be happy with the US tranny gears. Oil pan seepage may be something to let go as some of us have replaced it and we still get some seepage (the pan oil may be coming from the cam seals/valve covers - very hard to tell). I think we will all agree on your proposed plans, except for the test pipes. Have fun with your "restoration" he-he.

I didn't think about the brake flush, but might as well. I am leaning against the test pipes the more I think about it. Mostly due to car being much louder. As for for the oil seepage, I verified it is from the oil pan gasket. I had driver side boot replaced two years ago, but you brought up a good point, I will swap out the other side. Thanks for the input.

 

[MotorMouth93]

If you haven't bought it already, the cedar ridge fabrication oil pan baffle is a little better FYI. Fits the sump tightly so you'll have less oil splashing through it. The SoS baffle has huge gaps.

 

[TANTO]

I mis-spoke on my CV boots as i've replaced them all recently as i did have one crack and a CV failure would be so scary. Not that MM93 needs my reinforcement, I also did the cedar ridge oil pan baffle for my new build - "Titanium Daves" work is legendarily top notch (i'm sure the SOS is very good though), but if you are not going to track the car a lotjjj, it's likely not needed. If your car follows others you likely will eventually need to do cam seals and valve covers which arguably to guarantee success will require an engine pull and you could wait until then to do all that stuff at once (?)

 

[Nukem]

If you haven't bought it already, the cedar ridge fabrication oil pan baffle is a little better FYI. Fits the sump tightly so you'll have less oil splashing through it. The SoS baffle has huge gaps.

I already bought the SOS one and have it in my possession.