Hi all,

I'm new to the forums having just acquired an S2000 in the last month or so. I'm based in Dublin, Ireland. I'm having problems with the car. The car drives great but I bought it with this grinding sound on overrun (ie. when you shift down from 5th to 4th or 6th to 5th or let off the accelerator). There is no problem engaging the gears

The car has a bit of history. It was driven hard for all of its 37000 mile history and has had an accident before (driver's side and rear). I've gone through the drive train including opening up the gearbox and replacing bearings:

1) Changed the propeller shaft (2nd hand item)
2) Changed the final drive (J's Racing 4.7:1)
3) Changed the clutch and flywheel (Clutchmasters FX 400)
4) Changed 2 rear wheel bearings (opened up the bearings and they were all scored from donuts)
5) Changed right hand side engine mount (left side looked fine)
6) Replaced original gearbox with a 2nd hand one from a reputable scrapyard after the sound was still there with the replaced bearings (same sound still there)

I was wondering with all the great minds on this forum if anyone has had a similar experience with this grinding noise on overrun. It sounds very much like bearings but the bearings were completely re conditioned in the first gearbox and the sound was still there.

The 2nd gearbox was dropped in yesterday but it still has the same sound when you lift off the accelerator at about 4000 rpm and especially when you downshift.


heeellp meee... please. Before I give up!

 

I hate to tell you this, but what you are experiencing is the typical S2000 clutch decel buzz. It is a characteristic harmonic vibration that originates from the tranny and manifests itself in the springs of the clutch. When you decel from about 4500 rpm, it will make this buzzing sound. You changed all those parts to only get new parts. This buzzing is pretty normal for all OEM Clutch discs. The older the model of disc, the more the noise.

 

Thanks for the reply xviper.

I've uprated the bits that I've changed except for prop shaft and gearbox.

Clutch is a Clutchmasters FX400 with flywheel (4 paddle clutch) Double sprung.

Is there any way I could reduce the noise of that sound. It's quite disconcerting when you go down the gears and you get this buzzing sound. There seems to be a lot of vibration through the clutch pedal as well.

Could new engine mountings make it any better?

 

The 02 and up Stock clutch disc eliminates MOST of the noise. It's not completely gone, but nowhere near as noisy as before.

My ACT street clutch uses an OEM Honda organic disc, and is just as quiet as the 02 and up disc.

 

The noise and vibration may simply be a function of the type of clutch you are running. Puck type clutches have been reported here as having their own peculiarities and assuming the clutch job was done properly, there may not be much you can do.
As for the engine mounts, inspect them first. If they aren't leaking, putting in new ones may have little impact. You might be a candidate for an engine torque damper. A stock car wouldn't really benefit from this but you have a fairly aggressive clutch by OEM standards.

 

I have everything stock and at the moment i am passing thru hell to find some buzzing problems. I do have the clutch buzz on desc problem and is also felt in the clutch pedal like you described. I never read on this forum that the clutch buzz can also induce vibration in the pedal. At least am not alone.

As suggested by the man in person Xviper. I will remove all heatshields, change tranny oil and get a new OEM 02 clutch. While at it, i'll change to comptech flywheel and ACT pressure plate. (Hardtopguy)

In your case, I don't think i can be of help, but keep this thread updated with the vibrating pedal after the clutch change.

Off topic..what tranny oil do you recommend in terms of weight/viscosity?

 

Honda MTF is a very successfully used widespread tranny fluid. I don't know if you can get this where you live but if you can, GM Syncromesh Friction Modified appears to be an even better fluid. You don't need to worry about weight/viscosity. These two fluids only come one way.