I just got a new clutch (after the old one welded itself to the fly wheel) and input rod bushing instead of bearing, as the previous bearing blew apart, so a bushing should work better. Except now, when i am in fifth gear and going faster than 60 mph, i hear a strange high pitched sound, kind of like a tuning fork, but only when i'm pressing down on the accelerator. it sounds kind of like it is coming from the center console, and i can't really hear it if i have a window open, but it kind of bothers me. at first i thought it might just be the car literally whistling through some odd hole or something, but regardless of speed, letting go of the accelerator stops the whistling, although at higher speeds, the whistiling is higher pitched when i am pressing the accelerator. could it be the bushing doing it, and therefore inconsequential?

it's an all stock 1980 SA LS, even still has the rat's nest (but that will be on its way out soon ). idles around a 1000 after a warm up (a little high, i know, but i haven't had much time to mess with it lately).

 

Interesting problem, new guy. Let me take a few guesses at it.

Having replaced my fair share of clutches on an 80LS and my current 84SE, I can say that the input shaft needle bearing is a serious PITA to replace. The last one I put in, I greased the holy hell out of it along with Never Seize in hopes that when it grenades in there (and it will), that it's easier to get out next time. Also, using the rubber grease fitting also helps to keep the grease on the needle bearing where it belongs.

That said, the bushing idea that you have is probably just fine, since if the clutch is out (your foot is off of it), then the engine and transmission are spinning as one unit, i.e., there is no slippage between the input shaft and the eccentric shaft on the engine. The only time you get the tranny input shaft and engine output shaft running at different speeds (and thus needing the bearing) is when your foot is on the clutch and you're switching gears, or you're sitting at a light with your foot on the clutch and the transmission in 1st. *THAT* is the time that your input shaft needle bearing (also known as a pilot bearing) is getting a workout.

When these go, you'll start to hear quiet grinding in the 'clutch in' conditions, which will gradually get worse, and then suddenlly... it all goes quiet. (Psst - that's cause the bearing has grenaded itself to death, and now there's nothing in there to grind...).

The only way the bushing could be causing a problem is if your clutch is slipping at high speeds, and I kinda doubt it. If you're going to get clutch slippage, it's going to be in 2nd or 3rd gear, as these see more torque from the engine - higher gears normally won't slip even a heavily worn clutch. (Are you a fan of the 'smoky-burnout'??? I'm not.)

Anyway - I would look somewhere else for that high speed whistle. More than likely, it's a vacuum leak somewhere under your hood and you're hearing it through the air intake path. HTH,

Edit: Also - when changing a clutch, on removing the tranny, it's not unusual to lose some trans fluid out the back of the tailshaft - did you also recheck your trans fluid (gear oil) level after reinstalling the transmission? This whistle could be your trans running on low gear oil, and you're hearing gear whine... Check it out.

 

i've burned out a little bit getting used to the new clutch (since it doesn't slip) but only getting into first from a dead stop. thanks for the info on when the bushing gets used, that actually explains a bit, since i tended to sit at stop lights clutched and in first a lot, guess i'll cut that out as much as i can. another friend recommended checking the gear oil as well, so i'll give that a shot (from what i've read on the board, w90 is the best to use, right?)

i actually had a shop do the clutch replacement, since i can't/not comfortable doing that on jack stands. they seemed very proffessional though, apparently they work on a lot of performance cars, and they machined the bushing for me as well. the previous clutch overheated probably due to slippage (at least according the mechanic), and up it welded after i had been driving in fifth for quite some time on the highway.

 

Yep, 90w gear oil is the way to go. Find something that doesn't small too badly, because with the condition of most of our shifter boots, you're going to get a 'gear oil' smell inside the car when you drive it!

(That's a free tip from 25 years of RX7 ownership!)