I'm having a problem with my clutch i think. When releasing the clutch coming out of first gear, the drive train seems to vibrate and clunk unless i feather it very delicately or rev it up past 1800. I thought it was possibly motor/tranny mounts but they are good. I also checked the drive shaft but no play in the u-joints.

Any suggestions.

I have a new clutch just in case.

 

Kinda a common issue, enough that RB made a brace for it.
RX7 1975-1985: Engine - External: Engine Torque Brace - 79-85 RX-7 -

Have you just looked at the motor mounts, or have you jacked it up/picked up on it with a hoist?

 

I've had the same issue. lol

 

Semi solid mounts was my fix

 

I haven't picked up on it, I'll do that tomorrow. I also have the rb brace on the car. I'm going to look up the mounts mentioned as well.

 

I have this brace on my car, Doesn''t do a damn thing.

 

Yep, thats an rx7 for you. Check your motor mounts as mentioned and also make sure that
tranny mount is actually solid as well. Otherwise this is normal and the RB brace was made to
help eliminate this but I never felt a need for it myself.

 

I cant compare the car without the brace because it was on it when I bought it. Lol.

 

^Oh yeah? Unhook the brace, then drive it around. You'll get a before and after that way.

Guys, RB sells a competition trans mount and motor mounts which are 40% stiffer than stock. They're perfect.

I've never tried the RB brace and now don't feel the need thanks to upgrading to competition mounts.

Hockey pucks are another option. I estimate they are 60% stiffer than stock. They only absorb during the compression phase. A bit more vibes than competitions but not too bad. So far so good on longevity.

I've tried a solid trans mount. In two different vehicles. They sucked. Vibrations and tons of drivetrain noise. Not worth it. Basically they consist of a stock trans mount, usually where the rubber is just beginning to separate from the steel. You find a good grade 8 or so bolt, usually in 3/8" or 10mm, then drill a horizontal hole through the outer steel wrap around and the inner steel part. Insert bolt and a nut on the other side with either a weld tack or a lock washer. Or a nylock nut if you're into that. The vibes might loosen the nut, it why. Speaking of "why", why would you try this? :p

I've tried solid motor mounts. These were aweful. They caused the bolts in the front cover to loosen up a little and wear the aluminum threads. I enjoyed the better shifts, but the noise and vibes were terrible. Now it's got competitions (engine and trans) and I couldn't be happier.

 

Your motor and tranny mounts are tired. At this point it's best to get new ones. Get competitions. Even if that doesn't solve the "clunk", you'll love the results.

The clunk could be a u-joint in the driveshaft. If you do decide to change the clutch, you'll have the driveshaft out and easy access to the trans mount. So you know what to do.

 

Ok, so I rechecked the mounts with my hoist and they are ok and the trans mount. I'm still going to replace them with the comp ones from RB.

Could the play also be in the diff gears? Just a thought.

 

you say you checked the driveshaft? did you remove it to check it? I had the same clunking noise, and it was the drive shaft universal joints. It seems to go out every 10 years

 

What I did was what one of the members said. I put it in gear and turned it by hand back and forth and checheked for play and dindnt feel any. I was going to take it out this weekend and take a look at it just to rule that out.