Good day/night guys,

Very new to the forum and VERY new to rotaries, but this site has been a GREAT tool in helping purchase my new FD, and first ever rotary just a couple of weeks ago. Was very overwhelming at first, but a bunch of guys made me feel very confident in my purchase & also welcome here in the intro section of the forum.

But enough about that, I’ve read up a LOT about the rear suspension pillowball mounts that go bad and I seem to have a similar, but not the same, problem. I searched & tried to find anyone w the same problem as me, but I’ve had no luck, so please don’t roast me if I’m really being a newbie with this thread. I’m also gonna try to be as elaborative as I can, so PLEASE BEAR WITH ME 🙏🏽 I read that bad pillow ball mounts will cause a light “clunk” in the rear. In my situation, there’s no clunk. Whenever l drive the car and shifted gears, if that gear shift was not absolutely perfect, it would make a bang in the rear diff area, much louder than a little clunk. Also, whenever I launched the car hard, there would be an even LOUDER Bang at the rear of the car like the diff was swinging and hitting the chassis or something. Almost sounding like it was gonna fall out the car, got me really worried. So, BEFORE reading up on the pillowball mount issue, common sense told me that if the noise was coming from the diff area, diff bushing were needed. Which they were, so I installed some polyurethane bushings, all by myself I might add, using the DIY threads on here. THANK YOU RX7CLUB!

Now, since the diff bushings have been installed, the normal casual shifting has improved tremendously. No bang during normal shifts anymore. But if I go to launch the car from a dig & dump the clutch, it still has a loud banging noise. Sounds like it eased up a bit & not as harsh, but def still there. I already looked at the PPF, I did not take it out, but just from a quick inspection under the car, it does not look cracked. If that could be the culprit, I don’t mind trying to take it out to see if it’s cracked up top. Otherwise, are there any ideas that would be causing this loud bang? Would it still be the pillowball mounts that would cause this loud bang? The car handles flawlessly & doesn’t make any noise when cornering or anything, so I honestly don’t know.

Just from a quick eye inspection, the rubber boots over my pillowball mounts look intact and in good condition. I just wanna see if there are any other thoughts on this before I change them out. I’m no expert mechanic, but my experience & Dealing with other car’s suspension in my years, idk if a pillowball mount would cause such a noise, but As I said, I’m new to the FD & rotaries, so PLEASE HELP! 🙏🏽
Any assistance you guys could lend would be greatly appreciated. If you made it this far in my post, I commend you, lol

Thanks for your time, Ryan

 

I had a cracked PPF that gave me a banging sound that came from under the shifter a bit towards the rear.

I couldn't appreciate the crack until I removed the PPF. The crack was exactly where the banging sensation/sound was heard in the car.

I guess you could crack the PPF at the rear.

Replaced the PPF and the banging was completely addressed.

Good luck.

 

Exhaust banging on something?

 

I saw a few ppl mentioning that, but I highly doubt it. Only because of the depth of the “bang” that it makes, it feels much more than an exhaust bang. And I had checked the exhaust hangars and everything looked fine. But this kinda shakes the whole rear of the car a bit when it happens.

 

Very interesting. I will see if I could remove the PPF sometime this weekend and see if that is the culprit. As I said before, I didn’t take it fully out to inspect, so you may be on to something there. Thanks for the insight 🙏🏽

 

Wheel hop?
Got a recording where we can hear it?

 

Not that I can remember, but tbh, I'll have to try another launch. I got so focused on the banging noise that I honestly didn't think to be on the look out for wheel hop. I'll see if i can take a video when I drive it again. It's not really my daily, but I'll try to take it out again tonight. Thanks

 

Pillow ball clunks are not very loud -- just enough to be be annoying, and they are constant on a bumpy road surface. They also sound like they come from one wheel or the other (or both), but not the center of the car. Your problem is something else.

 

Yeah pillow ball is just a moderate clunk. I would get the car up and grab and shake the exhaust around to rule out the exhaust hitting something. If it's fine and not hitting, pull the power plant frame and inspect.

Dale

 

My natural instinct from dealing with cars kinda ruled them out from the beginning, but I wanted to make sure, as I had never dealt with an FD before. I appreciate your input, thanks.


Will be pulling the PPF soon. The more I dig in the threads and talk to you guys, the more I am beginning to think that the PPF is the culprit. I know this may be premature, but where would be a good place to search for a replacement one of those? I should have some time to pull the PPF to inspect it this weekend. Thanks again for all the help guys 🙏🏽

 

Good luck.

I picked up my PPF from a part out.

 

Guy up here broke his PPF at the back. There is a narrow neck near where the bolts mount.

Are you sure it is not actually after burn? Can you mount a go-pro back there to take a look and listen.

Clutch fork is next BTW. Best have a spare lined up.

Wheel hop has been an issue since day one. Later cars had some additional reinforcement.

Two fifty pound bags of sand in the trunk, might help with that.

 

Wheel hop can destroy the differential. That has happened to many people, so be careful.

 

Might be a novice question, but what would cause the wheel hop in the rear suspension? I have Tein Coilovers installed. Those and the pillowball mounts look to be in good condition & feel great when cornering. I also installed brand new polyurethane diff bushings. Not sure if you read all that, just trying to rule out everything.

 

I apologize, but what do you mean by “after burn”? Like flames shooting out the exhaust? Sorry for all the late responses, this weekend ended up being a busy one for me. I should be pulling the PPF tonight for inspection. I asked this already in my previous response to another member, but what causes the wheel hop? Would it be the PPF?

 

The 265 hp simply overpowers the suspension.

The car is too light to compensate.

 

Wheel hop is typically only seen when trying to do a hard drag race style launch. The RX-7 has a really nicely designed independent rear suspension that's designed for the track, but in some instances it won't do well with hard drag race style launches.

Pillow ***** won't affect anything as far as wheel hop - the worst things they do is clunk. Going with stiffer differential mounts and a polyurethane trailing arm bushing helps a lot. Many times wheel hop is the suspension/bushings loading up, then the wheel breaks loose, they unload, load up again, etc.

Of course a broken power plant frame will cause all sorts of problems. You need to know 100% if that's a problem before troubleshooting any farther. The PPF will have to come off the car for an inspection, you most likely won't be able to see cracks on the car.

Anything else at this point is just wild guessing.

Dale

 

Really appreciate the help & info. I had just recently upgraded the diff bushing to polyurethane myself about 2 weeks ago. It really helped a lot, but I did not do the trailing arm, I will look into doing that as well. I’m trying to get the PPF out soon, I’ve just been fasting during the day (which means no food or drink from sunrise to sunset) and the heat outside is about 90°+ during the day, so kinda difficult lol. I’ll try and get to it as soon as I can tho. The forums has been a GREAT help, appreciate you guys.

 

Ramadan Kareem!

 

It's been a while, but my recollection is that the hatch can be pretty loud if it doesn't shut firmly. If you haven't ruled it out already, try checking the rubber stops, latch & hinges.

 

Ramadan Kareem to you as well, bro. Much thanks.

Yea, I know about the trunk being a little bit difficult to latch. Honestly, idk if it's just my car, but I find all the doors need a good amount of force to close as well. Nothing crazy, but more than usual. But yea, the trunk is definitely closed.


Thanks for all of your help guys. I haven't pulled the PPF as yet, I know I'm taking a while to get to it, just been caught up with work and bunch of other stuff. But your input and assistance does not go unnoticed. I appreciate it very much.

-Ryan

 

Hey Ryan - what he means is the truck can be closed, but make a lot of noise due to the rubber bump stops getting hard over time. The result though is much more of a loud squeak than it is as what you describe.

 

Hey David - Ah, ok. Yea, definitely misunderstood that. I will check the rubber stops today and see, but agreed, I highly doubt that, that is the culprit. Thanks for the input, I will send updates with what I find, thanks again.

 

worn rubber hatch stops will definitely cause a loud bang. Forgot about that.
You won't easily be able to visualize a worn stop unless you are comparing to a new one.
Ray Crowe sells them at a fair price. Get 2. You'll need to do them eventually if you haven't

 

Cant you inspect the PPF without removing it.? I believe you should be able to see most of it when the car is on a hoist. The weak spot is where the neck connects the main PPF beam to the mounting points.

Check to see if the bolts have worked loose.

I suspect that weakness is built into the PPF so that it breaks first before the dif or transmission housing would reach their breaking points, if the undercarraige experiences some blunt force trauma (i.e. , potholes, groundings, etc.).