Here's the symptoms:

1984 GS 12A with GSL LSD/Disc rear end swapped in. Car has 210k on it and is pretty solid save some worn suspension bushings. No damage otherwise

What I'm getting is noise and vibration from the drive line in all gears becoming extreme around 40-45 mph

Checked drive shaft, there is play in both the front and rear u-joints, so I'm assuming that is the cause. The rear trans mount looks to be intact and the engine/trans moves very little underway BUT

The vibration is especially pronounced in second gear - and seems to fade as the rpms near 5k but is otherwise consistent with the other gears

Transmission? U-joints really don't like 2nd for some reason? Maybe rear trans mount 'looks' good but isn't?

Any suggestions would be appreciated, especially with the question of which drive shaft do I order for a GS with a GSL LSD in it?

 

Sorry guys I forgot to add that I will be building this car up - this is the first step, to be able to drive it!

 

Here's the car as it is now, I have an Optima Red Top that I will relocate to the passenger-side pocket very soon.

I picked the car up from B & B Rotary in Sacramento, CA with two sets of wheels and it made it back home no problem! I reconnected all the 'improvements' under the hood and it seems to run quite well now! No cracks on the dash and a very tidy interior means it's a keeper.

This will be my first FB and I'm looking forward to running the lightest of RX 7 models

 

Actually, the Second Lightest - for that year. The "S" model has even less options.

As far as your vibration issues...

Replace both u-joints, transmission mounts, and engine mounts (the engine ones are probably worn out from all the play).

It WILL make a world of difference.

Congrats on the purchase!

 

Thank you very much. I will be getting a new drive shaft made today with replaceable Spicer joints for $250. Too much?

Today it's the factory radio that's coming out. I have the top-range setup with amplifiers but I have decided to leave the wiring intact and just add harnesses to the factory connectors and install my free Alpine logic cassette deck that came with the car...

 

You might also want to check that your rear axle input shaft is at the same angle as the engine/transmission. If they didn't mess with the mounts when they did the swap it's probably fine. Unless you did the swap yourself you never know. The angles should be close or you can induce vibration and early tailshaft wear in the transmission.

 

Thanks for the tips and replies. I'm really enjoying the site now that the, erm, posting 'requirements' are met

Had a look at the input angle and it seems to be normal though there is about 3,5mm of free movement in the rear u-joint! I can get a nice aluminum drive shaft for $400 so why not?

I tried to further narrow the noise and vibrations today after my radio install was complete and discovered that the severe vibration in gears 2, 3 and 4 at up to 4k rpm is not present when I reach ~45 mph and depress the clutch! It all but disappears completely leaving a subtle hum instead of the 'two subs in huge box' sound that it normally is

Maybe the clutch disc itself is missing a puck/friction pad/spring and is severely unbalanced? I thought that if the drive shaft itself is out of balance or failing that the vibration would be more consistent but it is not, it seems to be the heaviest in second gear at 2.7 to 3k rpm but goes away over 4k and with the clutch in

Looks like the trans will have to come out to see for myself. Cost is no object but I still want to make sure I'm not just throwing money at issues that don't need it

Images of the radio install detail will follow, I used the factory wiring and did not cut, damage or modify a single wire or bracket in the process. I try reversible methods in car modifications whenever possible due to prior experiences... any future owner(s) will appreciate that! The factory top-range unit and amplifiers actually work well but I prefer a single powered head unit to the discrete setup that the car came with. Now to fill the large empty space left behind... maybe fit a carbon fibre or aluminum sheet with the DIN opening for my radio? Mesh maybe?

Next: Remove air pump and install block-off plate and header! NO inspection or Aircare to worry about!

 

Finished! I removed the ACV and the pump together today. The Rotary Engineering block-off plate looks brilliant once fitted. Lost a bit of weight as well!

http://i51.photobucket.com/albums/f3...S/IMG_1424.jpg
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http://i51.photobucket.com/albums/f3...S/rotated2.jpg

Sorry about the links, teh PB photo-links are not working atm

Simple job, just remove three bolts, the ACV and pump, install your block-off plate (I found mine on a SA22 at a breaker's) and off you go. I had to make a custom gasket as shown but it fit great and there's now zero backfiring or vacuum leaks! The engine bay looks tidier too

I blocked off the front air lead on the air filter housing and the hose nearest the passenger-side wing can just be left off, it's just a crude sponge filter adaptor that's outside the filter anyways

Cheap fix as the block-off plate came from pick n pull! The SA22 also has the two-piece header I'd like to have on this car. Hmmmmmmmmmmm

 

Hello once again!!

The great 90's style 15x7 wheels are set to go, sorry for the crap image quality on that one - mate's iPhone super camera wasn't so super. Much wet-sanding and polishing in store! These wheels would look perfect if I had them blasted, painted satin red then polished the aluminum lip? Maybe?

http://i51.photobucket.com/albums/f3...enty/white.jpg

The real catch was the header. It came off the SA22 p'n'p donor car perfectly, hardware and gasket intact! Old split-flange setup. Strange, but true. Bolts up perfectly well and has a nice 2-1 already fitted below to weld up to my single setup. Is it worth it to paint the header with high-temp paint before fitting?

I'd like to have a really nasty single straight-pipe exiting on the passenger side just ahead of the rear wheel - but - this car will also be a road-tripper so tame it is

For now

More pictures as soon as there is light!

 

Here's the header I found on the donor car, any ideas as to who it's made by? Looks like some old RB flanges...





Can't wait to fit this and have a go around the block at maximum volume!!!

Also, did I put this thread in the wrong place? Seems like next-to-no response here in the 'build threads'. Can I move it to 'non-technical'?

 

I found it! The drive shaft had a bad u-joint and I followed every tip above and found the issues

Rear trans mount and new drive shaft should do the trick!

The header will be fitted soon and images will follow, I've also painted the face with some 'Heritage Red' from a can :F

Images soon! This car has many hidden issues related to corrosion. Anyone also face this? Grinding off corrosion for the spark plug wires was quite a task

More asap

 

New drive shaft!

Built all-new by Dean at Driveline Service of Carson City, NV for $250 otd

Looks great, uses all US-made components and has replaceable u-joints that feature a grease fitting! Dean says it will likely outlast the car

I also bought all-new grade 10 hardware and stainless lock washers to ensure it doesn't go anywhere

 

Anyone interested in the factory radio and amps, cruise control switch and stalk and ACV and AIR pump?

 

Looking good, better keep that driveling for your next rx7 as well I have a stack of bad stock ones, they don't respond well to abuse or age.

Your original question would have been better suited to the 1st gen tech section, and likely garnered more replies, but if you are turning this into a build thread then this section is the one you want.


Isaac

 

I've noticed that, seems it was in the wrong spot initially but maybe it's right now since I'm bringing this car back to life in a 'build'.

Maybe it's too ordinary for a build Maybe there should be a 'resto' or 'revival' section

Thanks for the reply!

 

Picked up a set of great condition Enkei Apache V 13x5.5 today - and they fit!

I am beyond happy to throw these on since I have stock wheels that really need to be refinished before they'd look good at ALL

An amazing buy and a hard-to-find classic wheel - with only one centre cap!

Anyone know where to find a few?

Still need to fit the header and put the interior back together... more soon