allen6908

Hi Guys,

I've been gone from the rx7 world for awhile after loosing my TII and giving away a GTU. However I just got my hands on a 88 convertible a couple of days ago.

Everything on this car is great except for the shuddering problem durring take off. This is the problem when the whole car shakes when trying to engage into first gear and it's stops if I drop the clutch faster or just release the clutch.

I had this same problem on my GTU, but I could never figure out what caused it. I checked my engine and transmission mounts and everything is fine. I even checked the TPS also, but this feels like a mechanical problem like something in the drive train is not balanced. Also I noticed this problem to occure more often when the transmission is hot.

Any help would be appriciated. I read a lot of threads about installing an engine torque brace, but read nothing to confirm if this resolved the problem or not. Thanks in advance.

-Allen

cswanson

Is your shifter sloppy? Have you replaced the shifter bushings? I have an 86 GXL that had the same problem. My mechanic checked the clutch, u-joints, engine and trans. mounts, rear driveshafts, etc. They were all fine. I did the shifter bushing replacement and the shuddering has disappeared!!! I'm thinking that my shifter was so sloppy that it wasn't getting into 1st gear correctly.

allen6908

BTW I did couple hours worth of searching on this list and other RX7 lists and couldn't really come to a resolution. So any help would be great.

rx-7s rock

I have that problem very slightly every now and then. I have not taken a look at my trans mounts motor mounts etc. but I am pretty sure they are all fine since the motor was rebuilt 43K mi. ago. my friends miata has this problem REAL bad, so maybe its the clutch plates? I dunno...

digitalsolo

iTrader: (2)

The engine torque brace, or triangulated strut tower/engine brace w/ torque brace are supposed to help a lot with that problem. I think CP racing and corksport both have one.

White_Seven

I got that problem a few months after installing a Centerforce II clutch. Prior to that, it never did it. Slow take-off in 1st (like in a drive-thru) was terrible, same with backing up

poor college student

it's called driving better.... just playin' but i never had that problem w/ my gxl

Black88

Same here. I always heard of it never, never had it. From what I hear those strut braces doe wonders for it though. check racing beat or clubfc3s.

Ed88convert

I've also got an 88 vert with the same problem. Replaced the clutch and shifter bushings, to no avail.

Icemark

Probably worn out engine and tranny mounts

boosted12a

what timing! i just put a 4 puck clutch in my 87 and it started doing this ****! it didnt do it before, but then the clutch was so worn out i could barly break loose the tires in 1st....ill have to make an engine brace this weekend, with some luck, it will work!!!!

allen6908

Here's my assumption base some more testing in my car. First I thought it was the engine mounts. I lifted the hood and engaged the clutch while in first gear. I didn't see the engine budge at all under load.

The next thing I tried was cutting a section of 2x4 and wedged it between the fender and the engine block. Cheap temp torque brace. However I still got the shuddering problem. So at this point I assume I sort of confirmed my initial inspection that the mounts are fine.

So after thinking about this for alittle while I came up with this theory. Please correct me if I'm far off. Based on these conditions:

1. Problem only occurs when engaging into 1st or rev from a stand still.
2. Occurs more often when the transmission is hot.
3. The effect is attenuated when the clutch is engaged fast.
4. The effect is attenuated when the clutch is enguged slow.
5. No problem when the car is going over 10 mph

From these results I believe that there is some parasitics that is effecting either the clucth or flywheel. My guess is that there's might be large hot spots on the flywheel. This would explain the five observations above.

But before I go hack away at the clutch and flywheel what do you guys think? Other than this the clutch plates seem like they still have a lot of bite left in them.

RRTEC

iTrader: (13)

I feel you need either a new clutch or Driveshaft.....My car's clutch is almost extinct and occasionally i do the same thing...try replacing that and while you are at it resurface the flywheel and have it balanced... Have the driveshaft checked it could be that if you hear a *clunk* when it does it....

BobbyRX

It is clutch and a glazed flywheel. do what RRTEC said, he is more than likely correct.

JGard18

I had this problem, and it seems like oil on the clutch was the culprit.

I put the car in second gear (at a stop) and engaged the e-brake. Then I just rode the clutch a while and burnt it up good...

Smelled like burnt oil all over the place...but the shuddering is gone.

You could also check the slave/master cylinders and see what the fluid condition is like

cjbechtel

Does the clutch pedal feel stiff or jerky when you release it? My 91 does the same thing you guys are describing. Im going to rebuild the clutch master cylinder and see if that helps. However, the two could be unreleated.

jeyjey

the problem is the pressure plate fit a complete new clutch.

cjbechtel

The car was jerky in first and reverse. I had replaced the clutch because it was wasted. I replaced both the plate and disk and it still acts exactly the same as before.

JGard18

then check the hydraulics

cjbechtel

thats my plan

Mr. Eccentric

Racing beat engine torque brace, and like Icemark said check your mounts.

kaoliu

My car used to hesitate when i dump the clutch. But that was before i changed my spark plug wires to some used racing beat ones that i got for free. And my hesitation stopped for a while until i kept on pushing my car and now its back. Probably my spark plug wires are worn out already! since they were used. Maybe probably checking your spark plug wires might help. iono...

rexman13b

iTrader: (7)

dude good luck fixing this problem. i had a 88 gtu and i had the clutch and pressure plate replaced with an actual mazda clutch, pp, release bearing and new pilot bearing. even with the new clutch and all my car started doing the same thing. that leads me to believe that either the tranny or motor mounts needed replacing or maybe the clutch wasn't broken in. but even after having the clutch for over a year it would still do it, but it wouldn't do it every time from a dead stop it would just have it's days. and i know for sure that there were no leaking main seals or tranny seals so that was not the problem. so if you do have a new clutch give it a while and see if it still does it, or just go ahead and replace your motor mounts and tranny mounts, because from removing engines from so many rx7s i've seen that %99 of them have a broken pass side motor mount especially 86-88. and old motor mounts are crappy anyway. the rubber gets very flexible over time, or the rubber insert just breaks away from the metal foot thing. so buy some piece of mind and get some new solid motor mounts and maybe an energy suspension poly tranny mount. hope this helps you out.

rexman13b

iTrader: (7)

and the guy that brought up the point about the driveshaft probably has a good assumption also. weak u-joints might cause that also.

RX7 allnight

i also have a 88 vert and the take off from a stop is horrible, ive had a new clutch for awhile now resurfaced flywheel new drive draft new u-joints and still the same problem after all this time only thing i havent replaced is the trans mount. i just bought a GTU with a rebuilt tranny than iam going to install so iall see if this helps
if any of you get help from this with a toruqe brace let me know, iam sure all of us with the surdding problem feel the pain. =/