anthology1987

i own an 87 non turbo and its my everyday driver. According to my mechanic, upon inspection, my engine mounts are fine and should be, i replaced them only about 25k miles ago, but my tranny mounts (the two small mounts on the sides) were looking pretty tore up. this is believed to be causing a very annoying vibration between 1400-2100 rpm seeing how the same vibrations were fixed about 35k miles ago by replacing them along with the tranny mount bracket that has the hole in the center for the Y-bracket to slip through (this piece's grommet as of now looks totally fine). well any way, i replaced the two small mounts with polyurethane mounts and bolted it all back up perfectly, with the drive shaft having very little play where it connects to the tranny which is in the exact same position as it was before i touched it (i didnt really have to move the tranny around at all), but now the vibrations i described earlier are gone, and now there are really bad vibrations after 2000 rpm and feels like the cars about to fall apart above 3000. i visually checked under the car while someone else increased the rpms to see if there was something obvious but found nothing. i know its nothing to do with the rear, seeing how this happens weather im in neutral or moving. does anyone have any ideas?

jjcobm

iTrader: (18)

Well stiffer mounts will transmit more vibration throughout the whole chassis. If your problem was bad before it would probably make it more noticeable now.

That aside, if the problem is still happening in neutral, that will rule out driveshaft issues. Double check the tranny mount, go underneath and give it a good shake. Do the same for the engine mounts.

By the way, what type of engine mounts did you install? If they solid they will absolutely transmit vibration and that range 1300-2100rpm looks like the range that will have harmonic resonance on the chassis from my experience.

After 3000rpm is the car pretty much non-vibrating? Is this vibration like massage chair vibration or train about to crash vibration?

anthology1987

ill have to check and see which type of engine mounts were last put in, it was done just before i got the car. and after 2000rpm and up past 3000 it feels like a train wreck/somethin is about fly or fall apart, with that said, i've only taken it up to 4000 so far, just to see how bad, it only gets worse and worse. everything under the car is tight as can be, i double checked after takin it around the block too.

under 2000 is smooth so i made plans to take it out this weekend to my budy's shop and see what he find.

do you think the stock tranny mounts would have been better or is poly ok?

jjcobm

iTrader: (18)

Ok, in that case if everything past 4000 gets worse and you have made sure your mounts are snug I would be looking at issues with engine balancing such as flywheel front counter weight, or maybe internal... If you have the wrong flywheel it will mess with your engine balance. Same goes for other components.

anthology1987

thanks for the tips!

ill post what i find this weekend.

kcdclan

Well it it only when your going?
Does it happen in nutral?
If it dosnt then your driveshaft is probally the problem...
replace it asap... you cant just replace the u joints on it ither only aftermarket ones you can...

gxl87turbo

iTrader: (15)

Its either a driveshaft, front or rear bearing in the trans, or your flywheel is coming loose. It could also be your diff, you have to get more into the problem to see what the cause can be.

anthology1987

ill probably end up looking at bearings, fly wheel, clutch and others up front.

it happens just the same, weather in neutral or driving, it actually feels a tiny bit better when driving (probably because the vibrations have more to travel/dissipate through)

i checked drive shaft connections and u joints and its all tight and right

hopefully its nothin too bad, due to economical times, i only have one shot at trying to resolve the issue before i get too in debt, lol

PvillKnight7

iTrader: (16)

I had the same problem and it was a broken rear driveshaft u-joint. I experienced increasing vibrations with mph. I couldn't go faster than 45mph. The u-joint had cracked just before one of the bearing caps.

I would throughly check the front and rear driveshaft u-joints. I would remove the driveshaft to feel the movement of the u-joints with my hands.

PvillKnight7

iTrader: (16)

I just re-read this...

The vibrations occur while the transmission is in neutral and the driveshaft is stationary? If that is the case you can eliminate the u-joints as the problem...

anthology1987

i just found that my clutch has been pretty eaten up and my flywheel feels a little wavy where the clutch disk meets it. so when finding out that i would have to wait till tomorrow for my clutch set to come in, I've decided to just remove the flywheel tomorrow morning to see if i can get it resurfaced around town

im also going to replace the pilot bearing and throwout bearing while im at this point.

i really havent found anything else that looks like it could contribute to my vibration problems unless what i mentioned above is enough to do so.

also, how do i check if my counter weight is good?

st1llet0

iTrader: (2)

Stock flywheel is your counter weight right?
If it's not, I've been doing things very wrong.

anthology1987

yes, i have the stock flywheel which doubles as my counter wieght, i most recently found this out by comparing pics and other info. and actually i havent even been able to remove it yet to get it resurfaced due to other things happining (work, school, etc.)

ill be going out to sears tomorrow to buy an impact gun to remove the flywheel nut, which by the way is almost impossible with hand tools unless you have more than 1-1/2ft of clearance under the car or your engine is out and on a stand. so it wont be till Wednesday or Thursday that i can get everything back together and see if vibrations are cured.

what have you been doing wrong?

jjcobm

iTrader: (18)

Make sure your flywheel matches the series engine you have....

anthology1987

ive been able to get the flywheel nut off, but now the flywheel itself is stuck and WILL NOT budge.

ive tied what mazdatrix suggests (ive been beating on it all day with a copper mallet), prying all around it, and using a flywheel puller which started to break from how much force was being put on it. (i hope that i didnt put too much pressure on the eccentric shaft seeing how the puller was breaking) hell i even pried while there was tension from the flywheel puller and still nothin!

the flywheel nut is on but only by a few threads and is totally out of the way. ive also soaked the flywheel front and back with liquid wrench. if i could only get this off i could finally work towards putting it all back together and see if my vibrations were fixed and maybe even drive my baby again.

does anyone have any ideas before i just give up and end up paying someone to do this for me?

jjcobm

iTrader: (18)

Search is your friend....

I really think your wimping out, hit it like a man!!!

https://www.rx7club.com/showthread.p...flywheel+stuck

https://www.rx7club.com/showthread.p...flywheel+stuck

Oh and upload a video on youtube so we can watch

What I would do though, use the flywheel puller, add tension. Whack with hammer. The vibration from the hammer is what will get it loose, so you must get that vibration going....

Or try the other suggestions on the other threads...

anthology1987

well thanks for the encouragement and links from searches i forgot to do.

i got on it early this morn and tightened it down with my steering wheel puller rigged to work in this case and got a pattern of beatings around all the three spots and within 5 min "POP"! i didnt have anyone to hold my phone for videos but i did get some pics of my rigging and of something i found after getting back home from having the flywheel turned.




what i found after my flywheel was resurfaced by Florida Powertrain was just this, the pic below shows where there is flat metal between the two blue lines, then the second pic shows where the other side lacks the same amount of metal within the red lines, but within the same distance between the contact surface and where the raised plateaus start, where the bolt holes, pins or hammer blows would go;





at first i thought that Florida Power train messed up but then noticed that the distances between the outer edge of the contact surface where they machined and the little plateaus was the same all the way around so it must have been made this way on purpose, but i thought that all of the offset weight was being done on the back side of the flywheel. has anyone noticed this before?

(im waiting for a new clutch kit to come in tomorrow morn because the throw out bearing that came with the last kit was defective(off center) and advanced had to mark the whole kit i originaly bought as defective.) so tomorrow when all is done, we'll see if vibrations are gone.

anthology1987

sorry it took for ever to get this all done, but if it isnt one thing its another. nothing was wrong with the flywheel, i had it inspected by an experienced rotary tech at a mazda dealer just to be sure. i think it may have been the TOB and the old worn rubber tranny mounts were absorbing most of the vibrations before i changed them to poly.

some slight vibrations are still there between 3000-5500, but nothing close to what i was feeling before changing bearings and clutch. u can definitely tell its the tranny mounts, so i plan on going back to rubber.

also found that my oil pan seal is slowly leaking, yay......

FCJoe

I really don't see why you would think its the flywheel. It seems like you're just ripping your car apart without any actual thought behind what you're doing. The TOB would have nothing to do with it either, the only effect a bad TOB would be a whirling noise at idle when you're not holding down the clutch. Hows your motor running? Rough idle? What "mods" have you done to the car?

FCJoe

One more thing, your best bet would probably be taking a video and posting it up on here. Take a video of the motor while someones stepping on the gas. That should give us all a better idea of what you're talking about.

jjcobm

iTrader: (18)

Oil pan is an easy fix. Just use RTV sealant. As mentioned before, stiffer mounts will increase vibrations into the chassis. If the engine runs fine before and after that "vibration zone" then its definetly the mounts, but then again this should also feel more like a massage chair than a "train wreck".

anthology1987

well i was suggested by a mechanic that there could be some problems with the clutch or bearings that were causing the vibrations and that the old worn rubber mounts were probably absorbing most of it. so thats why i went ahead and dropped it to check. and while i was down there i replaced any worn parts i found; clutch, TOB, pilot bearing, and of course resurfaced the flywheel and now those vibrations that made the car feel like it was going to fly apart are gone so riddle me that. not to mention, upon inspection, my engine mounts are good and the engine runs just fine.

a mod that was done by the person who rebuilt it 36kmiles ago was the air pump and vdi's and of course rigged all ports open. ill try to get a video by this weekend, but it doesnt look like the engine is vibrating out of control nor has it ever.

anthology1987

at first, yeah a train wreck, and now after what i've done, a massage chair is a pretty good analogy. it even feels like its coming from where the mounts are. and yeah, its totaly smooth outside of the "vibration zone", hell my passengers cant even feel it at first. we'll see after i replace with rubber.

jjcobm

iTrader: (18)

Yeah that's your new mounts. Glad you got the problem solved.... One thing to consider, those stiffer mounts help to keep the tranny from moving around during hard acceleration (due to the torque). It might help shifting a bit since your tranny doesn't move around as much when compared to the stock mounts.

But it's all dependent on what you feel comfortable with.

By the way, I do have 2 stock tranny mounts laying around. I'll PM you...

hbtl300

funny i have kinda the same problem, but mines happen at 1-3 gear and its between 6-7.5k when i rumbles. even when its stand still and rev'd up the rubbling/vibration is evident. but when i get to 4 and 5 its ok, well at least not noticable. i do not know what the problem is? please provide assistance. is it the tranny mount, motor mounts. and my shifter rumbles as well, so can that be more on the lines of transmission problem