is my na fc supposed to vibrate like a **** above 6k rpm? i bought it with a rebuilt motor so i have no frame of referance

 

rotary engines are one of the smoothest revving engines if balanced properly(to within OEM specs), if it vibrates when revving up in neutral while not moving then there is an issue with your rotating assembly: either someone improperly built the engine or you are having an issue with an accessory or clutch/flywheel.

some minor vibrations can be felt with torn engine mounts but not enough to cause alarm and will be noticed by clunking on accel/decel from the engine area.

 

it also feels like the engine is being restricted really badly

 

wow i have had this problem for about a year and cant figure it out, finaly somebody else knows what im talking about.... none of my accessories are causing it and the only thing i havent looked into is the clutch/flywheel assembly cuz i just dont have time to pull the trans to check it out. other than a loose flywheel, what part of the assembly could put it that far out of balance? at one point i thought it could have been a bad miss on only one rotor but i dont think it could cause a vibration as bad as what i have..

 

im about to push this car off a cliff. i've only had it for 2 weeks

 

a blown apex seal will turn the motor into a paint can shaker at idle but it generally will smooth out at higher RPMs.

basics for rotating assembly out of balance would be what i listed above and are the only really places where a rotary engine can go out of balance aside from inside the engine. it is easily likely that the builder used the wrong parts and the assembly is out of balance but that is the last place you should look for this problem.

 

do you think a clogged cat could cause this viberation?

 

doubtful unless it is misfiring/backfiring at the RPM. a clogged cat will usually cause a lack of power in the mid to high RPM ranges so if the power is normal up and through the vibration then i would rule out the cat.

 

i think there is a lack of power above 6k

 

well....if it's stock, you shouldn't have much power over 6200 RPMs IIRC....

 

in a wastespark ignition like our leading plugs, if only one of the coils go bad will it affect both of the leading sparks or only one side of it, like one rotor is getting full burn and the other leading plug has a weak fire? or would it effect both rotors since the voltage travels through both coils... i just installed a mallory 6a and blaster2 coils and im getting less vibrations...
rotaroy, how long have you had the vibration and did it happen suddenly like mine or gradually?

 

He has a 91 so if his vdi and aux ports or opening he should pull higher than that, and even if the power does fall off there it shouldnt vibrate anyway.

 

im just getting past the break in period for my rebuilt motor so im just begining to open it up. tonight is the first time i've gone above 6k rpm ever in this car

 

check transmission mounts and U-joints too...

 

first, is it only vibrating while moving in gear or does it do the same thing in neutral while stopped....

 

thats a good question... i'll check that in the morning

 

if it only happens while in gear it is a problem between the trans and the rear end, possibly bent driveshaft or just worn ujoints. sometimes it can just be that when the driveshaft and trans are taken off they didnt mark their allignment and put them on 180* off, in this case you can just pull the shaft off and rotate it and put it back on and the vibration is gone....

 

mr mazda says my 6th intake port wasnt opening properly

 

wow i was acutally going to say that. as soon as i read your first post actually. when i was repairing mine i got one to open and the other one was still stuck, i took it for a drive, pulling in to my driveway, one stuck full open and one stuck fully closed, and at idle it felt like i was sitting on a vibrating bed. heh.

 

i used to have that problem even on neutral vibrate and then i find that the engine mounts were torn after i replace them it went away

 

Engine mounts and/or waterpump vibrating?

Non-working 5th and 6th ports won't cause vibration BTW...