Hi,
I was out driving my rx7 turbo2 yesterday and suddenly it startet to vibrate wild.
I drove home at once... When i came home i parked the car, put it in neutural and reved it carefully. It still vibrated.. So, i know it is the engine, i didnt/still dont hear any sounds,, What can it be?

Sindre

 

Engine mounts?

 

nope, its the engine it self

 

are u SURE it aint the engine mounts? those rubber things make a big difference

 

no im not sure, but when the engine idles i cant see whats making the vibration. Is the engine so unbalanced that it wobbles that wild? The entire car wobles/vibrates wildly and the frequence of the vibration goes with the rpm.
how can the engine mounts get That bad so suddenly?

 

Apex seal gone South. Do a simple compression test using your finger.

 

Rgr what hailers said, give her a comp test and let us know..

Stealth

 

Blown apex seal. The imbalance is power impulse imbalance. If you've blown an apex seal, two out of the three chambers on the blown rotor are gone, so instead of 6 evenly-timed power impulses, you're down to 4 unevenly timed. Make sure you inspect the turbo when you pull things apart, as broken apex seal pieces have been known to damage the vanes. The fact that the engine is still running means you still have a strong rotor. I'd stop driving the car or even running the engine as this kind of stuff usually results in further damage, sometimes overheating and warping of side plates.

 

i tested with my finger in the leading plugg hole.. it feelt normal and it was a constant even rythm (and it sounded okey to).... i tried to start here on only one rotor to see if it was just running on one but it wasnt the same. It runs on both, the engine sound is normal and i cant hear anything unnormal besides all the vibrations

Sindre

 

have you tried to remove the leads on one rotor at a time to see if it's able to start on either the front or rear? If it's able to start on either one, then there's something else. Get a regular compression tester and remove the check-valve at the end of the hose. Have an assistant crank the engine as you watch the needle. The gauge will not record a reading but will give you an idea as to what the spikes look like. If the spikes are even, put the check valve back in and get a reading. A good used engine should still generate 90-100 psi assuming the battery and starter are OK. You need to check for compression evenness more than anything.

Incidentally, a broken engine mount will not result in what you're describing. A lot of people don't even know they have a broken mount until they decide to upgrade the mounts or remove the engine for service.

Are your plugs OK? Is all the electrical OK?

 

it managed to start with only the front rotor. i also had to drive it home, and it was still going strong, didnt feel power loss..
I change plugs, no difference. i had a compresion test some weeks ago with 8, 7.8 and 7.8 bar.. thats good...
Ill do a new comp test and check my ignition maps.

sindre

 

If the compression was checked some time ago and this vibration issue just came up, I'd check the compression again just for peace of mind.

 

ill do that!
Its time for rebuild very soon anyway, but i hoped to have a usable car until the snow comes...

sindre

 

i did a simple test today with a regular comp tester.. i got 3 nice spikes and when i pressure tested it it was around 80-90.. the sound is also like .. posh posh posh...
the car runs nice and clean, and starts easy.. I did check the engine mounts again, the right one was actually loose but when i tight`n it it didnt help mutch (maybe some)..
Still heavy vibration and i dont know what to check.. i havent checked the ignition but the microtech has correct values..

Sindre

 

can u feel the vibration when u acclerate/ gas padel? is the whole driveline vibrating as well let meeh know i think i know whats wrong wid ur car i had a similiar problem torwards it

 

Is it an auto or 5 speed?

 

its a 5 speed. it vibrates when the engine is running. Doesnt mather if im driving or not.

Sindre

 

does it vibrate while idling? Does it clear up if you rev it or is it there all the time regardless of RPM?

 

It feels like the vibration follows the rpm but at lower rpm its easier to feel because the frequence of the vibration is lower..

Sindre

 

Check your cooling fan to make sure that none of the blades have fallen off. I wouldn't think that it would make the whole car shake, but its worth a shot.

 

you did check compression on both rotors correct? your description made it sound like you only checked one rotor.

 

yes i did it on both and the result was exactly the same
Today the engine is going out! Im gonna look at the flywheel and clutch since thats the last parts i changed!
If i cant find anything wrong ill just rebuild the engine... Confusing not finding the cause though..

 

um i would recheck those engine mounts. they are the only thing that secures the engine to the car. with shot mounts, the engine moves around however it wants... it will shake the car.

 

scary

 

very very incorrect.....

something is wrong with his engine. (i dont know what it is hard to tell over the internet)

if his mounts were bad the vibration wouldnt be as bad since the engine wouldnt be connected to the car. his mounts are probably in good condition since he can notice the heavy vibration throughout the car.

my car had a vac leak once that caused vidration at idle. i thought it could have been the mounts but when i found the vac leak the vibration was completely gone.