farberio

iTrader: (7)

In order to keep my other thread strictly about rubber engine mounts and solid trans mounts,

In this thread I would like to know, what are the shaking characteristics of a wrong counterweight?

Specifically I am looking at a S4 motor with a S5 counterweight.

At around what RPM does it start shaking? Does it get worse with higher RPM? Does it smooth out near redline?

Bruceman

iTrader: (5)

I used the wrong counterweight on a 12A once and the vibration was very noticable from the first time the engine was started. This did not smooth out at any engine speed and was noticable maybe as low as 2000 rpm.

Spectator

iTrader: (1)

You might not even feel the shaking, but the main bearings will.

Spec.

farberio

iTrader: (7)

It has to get by for 3 months and if I know its a mismatched counterweight I will not be redlining it. More or less, I will be going over the whole list of car shake possibilities just my friends and I are debating if it could be a wrong counterweight.

My buddy put 1k miles on a car with 1 s4 rotor and 1 s5 rotor, but the shake characteristics don't line up 100% due to mine smoothing out at near-redline RPM.

mcoman

I think you should take a look at the possiblity of the combination of solid mounts and rubber engine mounts

misterstyx69

iTrader: (142)

Farberio,I just answered your Other thread,But I Wanted to ask if you can Check the Motor Mounts?..sometimes Due to Having Solid mounts,the Old rubber Engine mounts will go Kablooey..and then you get some Funky Vibe..Feels like a Flat tire,or Rumbling in the Engine bay..it is Noticeable when accelerating but you can't notice it when the car is Still..Try to Move the Engine By hand,back and forth..You may need to get Under and Feel the mount to see that it isn't Broke,maybe even Trying to move the bolt on it to see if it is broke..Good Luck man..STYX.

farberio

iTrader: (7)

1. The motor mounts were fine, nothing wrong there.

2. The driveshaft is a little gummy in one direction, but is not at the point where it would cause vibration.

3. The counterweight turned out to wrong....fooey.

For future people,

My shaking was not that noticeable under 3k and could possibly pass for something else. After 3.5 k it was very noticeable. At 6k it went smooth till 7k. I never took it over 7 k.

And remember to look at the mazdatrix website about ID'ing a counterweight because that would have saved me a lot of work.