X-Drilled Rotor Direction...

[SprintStar]

Happy New Year, Gang!

My first question of the year... Are the Zimmerman cross-drilled rotors for the front of a Carrera directional? I got 2 in a box that are in the in the same direction. Needless to say, when installed, the right rotor spins nice, while the left rotor spins in the 'wrong' direction. Normal or did the local shop goof up?

Thanks.

Sprint.

[ChrisBennet]

What year and model car are we talking about?
If it's an SC or Carrera I don't think it matters much. The drilled rotors in that application are a street only application anyway. You'll want to replace those drilled rotors with non-drilled rotors if you did any track work. They won't pass Tech in my region (because they can fail catestrophically). The thin rotors were never designed to be drilled.
-Chris

[89911]

There is a left and right rotor. The rotor vents at the 12:00 position should be directed to the rear. Sort of like this for the left side:
(
.
)
As far as cracking, I know that zimmerman, who makes the oe rotors, has recently made cast perforated rotors for Carrera's. In the past, drilled ones were much less durable. Preformed cast rotors like my 930 rears came standard on turbos.

[SprintStar]

Originally posted by 89911
There is a left and right rotor. The rotor vents at the 12:00 position should be directed to the rear. Sort of like this for the left side:
(
.
)
As far as cracking, I know that zimmerman, who makes the oe rotors, has recently made cast perforated rotors for Carrera's. In the past, drilled ones were much less durable. Preformed cast rotors like my 930 rears came standard on turbos.

Thanks Chris and 89911!

I'm doing a Boxster conversion on my '67S. I did research the topic on the BBS by searching old posts and while I agree the X-drilled rotors may crack and fail on SC and Carreras, I might get away with murder on my light car. Besides, Katie only sees track duty about 4 times a year? Other times, she's my faithful daily.

And besides, I was due for major brake work anyway. The front left piston is seized. Car pulls to right on braking, so I figured I gotta spend money on new hardware, so I might as well get the Boxster brakes.

So, there is a left and right for the fronts. But I suppose the rears are universal? I'm doing a Boxster brake conversion and using SC rears. The holes seem to have no direction. As in, as far as my lousy eyes can tell, there's no direction for them.

Correct?

Sprint.

[RickKlem]

So, if they are directional and you run them this way, what issues will you see?

The reason I ask is that I installed a set of front zimmerman rotors from Pelican and they are the same as well. My car has been sitting up for a few years now and while I was upgradeing to a 3.0L I did some other work which included rebuilding the calipers and replaceing the front rotor's. Every now and then when I drive it for a about ten miles or so the car begins to shimmy and vibrate at all speeds and then suddenly it will quit and drive fine. I was wondering if it could be the left rotor.

Rick