I am about to assemble a 20b motor and I have everything for it apart from the rotors but I do have 2 excellent pairs of 89-91 Turbo 9:1 rotors but 2 of them are D weight and the other 2 are E weight, the question is can make a set of 3 using 2 d and 1 E weight or vise versa?and will the rotating assemblythen need balancing?any input would be great.

 

The person to answer this question would be Carlos Lopez in Miami. His contact info is:

Carlos Lopez
CLR. Motorsports Ltd.
(305) 235 3696

He does a ton of lightened second gen rotor projects. All the rotors need to weigh the same and I'm unfamiliar with the differences, if any, between D and E weight rotors. Besides the obvious need for them to all weigh the same, do they differ in design? For example, you don't want to mix 13B rotors with 20B rotors.

Carlos will know the answer to this.

 

What's the weight of the rotors that came out of the engine in the 1st place? The factory balances each rotor/shaft assembly on every engine. You ever notice the drill holes on the rear counter weight? My 20b had all "C" rotors. Since your planning on switching to hi compression rotors, it's best to match the same letter codes from what you previously had in the 1st place. This will help you stay as close to the factory balance as possible.

Here's something to think about and is easily missed by a lot of people here! If your engine had all "A" rotors and you were trying to install a set of "F" rotors, your engine would be way out of balance because the the "F" rotors are lighter as an assembly and would not balance with the counter weight that was balanced originally for "A" rotors. The two letter weight rule only works if you stay with-in the two weights of the original rotors. A lot of people don't realize that.


I personally replaced a set of A-B rotors with two C's in my 13b. My engine vibrates more because of this. This was b4 I knew about the counter weight balancing.

 

Thank you for the reply.
The motor will be a turbo 20b I have the front and rear 20b counter wights but I am missing the rotors that came from the 20b and I currently have 2 pairs of 89-91 Turbo rotors D and E weight , I will call Carlos Lopez just to make sure and see excactly what is needed before I put it together.