What type of rotors do I have?
 

Hello,

I have had a 90 GTU sitting in my garage for the past two and 1/2 years and am finally getting the time and money to put it together. I bought the body that is in great condition off of Ebay and about a year later bought an engine from a local hole in the wall shop. I took the engine apart and began to clean it out. I found that one of the rotors had a corner piece of the apex groove edge nicked out. I went back and picked up two more rotors and found that one of them had an apex with the groove slightly bent in. They were very cheap so I am not complaining (yet).

I asked the mechanic for two matching rotors and the guy pulled out two rotors from a cabinet and told me which one was the rear and which one was the front one. Well I didn't know which of my rotors was the bad rotor. To confuse me even more one of the good rotors has two holes drill holes (the best that I can describe) on one side near one of the Apexes. The "drill holes" look like they came that way from the factory.

I don't know what year these rotors are from nor which is the front or back. I have an atkins rebuild kit on the way and hope that the rotors I have will do.

Any way to tell what year engine my rotors are for? What would happen if I mix and match?

Thanks!

There are several different compression/weight rotors that you do not need to mix due to power and balance issues. Post some close up detailed pics of the compression "bathtub" of the rotor from several angles and I can probably tell you just by looking. Also, front and rear rotor for 86+ do not matter at all; they are all the same in that regard. There are also weight balance letters, stamped with a capital A through E, on the gear side of each rotor...you want to build with rotors within 1 letter of each other, for instance a B and a C but not an A and a D.

the best you're probably going to get is which generation (series) engine they came from - a specific year is probably not going to happen, but i guess all you need is the generation. large, high-quality pics should help to narrow it down. the rest can be figured out by a precise weight. show what you've got.