When the machine shop asks me what surface finish I want, what should I tell them for an Ra number?

 

Stock is about 15.

 

I'm rebuilding a motor for my '87 TII right now and I'm concerned about how I sit with regard to irons.



I took my irons/housings/rotors to Arnold Motor Supply to have them hot tanked and I had the guy there check the irons for flatness. I'm pretty sure the shop guy told me that my irons are flat to .01", and he said that was very flat, but he doesn't know rotaries. It might be very flat for the head on a 1996 Neon, but I doubt that's the case for reusing irons. So if taking .005" off the surface is recommended against, what would you guys recommend I do? I think that the deepest part of the wear is where the corner seals rode. As far as I can tell everything else looks pretty good... I'd hate to have to buy more parts, as I thought I just finished and could start porting/building soon, but if these irons won't help make a solid engine to eventually make 300+ hp reliably and hopefully last 40k+ miles then I don't have much choice. I'm trying to make this build as strong as I can.