This came out of an S5 T2 motor. I don't think I would use it, but I am curious to know what the consensus is on blemishes like this. Other than this one apex seal groove, the rest of the rotor is in great condition. That little dip would expose more of the apex seal to the gasses in the combustion chamber and I'm thinking may cause a failure. It would likely be a perfect candidate to be milled to 3mm apex grooves because doing that would get rid of the blemish. What do y'all think?

 

So I cleaned and inspected the rotor further tonight, and found that there is similar damage on every apex.. One looks pretty much identical to the one pictured above, except strangely one is on a leading edge and one a trailing. The third apex though, I'm not sure how I didn't notice before, had a v shaped dent in it that protrudes into the apex seal groove so much that a seal can't fit (barely, its a pretty small dent). This same apex is where the only damage to any of the seals happened, the corner of that apex seal was cracked but still in it's place when I tore down the engine. I already used an old seal to try and push it back from the apex groove and then used a file to finish it flat and clearance the new seal. I want this motor to be able to handle up to 14 lbs of boost from a decent sized turbo without issues. The build always comes down to the preference of the builder, and honestly if good used S5 T2 rotors were easier to find now I would much rather use one with less damage, but I may end up having to buy one brand new if I want to get something flawless, so I'd like to hear opinions of others, and it would be good for the forum to show people what is normally deemed acceptable amounts of wear

Here's a picture of the third apex after I un-dented it a bit


Thanks for stopping by, oh and,

 

oops

 

that last pic, it would be easy to file that thing away and it would be fine, the first pics may clean up too.

i would measure ALL of the grooves, and if they are all in spec minus the damage, then i would clean it up and use it. if the grooves are not in spec, you're kind of done. Apex and Side seal grooves

 

Like j9fd3s said, Clean it up and get out your feeler gauges and see what kind of clearances you have. From that first picture you may be out of luck for 2mm apex seals, though the rotor may be usable if machined out for 3mm seals.

 

Thanks guys for the input. The clearances for the apex seal are all good actually, I had to file the one pictured in my second post a bit more and it checked out with the feeler gauges. If you look at the 3rd and 4th photos in my first post, you can see that the dent/gouge is relatively perpendicular to the face of the apex seal, so it doesn't really affect the clearance of that groove much, just exposes more of the side face of that apex seal to the combustion chamber. Equivalent to a small nick on the very outside of a piston head with a new piston ring that will have slightly more exposure to the combustion action than the rest of the piston ring, but most of it is still concealed in the piston ring groove. I just bought an RX-8 a few days ago that needs a rebuild and I want to prioritize and get done first, so in the meantime I might keep my eyes open for any used qualifying rotors that pop up, but I feel better about using this rotor than I did when I first looked at it.