I'm currently in the middle of rebuilding my 13bt engine, and I've come across some concerning finds and need some advice on what can be reused and what can't. I assumed I had blown an apex seal and my one of my housings would need to be replaced, but to my surprise, my rotor housings were actually in decent condition and will be able to be reused. In fact all the apex seals were in their respective positions. The weird part was that in "blown" housings rotor, most of the seals, apex and side seals, seemed to be pressed super far into the rotor and cemented in place so that they(side seals) were flush with the rotor which I figured was toast(I will include pictures below). Upon further inspection, the rear irons surface was smooth, but with black marks where the rotor was sitting. The center iron had similar black marks, but with a small gouge you can just catch your fingernail on. So my question is, why where the seals pressed so far into the rotor causing no compression, and is my center iron reusable? (Pics below)
Any advice is appreciated!

 

Oh yeah, and this is S4 J-spec engine, and was shipped to me with no compression in the rear rotor, so I'm assuming the engine had been sitting for a long while.

 

Only way to tell is to clean up the parts and make sure the pitting isn't too deep. Check for flatness. Soak the rotor in strong degreaser to get the seals out if you can. This is very common in a sitting engine that has been stored in a moisture rich environment.

 

So I cleaned up the rotor even more, and with some creativity I was able to get out the stuck side and corner seals. I'm still not convinced I'll be able to reuse this rotor, won't new seals just get stuck/flattened again? As far as the center iron pitting goes, it looks like the front iron has similar pitting, and it was making decent compression when I pulled the engine, so I'm considering reusing it.

 

not necessarily. in my opinion, it's not even likely. engines don't have to die because something breaks. some engines lose compression because the springs go dead, some get carboned up. i have also seen engines that run hot do the same.

obviously, i can't be certain, but my guess is your rotor should be fine once you clean up all the seal grooves. that's been my experience with 90% of the engines that i've encountered with flattened springs/stuck seals.

 

Thanks diabolical1 I hope thats the case! Maybe I'll only have to get a new center iron then?

 

Probably not. Just check your clearances on the seals, and make sure they float under finger pressure in the grooves.

Some light pitting on irons is very common. It come down to measuring to determine if it is going to be an issue, and how tight of an engine you want to end up with.

Note that you CAN lap the irons, or have a machine shop do it, but that removes the nitriding from the surface. They either then need to re-nitride, or you understand that you now have a softer iron that won't last as long.

 

What do mean "float under finger pressure"? And thanks I ended up getting a new center iron.

 

The seals should ride smoothly in the grooves on the spring. Push them down with finger pressure, and they should pop back up.