13bbuggy

iTrader: (2)

I am fairly new to rotaries and have a 1986 13b NA that was overheated by the previous owner to the point of the bearing welding to the shaft, but it was running when I got it just not for long. I also have a 1990 13b NA with good compression and everything and no compression on the other one. I am wondering which is a better candidate for a rebuild and if it's the 1986 can I use the eccentric shaft and bearings from the 1990 inside the 1986? Also does anyone know what other damage might've come from the bearing failure?

Aaron Cake

iTrader: (1)

Bearing failure typically chews up the stationary gear the bearing is in, plus the eccentric shaft. It is also highly likely that bits of the bearing went through the oil, destroying all other bearings, possibly the rotors (if the rotor bearings spun or metal ended up on the thrust surfaces) and maybe the housings (metal bits on the thrust surfaces).

An overheated engine to the point of bearing failure is likely to be complete junk, save for maybe the rotors. You would need to carefully spec out the housings and irons to make sure they have not warped or shrunk from the overheating.

A blown engine will likely have one bad rotor housing and one bad rotor.

If faced with the situation you have here, I'd use the irons, eccentric and stationary gears from the S5, with the s4 rotor housings if they are still usable. If the S5 rotors are usable, I'd use those as well as the matching counterweight as well (lighter, higher compression).

However, you won't really know what can be used until you tear down both engines.