After we have sanded and measured all the side seals, installed them with the springs, corner seals and made sure the apex seals fit properly, we assemble the motor. Got all the long thru bolts in and finished the torque sequence, we get to the other stuff.
Just as important as the three main rotating components, we get to the oil pump and end play components (thrust washer, needle bearings, counter weight and drive gear).
As with all builds, paying attention to details is where good results are built. After putting in the main shaft components, we get to the oil pump & chain. Now, I like to take the pump apart, measure up clearances and check for stretched chain. On this motor, the chain was stretched so we bought that with the main Mazda order for this build.
What I didn't expect was the way the oil pump went back onto the front housing. While snugging up the four 6mm x 1 bolts, I like to rotate the oil pump / chain without the keyway in to make sure that the oil pump isn't binding or adding resistance because of an interference issue. Sure enough the pump rotated fine until the last bit of tightening, then it was binding.
The reality is that these motors are pretty stout when you take the time to do it right. We didn't just replace the oil pump, we put the larger turbo oil pump, more volume, increased protection.
This motor is back in the owners hands and looks like it will be back on track soon