i have an fc3. after building the motor it ran perfect for about 5 months. the car is moded to almost the max. t70 turbo,wolf3d,1680 injectors, ported, no ac,no ps, aluminum flywheel,rotary aviation seals, atkink thermal pellet, anyways. the front plate cracked by the oil feeder outlet to the turbo inbeetween the housing and the plate. I figured it is an old motor ant it was time to bust. during the time of taking the motor out i did a cosmo 13bre swap. every thing went smooth. i used my fc's housings, rotors, and shaft with counter weight. and the cosmo's plates. the car turned on perfect on the first try, drove the car for a few miles on 2 difrent days , the motor now has about 35 miles on it, No boost by the way. just decent driving, i checked the engine and again oil leak but this time from the rear plate . took it apart and it is also cracked the same way my front fc plate had cracked. am i doing something wrong? car never overheated, oil pressure always between 40 and 60. are the dowels no good? I just cant figured out what can cause the plate to crack like that. i it just another old plate?

 

maybe the plates have been warped before some how...

 

One good detonation is all it takes, but from what you're saying, you haven't gone there yet.
Rushing the tension bolt torque process, or torquing out of sequence maybe?

 

Sounds like the crack was already there when you rebuilt the motor..

Engine might have detonated previously.. which might have been why it was "junked" back in japan..

The front iron leaking oil on the previous motor sounds like it was cracked iron at the dowel pin as well from result from detonation.