what causes main and rotor bearings to spin....and also what causes side seals to break? thanks. my motor was rebuild 2 times in 2 months first i was told that the side seals broke causing it to have blowbys....next it rev to about 9 grand and all the bearing spun....when the front rotor was removed the bearing fell out when i lift the rotor up.....this time i'm gonna try and do it myself....thanks alot for the info if you guys can share any.

 

Bearings spin because of lack of oil. If there is not enough oil for them to spin on they contact the bearing and cause them to spin.
A solution is to increase oil pressure.

 

Basically your engine was not cheked for proper tolerance and clearances. Side seals get stuck when the sideseals to rotor groove is too tight. When the engine warms up and metals expands, a tight fit becomes tighter. I wrote somewhere in this section about side seals and rotor bearing clearances. If you look for old threads you will find. If you dont find it, Ill come back and try to help you.

 

checked the last 100 posts and didn't find it, probably because i don't know what topic it's under. thanks for your help.

 

An engine out of balance can stuff your bearings aswell.
Were the rotors and stationary gears replaced the first time the bearings spun? because the the bearing housings would be stuffed and simply pressing new bearings in its place wouldn't be good enough, it would only be a matter of time before they spin again
Is the motor ported? check to see there is surface on the plate for the leading edge of the side seal to rest on.

 

the last time the motor spun the bearings was the only time, the motor is ported, i was noticing on one of the ports that it has a little mark or cutting on it. also the flywheel and the rotors were 88, and the motor was a 90. i've received some 90 rotors so i won't be using those rotors again, i currently checking out a 90 flywheel. would you still recommend that i balance the rotating parts? also the bearing spinning a little in the stationary gears would that have any effect on the stat. gear housing? just curious. thanks for you help.

 

I have seen guys do cheap rebuilds that pair up rotors to counterwieghts of same engine make, and it worked. This is how an aftermarket flywheel is fitted afterall. They use counter weights of automatics to accept the flywheel...... and it works fine!
But I recomend you get it ballanced unless u know that the rotors, counter weights and flywheel came from the same engine, that haddent been mixed since mazda built it.
My last motor/clutch assembly only cost $180 NZ to balance, its worth doing for that price

Change that stationary gear too, because once that main bearing spins it shuts of oil to your rotor bearing causing them to dry up and spin too
you can modify the rear stationary gear to accept 3 window bearing. Take the replacement stat to an engineer and get him grove an oil gallery on the housing the same dimension and location as on the bearing and then die grind 2 extra windows on the new bearing before pressing. You can do this yourself with a drill bit and 1/4 inch cutter. $20 mod that helps keep those bearings lubed.

As for that mark... does it look like a slip with the porting grinder? in which case it will probably be fine! or is it close to the track of the sideseal at the top of the port. which could be un unsuported sideseal calapsing into the port and smacking into the wall of the port. it may also be damage left over from the broken side seal? dont now? have another look. How many side seals did you break? do they pair up to that plate?

 

Is there a chart that tells the weight of the counter weight and the coresponding flywheel?

This would be helpful. Thanks

 

the mark on the housing looks like the side seal made it. when the engine blew the first time i didn't see anything, they just told me that it was the side seal that broke causing the engine to have blowby. i don't know how true it was to know what esle was damaged. the last time the motor spun the bearings, all other internal part were ok, it's just the bearings that were messed up. thanks for the tip on modifying the stationary gear, i had purchased the 3 win. bearing, but i didn't know that i had to get that done to the stat. gear. i'm also thinking about getting mazda race rotor bearings, and i'm supposed to buy this flywheel from this guy, he says it's a 90, but i'll know once i see it. the number on the flywheel should be 350. once again thanks for all the help. do you have an email address, i would like to keep in contact.

 

Are you sure the oil pump is good?

 

9 grand? Are the bearings and gears stock? I didn't know you could spin stock stuff that high. Our PP spun 10.5k, but it had all the race goodies.
Don.

 

killa! did u get my email address

 

everything in the motor was stock except 3mm seals and racing corner seal springs. as far as the oil pump i'm not sure the condition it was in when they build the motor....gonna check this time......Mazdas...no i didn't received it try sending it again. thanks