Mazdax605

iTrader: (5)

Hey guys,

I know this is the 1st gen section,but I like you guys. I have been helping a friend of mine the past few days with a car that he bought.The history of the car is it belong to another friend of mine for the last year,and between myself,and another friend we have put just about everything you could short of a turbo on this car(87 sport).The most recent thing that we did to it was install a light-weight aluminum flywheel,under-drive pulleys,pineapple six port inserts,and an Apex-i SAFC.Shortly after(about 2-3 weeks) doing this work my friend drove the car home one night,and then the next morning it wouldn't turn over.We thought starter,but that didn't fix it either.We tried pull starting it,and that just slipped the clutch!!!!


Well long story short my friend gave up on the car as even with a breaker bar,the engine wouldn't turn.Now my other friend decided to get into 7's so he bought it,and a parts car that has what appears to be a good engine.We removed the engine the other day,and tonight we tore the engine down,hoping to see something obvious that would cause the locked up engine.Well I will get pics of it tomorrow(batteries dead in camera),but I didn't see anything obvious that would cause the engine to not turn at all.The apex seals are/were all intact.The housings seem fine with what appears normal wear,and the rotors seemed ok,but did have what I would think is a fair amount of carbon on them.Could that cause an engine to lock up?The exhaust ports seemed not too carboned up either,but they did have some.i know this is tough to diagnose without pics,but I am working on that.Could you guys tell me if the housings,and such are usable again with pics?Sorry for being long-winded.Thanks in advance.

Chris

trochoid

iTrader: (6)

What did the bearings and stationary gear teeth look like? Did anyone try turning the engine backwards before it was pulled? Other that, I would be looking at the clutch or tranny.

steve84GS TII

When you changed the pulley,did you keep the clutch pedal pushed down the whole time?
If not,I almost garuantee that the thrust bearing fell off its ledge and you crushed it when the center bolt was re-tightened.
The good news is that it doesnt ruin the engine,but you will have to pull the front cover to fix the damage,which will be the bearing and possibly the gear.If you can loosen the center bolt and the engine will turn over,then thats a sure sign that this is the problem.

Read and look at this.......
http://www.mazdatrix.com/faq/pulley.htm

Mazdax605

iTrader: (5)

Thanks guys,


Steve,

I/we knew about the thrust bearing thing,and we made sure we didn't do anything that would allow it to fall off its ledge,and it looked great when we took the engine apart.We had the tranny out at the time,and used a large ratchet strap to hold the flywheel forward so that the thrust bearing didn't fall off.

Trochoid,

We did try turning the engine both ways before we tore it down,but it was locked solid.I will have to look at the bearings,and the stationary gears closer,but they appeared to be fine.I thought tranny as well,but the tranny is fine,or seems to be fine,and the engine still wouldn't turn over while it was removed from the tranny.Thanks again.I will get pics ASAP.

Chris

trochoid

iTrader: (6)

Now you have my interest peaked, as all the normal causes seem to have been eliminated. Do the torrington bearings look good? Only other thing I can think of is maybe one of the oem 3 piece apex seals rolled and jambed. Look fo a single line depression across a housing face somewhere. It may not show visually but you should be able to feel it with your fingers.

Siraniko

iTrader: (13)

I doubt its the bearings based on his description.

steve84GS TII

Hmmmm...
FC engine has the unreliable oil thermal pellet in the Eshaft.
Possible it went bad,the rotors got way too hot, and semi-fused to the irons after shutdown?.......

Mazdax605

iTrader: (5)

I am not sure what you mean by Torrington bearings,but I really didn't see naything that was out of the ordinary,but I am not really experienced in the inner working of the engine.I know how they work,and what everything does,but I have never rebuilt one before. My first thought was maybe one of the pineapple inserts came out,and jambed one of the rotors,but that didn't happen.My next thought was an apex seal that was jambed into a housing,but I didn't see that either.It seems to me we maybe took apart a perfectly good engine that wouldn't turn over( I guess that isn't perfectly good).I will get pics tomorrow.

Chris

trochoid

iTrader: (6)

Torrington bearings are the thrust bearings.

84rx7gsl

i dont know if im on the right track but the engine is aluminum and it can warp from excess heat that could be the problem, ive heard of this happening but i dont think there could have been enough heat to do this because other things usulay go first good luck finding the prob

RXDad

iTrader: (2)

I once bought a seized 12a from a junk yard for $25. There were indications on the eccentric shaft bearings and rotor bearings that the engine ran out of oil for a short period of time. There was a groove, showing copper on the lower side of the eccentric bearings and a similar groove on each of the rotor bearings. The torrington bearing were intact and in place. The engine did not move at all before dismantlement. The only thing I can guess at is that the engine heated up and the grooves lined up perfectly, causing the rotors to jam against the rotor housing. Not much carbon build-up was evident.

The only real damage to the engine was the yard allowed the engine to be exposed to the weather for considerable time and the rotors and plates were junk. I did get a really nice set of rotor housings since the engine was a rebuild and had very few miles on it.

RXDad

steve84GS TII

Did you guys retain the E-shaft oil thermal pellet when you installed the pulleys or did you put in a delete plug in its place?

How was the oil pressure, and oil cooler condition?

trochoid

iTrader: (6)

Ah, didn't think about checking the oil. How did the oil look, can you see shineys in the oil pan?

Mazdax605

iTrader: (5)

we did retain the thermal pellet,and I have no idea what the oil pressure was as I wasn't driving the car.As far as I know the oil cooler is in good shape.