ok some of you know i'm rebuilding my engine. after some work and really screwing up i found i couldn't turn my engine over. i tried quite a few times but no avail. after i pulled it out, and look down exhaust port... found 2 apex seals fell out so.. i tore it apart. but i have a slight problem and worry about my rear rotor housin. anyone think this is salvageable? i can take a better pix. the gash is about a piece of paper deep. if i need a housing... anyone got one? or is there a spec where as i could, (in reference to a piston engine....) rebore? or something of the like? thanks!

Carlos

 

can't see pix

 

if can't see above here's another try

 

So let me get this straight. Your engine locked up, and wouldnt turn. So you pull it out and find apex seals in the exhaust port? None of that sounds right to me in my experience.

First off. The pic of the rotorhousing looks fine. That is normal wear on the back edge...caused by the 3pc apex seal design...any used housing with more than 50k miles or so will have some wear and chrome flaking there. That's normal, it's reuseable, though compressiom may suffer a few psi versus a new housing, the engine will break in and run just fine. But, there are those here that will argue that you should always use new housings, but not everyone has the extra 1200 bucks laying around.

That housing doesnt show any signs of apex seal damage. It's basically impossible for a chunk of seal to exit the engine without doing some damage to the housing...usually right by the exhaust port, and again right by the trailing plughole is where the damage will occur, and it'll be obvious, deep scratches and gouges. Same on the rotor itself. The seal wedges itself between the 2 parts as they move, and there is not enough room for the seal so it dents the rotor and housing on the way out.

Even if you did have broken apex seals, they won't cause an engine to lock up while running...well, VERY rarely they can, at idle/shutdown/startup. Usually a locked engine is carbon or rust from sitting too long, or it is an oiling failure where a bearing spun.

I dont think either of those things happened to yours...your comments make little sense to me right now. But, that housing looks okay to me.

 

What is that silver blemish at the bottom of the rotor housing, last pic? Looks like a ding.

 

This may be a dumb question but... I have torn down my enigne as well and as all used engines, it has the seal wear mark on the edge of the housing. Quite normal as the tip of the corner seal is narrow where it touches the housing.

Let's assume you find your housings to be good enough for reuse.Would it be wrong to put in the apex seals the other way. in this way the bigger piece of the apex seal will now cover the 'old' corner seal area and vice versa.

Does that make any sense?

 

how did 2 apex seals fall out???? only thing i can think if is you used 3 piece and put the rotor in with out the stationary gear bolted in, that might have gave it enough room for the apex to fall out. Glad you didnt mess up the housing, good luck next time.

 

that's something that I've seen done by a few rebuilders to give the 3rd apex seal corner piece some new "meat" to chew on. It really wont help compression much if any though, and it makes the seals slightly harder to install too. Most people are using 2pc seals now, like atkins seals with the longer corner piece...which negates any benefit of installing the seal backwards, since the corner piece can no longer fall down into the groove anyway.

 

i apologize i wrote up the message too fast. here's the story.

flywheel ringgear, (part the starter hits to start car) seperated somehow from my flywheel, (it's a stock fly) so i pulled tranny out. i figured. while i got it all out, might as well change rear main, well i look on mazda's website and found a TSB on the rear stationary o-ring. to replace b/c most of the time it's the one leaking NOT the rear main. so i did. BUT! i didn't know nor did it say to release the tension from belt b/c the e-shaft will kina **** <-no pun and make the rear stat harder to put in... so i figured "maybe" the teeth are slightly miss aligned.... so i turned the crank back/forth a bit so i could try to realign the teeth. finally got it in wiht a mallot tapping all around.. but when i tried to spin the motor the crank would rotate only about 320 deg. in either direction. after trying a few time i pulled the plugs as reccomended here and by our master tech. see if it's a compression deal. no luck. so i said screw it i'll pull it out rebuild it. and figure out what went wrong. when i put it on stand. my mastertech asked me to spin the engine while he looked in rear exh port to see if he could see what's going on. as i spun it he says something shiny, stuck a magnet in, found an apex seal. turn it over for the next stroke on same rotor, found another one.... pull engine apart found a gash on the back most part of the rotor housing. wich i show in pix. if you need a better one i can get one. that's why i ask if it's ok, if not i'll get another housing, (offers anyone? )that's my issue. when i looked at seal and my M.Tech looked, and 2 of mazda's regionals, they said they we're already worn and ready to go anyway. so lucky me it happend now instead of when driving. now my qustion is, ya'll say it's normal wear... but wouldn't it be all the way around? or only on a certain spot? would you reccomend me going ahead and using it. or find another good used/new housing and be on the safe side? thanks!

Carlos
sorry so long.

 

The only thing I can figure is that perhaps you got the rotor/shaft so far out of alignment/center (I wouldnt think it possible, but I might be proven wrong) that the apex seal tips actually had enough clearance to come right out of their slots...the stat gear holds the shaft and rotor in time and in position relative to the housing. Still, this would have no impact on the wear on your rotorhousing...that is normal wear as discussed above. The wear is usually exhibited in the lower half of the housing closest to the exhaust port...my theory is that this is the hottest and most stressful part of the engine so it begins to flake before the rest.

IF you are made of money, then fine, replace it (both of them will have similar wear, so do them both) and sell the used ones to someone else who needs a budget build.

 

that's the funny thing... only the rear housing has the mark. the front is perfect. is this common? i won't say i'm made of money, buti'd rather wait a little longer and it right the first time then cheap out and spend double in the long run. hehe.

Los