good luck...

 

Thank ya, I appreciate it!

 

Well, after multiple Christmas obligations and a killer bout of the flu over New Years, I finally got the engine split apart yesterday. The damnedest thing is I can NOT see where the leak is, but once I made sure everything was oil coated and rust free I didn't investigate a lot more into it. The freeze plug on the bottom of the back cover was bulged out about a centimeter, but no penetration (which as someone pointed out, wouldn't have introduced coolant into the oilpan anyway.)

I was really sweating it after seeing the horrible pictures of engines that blew coolant seals and were left "until the owner had time" that were rusted through and rotted. Everything at first glance still looks fine, other than the teflon split off the inner coolant seals. Also, are the corner seal slots not supposed to be in line with the apex seal groove? Mine were all sorts of crazy directions, and if they're not supposed to line up, I just don't see the point to them being slotted at all.

Also, compression was still pretty strong on all faces, even though it let out a nasty gurgling and spit sludge out of the exhaust ports.

Just curious - what if the inner waterjacket seal blew and allowed water into the rotor housing - is there a port that would let the water and oil from the housing back into the oilpan, like the injection holes in the eccentric shaft or something?

 

General question - the o-rings that go over the dowels, are they just common O-rings from a hardware store? Mazda's price on these is $4.50 a/piece, which is another $20 on the rebuild. If I can pick them up for a buck I'll do that instead. Any engine (re)builders have opinions on this?

 

Water leaking into the combustion chamber would not cause water to get into the oil. Keep looking for the freeze plug/crack.

 

Gotcha - I'm going to spend some more time with each piece after work this afternoon - something will present itself, I'm sure.

 

Alright, I've been all over the the inside and outside of every water channel with a flashlight and a small screwdriver. I've looked along every oil passage and every lower half of every section. I've examined all the coolant seals for defects. The only thing that even comes remotely close is the crack in this picture. I can barely catch the tip of my screwdriver on it, and I can't get into it. I can't tell if it's actually a crack or a casting line, but it's the only thing I've found so far. It just doesn't seem like the engine would crack that way, it seems like it would go front to back. I tried to keep as much size and quality as I could. It's in the center housing, directly above the water drain plug. Any opinions?

 

Any opinions?

 

that's just a casting line in the iron, nothing to worry about.

the oil galley o-rings are viton, you can't put generic o-rings in there or they will be destroyed rather quickly and cause some serious oil leaks. you can reuse the originals if they are not too flattened out but i would surround the sealing areas with some ultra black RTV to help keep them sealed up.

if there is no cracks or obvious popped out core plugs then you will just have to inspect the outer coolant seals. if an outer coolant seal was leaking then it could have dumped the water into the pan so look at the outer coolant seal walls on the irons, the outer coolant seals and the rotor housing seal faces for pitting. the only areas they can leak into the pan are around the bottom circumference area just above the oil pan.

the corner seals do need to align with the apex seal slot, i am not sure how they would be facing any other direction as the apex seal and the corner seal boot will hold them in line with the groove, if you forgot to install the apex seal boots i can see them being able to spin in any direction but IMO i doubt the car would run without the corner seal boots.

 

When the oil moves through the engine, does it move just through the dowels, or does it move through some of the chambers around the outside of the irons, too? If it's just the dowels then I can rule the rotor housings out right away.

Sorry, I meant to say the corner seals were aligned correctly, but the rubberish insert (is that the corner seal boot?) was rotated. Who knows? It could have happened when I unstacked the engine. Even with that insert rotated, it didn't appear to affect the apex seals ability to compress, because the first one I noticed was compressed by the rotor housing.

I'm at a loss then. I really would have felt better if I could find some glaring problem with this. Now all I have is that I vaguely remember one of the outer coolant rings looking a little scorched or messed up when it came apart. Now that they're all out it's hard to tell. I'll look them over again, flashlight test all three of the irons and if all else fails, I'll bolt the freaking thing back together on a stand next to the sink and run water into it to see if it comes back out.

I could see how water expanding in the coolant jacket would take out one of those coolant seals - It'd be nice if it was just a bad coolant seal, but it'd be nicer to KNOW that's all it was before I spend another $100 on seals and put it back together. :P

 

Finally found it - I went over every housing and iron and found nothing - so I put it back together on my kitchen counter without the rotors and e-shaft with just RTV, then suspended it over my sink so I could see where water was coming from and ran water into it. Once the engine block was almost full, I started getting a trickle out of the bottom, and out of an exhaust port, so it looked like the intermediate iron.

So I pulled it back apart, with great difficulty - I discovered that without coolant seals, rotors, and eshaft, it's incredibly difficult to get the housings back apart - I actually had to disassemble it backwards. Spent about 30 minutes going over the iron, couldn't find anything. Same story rotor housing. Nothing.

So I started cleaning it back up, figuring I must have not put enough RTV there. I was cleaning the intermediate housing, and I noticed that there looked like an imperfection in the seal groove at the bottom, like the casting wasn't perfectly round. It was probably no more than 1 mil in depth little ^ shape. So I took my eyeglass screwdriver that's the perfect size for cleaning those grooves and pressed on it. Son of a bitch flexed out about 2 mils! I pressed a little harder and came away with a centimeter sized chunk. It was almost invisible!

At least I found it. Luckily I found a guy parting out an engine across town, so I'm going to pick up a new iron from him, and be back in business. *phew* At least I didn't get it back together!

 

Wow, that was some detective work.
Congrads on finally nailing it down.
Good luck with the fix!


-Ted

 

Wow, I am proud of you man that is some kick *** trouble shooting. Something else the housing warped before it cracked. Well, I guess it never really cracked.

James

 

I think what happened is that it cracked, but right in the corner of the seal groove, and not enough to break completely off - it was weird because it held water until it was almost full, so the weight of the water pushing on that seal opened it enough for it to escape.

Are you back again? I could sure stand to look at your TII for some pointers on putting mine back together!