Rebuilding engine

[speedjunkie]

This isn't a whole car rebuild so I figured I'd just post this here.

I had the car on the dyno last Saturday and after only the second pull the car died as the rollers were slowing down, and it wouldn't start again. We tried quite a few things and just couldn't get it running again. We tried pull starting it and ended up just ripping off one of the oil coolers. Not happy. So we trailered the car back to C Springs (the dyno was north of Denver) and Thursday night I started pulling the engine.

Progress for the few hours of work Thursday night...



Actually I went back and pulled out the 2-cycle oil reservoir that night too.

Last night I got cranking on it again about 8pm and finished around 1am. I cracked open my exhaust where the DP and MP come together and coolant starting dripping out. Hmmm, I guess the coolant seals are gone. That's what happens with the dyno owner asks you "hey, what's this?" when the temp gauge is reading around 240 or so and the red light is flashing. "Hmmm, I'm not sure, it does say 'water temp' and it's reading 240, what does that mean to you?" I'll never go back there. (I was not in the car by the way). For whatever reason my fans weren't coming on and they were set in the PFC to come on at 85*C I believe. Anyway, I haven't broken the engine apart yet, I'll be doing that today. But here is the progress made last night...


I thought I took more pics than that last night haha. I'll take more pics today and post up what I find.

[speedjunkie]

Progress so far today...


I believe my oil seals may be gone too because I had a TON of oil in the rear housing, and it looked like there was a little in the front too. I turned it over and oil poured out through the exhaust port as the rotor passed by. I checked all the apex seals and they looked good from what I could tell and they were still springy so I guess the springs are good too. We'll see what all is bad. I'm at a stopping point right now because the front bolt is being a MAJOR PITA to take off, so I'm gonna have to break out the impact tools finally.

[TitaniumTT]

Damn good progress Eric.... I haven't even finished cleaning my car out from The Epic Road Trip V1

The last front bolt that I took out was a factory original. My 500ft/lb gun wouldn't touch it. Had the flywheel stopper on, broke out the 3/4" breaker bar and a 5' pipe.... the best was at Glenns, we couldn't get the flywheel nut off. Had to use the Mazda factory tool and one of the legs off his hoist as the "Bitch Be Cool Bar"

I wanna see pics. This is an odd failure for sure thus far

[Prodigy]

You could give the front bolt a little bit of heat, only thing is if you give it to much heat the thermal pellet springs will have a chance of getting ruined...

My suggestion would be put a little bit if heat of it, and replace it with pellets that a number of different companies that make the bypass the oil so it has oil all the time instead of just once warm



the rest of the teardown looks good so far... Waiting to see more pics...


J.

[GorillaRE]

I do not recommend using heat, in this instance. Flywheel stopper and a long breaker bar aka "cajun persuasion", end of story!

-J

[Prodigy]

You don't need much heat at all... If you give the 'ring' that mounts to the E shaft a little bit of heat it heats uP the locktite enough that the bold can be spun out by hand... Don't get the bold red hot, thats way too much, but just enough to heat up the red locktite..


J.

[TitaniumTT]

Odd, 2nd gens were blue locktite.

I agree though, heat is a last resort.

[vex]

My bolt required a butt load of heat. STupid thing wouldn't budge with a torque bar or a heavy impact gun.

[speedjunkie]

I just got back from eating some good Mongolian BBQ a little bit ago, feeling kinda lazy haha. I can't rest though, I gotta get this going. I'm gonna work on getting that bolt out tonight and get the rest of it pulled apart so I can take the pieces to Denver and get them spec'ed. More to come...with pics! Just for you Prodigy LOL.

[speedjunkie]

Wow, that thing really is not budging. It's ridiculous LOL. I guess I'll take the engine still assembled tomorrow and see if Matt has something to aid in getting it apart. I had a piece of angle iron with holes drilled in it to work on the flywheel but I let Simon borrow it a couple years ago and he says he still has it but I don't know where it is haha.

[speedjunkie]

I took the engine to my buddy Matt's house in Denver today. We actually got the front bolt off fairly easy, then the flywheel nut gave us a hard time but that came off not long after too.

Wow, this is going to be an expensive build.
-The bearing in the rear gear is completely shot (which I guess explains why the rear housing was filled with oil). More accurately, the engine tried to shit it out the back lol. And because of that...
-...the e-shaft is a little eaten up in that area as well (I got a replacement from Matt for $20).
-The rotor bearings are decent but I might replace them anyway.
-The front and rear irons are toast, groooved up beyond reuse.
-The center iron is still well within specs.
-The housings look OK but I still need to spec them. There is the usual scorching at the spark plug ports and there are slight chatter marks all the way around but they're still in decent shape. I still need to inspect them better though.
-The rotors are in still in good shape. I broke one side seal on the rear rotor, I guess it welded itself into the rotor, and I believe that explains why it sounded like a side seal was bad. These rotors were practically brand new when I built this engine in 08. They had only been run in a reman to break in the engine.
-The apex seals were in great shape, not a single problem that I could see. I might still switch to RA seals, not sure.
-Some of the corner seals were ground down a bit. These are Atkins solid corner seals and the lip on some of them were ground down a bit, that's what I mean.

The front and rear irons are the ones I had sent to Mazdatrix to get resurfaced but I did not nitride them afterwards. Would this be enough to make them wear so much faster than the center iron?

I'll post some pics tomorrow, I gotta get to bed for work tomorrow.

[diabolical1]

wow! that sucks! i await the photos.

[TitaniumTT]

Damn Eric, that sucks, but at least you didn't kill the housings and rotors, that would've made it really expensive.

What's the clearance like on the e-shaft to main bearings?
E-shaft to rotor bearings?
Any signs of the rotors contacting the side housings?

If you're in need of new main bearings, I'd go with the RX8 stuff. I'd even look at the RX8 e-shaft based on the clearances found on the new e-shaft you've acquired.

There are a few different theories regarding the re-nitrading. I just tore down an engine with 200k+ miles and the housings were some of the nicest I've ever seen. N/A ran premix almost all it's life. (rotors were damn near spotless too) However, seeing as how your un-resurfaced plate is good, and your resurfaced un-re-nitraded plates are fucked, I'd say that's a good arguement for re-nitrading.

Any chance you have someone local that could do a rockwell hardness test?

[speedjunkie]

Well I'm not absolutely sure yet that the housings aren't toast as well haha. But at first glance they look pretty good. I'll have to reassemble to see what the clearances are on all that. We were disassembling outside and it was cold, so we made it as fast as possible haha. I'll post pics of the rotors but I think they might have made contact with the housings in a couple spots, right at the corner seals. As I mentioned some of them were ground down a bit and you can see those corners of the rotor have some markings.

I thought about getting RX-8 parts but I wasn't sure what all I needed. I know the e-shaft is half a pound lighter but other than that I don't really know much about it all.

So you're saying the engine you tore down had been re-nitraded?

I have no idea if someone local can do the rockwell test, but I can find out.

[TitaniumTT]

I'm using an RX8 e-shaft, and front and rear stat gears that come with the bearings. Some say don't use the Renni shaft, but I only know of one failing. All my internals are also cryo treated as well.

The engine that I tore down was factory original. 200k miles, virtually no wear on anything. This was also an n/a engine though. I couldn't believe it really. West Marine generic TCW-3 oil mixed at 128:1 for most of it's life. SUPER clean internals. There were also 2 failed coolant seals. One in each rotor. I'm wondering if the coolant didn't stream clean the engine as he said he ran it for a few months until it got so bad it wouldn't start.

Either way, I've heard that the nitrating only lasts like 30k miles. I strongly disagree with this though.

I'd be curious to see the rotors, see if they made contact. I thought you said that the corner seals were worn down, not the rotors itself... my bad.

Question for ya though.... are you premixing as well? Or using just the RA MOP adapter? I'll be honest, first engine in this build was using just the RA adapter. There were signs of wear on the outsde edges of the rotors/seals. Now I run the RA adapter with the Idemitsu premix and I also put 1/4 oz per gallon of gas in the tank. The wear seems to be very minimal (and by minimal I mean there was virtually zero wear on the apex seals/housings/plates. The side seals I set to .0025" and they wore to .0038-.0051" after 10k miles and 100+ dyno pulls. Still < Mazda min spec ) but more importantly it's more even across the seals. The reason I believe is the pre-mix in the tank will get to more areas of the combustion chamber than just the factory MOP system with the 2-stroke adapter. The factory system was a compromise. I do like the variable rate of it though. There's no need to soak the engine with oil when you're just cruising down the highway. Then again, when you're on decel and the injectors are off, you're not getting any oil at all. So, it's my opinion that the RA adapter with some pre-mix in the tank gets you as close to the best of both worlds as you can.... just my opinion/experience.