Well, if the rod was busted you'd have oil all over the road.

Shit runs deep:

Blown Engine - Mazda CX-7 Forums
2007CX-7 needs new engine!! - Mazda CX-7 Forums
what do i do?? - Mazda CX-7 Forums
Engine died: no compression - Mazda CX-7 Forums

sooo lex...do you use seafoam occasionally?

and another one bites the dust. this car is failboat

my buddy is trying to source the wynn's DIY engine treatment. he's pretty concerned about carbon build-up since his wife has a GTI as well....hope he'll post that info on here soon.

Nah, meth is my poison

http://www.mazdaspeedforums.org/foru...1&d=1269922397

Wheres all the guys saying stock motors dont blow, and asking why we dont see cx7's blow up? Where are they at now?

No two cars are alike and while most may be ok, sometimes there are lemons.

I'm currently researching what preventative mods I can do for the new motor.

That was the hubby (I call him my wifey ;) ) It was a last minute decision right before a road trip. I still need to find out what tool I need for the cartridge oil filters. I have done much more to cars than you know. I change the oil all the time on the miata, replaced the clutch, tranny (for fun cuz I had a spare 6spd), water pump, timing belt, alternator (just the other day), put in a new built motor (built by a spec miata shop), among other small things like o2 sensors, intake, exhaust, etc.

There was no oil leak nor any other fluid. I looked.

lawl

Hiding in fear of the inevitable...

ugh thank god... now how do we get rid of you?

good luck to the OP, i hope you get everything straightened out!

I'll bite on this. ::flame suit on::

There's only 4 cross links, maybe there's more but from what I've gathered reading on them, they're all pretty bad cases imo. Only one of them seemed to hold water and even then, not much information was posted on it other then "it blew up".

1 was taken in as a used car, like our poor girl here, another was driving on 87 gas, and the last one supposedly went through 4 motors in 3 years.

Still, not gonna say that none of the stock motors blows, but at least SOMEONE finally posted up some examples, albeit not very good ones. It still seems like a relatively rare occurrence though despite these examples.


Grass is greener on the other side (at least from trolling a STi/WRX forum)

Blown Engine Please Help!!! - IWSTI.com: Subaru WRX STI Forums
2009 sti engine blows up! - IWSTI.com: Subaru WRX STI Forums
2009 Impreza WRX motor issues - Page 160 - NASIOC

Wankel engines are a bitch when it comes to maintenance. I do recall from lurking on the 8 forums that it's more or less a requirement to top off on oil every other gas station stop since they drink the stuff. That and they really need to be abused fairly often to properly set their seals iirc. The general consensus was that too many people were babying them/not checking their oil levels and they ended up zoom zoom booming. Still, I also remember reading either here or elsewhere that Mazda is (hopefully) doing something about the RX-8's engine issues.

Couple things about CX-7 failures; they're almost never catastrophic, rod busts through the block, trail of oil down the highway fails. They're usually "the car wouldn't start, I took it to the dealer and they told me I need a new engine" fails. Failed rods and holes in pistons are not an issue.

Honestly, the majority of CX-7 drivers are not enthusiasts. They do their oil changes at the dealer and take their recommendations as fact. I mod on that forum and I can't tell you how many people have come on saying "the dealer says that 5w20 is fine for my car" or do oil changes every 8,000 miles. The fact that there are so many timing tensioners failing on CX-7 suggests that maintenance is a contributing factor to the failures you see. You also have the shady dealers that tell people with smoking turbos that they need a new engine. "That'll be $10,000, please."

Not saying that if you look, you won't find people who's engines exploded, but it'd be like finding a unicorn...

Nah, it's just you...! lol

Nice to have a CX-7 mod around here. Was there a known issue with the CX-7 timing chain for early engines? I remember reading something about that. Seems that the complete loss of compression some CX-7s have is due to a broken timing chain or skipped timing.

That being said, a hole in a piston of a stock car does not sound like a power related failure because:

1. It likely happened within a short period of time. The car did not just run with a hole in the piston for any amount of time so it was not a progressive failure now can be blame the hole being there when the OP bought the car.

2. The car was stock when this happened.

3. Hole in piston failures on a stock motor indicate something was wrong with the motor - either fuel delivery or some sort of strange preignition due to debris in the chamber.

In any case, there's no sense in being paranoid because if this is going to happen to you it will happen stock or modded. So just enjoy the car while you have it!

just purchased my car and running it hard everyday. although keeping it stock for a few months just in case something turns up (i bought it used). then the real fun begins lol! :silly:

What I meant by that you little Twat was that my car was having issues thus I got rid of it. Oil leak from the head to be precise and a sinking feeling in my gut that she was going to blow at anytime. I drove in fear of every hill I came across for over 6 months. So I traded her in with 59k on the clock and it feels so damn good to not have to worry anymore.

And don't worry about getting rid of me. I was only on to sell my AP. I have been done with this forum for a long time due to proliferation of twats like yourself. There has always been good information here as long as you know how to wade through all the childish garbage this site contains.

To the OP, I feel your pain and sorry for your loss but in the end you will be better off with a new motor and a new warranty to go with it (assuming they will give a 12 month warranty on their work).

Nothing documented, but yeah CX-7's see timing chain issues; mazdaspeeds see rod issues. Amazing, really, when you consider they're mechanically the same.

I've been convinced for the longest time that the torque converter is saving CX-7's from putting a rod through the block (no crank walk)...

The CX-7 also has a smaller turbo compressor along with a different torque curve/peak and lower boost limits, etc. I can't say for SURE, but I would think that practically ALL the ECU tables are different as well.

plus its driven at much lower RPMs in general.

I don't think either of these work in the CX-7 bottom end's favor. Smaller turbo, huffing hotter boost at nearly the same pressure (14 psi vs. 15 psi), driven at lower rpms, spooling even earlier, with a tranny constantly trying to maximize mpg. If low rpm boosting was really the killer in this engine, I'd anticipate MORE failures on that application! Point taken though; obviously there are more differences. I was just saying; mechanically the engines themselves are the same...

And now, I've officially jacked this thread. Sorry for all of the CX-7 talk. Good luck to the OP...

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I am SUPER happy with the outcome. I just got a call from the service manager and the Mazda rep: the motor will be in today and they are going to replace the turbo as well due to damage from the metal shavings when the piston got a hole blown in it. They went on to say that an over rev in the car's history caused the damage. The valves were bent. I'm not sure if he meant to imply that I over revved the motor but I know I have not. No worries though, I'll have a new motor soon and will baby it the same as I started with the old motor.

North Park Mazda wins a well deserved high recommendation from me.

I've had a few older rotary vehicles in the past: a 76 REPU and an 84 fb RX-7, so I know a bit about rotaries; enough to know pushing 238hp out of one N/A is a bit much. Having worked at a Mazda dealer when the RX-8s first came out I saw many a car get the motor replaced including mine. You don't want to know all the other stuff that was done, but the engine and transmission rebuilds were the largest. I was privy to inside info, so I saw that on my car alone Mazda spent over $7600 in repairs.

The thing about the RX-8s original problem was the fact that A) Mazda tried to make them as clean as possible, a hard thing to do since the motor is designed to burn oil to keep the Apex seals lubricated B) As such, the Oil Metering Pumps were starving the motor of oil in efforts to keep the emissions clean. There were other miscellaneous problems, but none as catastrophic.

You are right in saying rotaries have to be driven at high RPMs to keep them healthy. The reason for that is that if too much carbon builds up it can damage the engine/seals. Revving the motors high keeps the carbon from building up. That being said the biggest problems with motors failing was with the automatic cars because the transmissions kept the motors at low RPMs.

Jeez, maybe looking at all this I should get away from Mazda and go to Toyota, where the cars run forever...literally! The damn things won't stop! LAWL

To the OP you got victimized it happens. Check behind the glove box for your note.

Although you're angry and probably consider yourself unlucky here. I consider you the luckiest person alive!!

Brand new engine right before the warranty expired. And don't they re-extend the warranties again on new engines? Wow, you are incredibly fortunate. If I was you I would have been hoping it blew before that warranty expired b/c you HAD an unknown on your hands. Now you don't.

Wow thats awesome that they are going to give you a new engine. Thats damn lucky it didn't happen just a couple thousand more miles down the road.. +1 for basically a brand new car at the used car price!

wat??:33:

New engine AND turbo. Turbos don't last a lifetime either ;)

I'm not angry I am very happy. This could have turned out much worse, and as you guys have pointed out, I'm better off than if I'd just have the old motor. :)

The said the warranty on the new motor/turbo is going to be 12mos or 12K. Believe me, I asked.

get that chick who bent over the miata to bend over the ms3


and congrats on the new ticking time bomb!

So the valves were bent on top of there being a hole in the piston? This is sounding fishier and fishier. These cars have solid lifters so there's no valve float damage. How the hell are the valves going to bend due to "over-rev"? If you were driving around with bent valves you'd know it.

The only other possibility is jumped timing.

So here's my take on it. There was no "hole in the piston." You had a sweet bent or broken rod that sent the piston into the head which bent the valves and shattered the piston.

You sure you didn't see a trail of oil down the highway?

I would be skeptical of someone's blown motor analysis that tells me at some point in the past, the motor revved to the point that the valves bent and not mention timing being off. It's not related to hole in the piston either - a piston does not get a hole in it by touching a valve unless it is pounded by a broken rod.

Something is not adding up but glad you got taken care of.

I'm sure her info was coming from the Service Manager who are more natorious than the "techs" for being litteral dumbasses. By the time the tech explained it to the SM, and the SM tried to remember what to tell the customer, it was even more wrong.....

Congrats on the new motor but why are you going to "baby it"?

I got the info about the hole in the piston directly from the technician working on the car. I stated that in a previous post:
The info about the "over rev" :rolleyes: came from the regional Mazda rep that had to approve the motor install. It's all speculation after the fact anyways. How can you over rev a motor at well under redline?

Seriously? Why would I NOT want to run synthetic? Why would I NOT want to change the oil at sooner than manufacturer recommended intervals? Why would I NOT want to run Chevron 93? Why would I NOT want to let the turbo cool before shutdown?

I could go on, but maybe you have a different idea of "babying it" than I do. :eek13:

Who said anything about performing general routine maintenance / letting the turbo cool??? You said you're going to "baby it" which typical means you're going to pussy foot around for a prescribed period vice driving it like normal. No one was asking why you wouldn’t perform routine maintenance and put fuel in your car, etc. Yeah I suppose you could “go on” typing a bunch off topic crap but then again that wouldn’t make much sense.

I’m having a difficult time figuring out how you actually confused my question the way you did but anyhow you did, big time. If you do have plans to “baby it” meaning, not running the engine hard for a prescribed time; I would advise you do some research on other methods that have proven to be much better for engine break in. They don’t include “babying it” though. There's a thread here on the forum about it.

P.S. What makes you think Chevron 93 is any more superior then say Shell 93 or others?

I'd completely disagree. Changing your oil every 5,000-8,000 miles if your using synthetic SHOULD NOT cause blown motor damage at under 100,000 miles. ESPECIALLY a motor build in 2007-present. I change my oil every 3,000 miles because 1. I'm OCD 2. I beat on it. Like you said...most CX-7 owners are not enthusiasts...they drive "nice". So there is NO excuse for blowing motors at under 100,000 miles unless your literally NOT changing your oil.

There is a obvious problem with the motor. It kind of makes me feel a little better that the problems are occuring with stock vehicles as well...because now I know I'm not digging my own grave by modding (I did blow up last year...but the cause was known). I guess ya just gotta hope for the best and that you have the super duper rods :D

I agree on the not babying it. I'm a firm believer in breaking an engine in (properly) hard. You only have a short time on a new engine for the rings to seat properly. Probably less than the first 30 miles. In that time I recommend several hard runs (probably don't need to go over 5k rpm's though) through the gears. Don't abuse it, but definitely run some good hard runs to seat those rings right. If you don't do it by then, then you missed your opportunity. You get ONE shot at it! Don't miss it.

Doing it this way yields some really nice benefits. There is a thread here, but Google it and there are websites that go into great detail.

p.s. I agree the term "babying it" has absolutely nothing to do with maintenance and usually means putt-putting around.

Like I said, you guys must have a different personal opinion on the definition of the phrase. Perhaps I should have said "pamper it".

You're going to put diapers on it?

Funny, b/c that one actually makes me think of good maintenance. lol Guess we're ass backards. ;)

For an over rev to affect the valve timing you would have to rev it to over 8500rpm, there would be a hole in the block long before there are any issues with valve float.

I doubt the rod bolts are even rated to 8500rpm.

The "drive it like you stole it" break-in mentality is nothing but a theory perpetuated into the auto sector from the small engine segment of the auto sports world of old. Older 2 and 4-cycle small displacement engines never went through fine honing processes like some modern small engines and ALL large displacement engines do. The fact that you don't have to beat the shit out of a car to properly seat the piston rings is affirmed by numerous engine R&D experts throughout the auto industry.

Essentially, you can do one of two things: follow break-in instructions that were written and published by engine techs with 100's of years of experience combined, or follow the advice of a handful of internet self-proclaimed performance gurus.

Here's a good read:

Car & Engine Performance - Technologue Editorial - Motor Trend

Well, it's always worked for me to great success. You have to believe someone at some point. Pick who you will.

hahaha huggies with extra absorbency so when the motor blows again no oil will be spilled.