wont matter because if you were operating the engine out of stock spec their parts werent designed for that.

So were all fucked unless forged. Awesome

do compression check

What would it prove? Would an already bent/fatigued rod measure less compression?

It did on Cpolly's car

It's the steps where you add oil and watch the reactions during a compression check that show you the potential source of the problem

A bent rod will most likely affect your compression reading but that is not THE ONLY thing that will give you a poor compression reading.

Mine read down 5 psi on number 3 which is hardly conclusive of anything. The piston would have to be pretty cocked up for a long while to offset mill the rings enough to be an instant compression test giveaway. Best to run a leakdown and see where the leak is coming from. If it's done the rings, it'll blow through the oil fill cap hole. done the valves, out the exhaust or out the intake, depending on what's fucked. you can learn alot from this.

did you do the oil in there and see what happened?
another cylinder 3 down a little - man i really wish we could convince more folks to do compression tests and post the results - i'm done with this car and giving up, but for someone who really wanted to try to make a case to a dealer info like that would really help....

no valve issues, piston rings, head gasket, hell even imperfections in the cylinder wall are all potential causes of lower compression but doing this test with the oil at least points toward the source of the problem -
a total leak down test can pinpoint even further - but those are tougher to do

It was within spec for the cylinder so I didn't oil it. Oiling a cylinder will almost always raise compression values a little, even if there's no damage, especially if the test is done on a cold engine. I can't see how that would conclusively demonstrate anything beyond possibly isolating the ring seal being an issue. But, if it passes the objective #s test, what have you learned and what can you say to Mazda?

I now have a small compressor at home, maybe I'll buy a leakdown kit and run that test, if I can find one not too expensive.

oil follows the rules of everything else man - gravity - oil goes down into the piston ring making a temporary seal - if you get increased compression that's probably the source of the problem - i don't think it does the some thing to a valve stem - when you are turning the engine over it's not going to splash up past the base of a valve and make the same temporary seal on the stem before it enters the upper valvetrain area - so if it doesn't raise it's a valve leaking instead of a piston ring -
everything i'm saying is explained in the factory service manual page 01-10B-9
oil tests are not definite (they can point you in the right direction), but compression does not always raise every time you add oil - the other scenario is where you have one higher then the rest and if oil makes no difference here, you probably have head gasket leakage

So this is all pretty bad news

no easy fix here...Replace the bottom end or go home. I wouldn't take any chances. If you can pull the motor yourself, and tear off the head, you can probably replace the rods and pistons relatively inexpensively. It's a MUCH better option than needing a new block down the road.

Just when i was startin to have some small ounce of hope for this car. Another bomb gets dropped :( too bad i'm too deep into this thing to sell

i don't see any bombs. all i see is a great mazda. stay positive. How do u know that the internals he has aren't just a few coincidental bad ones. A lot of people beat the shit out of there cars and have no problems. Lenny is probably the worst. I take my own chances now. When i owned a SRT4 neon i wanted to go big turbo but i never did because i listened to the forums and they all said im gunna blow if i don't build. guess what. years later they find out how the motor is a solid mother fuker well capable of handling BT's on stock internals. FML for not staying SRT.... anyway i really feel that these motors get to this point because of knock and abuse. causing these clearances to increase. take good care of your car and change the oil and what not and hopefully ull be fine

It's just not worth the risk, monetarily. How much do rods/pistons cost? If you can do most of the work yourself, it's worth it.

Do it right the first time, or you'll end up knee deep in shit.

Also, lol @ all of those pistons being a 'coincidence'

H1N1 is bad...people actually die from it...and yeah, I hear and read a lot about it...it scares the shit outta me...but hey, I wake up in the morning, and put my pants on one leg at a time...

I'll get the vaccine once it comes out...but in the meantime, I bitchslap my car left right and centre and she loves it...

As others have stated.... The failure rate is FAR BELOW the recall threshold. Its possible that this defect is apparent in only a portion of the build. And it could be that this is a large contributor to those that blow.

Thus, if you havent blown, then dont stress on it. Take care of your car and drive your car. Dont be a douche and do your regular car care and just pray to little baby GSR Jesus that your rods dont have the tolerance stackup issues.

Shit, your car could blow the fuck up because an injector dies... Does this mean you should stop driving? NO, get the fuck out there and have fun with life!


(FYI, Im going to knock on wood so I dont jinx myself KKTHX)

Lex,

I can send you my pistons/rings, rods/bearings, all four of them. My engine did not blow.

The guy at the Machine shop say they look perfectly fine, motor has 10k and I started pounding on it since it had 30 miles on it.

PM me where u want me to send them.

i love the car - i just got the shit end of the deal -
and as far a people running their cars and being fine - i gotta ask - are they just fine because they drive everyday and it still functions well enough to run - so they assume they don't have any issues or are they really doing scientific tests to know they are really "fine" the car will run on seriously decreased compression - i'm living proof of that - my things is - do some tests see where you really are - weigh your options and if you aren't where u are supposed to be - change the bottom end

I realize that all of this is alot of forum hype and crap but shit its hard to stay positive with all this negativity!!!! And cpolly69 as far as the comp check goes my cylinder 1 comp was so low it blew my pcv valve apart lol not a bent rod either i torched an intake valve shut and it woulda been runnin way lean but by the grace of God my injector was also leaking in the first cylinder so that extra fuel leakin in kept me safe i'm pretty sure. Dumb luck i suppose. Still not a cheap repair :(

my 07 ms3 blew up just over a year ago coming up an on ramp. i had only a tbe and cai, and they voided my warranty for mods. i solved this problem a few months ago by buying my brothers srt4. i can get everything i want out of it on stock bottom end. :)

sorry to hear about all the blown motors, and with this many, it is safe to say there is a problem with those cars from the factory.

heres a thread on my site with some pics, nothing technical, but if you want to see some pics theres are a few to browse.
BOOM! Now with pics! - Midnight-Racers


heres a pic of piston #3 after we pulled it

http://i24.photobucket.com/albums/c2...r/DSC00722.jpg

i think your the first picture i've seen of a piston breaking

part of the broken rod that was connected to that piston can be seen in the top right of that pic.

I built my motor and just got it back and am trying to put it in the egine bay. PITA anyway I looked at my stock rods and pistons and to the naked eye they look twisted and bent a little. I did take care of my car, always let off when I saw knock and regular oil changes. Lex if you want the rods and pistons I can send them to you. Just PM me and you can check if they really are bent and/or twisted.

Holy cracked piston batman! You musta really raped this car constantly!

Im getting mine back either Wednesday or Thursday!

Now just need a how to to pull engine and head. Wish some of these were doing oil analysis' to see metals spiking before they blew. Good info.

How to pull motor out of front of vehicle would be worth its weight in gold.

Pulling the motor out was hard. Putting it back in with the tranny still in the bay is a bitch. I got the tranny sitting on the ground with the driveshafts still in it, the block is up top with one motor mount and a jack under the oil pan. Doing this in my basement with no room. Hopefully I can
lift the tranny Ono place cuz dropping the motor then lifting the tranny up. Ugh so frustrated!!!!!!!

Fuck it i haven't had a motor in my car for 4 months now. I'm just gonna tear it down again and go forged. Shoulda done it right the first time

we have forged internal but obviously some have defect and boom...

but yes....aftermarket forged is better/:biggthumpup:

actually, it was rarely driven hard. most of the cars i hang out with would rape that pos anyways, so there was no point in racing it.

Thank you
 

I needed a good chuckle.:haha:

P.S. Mike.B,
I intend no offense nor do I question the sincerity of your post, but rather I find the message you relayed about the car amusing.

Since I have a broken down Speed3 in my driveway, I understand your frustration.

i love how everyone assumes a car was beaten on because it broke. there are stock speed vehicles blowing motors, thats shitty engineering. i didnt say i never raced it, of course i got on it sometimes, but all the time? definitely not. i'm not trying to prove anything, and if you dont believe me, i really dont fucking care. im just throwing this in the observation thread for reference purposes.

i used to read everyone's failures and say to myself "yeah they just treated it like shit" - i've never been to the drag strip - never been on a dyno - and never done a burnout - i had mild bolts ons and did a total of 2 drives at 18psi - i took my car's maintenance seriously changed oil on schedule (and proved that to a dealer w/ receipts) - i have low compression in one cylinder now - go figure

u didn't drive it hard enough thats why. Breaking that shit in WOT helps seal the rings better and u will get better compression.

I doubt that, highly.

Not to go too far off topic but i'm still fairly new to the whole heavily modifyin shit and i realize the longevity of any car eventually reaches zero but are these failing comp ratios gonna happen super quick with forged guts just like stock? If so whats the point? Thanks

Just to bring this back on topic. The reason for the rod imperfections is the manufacturing process. Without fully machining the entire rod surface to spec, you will see these imperfections. Fully machining the rod is left to aftermarket manufacturers where they can charge a premium for the parts.

NRSpeed know's all about Rod Bending....LOL...he has been practicing, it seems daily according to his avatar!!!
Sorry Lex,.could not help myself...
now PLEASE back on topic...