Thanks for the photos.

I have completed the analysis of the chicken and the egg with your motor - in other words what went first. The answers is the rod was bent for some time. The motor ran this way and eventually the piston ring got snatched on the bore, locked the piston in, rod twisted, broke, and hammered its way out of the block. I will have a more descriptive doc on how this was arrived at within the next few days.

The next questions are - why was the rod bent and are any of the other bent? Was there an issue with the rotating assembly as a whole?

The picture above shows me that there is uneven wear on the wrist pin bearing. I saw uneven wear on all your rod bearings. This means that rod #4 is either bent as well, or the combustion is happening off centre, or that the entire rotating assembly is offset.

Can you please look at the rod for any bends (along any axis) and take a picture?
Can you please grab pictures of the rod lying flat on a table from both sides (I want to see if it contacts the counterweights on one side more than another?
Can you please grab a picture of the wristpin showing where the wear marks are (from rod bushing and piston)? The wear marks are likely offset from centre on the wristpin.
Can you please grab a picture showing the underside of the piston? Looking for possible rod/piston contact.

If possible, I would like to take a look at all the rods/pistons/bearings first hand, and will gladly pay shipping for them both ways (and of course return them) if you can get them to a post office.

Thanks!

Here is a diagram showing how the injector spray pattern was on your piston (in red). The blue shows how the injector spray pattern SHOULD have been.

This means the piston was rotated in the bore for at least a little while or that the injector had an issue.

A small update on this. From the information and pictures posted, it appears the entire rotating assembly was misaligned in this motor. From the rod bearing wear spots (http://www.mazdaspeedforums.org/foru...-needed-39021/), to the wrist pin and small end bearing wear.

There is likely a manufacturing/assembly error on Mazda's part in this one and that this motor would have failed one way or another. If you have the ability I would take this up with Mazda.

I know I have promised a full report and it is coming, just been too busy to compile it. I am going to make sure the report is thorough and is posted in as many forums as possible. I would not be surprised if a lot of these "strange" failures are indeed manufacturing flaws.

Sorry to hear!

Shots of the main bearings, from the girdle side.

oh my goodness. this is ugly

Thanks Ryan! Do you still have the parts listed below and can grabs shots of these while you're with the motor?

- Can you please look at the other rods for any bends (along any axis) and take a picture?

- Can you please grab pictures of rod #4 lying flat on a table from both sides (I want to see if it contacts the counterweights on one side more than another?

- Can you please grab a picture of the wristpin for rod #4 showing where the wear marks are (from rod bushing and piston)? The wear marks are likely offset from centre on the wristpin.

- Can you please grab a picture showing the underside of the piston #4? Looking for possible rod/piston contact. Do any other pistons have marks of the rod rubbing on their underside?

Here's the results of laying rod number 4 on a straight edge. Rods 2 and 3 checked out fine.

Also, see attached rod #4 wrist pin

I can't tell from the rod pics - is #4 bent?

Yeah, on the flat of the wrist pin end... on one side, light comes through from the right, on the other side, light can be seen shining through on the left. Indicating a bend in the rod, the other rods 2 and 3 lay perfectly flat on both sides.

Was the #4 rod touching the underside of the piston on the small end?

How do the other wrist pins look from rods 2 and 3? #4 shows uneven wear. Do the other wrist pins also show uneven wear?

3 wrist pins, from left to right, we have 4-3-2

And the underside of piston 4, with highlighted rod to piston contact marks.

Pistons 2 and 3 were clean.

Thanks for all the pictures; they've been a great help and I hope an eye opener for the community

So after all, the random blowup was some time coming. I wonder how long it ran with 2 bent rods until a simple shift did it in. The mystery of blowing up coming out of a parking lot is solved. All these cars that blow have prior damage and the pistons finally lock.

I know you mentioned you had some knock - how much knock did you have? Any during WOT? Part throttle knock?

How long was the AP tune on the car for and for how long was the car modified?

The clean oil in the intake manifold is still a little strange to me.

-Last few runs I had the car on.... I got up to 4 knock under WOT, It would also give me Part throttle knock up to 4KR

-noticed my fuel pressure falling to 1200 (was just gonna order internals)

-The tune had been on for 500 kms

-First mods were Cobb SRI, installed around 10K kms, then gradual addition of other mods, the last two being, the AP at around 30K kms, and the FMIC around 35K kms, and KaBoom around 39K kms.

-Oh, the clean oil in the intake, wasn't so clean when I drained it out. It appeared to have some antifreeze mixed in, so I believe it came out after the accident.

Great info, thanks Ryan. The oil in the intake did most likely come out during the incident.

Piston 4

^ Piston #4 also has an uneven spray pattern indicating it was likely rotated in the bore.

Ryan, if you could get the last few pics of #2 and #3 small end rod bearings that would be great!

csi msf. find the killer, lex!

Wow. It would be something if this is a manufacturing/assembly flaw and it wouldn't be the first time Mazda has done this. Miata's had this problem in 99-00 with many of the most reliable motors Mazda had ever built grenading for no reason, mainly during shifting because of excessive endplay.

Lex I'll have these for you by tonight, putting a roof on the house atm.

Thanks Ryan, good luck with the roof!

Alright, here they be.

Thanks Ryan - correct me if I'm wrong but the wear looks even across the width of these bearings.

That is correct Lex.

Damn this is crazy, sucks its been happening. Hope you find out the cause man, thanks for all the pictures and research

Alright, well just for an update. The new motor fired up today!

No issues or concerns.

Updates later

Super!!! Man, i wish i had the smarts and the time to do something like this myself...very happy for ya and i hope all works as planned.. keep us updated on how the car runs.

Yeah, It was the nicest sound I've heard in a long time :)

One thing, I know people have mentioned their upgraded CDFP's being louder than stock, and this is definetly the case with my KMD V2. there's an audible clacking sound when you hit the gas, and I got my scope out, and it's definetly the pump. Just wondering if others found this.

Here's a pic of her after her first trip out of the garage and down to the ramps (to check for leaks)

hope I never have to be posting a thread like this

LOL at those ramps! Absolutely genius.

Nice work bro, glad your back on the road.