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[Crankee]

Well im onto the next engine. I blew the BPT, totally grenaded. The place I bought it from wouldnt cover the engine under warranty.
So I have found one wth about 100,000 miles on it for 400. Going to swap the BPT parts that are good over to the BP.

Parts lost in the BPT

Block has fist size hole in cylinder wall into coolent vain
Oil pan has stress crack with part of windage tray hanging out
Cylinder head has two marks that look like the wrist pin bounced off it
Bent valves, which chunked up the seats a little.

So my plans are to Take off both mannifolds on the BP, and replace with the BPT. That includes the injectors with fuel rail. Use the coolent line from BPT in front because it has the line off for the turbo.
Need to know what size nipple on the oil return line from turbo to oil pan I need, Plus what size hole to drill.

[Shifty]

Sooo....What are you doin to fix the exploding problem?

[Crankee]

I was just sold a bad engine. They wont cover it because I took so long to put it in my car.

[phillyd]

I was just sold a bad engine.


what was wrong with the engine/block? sounds like a classic case of too much boost and not enough fuel! just curious...:cool:

[Crankee]

Well when I bought it the compression was a little lower in that cylinder, but nothing to worry about at least I thought. I think the rings collapsed in turn seizing the piston. After that all hell broke loose.

[VR4Rob]

Well when I bought it the compression was a little lower in that cylinder, but nothing to worry about at least I thought. I think the rings collapsed in turn seizing the piston. After that all hell broke loose.
Hm, maybe its a Mazda thing but I've seen plenty of cars wipe out ringlands halfway around the cylinder and the car still ran, albeit rather roughly ;) . I'd be surprised if just the rings collapsed/blew/etc and caused enough carnage to seize the motor. You could have cracked a piston in half, sending large piston chunks flying around, but that sounds more like a tuning issue than a bad motor issue :eek:

[Crankee]

Hm, maybe its a Mazda thing but I've seen plenty of cars wipe out ringlands halfway around the cylinder and the car still ran, albeit rather roughly ;) . I'd be surprised if just the rings collapsed/blew/etc and caused enough carnage to seize the motor. You could have cracked a piston in half, sending large piston chunks flying around, but that sounds more like a tuning issue than a bad motor issue :eek:

Tuning issue as in how. I could see if I was running lean, or out of time. Like early detination. But I know enough to keep from doing that. Plus the ECU has a boost and fuel cut if it runs too lean at high rpms.

[VR4Rob]

Tuning issue as in how. I could see if I was running lean, or out of time. Like early detination. But I know enough to keep from doing that. Plus the ECU has a boost and fuel cut if it runs too lean at high rpms.
A tuning issue that would cause enough knock to crack a piston, like lean AFR and/or excessive timing advance. How do you know that you were avoiding these things? I don't know how your ECU works to protect your motor but I'd be surprised if it was "smart" enough to cut fuel AND boost because it saw "lean" conditions. How does the ECU know that the car is running lean? NB02s? That doesn't make much sense to me beacuse I'd think that would cause a lot of driveability issues since NBO2 voltages fluctuate so much and are largely unreliable as a good indicator of how healthy your "tune" is.

For example and clarification, my ECU works to protect the motor largely by pulling timing when it sees knock and/or injector duty cycles above 80% or so, cutting fuel entirely when it sees 100%. It doesn't see or care what boost you're running.

What I'm getting at is, how are you sure that your car was running completely fine? Did you ever log anything that the ECU saw, things like I mentioned earlier?

[Crankee]

Engine has knock sensor, and I intalled air fuel ratio. Its a low band but it willl tell if rich or lean.

Ok I was wrong on the boost cut but it does have a fuel cut.

[Byrd]

Engine has knock sensor, and I intalled air fuel ratio. Its a low band but it willl tell if rich or lean.

Ok I was wrong on the boost cut but it does have a fuel cut.

:flame: I say user error my friend. An ecu can only cut out so much knock before it just lets go. There's a stepping down affect (ecu retarding the timing to combat knock) but when you keep that bitch floored it's really hard for it to keep up (if at all).

Even if you were running lean, what could you do about it?

If you have an electric A/F gauge those are REALLY inaccurate and NOT a way to tune at all (I hope you already knew this) - They are more show then anything really (I've had one).

Get yourself a innovate wideband with the gauge - You'll enjoy it.

And last, why spend all that money and just guess (or have the ecu guess) at a tune. Tuning devices are critical when modifying an engine. :bang:

Possibly an expensive lesson but maybe you learned from it? who knows - either way it looks like you have a new project ;)

[Crankee]

For my application you need to tune the MAF sensor, by using voltmeter. To change the air/fuel ratio. I had been checking it about every day to make sure not lean but a little rich.

Everyone thinks I was modifying this engine but I wasnt. This engine is a completely stock swap from the JDM Familia AWD 323. I bought everything so as to keep it stock, it is mostly plug an play. Stock turbo engine stock ECU, stock wire harness, just need to splice in gauge and ignition wires.

[Byrd]

I see said the blind man:cool:

Tuning using a voltmeter sounds REAL old fashion. You could more then likely use an SAFC and a logger.

[Crankee]

Its what I had:D

[CPMaverick]

You should at least approach a new engine as if it was your fault the other one went, just to be on the safe side. There's not really enough info to say either way.

On one hand the engine seems pretty stock, on the other, engines generally don't just punch holes in themselves (whether or not they were 'bad' to begin with), and sounds like you are doing some very rough tuning without any quality feedback sensors.