Melted Piston (56k IF it has the lube, but don't try dry.)

[Maxx Mazda]

Ya, all the guys here at work that have done that, it's always been in cyl #4...

 

[iracemine]

what does the rod look like? i havent got that far yet is it somthing thatis going to need replacing (ordering) too???

 

[iracemine]

incase anyone surches this. ill post that the rods where ok but the rod bearings where toast. crank surfaces were good main cap bearings are good as well. changed out to a lower compresion pistons and new rod berings old rods. hone to hell cylinder walls. no deep scratches but one small pit.

p.s. it was cold as f**k

 

[Rogue]

Yup. #4 went lean after spiking to 12psi. Will be replaced with the Arias / Pauter combo. Melted the piston, (IIRC EGT was approaching 1400* after turbo) and then oil rushed up into the cylinder. All this at 6000RPM. I'm surprised it lasted as long as it did to be honest. As you can see, the head will need a bit of polishing, there's some of the piston melted to it if you look close. And the cylinder walls are scored, but I'm going .020" over anyway, so no problemo. Anywho, on to the pics.

Is that high? I have my EGT on cylinder #1 (closest to passenger side), and it'll read 1400* at about 4000 rpm cruising on the highway. Doesn't cylinder #4 (closest to transmission) usually run the richest since it's the first to get fuel? Were you using stock injectors? A friend of mine found the website that has flow rates for almost all injectors, including the stock ones. Cylinders 1 and 2 running a little higher cc than 3 and 4. That's why they're different colors.

 

[Maxx Mazda]

Well measuring it after turbo like I do is less indicitave of mixture as it is measured like you have. I used mine primarily for turbo health over AFR, I've got a wideband now for that...