Very strange pistons!!
- Thread starter PorterzSupra
- Start date
jdub said:
Agreed.
At the very least that stuff needs to be smoothed out, sharp edges in combustion chambers create hotspots and cause detonation.
Probably a screw, nut or bolt went through the motor.
PorterzSupra said:
That's nasty. A lot of debris had to go through that motor to make that much of a mess.
I was going to suggest a broken spark plug - Broken ceramic or electrode. 4 cylinders though... Yikes! How do the cylinder walls look?
Proof that just because it's a JDM motor, doesn't mean that it's going to be a good, low mileage, high compression tested engine that will be reliable. This could happen to any engine, be it american 7M or JDM ones. I still can't figure out what the hell it was though that caused that mess...
I have installed a few JDM motors from various dist and all of them are like that and there is ALOT of sludge in the pans and sometimes rust on the cranks and connecting rods. They dont really compression test them because on the NA you have to remove the intake Y pipe and TB and they are all in stock attatchment when you get them. Sometimes you get better ones, usually you can tell by the paint on the valve covers and the condition of the inside of the valve covers (amount of sludge and oil stain) and the amount of oil residue on the outside of the motor. Using that you can guess the approx cond and milage and compression testing also helps further.
Who said JDM motors are good? Shittt... half the time the dang japs dont even change the oil for 30k miles.
Yes, my Japanese 1JZ-GTE had problems from Japan ,and it was bought direct from the recycling yard in "a" grade. Looked pretty inside and out, but had a slight bhg
Detonation doesn't put dents in pistons and/or valves. It might crack them, but not that. Could be detonation broke a spark plug, but detonation in and of itself doesn't create damage like that.
Ric said:
As far as I can recall the pistons don't hit the valves if the timingbelt snaps in a 7M...
My vote is also on mechanical damage, some crap went in to the motor...
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it's detonation
probly bottoms of the plugs broke off maybe
but i seen this exact same thing on a 1j, all those "gauges" were in the piston dishes and on the head all over the place
probly bottoms of the plugs broke off maybe
but i seen this exact same thing on a 1j, all those "gauges" were in the piston dishes and on the head all over the place