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Now THIS is what i consider valid data on an engine mod

 

http://forums.nasioc.com/forums/showthread.php?t=1187722

 

 

drool

 

BROKEN IN???

 

"Then the day came that 500 miles were on the odometer. So I decided to do a pull to 7000RPM. First a 6000, then 6500. But I noticed a strange sound. My stomach started hurting, as this sound was rod knock type sound. This was bad! Babying the car back to work the next day, the sound got worse and valve train noise starting happening. This is not good. The engine came out, and was disassembled. Sure enough, rod bearing #2 has a little more clearance than the rest. Say about 50 times more clearance! Thank goodness we paid the engine builder to assemble it, because it would have a warranty, right?? WRONG!!

 

The builder of course blamed it on oil supply, or improper break-in, not enough oil pressure, too much boost, or knock, but nothing that they did of course. Being a reasonable person, I looked into his suggestions. Boost didn't cause it, knock didn't cause it (have logs), so I looked to oil. Plenty of oil was in the engine and not a bit was ever consumed. Oil pressure, ya right this thing runs 100+psi, and that wasn't' the problem. The argument back was that was way too high, and the added friction from the added pressure could have broken down the oil (due to heat), and caused this. I don't buy this at all, as all JDM STI's have shims to add oil pressure. It basically came down to there were too many things that could have caused it, none of which could be proven it was their fault or mine."

 

Just some thoughts here.

 

Unless something is learned from this, could be doomed to repeat it. First, why would a person be running 100+ psi in a Subaru at the RPM listed? At operating temperature, 10 psi per 1000 RPM has never let me down.

 

Now, a lot of unknown factors come into play with this particular engine. The original clearance for one, as he stated. The actual oil and weight used when it failed. The actual oil temperature. He added coolers for this phase of the build and as stated, he said it ran hot. He could have had the oil he pulled out tested. Might have told him a lot.

 

On the throttle under boost with a conventional oil. That oil in certain parts of the engine could have been close to 400 degrees, or more. I don't know of course. He may have ran up against the thermal limits of a conventional oil. Or not. Like I said, I don't know all the facts, and I'm certainly not pointing fingers.

 

I do know what a modern synthetic oil is capable of in regards to heat.

 

Doug

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