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Posted
  TheWelsho said:
Yup, nice find indeed.

Here is a video of what it looks like when it all goes wrong!!!

What did the garage say caused the damage to the piston ?

Posted

another reason for the lands to break is from running to much boost on weak(standard wrx) pistons .

Generaly speaking detination would not cause this , but if there was dedenation your pistons would normaly fail at the crown of the piston. :wacko:

Higgy

Posted

Sorry, but the piston out of my GT-B took a bit more abuse than that, but then, there was no chance of mine running at the end of this :

Deadenginebits003.jpg

Deadenginebits002.jpg

Deadenginebits001.jpg

That is some nice damage to your piston that wouldn't show without careful inspection though.

Craig

Posted
  higgy said:
another reason for the lands to break is from running to much boost on weak(standard wrx) pistons .

Generaly speaking detination would not cause this , but if there was dedenation your pistons would normaly fail at the crown of the piston. :wacko:

Higgy

I keep forgetting John's car was a wrx B)

Posted
  Dipsy said:
CraiddMcd that looks terrible what did the engine look like after that

The alloy triangular section is a chunk from the n/s cylinder block, and 2 valve heads got snapped completely off the stems. As you can guess, the engine was totalled, and could only swap the ancillaries to a new engine. The inexperience of running a JDM on standard UK fuel, a low fuel load, and a giving chase to a Merc at continuous high revs was an expensive learning curve.

Posted
  Dipsy said:
TheWelsho what state were the piston rings like with that damage to the piston and was there any damage to the liner

Never saw the rings mate, but they must have been ok because they held the broken part in place otherwise it would have totally shafted the liner. As it was, the liner had some markings, but nothing too drastic.

Posted
  craigdmcd said:
The alloy triangular section is a chunk from the n/s cylinder block, and 2 valve heads got snapped completely off the stems. As you can guess, the engine was totalled, and could only swap the ancillaries to a new engine. The inexperience of running a JDM on standard UK fuel, a low fuel load, and a giving chase to a Merc at continuous high revs was an expensive learning curve.

Holy crap, what a MESS! I saw an Impreza at Hypertech with lumpbs of engine casing all over the engine bay, was that yours? Dunc did say that the car in question was pursuing a Porsche. Maybe he got his cars mixed up, so, WIY?

Posted
  TheWelsho said:
Holy crap, what a MESS! I saw an Impreza at Hypertech with lumpbs of engine casing all over the engine bay, was that yours? Dunc did say that the car in question was pursuing a Porsche. Maybe he got his cars mixed up, so, WIY?

No, that was not me, I fitted my engine myself and mine is a Legacy GT-B. The con-rod and the gudgeon pin, I had to retrieve from the bottom of the sump. People ask what broke first, and to be honest I never studied it hard enough to find out, and let's face it - knowing wasn't going to help me rebuild it.

Posted
  higgy said:
another reason for the lands to break is from running to much boost on weak(standard wrx) pistons .

Generaly speaking detination would not cause this , but if there was dedenation your pistons would normaly fail at the crown of the piston. :wacko:

Higgy

Andy.F was telling me that the 2.5 cars run much tigher tolerances due to emmissions etc. When the 2.5 car had its debut in the US there was a whole load of cars nicking pistons in the tigher-than-normal bore. They had them a year before us, so in that time hope/think that Subaru would have sorted it. Its possible that this is what happened to my car.

Posted
  TheWelsho said:
Andy.F was telling me that the 2.5 cars run much tigher tolerances due to emmissions etc. When the 2.5 car had its debut in the US there was a whole load of cars nicking pistons in the tigher-than-normal bore. They had them a year before us, so in that time hope/think that Subaru would have sorted it. Its possible that this is what happened to my car.

ahaa

I had two pistons go when i did my rebuild last year , luckely i caut it before it went bang, i was running tomuch boost on them and the lands decided to go . Could have made some mes like yours did.

When i get my turbo back im going to be upping it a little more in the quest of 550 bhp :D

Higgy

Posted
  TheWelsho said:
Andy.F was telling me that the 2.5 cars run much tigher tolerances due to emmissions etc. When the 2.5 car had its debut in the US there was a whole load of cars nicking pistons in the tigher-than-normal bore. They had them a year before us, so in that time hope/think that Subaru would have sorted it. Its possible that this is what happened to my car.

This seems to be a prob with the 2.5, thats what puts me of getting one. I think i will stay with

my 2.2 CDB. :D

Posted
  higgy said:
ahaa

I had two pistons go when i did my rebuild last year , luckely i caut it before it went bang, i was running tomuch boost on them and the lands decided to go . Could have made some mes like yours did.

When i get my turbo back im going to be upping it a little more in the quest of 550 bhp :D

Higgy

Looking forward to this one,its going to be a real flyer :D

Posted
  JAC said:
This seems to be a prob with the 2.5, thats what puts me of getting one. I think i will stay with

my 2.2 CDB. :D

Put the Wossner piston in and you'll be sorted!!!

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