2002 subaru wrx knocking - damaged piston from running lean

[sirzycki81]

Y weren't any of the pullies spinning? Or belt was the motor even running

[DirQ89]

this may sound dumb but could it have been an exhaust leak from either the up-pipe or downpipe?

[R1Wagon]

Must have a lot of CEL codes without strap and MAF!!!!!!! lollll

[Syzygy236]

heres another way to look at it, this is just a good excuse to take the engine out build that bad boy.

[Jallandhara]

@ZINK454545 Could you possibly be any madder?

[ZINK454545]

should have baught a 572 chevy motor put holly headers and an edlebrock raceing varb on it might only get 5 miles a gallon but it would be a shit ton better that all that imported shit,fuck ricers imports tuners , american muscle all the way

[fastflat4]

@ZINK454545 your a troll. get out. imports are sick. My 2.1 stroked subie walks muscle cars. usually when they are left looking for traction wishing they drove awd :)

[badmoonryzn]

@ZINK454545 All of this bravado from a kid who rides a bike every place he goes. What a yo yo! Yea, that Schwinn of yours really gets the chicks. By the way your spelling, punctuation and inability to form a sentence puts you at flunking third grade. Picking on someone when you are obviously the one who needs lots of help makes you look like such a moron. I hope you go back to school, get some psychological help and quit doing drugs.

[AWDfreak]

@ZINK454545 obvious troll is obvious :P

[mrchopasaurus]

@ZINK454545 Fuck off, u redneck hick.

[SteveSupreme5k]

HA,nice they dont actually burn rice, its called Premium 93 octane

[sk8nsnow14]

what are your headers?



[topher170]

@sk8nsnow14 tomei UEL

[97gstmodded]

@sk8nsnow14 not headers its called a manifold

[sk8nsnow14]

@97gstmodded yeah thanks but i wasn't asking about the intake manifold.... i asked about the exhaust headers.

[jerbull88]

who needs a timing cover anyway....

[CVRealMan]

By the looks of things, you didn't build your bottom end did you?

[topher170]

@CVRealMan It was a stock sti short block. The pistons are the weak link in the sti blocks. It ran lean due to an intake leak and trashed a piston. It has forged pistons and rods now.

[Jettrap505]

that a bad sound if not takin cair of it could blow the engin

[STiChrisIsOn]

Is the bottom end factory? New forged pistons seem to commonly cause a knock sound quite similar to that, called piston slap due to sloppy PSW clearance.

[ecasco22]

that engine was runnig without the water pump belt,.......check the video.......the over heat shot some valves and head......

[tobywong]

@ecasco22 water pump is run by the timing belt.

[topher170]

@ecasco22 I just fired it up like that to record the sound. Also, the belts only run the a/c, power steering, and alt.

[reita357]

Hey topher I am having the same problem as you with the damaged piston and it just coincidentally happened also to be Piston 3, I also have an STi with EJ257 shortblock but EJ205 heads. Was wondering how much it cost you to fix ? and what job you did to fix it ?

[topher170]

@reita357 cylinder 3 is closest to the turbo and gets hotter than the others, which is why it usually is the first one to go. Cost will depend on what else you want to do while it's apart, and how badly the cylinder was damaged. I do all of my own work, so that saves a lot of money. I don't have a clue what it would cost to pay someone to fix it, but I spent less than a grand getting mine back going, and that includes buying the new pistons. I already had a set of rods laying around.

[bassbone1785]

@topher170 while that is true that cyl 3 is closest, the extra heat from the turbo makes no difference because the cylinder is surrounded by a water jacket, the coolant would absorb the extra heat. Cyl 3 is the more restrictive port in the header, so that's what I would blame the extra EGTs on that cylinder from.

[topher170]

It was a damaged piston. I had a intake leak in the turbo induction hose that I didn't catch in time. It ran lean for a high speed pull and that was all she wrote. It now has je 8.0:1 ratio pistons, stock gaskets, eagle H-beam rods, cobb intake, perrin induction and after maf hose, and everything else is the same.

[sDcMoo]

@topher170 How's the Trans treating you? I'm doing a similar setup like yours. Got a killer Deal rebuilding my short block with forged internals.

[topher170]

@sDcMoo I never had a problem with the trans, however, I just swapped in a sti 6mt and R180. I had 120k miles on the stock drivetrain before the swap. If you don't shock load it, you won't have a problem. Smooth is fast.

[E85WRX]

that sounds like a bearing or rod knock.