cracked piston

[wrxboy]

Hi guys,just got a question looking for advice.

i have a v7 sti semi closed deck block, it has a cracked piston(well its not cracked a peice on the side has broken off).

If i just get new pistons will it be ok to reuse? the block is only 4000km old and the cylinders seem to be ok,but could the block be worped or cracked?

Thanks

[Guest]

only an engine reconditioner can tell you the answer to this

[Kiwi_Fozze]

and im assuming said reconditioner would have to crack it open yes?

[wrxboy]

do they just do a crack test and harden test?

[soopersubaru]

like it or not it's an engine out heads off job.

with a bit of meticulous checking and measuring, you maybe lucky enough to just swap out the pistons/rings.

however the block may need to be split and machined.

if the block needs attention....I would get a closed deck one then spend the money on that... and rebuild from there.............Well worth it,stronger etc.

[WRXONP]

cracked ring land ? and it fell off when piston was pulled ? that's normally from detonation . . get the bore measured up . but if the ring land didn't scrape the Shit out of the bore then it may be sweet. i once did a closed deck block pulled from a bc5 and when i pulled piston the ring land fell out . .from being cracked obviously . bore still measured up mint and no scrapes down the bore

[wrxboy]

its already out, ive got it sitting in the garage, just the short block? i was thinking of getting it looked over and crack tested and then if thats ok go from there?

[wrxboy]

wrxonp thats exactly what has happened and from what i can see there is no scraping!

[WRXONP]

wouldn't be cracked block. you will see the damage in the bore if it has any . i would recommend getting the bores measured and if its within spec get the bores honed and new piston rings

[Joker]

lol durr's cant tell if its cracked without it being out in the 1st place

but you did at least get a few good answers above

[WRXONP]

yeah man it is possible for a ring land to brake off and not damage the bore . . . but i would say you have a detonation problem which ir well worth looking into . . . Mic the bores and check then for round ie warpage and go from there. i did one that done the ring land and only needed a hone and new piston and rings etc

[wrxboy]

yea thats what im hoping for! im just thinking il get it tested and it will be warped as its got hot through detonation

[soopersubaru]

 wrxboy said:

yea thats what im hoping for! im just thinking il get it tested and it will be warped as its got hot through detonation

Throw it out! Get a closed deck block and spend...You wont regret it if you do it right...You can build a closed deck block to handle over 400 Kw with 500n/M of torques.

Then you can run it forever at a lower Hp. So long as you do not detonate it to death that is.

After market computer to run it, tuned every 12 months or so by a professional and your sub will become the best car you have ever known.

$30-$40 K is not a lot to spend, when with good research and advice you can create a soopersubaru from a One thousand dollar car. Drive train,Engine,Suspension all done, maybe even a reasonable paint job too.

Thrash the pants of some $70k plus cars that's for sure.

[rex-leggy]

 soopersubaru']

[quote name='wrxboy said:

yea thats what im hoping for! im just thinking il get it tested and it will be warped as its got hot through detonation

/quote]

Throw it out! Get a closed deck block and spend...You wont regret it if you do it right...You can build a closed deck block to handle over 400 Kw with 500n/M of torques.

Then you can run it forever at a lower Hp. So long as you do not detonate it to death that is.

After market computer to run it, tuned every 12 months or so by a professional and your sub will become the best car you have ever known.

$30-$40 K is not a lot to spend, when with good research and advice you can create a soopersubaru from a One thousand dollar car. Drive train,Engine,Suspension all done, maybe even a reasonable paint job too.

Thrash the pants of some $70k plus cars that's for sure.

says who bill gates?

[vorigan]

give the guys at possums a ring well worth what they build for dollar value

[soopersubaru]

 vorigan said:

give the guys at possums a ring well worth what they build for dollar value

This is true!!! spend with the best an get the best! my 20k motor goes well.(Gary Capper tuned, now works at PB motorsport)

AND you would pay $30k- $40k for a top sti anyway so why not just spend on an older car instead. Certainly less attractive to a thief.

AND thrash the pants off most others with a much higher price tag on the window!!! All good

[WRXONP]

nothing wrong with open end deck especially in a street car . . .

[Shale]

I'm just gonna +2 doing it right and getting a PBMS block.

[gotasuby]

im selling a forged v4sti motor

[Stoffa]

sounds like what ever caused your motor to die originally wasn't corrected and thats why it killed another, something to think about with what ever path you take

[soopersubaru]

 Stoffa said:

sounds like what ever caused your motor to die originally wasn't corrected and thats why it killed another, something to think about with what ever path you take

Very True. Rebuild your engine...Put it back with the same set-up, without changing the tune....KKKK..Bang .Again!

Bit like removing the standard closed loop blow off valve and installing an open loop one...Set it nice an soft...Then when you cruise along at 15" of vacuum it can pull nice dirty air from your engine bay to further increase the chances of destruction. Not to mention the way it plays havoc with the tune on the standard computer!!

Do it Right, With good research and enjoy...Do it on the cheap and it only ends in heartache after some short term fun.

[WRXONP]

lol blow off shouldn't open when driving in vac . that's a very poor bov yah . and i use full atmo bov on stock ecu fine

[boon]

 WRXONP said:

lol blow off shouldn't open when driving in vac . that's a very poor bov yah . and i use full atmo bov on stock ecu fine

How brown is your bumper from all the half-burnt fuel falling out the back

[WRXONP]

lol its not :-)

[Joker]

OEM Bov + 95 = Black arse

Atmo Bov + 98 = Clean as a whistle (50/50 GFB on my TT Legacy)