Pistons not firing 100%

[tayl51601]

i cant believe the engine has let go, only just after ur final tune.......

its a fukn shame.......

take ur time building it and ask heaps of questions and speak to the right people and especially ur tuner.........

it maybe possible that the gaping on the new plugs where wrong and it let go with a strong detonation, or possible just coincidence it let go after change of plugs.

let me know if u need any help

Im sort of shocked as well, didnt expect it to detonate so early.

Ill have to check out the plugs and inspect everything, dont want to buy new pistons again after this rebuild, one time detonation is already too often

Thanks tom!

[Limbo]

plugs could do it but you should have noticed detonation, its really obvious.
doubt its the catch-can setup

[tayl51601]

The car got tuned first time end of last year i think.
Then i got new exhaust which allowed more boost and drove around like that for about 2 or 3 months, when adrain ran the first run before he tuned it he said it was running lean so maybe the detonation happened a few weeks ago and its just taken a while for the crack or whatever to show properly......

That shouldn't affect it. Also, PCV is not the same as EGR.
How long were you running your car without a tune, and how long did it take to reach the final tune? Were you driving your car with spurts of acceleration during the phase where you were still tuning it?

[IEVAQ8]

i think it might have been either on its way from previous old crappy tune, or the gapping on the plugs were way out

[tayl51601]

plugs could do it but you should have noticed detonation, its really obvious.
doubt its the catch-can setup

Could it have been a small detonation that just caused a crack in the ring land and when i gave it a boot the other day it decided to finally break?? Because when i first started to notice the problem it was minor and just got worse and worse the more i drove, first i thought i was getting paranoid when i heard the very slight wrx noise then as i got closer to home it was louder, i then drove 5 min down the road that day and noticed smoke starting to pour out of my catch can.

Maybe if im lucky its just a head gasket but i dont think im that lucky.....

[B18cEG]

when r u gonna pull the head off for a look?

[tayl51601]

Im going to start on it tonight, was going to do it last night but it was getting late after all the tests

Ill keep this thread updated so you can follow if you want, i think it might be starting to get into the wrong section on the forum though, mods can move it to forced induction or technical if they want.......

[aaronng]

The car got tuned first time end of last year i think.
Then i got new exhaust which allowed more boost and drove around like that for about 2 or 3 months, when adrain ran the first run before he tuned it he said it was running lean so maybe the detonation happened a few weeks ago and its just taken a while for the crack or whatever to show properly......

If you increased the boost without retuning and it was running lean, then that could be the cause of the failure. It doesn't need to detonate to cause damage. Just by running lean, the cylinder temperatures are very high and can cause gradual damage.

[Alexx]

let me know if you want me to drop down the road and help man

[tayl51601]

If you increased the boost without retuning and it was running lean, then that could be the cause of the failure. It doesn't need to detonate to cause damage. Just by running lean, the cylinder temperatures are very high and can cause gradual damage.

Yea it could have been because it was running lean for so long, i did do a road trip to sydney running lean aswell...... Will find out soon!

let me know if you want me to drop down the road and help man

Thanks man! Your always welcome to just come around and have a look if you want!
Will let you know if i need help

[tayl51601]

Looks pretty clean imo

[TODA AU]

If i lower the compression of my pistons to about 9 (use the Mahle pistons) that should also help shouldnt it?

Yes, a little lower in the compression will do wonders for reliability.

Sorry about all the questions but what about CP Pistons PN: SC7000 - 81.00 9.0:1 C/R

They will give me a lower compression ratio and are standard size so i dont have to bore the cylinder??

If the bores are damaged from the pistons,
It's unlikey you'll get away with stock bore pistons.
If you have to hone it so much that the piston to bore clearence is compromised, you're better off using the 1st or 2nd oversize.