Right where the intake reliefs are, pieces broke off. No signs of detonation. I know this was an issue years ago but from some recent research sound like its still happening. Was wondering if this has ever happened to anyone else recently.

 

Now this is based on a bunch of assumptions since you've put no info but...

You have a block guard and stock sleeves.. It looks like the Sleeves have separated and the block guard has been shattered... which would lead me to believe that you've had some pretty dame serious detonation going on...

Do all 4 cylinders look like that or just that one?

Looks to me like the #4 cylinder pictured got extra hot because of the block guard which caused a hotspot on the intake valve relief which could have ignited a major detonation event.

Just a guess. More pics and more info would help.

What timing where you at?
How do all the cylinders look in regards to the piston the stock sleeves and the block guard?
What temp plugs?
When did it blow? Getting on it? Driving normal? Driving up a hill in 5th on a hot day?
How solid is the tune?
How solid is the fueling system?
Etc etc etc.

 

That whole cylinder is egged out. Was it machined prior to install? Line bored with a torque plate? then decked ALL AFTER the block guard was precision measured and installed?

Even then the block guard could cause that cylinder to get much hotter than it should.

There was def a big bang in at least that cylinder. #4 is always the hottest cylinder if I remember correctly.

 

those are some sort of aftermarket sleeves, not sure which kind.

3 should be the hottest since its always either firing or having an adjacent cyl firing however ive found that 4 can get right up there... perhaps since it gets the coolant last before it exits the motor for the radiator might have something to do with it


NonovUrbizniz is right though, we really do need some more details to be helpful

 

no block guard its darton mid sleeves 83mm, b18c, ls crank, manley rods, fuel is ID 1000, walbro 255, aeromotive fpr, ge rail, tuned on 94 oct and water meth. Cyl 3, the same area is starting to look weak as well.

 

Water meth could be your issue. Leaning on it too hard on pump gas and one cylinder is getting leaner/hotter than the rest? I don't really have much to add, but I do remember CP had that problem like 5-6 years ago.

 

those sleeves can really withstand some **** cant they? that looks like some serious detonation was going on there to break apart the piston, egg the cylinder, separate the sleeves at the joints, and shatter the block guard, without cracking the sleeve right down the middle.

 

Same exact thing happened to me... Too much timing & started detonating... trust me.

I got lazy with my tuning and tried to run 20psi on a 10:1 CR motor w/ 93 octane... Timing was up in the 19-20 degree range. Not a good idea. Needless to say, its torn apart right now and getting a new piston.

 

bump

 

also pistons are 9:1cr, timing is at around 14* at 21psi, water/meth is not being used as a power maker, just a small amount for safety. Also found this
http://www.dsmtuners.com/forums/cyli...ajor-flaw.html

 

they raise some interesting points about the hot spots

 

yah hate to say it but that does sound greedy. i think im around 12-13 degrees with 10:1 and 18ish psi on 93 octane.


op - how did your spark plugs look? were they showing any detonation? is it possible you were romping on it one day and ran out of water/meth? what power were you making with it?

 

10:1 a/f ratio ??? thats pig rich my friend and you dont have enough timing., to little timing can be just as bad as to much timing.

on 93 pump gas at 18 pounds of boost im at 16 degrees with 12:1 a/f ratio

 

lol..

two b16 engines had the same problem here.

first :
B16 block and crank with mid wet darton sleeves
CP 81.5mm 9.0:1 cr
1000cc ID injectors

3 of 4 pistons crack like yours.


second engine b16 oem block and sleeves
with CP 81,5mm 9.0:1 cr
1000 cc ID injectors

at 22 psi @ 508hp third cylinder cracked same issue at piston

 

Well my afr's are in the mid 11's region and timing is around 15-16* at 21psi. Power is 550/340
I seriously don't think this is tune related, there are so many other incidents which are the same

 

Same thing happened to me in 2005. It was caused by detonation. However I feel it is a weak spot in the piston design.

 

in the first engine i told you before the presure was 17 psi . the wideband says
11.5-11.7 at 15-17*

power under 370 crank power.. (with gt3071r)


in the second engine the oem sleeves cracked from presure?? (22 psi @ 508hp gt3076r)
i dont know but the third cylinder was cracked, the third piston was cracked AND the second piston was cracked BUT the second cylinder was OK.

whats going on ??

 

you wouldn't happen to have pics would you? I'm gonna call cp today and see what they say

 

Really OP look at your tune, my beat is to much timing not enough fuel of not high enough octane. Also there is a block guard in the pic and it is cracked, The sleeves have separated you ca clearly see it in the pic. CP pistons are good piston and I have worked on many B motors with CP pistons pushing 600whp+ with no issues.

 

There is no block guard, its darton mid sleeves, I went over the tune and it's running 15-16* timing up top afr's were rock solid mid 11's fuel is 94 oct and a small amount of water/meth, the water/meth is not being used as a fuel replacement or to make power its there just for safety. plugs are number 9's, ignition is aem cop.
The funny thing is I didn't even know that happened when the motor was leak tested, the rings are still sealing, the cyl walls have no damage at all no scoring or anything. The head was pulled because of a slight hg problem on cyl 3. Pulled the head, saw where the hg failure was, started cleaning up the block and saw this

 

no 10:1 static compression -air to fuel ratio is 11.8:1 +/- .2.

every engine is different and thats what my plugs/ torque curve lead me to on the dyno.

op - how old were the pistons?

i think im leaning toward it was just the upper limit of power on 94 to be run for a while, even with a bit of water/meth. the good news is that the cyl walls are ok. check them with a bore gauge for any out of round, rehone and get back at it. hopefully cp will work with you on this.

 

The pistons weren't old at all, car was tuned in november, sat till last week, put fresh gas, drove it around for 3 days for short distances and had less than 10 4th gear pulls total.

 

Im sorry i missread your post. that makes more sense now Blackeg

 

i have pictures from the second engine ONLY.

but in this engine the oem sleeve 3rd cylinder cracked...

maybe this is the reason the 3rd piston cracked.

BUT if you see the images carefull you will see that the second piston cracked too but the sleeve was ok..

 

^ are those Wiseco flat-tops?