Boom Baby!!!
 

Well this is the remains of the big boom...Cyl #5 like many of us expected

http://www.subaru-svx.net/photos/fil...sSVX/41105.JPG

http://www.subaru-svx.net/photos/fil...sSVX/41106.JPG

http://www.subaru-svx.net/photos/fil...sSVX/41107.JPG

http://www.subaru-svx.net/photos/fil...sSVX/41106.JPG

Nice huh?? I didn't pull the even number pistons yet but I did pull one through 5

Tom

Ouch! How did the cylinder wall look? Weird that only one cylinder went that severely. Makes me start to wonder if there isn't an issue with the fuel distribution on the EG33...
-Bill

the shortest distance to travel for air is the rear cylinders i believe... I understood it before but not so much now:o Anyway... The block went completely unscathed to the naked eye:D :D So this means this block will be sleeved and built

Tom

Slight blur + I'm not a piston guy = what am I looking at exactly?

Little pieces of the piston broke of or disintegrated?

Is that a piston ring?

doesn't look like it was hot...looks like ring failure maybe?

Do I see a broken middle land? :confused: Did anything pick up/sieze even slightly in the bore? :confused:

You are being sort of nasty presenting puzzles, while not showing all the evidence. ;) Quiz SVX :confused:

The piston failed between the two compression rings... Didn't touch the oil ringat all. The top ring was in 1 piece but bent up awfule nice... The lower ring was completely destroyed along with the middle ground... It also cracked the piston from the point of destruction all the way down to right around the piston pin... Luckily the piston never let go and all the broken pieces stayed withing their original locations. The cylinder walls were left alone like I said with no scratches and the hatch is still fully visible on a motor with 140k... Not too shabby for as much detonation as that motor saw

Tom

Here is the pic of the piece of the middle ground that fell out after extraction.

http://www.subaru-svx.net/photos/fil...sSVX/41112.JPG

Tom

Hooooray, I won the quiz, as I was correct regarding a broken land/middle ground. :D

im not surprised, :rolleyes:

Well when you push beyond the limitations of your engine... things like this will happen. I have since then taken the boost back down to 9psi until I have this spare engine built when I will go back to 12psi and then go from there with it...

Tom

After looking closer at the odd pistons I realized #3 had cracked as well and once I removed the rings... all the pieces fell right out. Then I pulled the even pistons where I found #2 and #4 had also gone the route of the dodo... Killed 4 pistons and the motor still ran:rolleyes: Only the #5 was the one that showed it in plain view... the others I hade to remove the rings to get the pieces out... All middle ground breaks... all on the top/bottom of the piston(if the motor is sitting as it does in the car). After looking at the bottom side of the piston I can see why. It seems there is very little material there to hold it all together and these are by far the weakest points in the piston.

Tom

Ah, destructive testing at its very best:eek: :p
-Bill

Exactly, but something must be learned from the losses involved. :( :)

In this instance a small cross section of material with very little mass has broken away. This could indicate multi stresses of short duration and therefore possibly detonation. Are there any other signs of such? :confused:

I had a bunch of audible knock with this motor... WE were trying new software to try and get rid of it when I blew it up

Tom