[Kerry]

2019 2 ss early 2019 build date.
Ok we were on a vaca in Florida about 600 miles from home. Hit it and lots of blue smoke. procharged lt2 intake about 11 pds boost, alkey control full meth.

Pulled over and oil all over the front of the motor clearly coming out the front seal.

uhaul was not working out so petted it home with 75 max speed on interstate stopping about every hour after a couple 10 min stops to keep a ck on things. as long as I did not hit it it leaked very little oil. did not have to add any oil on the way home.

Diag. did blow down test all cylinders 5% except 2. It was 22%. I also could feel hear air coming from the center hose location of the stock oil air separator.
That for sure means its not coming from a leaking intake valve or exhaust. That would not come from the separator (catch can) if you will. It means its going past the rings piston going into the crankcase.

So with a 22% leak on 2 their was a problem so 22% means it was holding 78% for clarity.

So I began the tare down and go ahead and do forged anyway. Found number 2 with a very very slight crack almost did not see it and was trying to figure how it was at 22% I even began thinking maybe it was bad rings but they looked fine no signs of deto plug looked perfect. Looking very close in good light I saw what I though was a crack going from the top ring land to the second. called the wife better eyes to look at it. she caught her finger nail on it a couple times and it popped out when she hung it. It was still slightly attached.

Next why? 7 pistons still great but one bad. everyone says ring butt, i checked the ring gap very thoroughly. Using dial caliper to make sure ring is even from the top showed 14 thou. I do not believe this is a ring butt problem. Even thats on the tight side. Also if a ring butts hard enough to break a piston then I would think their would be some bore scar. bore is perfect no problems.
I put a ring in a motor one time that was for a 10 over bore filed it down to have correct end gap and it still scared the cylinder where the ends met. was a 2 stroke motor.

So not a ring gap problem. no signs of deto or pre ing. plug looks perfect, rod Bering perfect, That only leaves me to one conclusion. defective pistons or they just can't handle the power level. it was 660 wheel. But some pistons can. Its just a luck of the draw. Some pistons are good and some are not as good. That's my thinking. Coupe I had before this with 9 pds had about 20000 miles no problem.

The 1.8 liter motors I used to build made 35 pds boost turned 9800 with an 11 thou gap.. running 220 water temp.

I have attached pics
so because it blew out the front weak seal, it let me know their was a problem before any real bad damage occurred. I will be able to do pistons and rods and be good to go. lucky really.

I will say this if you blow a front seal better do a blow down ck minim.

Doing rods and pistons in the car ? I would not do it any other way. I did not touch the cradle steering ect. just dropped the aluminum brace that unbolts lifted the motor to bell housing touching the car and the pan came right out I have a quick jack and an engine hoist. its not bad at all. I have pulled a motor and this is way way easier. Now if you are doing a cam at the same time I dont know about that. I will be upgrading the oil pump while I'm their. I might do a pound or 2 more boost, then the p1sc will be maxed. 660 is a fun car on the street and thats where it will be. Looking to do drop in rods and pistons.

DOES ANYONE HAVE A SET OF DROP IN PISTONS AND RODS. SEEMS EVERYONE IS WAITEING ON RODS. PM me please.

Not sure i want to upgrade the front seal. The ls3 is better stronger but the stock one acted like a fuse if you will letting me know their was a problem.
Hope this helps others.

[parish8]

I think my drop ins are set at .028 and .032z

[Drags1998]

Im sure there will be some"EXPERTS" Remark on this, However, If You are SURE that the ring endgaps were correct, I would say that You just had a piston Fail. The Pic's look like you had alot of blow-by. Sorry, Thats all I have for now!!!

[Spaceme1117]

Classic piston failure from piston ring gap being too tight for the boost level you are running.

11 psi is a lot on a NA engine.

Based on Wiseco recommendations, you should be at .020 to .025 ring gap.

[Joshinator99]

Originally Posted by Drags1998

Im sure there will be some"EXPERTS" Remark on this, However, If You are SURE that the ring endgaps were correct, I would say that You just had a piston Fail. The Pic's look like you had alot of blow-by. Sorry, Thats all I have for now!!!

Originally Posted by Spaceme1117

Classic piston failure from piston ring gap being too tight for the boost level you are running.

11 psi is a lot on a NA engine.

Based on Wiseco recommendations, you should be at .020 to .025 ring gap.

There have been many people on this board who are experts who have time and again said: it’s not the ring gaps. Meth cars suffer from poor distribution and virtually every failed stock LT1 shortblock running boost on this board either ran out of fueling or relied on meth. Every single one. Hopefully Jannetty or Toohighpsi will chime in and chip in their 2 cents. But this is the same discussion that we’ve had more times than I can count.

[KingLT1]

Originally Posted by Joshinator99

There have been many people on this board who are experts who have time and again said: it’s not the ring gaps. Meth cars suffer from poor distribution and virtually every failed stock LT1 shortblock running boost on this board either ran out of fueling or relied on meth. Every single one. Hopefully Jannetty or Toohighpsi will chime in and chip in their 2 cents. But this is the same discussion that we’ve had more times than I can count.

[laynlo15]

I have been there on 16 to 18 lbs of boost on a stock motor and not near enough crank case venting. Fueling wasn't our issue but I believe the ring gap is one of 3 issues we had. Never ran high boost without MS109 and some meth. The Manley motor we built after that was based on Manley's ring gap specifications for high boosted motors. Never had an issue with pistons/ring lands again. But broke the crank after 60 or so passes. Whew, glad I'm NA again on my C7.

[95 imp]

I'd doubt you'd see much of anything after running it 600 miles.

Understand the reason behind it, but any evidence of detonation would be long gone IMO.

Every failure of this type in this motor is always confined to piston damage. The walls are always clean.

For those that say it's the ring gap, there is no evidence of ring bind on the cylinder walls.

"Your hypereutectic performance piston will expand less than typical cast or forged pistons. Because of this and the wear characteristics of the hypereutectic alloy, you can run tight piston-to-wall clearances."
https://static.summitracing.com/glob...%20clearances.

Tighter ring gaps mean less blow-by which increases efficiency and reduces emissions. This is why the OEM's use that alloy.

[Kerry]

Originally Posted by 95 imp

I'd doubt you'd see much of anything after running it 600 miles.

Understand the reason behind it, but any evidence of detonation would be long gone IMO.

I agree but i had been checking spark plugs along with pulls before and no evidence of deto at all.

Every failure of this type in this motor is always confined to piston damage. The walls are always clean.

For those that say it's the ring gap, there is no evidence of ring bind on the cylinder walls.

Again I agree.

"Your hypereutectic performance piston will expand less than typical cast or forged pistons. Because of this and the wear characteristics of the hypereutectic alloy, you can run tight piston-to-wall clearances."
https://static.summitracing.com/glob...%20clearances.

Tighter ring gaps mean less blow-by which increases efficiency and reduces emissions. This is why the OEM's use that alloy.

I agree

[Spaceme1117]

Not saying this failure has anything to do with piston to wall clearances. I am aware that stock cast or hypereutectic pistons expand less than forged pistons.

But stock NA engines run tighter piston ring gaps that don't allow much margin when supercharging. Push the boost too much and it will break a piston.

As I read it, the OP is saying his piston ring end gap was 0.014. From that Summit Racing document, they recommend a 0.0080 multiplier times the bore diameter for street supercharged applications to be safe. That means 4.065 x 0.0080 = 0.0325 piston ring gap.

And the OP running 11, 12 psi of boost is a lot for a NA engine.

[s346k]

what do the bearings look like? any signs of detonation?

[s346k]

i ask because i witnessed the disassembly of the exact same scenario. front seal blew out, puked oil everywhere. compression test showed several cylinders low. tore the motor down and the top side looked great. cylinder walls perfect. top of the pistons looked fine. flipped it over and we could see the rings hanging down and pieces in the oil pan. checked the rod bearings and saw clear signs of detonation. cleaned the pistons with parts cleaner and they had a different story to tell.

bone stock motor, eb eforce stg 1, 6? lb. made 542 thru a8. we gathered it had to be the tune.

[Monroe]

Originally Posted by Drags1998

Im sure there will be some"EXPERTS" Remark on this, However, If You are SURE that the ring endgaps were correct, I would say that You just had a piston Fail. The Pic's look like you had alot of blow-by. Sorry, Thats all I have for now!!!

Please keep us informed with your knowledge.

[Kerry]

rod ber hard to get a pic without shadows their is no light dark colors on the bering just show's from the camera from light