Mildly Buit M20 Blew Head Gasket at 11PSI?? WTF?!

[SGT StudMuffiin]

So on the way to the E30 Picnic my turbo m20 decided to give in, but it doesn't make sense why it happened, and tuners and mechanics agree too. So please turbo experts, enlighten me

Engine is a 2.7i: Super eta block, with 2.5 885 head. Block is oringed, thicker headgasket for lower compression, ARP head studs (one stud is broken now), 284 degree camshaft, Ireland Engineering HD rocker arm set, plus the motor was rebuilt, car was tuned well by a reputable tuner locally on the dyno, car didn't seem to be overheating (I think) and lastly it was at only running at 11PSI of boost, and I was just cruising when the Head gasket popped on me.

Why could this have happened, and will it be worth doing rods and pistons now that the engine is disassembled?

Edit: I don't know how to post multiple pictures lol

[Nutzy]

She detonated man, almost certainly. That fire ring is mashed! Was it just the one cylinder? What fuel? What turbo?

It might be worth getting your injectors flow tested to check for issues.

[SGT StudMuffiin]

She detonated man, almost certainly. That fire ring is mashed! Was it just the one cylinder? What fuel? What turbo?

It might be worth getting your injectors flow tested to check for issues.

They are nearly brand new Siemens Deka 80 LBers, the tune is set up on 94 Canadian, which is equivalent to American 91, as tuners have told me, so at the time I was on Shell 92 American (Better than what tune is set up for), and the turbo is a GT35R, also the main cylinder that felt it was #2. But if it really is detonation, is that just from poor fuelling?

[Northern]

They are nearly brand new Siemens Deka 80 LBers, the tune is set up on 94 Canadian, which is equivalent to American 91, as tuners have told me, so at the time I was on Shell 92 American (Better than what tune is set up for), and the turbo is a GT35R, also the main cylinder that felt it was #2. But if it really is detonation, is that just from poor fuelling?

I've never heard that before, Canada and the US both rate gasoline octane by AKI, so I don't understand how a border would change the octane rating.

Could be shitty fuel, tune/fuel/timing, or a weak injector. I'd probably throw a new gasket on, swap the injector from that cyl to another, and verify that you're not running lean/overly rich/too much timing.

If it blows again at the cyl that you move that injector to, it would give you a good indication that something is wrong there.

[SGT StudMuffiin]

I've never heard that before, Canada and the US both rate gasoline octane by AKI, so I don't understand how a border would change the octane rating.

Could be shitty fuel, tune/fuel/timing, or a weak injector. I'd probably throw a new gasket on, swap the injector from that cyl to another, and verify that you're not running lean/overly rich/too much timing.

.

I'd rather not keep blowing HGs to test the injectors, are there any other ways? Also my Afr is at 12, and my timING from what I understand is slightly advanced. As for the gas, I think it may be something to d with their import and stuff, because my tuner has dynod his car on our gas and American gas, and there was some ting clode to 4pwhp increase with the American stuff (2JZ Swapped S14)
If it blows again at the cyl that you move that injector to, it would give you a good indication that something is wrong there.

[digger]

what do the piston crowns look like? what do the plugs look like (what heat range) and what do the combustion chambers look like? any signs of detonation or just being too hot?

what head bolting strategy and how many miles on it? did you check tension after a few heat cycles? why is a stud broken?

[jonnywadster]

yeah pretty interesting, faulty head gasket in a small spot? Stranger shit has happened.
I'm leaning towards the injector or something causing it to lean out in that cylinder.
I've seen crap fuel rails flake chrome/paint and clog crap up that way and create issues.

Keep us posted.

[SGT StudMuffiin]

Well thanks to all the advice, I've decided to get the fuel injectors checked, I just recently changed my in tank fuel pump to a oem style delphi pump, so I didn't want to chage it again to some thing like a 255LPH, now I'm thinking I'll add an in-line pump in conjuction with my Delphi Intank. Also, since I've been paranoid with the cooling since day one, I'm considering buying a Mishimoto performance radiator, or something similar. What else could I do to make my engine run cooler, I'm also thinking about water/mething it.

[SGT StudMuffiin]

what do the piston crowns look like? what do the plugs look like (what heat range) and what do the combustion chambers look like? any signs of detonation or just being too hot?

what head bolting strategy and how many miles on it? did you check tension after a few heat cycles? why is a stud broken?

[SGT StudMuffiin]

Figured out how to post more pics:

[digger]

doesn't appear to be immediate signs of detonation. the one chamber looks a little cleaner as far as carbon goes but could be because the coolant clean it off. the exhaust valve is a different color?

what coolant do you use?

id invest in an OEM headgasket to.