rb25_s13*CHUKI

So long story short I was driving down the road in my car and it was running very rich due to a bad fuel map but It cleared up once I was in boost. Bone stock sr20 that has been around me for 3 years

50 trim turbo, 555cc injectors, tune Etc.etc

I floor it and It over boosted by like 15 psi (30psi) and then boom! Subaru sound and white smoke, I pull over and shut the car off and check the damage oil everywhere from the maf (piston rings I assume) fine.

So i assumed it was the pistons so I let it sit and lastnight I tore it apart only to find the following!

1.pistons are not melted or damaged

2.rings are in tact and not cracked or melted

3.coolant in number 3 cylinder but the car didn't over heat and didn't eat a single drop of coolant. the head gasket was also perfectly fine when i pulled the head off, i seen no ripped marks or anywhere it was damaged.

4.cylinder walls are not scratched or scortched

5.no pitting on combustion chamber head or block

6.valves look good but I'm doing a valve check as we speak

I am stumped at this moment as to what the hell happned! Has anyone ever encountered this before? Could the head have cracked under pressure? I would think the head gasket would give or something would melt before the head and or block would crack

I'll post pics in a little bit to show you guys whats goin down

There was a little sign of number 4 piston started to pit a little bit but nothing that would stop it from running or not make compression

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Obliterate

95_S14

Must of been that Godspeed intercooler , what a asshat

rb25_s13*CHUKI

what the fuck are you talking about? i have 3 godspeed intercoolers laying around

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Obliterate

95_S14

Just giving you shit , kinda like you with the 900whp mustang guy that you will smoke the shit out of , lol

rb25_s13*CHUKI

Me and that guy have argued before and it wasn't about a 240 and his nova or cobra. it was about a foxbody mustang and his nova

long before that 900rwhp cobra he posted

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PureRush

What about the bottom end?

rb25_s13*CHUKI

The bottom end is all good!

Rods are in good shape and the main/rod bearings don't show signs of damage or scratching.

everything looks good lol it's like nothing happened inside of this engine! only the coolant in cylinder 3

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Obliterate

Sileighty_85

have you looked at the turbo..

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1998 S14 W/RB25- 250ish (For Now)
1986 SR86 - 200ish
1990 R32 GTR - 320hp
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rb25_s13*CHUKI

Turbo is perfectly fine no bent fins or shaft play, spins just like it did when i bought it.

The injectors were inspected and in working shape

The coilpacks are being used on a friends car

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Frank_Jaeger

Don't question it man. Roll with it.

LayNLow

Perhaps what you heard was a coupler blowing off? 30psi can make a big bang and smoke.

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waxball88

THIS
Is why you can't assume things. A compression/leak down would have saved you all that trouble... A boost leak test would indicate coupler failure. Now you have the whole block apart...

rb25_s13*CHUKI

I planned on rebuilding anyways so i just did it the "digging for gold" way .

I know the electrical was all fine, coilpacks are good and injectors are good. All things that would make it not run on all cylinders, I'm about to post a video in a little bit so you guys can see and if you read It had cylinder 3 filled with bright green coolant so something happened inside.

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Obliterate

rb25_s13*CHUKI

I'm 100% positive that wasn't the issue that was the first thing I checked when I pulled over, All couplers and piping. the car has already been sitting for a month or so and Its been looked over through and through as far as electrical and external issues. I barley took out the engine a couple days ago and tore it apart

I know it wasn't running on all cylinders when it happened cause that sound is all too familiar. It had all symptoms of melted piston or blown rings, I've melted rings and pistons before

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Obliterate

rb25_s13*CHUKI

I over boosted to 30psi once before and It popped off all vac lines and cold side piping. So I fixed all the pressure system with all new lines,couplers and clamps, I was having issues with the boost controller I thought I fixed it cause it ran fine for weeks but that once day It decided to do it again

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Obliterate

LayNLow

Or perhaps oil got all over the maf and shorted it out, causing it run like a subaru? Or maybe you lifted the head a bit?

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ashtonroche

If you sprayed oil all over the bay then you obviously pressurized the crankcase. There is only three ways this could have happened. PCV valve broke allowing pressurization of the crankcase.

Cracked the ring lands or melted a piston (which you said didnt happen)

Or lifted the head pressurizing both the cooling system and crankcase.

If you were on factory headbolts then you probably lifted the head. The gasket really wont show damage if this happens. It will just lift allowing boost into the oil and coolant and then reseat itself once out of boost

rb25_s13*CHUKI

Yea I was thinking that also two of the head bolts were very hard to get out and 1 of them had corrosion. come to think of it the two bolts that were hard to get out were the two middle bolts which is where the coolant was in cylinder 3. by hard to get out i mean I actually had to put power into getting them out unlike the rest that just spun out normally

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rb25_s13*CHUKI

The pcv valve did seem kind of jiggly i'm about to make a video right now when i go to my shop.

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ashtonroche

Factory headbolts dont like much more than about 400whp. and on that turbo and 30psi, even though you dont have the fuel for it, it was probably making over that and probably started to get some detonation from leaning out which only will escalate head lift.

ashtonroche

Its supposed to jiggle. You need to blow into it where the hose would connect and see if excessive amounts of air goes by the valve. It wont seal completely but it should be close.

omgosh

You probably lifted the head if stock headbolts were used.

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lilpiton

Found out anything on this?