Overboosted. Now what?

[S13Eye]

I recently got done swapping an engine into my car. During the swap i installed a Greddy Profec B Spec-II boost controller, which worked fine for a cople boost cycles. It soon failed, and my S13 SR20 over-boosted. It was still reading pressure, and i had last-boost on so it recorded the max pressure. Its bad - just over 25 psi. Mostly stock fuel system, except for Walbro pump and cleaned injectors, T25, and a front mount IC. No blow off valve. The fuel tank was drained, and whatever remained was diluted with 5 gallons of 102 octane gas. The engine has a total of maybe 10 miles on it since it was swapped.

The head gasket is not blown, but it now smokes white after running for about 30 seconds. Compression is fine, and there is no froth in the coolant. I'm assuming the turbo is damaged. There are fine metal shavings in the oil. Some have collected in the head, and there are also some in the oil pan. No chunks though. These shavings are not sticking to a magnet. They don't look like brass, so its most likely not bearing shells. Oil pressure is fine. Hopefully its just the oil pump thats broken and its eating away at the front cover.

The engine needs to be torn down. What should i be looking for? Is there anything i will have to replace for sure, aside from the turbo and oil pump? How would you go about cleaning out the oil passages? The bearing shells are most likely damaged. Overall the engine runs great, its just a timebomb at this point. Any input is appreciated. Yes, its a stupid mistake, but you would be suprised at how little power difference there is between a healthy 10psi, and 25psi of hot air.

Edit: Spark plugs show no sign of coolant consumption. The engine is losing coolant. There is no white smoke comming out the crankcase vent. It seems the smoking starts once the exhaust piping gets hot.

[sepulchral]

thanks for the detailed description, take your turbo off, or intake pipe off check the turbo for shaft play, doesthe turbo make any noise or antyingn, u could have fucked the turbo up.. SR's are strong motors, i boosted 22psi spiked in my sr many a time when my boost controller messed up, it didnt effect it.. Does the compression change when u add oil to the cylinders? What does the smoke smell like, is it definitly coolant?

I'm thinking your piston mighta chipped or something, or the babbot on your bearings or something.. tear that bitch apart.

[sepulchral]

ack didnt see your bottom shit, i Really think either

A) turbo waterline cracked and is somehow getting into the intake manifold (causing no crankcase smoke)

B) Blown Headgasket..

IF i were you, drop oil pan, take head off, pop pistons out, replace rings, rod bearings, headgasket, headstuds, and check cylinders for any egging or cracks.. also have your head checked with a straightedge and a feeler gauge,,

or just pull your motor, whatevers quicker for you

[S13Eye]

What is the max out-of-round spec for SR20s for replacing piston rings without having to get the cylinders bored? I haven't done rings on a used engine before, and as far as i know, cylinders wear into 'ovals' so installing a round piston ring would cause blow by. Can anyone elaborate on this?

[sepulchral]

i'm sure its a few thousandths, take a telescoping gauge and a micrometer to measure it with and check out the diameter at various depths, also check to see ifyou can feel the top ring where the piston ring stops, if you can feelit with yourfinger nail then you most likely have to bore it...

You can also take one of your old rings off and put it in the cylinder, measure the rring gap, then press the piston down on it further in the cylinder, keep reading the gaps, if it varies 0.010" or more i'd get it bored if it doesnt then hone it using a napa tool and get some rings for it.

[sepulchral]

but i cant remember what the specs are, sorry dude, and goodluck, i hope they aren't egged

[S13Eye]

Thanks for all your help sepulchral. I have not done a wet compression test, but it was fine and even during a dry test. I don't have the exact numbers with me, but off the top of my head its was above 150, on all 4 cylinders with a variation of 4psi. The smoke is pure white, and it actually smells more like oil than coolant. Its not gasoline vapor. The coolant mixture is 50/50 so the smell should be sweet, but i have heard of cases where the turbo is damaged and consuming coolant, but it doesn't smell like coolant.

Please explain how the turbo would leak coolant into the intake. I have never seen a cross section of a T25 so i don't know how the passages are routed and sealed off from the turbine and compressor. There was a black swirl around the compressor inlet as if it was sucking in a greasy liquid. The only source could be the PCV, but there was no water in the oil, and blow by seems normal and healthy. The intake is a cone from Apexi, and its pretty well sealed off from the elements, although i have driven the car in rain, and even snow. The wheel well liners were removed while i drove it. Still, i have never seen an SR do that. There are no signs of coolant consumption in the intake tract.

[gotta240]

holy shit... Someone give this guy a cookie(or at least decent help) for ACTUALLY EXPLAINING his problem in detail, and in decent english!!!

[bardabe]

to answer your questions in english.
replace crank and rod bearings
heatgasket
have motor profecionally honed and jetblasted (clean passages adn block)
if you are worried about cylinder stock bore is 86mm maximum wear is .2mm (86.2mm total MAX) :bow:

now for advice.

I say tear the bitch down. have it profecionaly Honed and jetcleaned (to clean out oil and coolant passages) replace all bearings (both crank and Rod) instlal new oil pump, new piston rings, clean the water pump and reuse it if in good condition. that should take care of bottom end. now for the head. I say get a cometic metal head gasket have your head cleaned and inspected make sure all valves are eating properly and have them cleaned, and that should take care of the block.

-Juantons

[sepulchral]

well i really think its your HG then, if you were just losing coolant i wouldnt be too worried, but shavings? It could be aluminum from pistons or babbot from bearings, or something, just dont be upset, when you're done you'll have a fullproff motor.

[S13Eye]

This isn't just a minor loss of coolant. At 15mph, 2nd gear, there is zero visibility behind the car. The coolant loss is taking place post combustion, since there are no signs of it being consumed within the cylinders. The engine runs beautifully which is inconsistent with the plumes of smoke exiting the tail pipe.

Either way, time to bust out the micrometers and torque wrenches. Thank you again sepulchral. I will pick up this thread when i make progress.