90AWDTalon
20+ Year Contributor
- 877
- 3
- Jan 5, 2003
-
Everett,
Washington
On memorial day while on the way to an autocross, after stopping to take a leak while getting back on the freeway I got on the throttle pretty hard. I noticed my knock gauge pegged, and blue and black smoke behind me. I immediately got off the throttle, looked at my oil pressure, still looked good. Then check water temp, still looked good. The car was still running, no issues noticed except it was a little rough and felt down on power although I didn't really test this out, and there was blue smoke coming out the exhaust. I was thirty miles from the track so I decided to keep going and keep a close eye on everything.
So I get to the track, pop the hood to figure out what happened. I open the oil cap to check for signs of coolant in the oil, there is none, the oil is still very clean. But there is a large amount of exhaust poring out the oil fill hole in the valve cover. I then notice that there is also exhaust poring out my breather hoses. I pull the dipstick, same thing lots of exhaust poring out the dipstick tube.
I kept looking around the engine and found what had caused the problem. My boost controller came unplugged some how. So I severely over boosted the engine. My normal boost is 30psi, I've accidentally hit 35psi for a short burst with no issues so I'm guessing I must have been close to if not over 40psi.
I didn't autocross the car, I drove my buddies S2000 for the first time. It was the only good thing that came of this, I really took to the car and had a lot fun. But anyways I drove the 110 miles home keeping a close eye on things. Oil pressure stayed good the hole time, coolant temp stayed good if not a little lower than normal. Blue smoke out the exhaust the whole time, the car felt very down on power. And stalled once at a traffic light, but started right back up no problems. At this point I guessing that I've cracked a piston.
So today I finally got around to doing a compression test. From left to right, 60, 155, 155, 150. Cylinder #1 is dead, I shined a bright flash light down the spark plug hole looking for damage. I didn't see any, I was able to see all the way around the piston for about 2/3 to 3/4 the diameter. The piston did look much cleaner than the other three. It was extremely clean, no deposits at all. The other three while not bad did have some deposits.
The question is, does it sound like I'm right and its a cracked piston? Could a blown head gasket leak exhaust into the crankcase? Is there any way to tell with out disassembling the engine? If it is the piston and needs a rebuild I'm going to do a stroker, best case scenario when I can do the rebuild is over the winter but more likely a year or so. If its the head gasket I'll fix it now. I want to keep the car in running condition until I can fix it, although I won't be driving it, just want to be able move it if necessary.
Thanks for the help.
So I get to the track, pop the hood to figure out what happened. I open the oil cap to check for signs of coolant in the oil, there is none, the oil is still very clean. But there is a large amount of exhaust poring out the oil fill hole in the valve cover. I then notice that there is also exhaust poring out my breather hoses. I pull the dipstick, same thing lots of exhaust poring out the dipstick tube.
I kept looking around the engine and found what had caused the problem. My boost controller came unplugged some how. So I severely over boosted the engine. My normal boost is 30psi, I've accidentally hit 35psi for a short burst with no issues so I'm guessing I must have been close to if not over 40psi.
I didn't autocross the car, I drove my buddies S2000 for the first time. It was the only good thing that came of this, I really took to the car and had a lot fun. But anyways I drove the 110 miles home keeping a close eye on things. Oil pressure stayed good the hole time, coolant temp stayed good if not a little lower than normal. Blue smoke out the exhaust the whole time, the car felt very down on power. And stalled once at a traffic light, but started right back up no problems. At this point I guessing that I've cracked a piston.
So today I finally got around to doing a compression test. From left to right, 60, 155, 155, 150. Cylinder #1 is dead, I shined a bright flash light down the spark plug hole looking for damage. I didn't see any, I was able to see all the way around the piston for about 2/3 to 3/4 the diameter. The piston did look much cleaner than the other three. It was extremely clean, no deposits at all. The other three while not bad did have some deposits.
The question is, does it sound like I'm right and its a cracked piston? Could a blown head gasket leak exhaust into the crankcase? Is there any way to tell with out disassembling the engine? If it is the piston and needs a rebuild I'm going to do a stroker, best case scenario when I can do the rebuild is over the winter but more likely a year or so. If its the head gasket I'll fix it now. I want to keep the car in running condition until I can fix it, although I won't be driving it, just want to be able move it if necessary.
Thanks for the help.
