Last summer I did the whole Altima/'91 cam swap bit. We didn't have the right torque specs and about 15 miles down the road, the car jumped timing and bent the valves. Over the course of the next several months (due to laziness/financial restraints/etc) the head was taken off, valves were replaced, head was put back on, etc.
I finally got everything buttoned back up and the car back on the road about a week ago. Was running fine except for some lifter tapping that I found to be a bit excessive but it often went away when the car was warmed up. I took it out on the interstate a few nights ago and was messing around with it a bit. Never did really exceed 5500rpm, and this was not the first time the car had been ran hard since I put it back on the road. Had responded beautifully, before.
Was probably on the interstate for about 10 minutes. As soon as I came off onto regular roads, the motor was knocking something fierce. My oil light came on about a mile down the road. I pulled over and was a good quart, quart.5 low. Added a quart and a half, cranked the car back up. Momentarily, it sounded normal at idle. Revving resulted in rapid, loud tapping/knocking.
Decided to take it down the street a bit as I was not in the greatest area of town. Was experiencing power loss and ridiculous knock. Creeped it to the gas station and did another oil check. Added two quarts and left about half a quart on the ground where I'd stopped the car. Moved it to the next parking lot over where a group of car folk were conversating, and parked it.
Car was still leaking oil, not dumping it onto the ground, but dripping rather steadily. Coming from somewhere under the header. My first thought was a head gasket problem, but that didn't strike me as too logical as I figured I'd be seeing water mixing with the oil.
The knocking was just absurd, though. After about 45 minutes of deliberation, most of us had come to the conclusion that the motor was toast, and I decided to go ahead and try to limp it home anyway. I did get a good few miles down the road and it went further to hell from there. Smoke starting pouring out the back of the car and the knocking was so bad I could feel it on the floorboard. Huge power loss, and the car finally cut off when I came to a stop at a light. Wouldn't crank over except for about 3 seconds and died again. Pushed it off the road to a gas station where it sat for the next day and a half.
The next day I did go back to check on the car in the daylight and found that not only had it not leaked oil, but the oil itself was actually about 1/2 a quart overfilled. This made no sense to me as the night before, it was leaking pretty badly.
So....what does it sound like happened? Incorrect oil circulation obviously, but was this a spun bearing as has been assumed? What would have caused this sudden damage?
I'm stumped. Ideas are appreciated...thanks.
