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OK...first the stats: 3100 in a 95 Lumina, 285K miles. Mobil1 ALL the time, and the inside of the engine is like new.
How do I know what the inside of the engine looks like....? Well.....
I was driving the other day, about 2blocks from home, when I heard a pop...the oil pressure light comes one and the engine runs like crap and dies. WTF....was running fine until then, although earlier that day there was a slightly louder than normal lifter tap. Got it fired up, but a)no oil pressure, but no rod knock. Ran, but had to keep it almost floored to get it running and home.
Upon teardown, I expected to see a chucked lifter that caused the drop in pressure and lack of all cylinders firing. There was no sign of any problems on the outside of the engine....and no oil in water or water in oil.
That was not to be. I found a blown LIM gasket on the rear head by the thermostat crossover. Damn! I guess the engine was wiped....or so I thought. I also found that the # 3, 5, and 6 intake ports were fairly full of fuel. Weird.
Sooooo...I have been debating an engine swap. I have a 3400, a 3.4DOHC, and a 5.3LS4/4T65ehd combos available..... Since the car is old, and it's cold....I was going to go the easy route and just drop the 3400 into it. But as I was driving around today....I still couldn't figure out the gas in the ports thing. Then it hit me....no oil pressure, and no valve action on the back three cylinders....broken cam? When I got home, I put a wrench on the crank and sure enough....front of the dam rotates, but the back doesn't WTF!!! A broken cam! Unreal.....I have never seen this before.
So, now I need a new cam/lifters......anybody have a set they want to sell?
I'm still debating the 3400 install, as it probably is as much work to change the motor as it is to change the cam.
My questions:
1) What would cause the cam to break like this?
2) If I were to put a new cam in....what else besides lifters and timing set should I also install?
Unreal.....I have never seen this happen....
Finally, MAJOR kudos to Mobil1! I ran the engine for maybe 2-3minutes, up a hill even, and not a rod knock to be heard. Engine still rotates smoothly....
How do I know what the inside of the engine looks like....? Well.....
I was driving the other day, about 2blocks from home, when I heard a pop...the oil pressure light comes one and the engine runs like crap and dies. WTF....was running fine until then, although earlier that day there was a slightly louder than normal lifter tap. Got it fired up, but a)no oil pressure, but no rod knock. Ran, but had to keep it almost floored to get it running and home.
Upon teardown, I expected to see a chucked lifter that caused the drop in pressure and lack of all cylinders firing. There was no sign of any problems on the outside of the engine....and no oil in water or water in oil.
That was not to be. I found a blown LIM gasket on the rear head by the thermostat crossover. Damn! I guess the engine was wiped....or so I thought. I also found that the # 3, 5, and 6 intake ports were fairly full of fuel. Weird.
Sooooo...I have been debating an engine swap. I have a 3400, a 3.4DOHC, and a 5.3LS4/4T65ehd combos available..... Since the car is old, and it's cold....I was going to go the easy route and just drop the 3400 into it. But as I was driving around today....I still couldn't figure out the gas in the ports thing. Then it hit me....no oil pressure, and no valve action on the back three cylinders....broken cam? When I got home, I put a wrench on the crank and sure enough....front of the dam rotates, but the back doesn't WTF!!! A broken cam! Unreal.....I have never seen this before.
So, now I need a new cam/lifters......anybody have a set they want to sell?
I'm still debating the 3400 install, as it probably is as much work to change the motor as it is to change the cam.
My questions:
1) What would cause the cam to break like this?
2) If I were to put a new cam in....what else besides lifters and timing set should I also install?
Unreal.....I have never seen this happen....
Finally, MAJOR kudos to Mobil1! I ran the engine for maybe 2-3minutes, up a hill even, and not a rod knock to be heard. Engine still rotates smoothly....
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