Hey guys
I'm gonna upload pix later.
ZJ 4.0 AW4, 260k miles. Alright here's the story - The car used to misfire at idle, tested for low compression in one cylinder, used to throw a CEL for misfire in one cylinder, but it ran great like that for a damn long time. But when the waterpump span a bearing, the shaft fell out, and the drivebelt was lost, my brother attempted to drive the car to the nearest autozone. Needless to say the car severely overheated, and it was driven the the point an audible whack was heard, and the car stopped.
After this it would not start and compression was 30psi in all cylinders except the one that had low compression, which had 0. Upon cranking, bubbles appeared in the coolant tank. I tried starting fluid - this caused the oil dipstick to blow out of the car! I figured the piston rings were shot so I tore into the engine to replace them.
After finally pulling the oil pan, I found some metal shavings in the oil pan pickup screen. When I pulled the head, I found that there were six big cracks in it. Worse, one of the pistons was badly damaged, with a good amount of metal missing and unaccounted for. It looked almost like the damn thing had lost timing!
Now I don't know what do do as Ive put like 300 toward parts - bearings, rings, gaskets, etc... and I'm wondering whether to slap in a new engine or rebuild the one that's there. I'll need a new head and one new piston. I'm worried about rebuilding as the engine probably has little flakes of metal in all sorts of tricky spots.
Also, the car has not lost timing and the rod is fine. why the hell would this have happened? Prolonged detonation? I did notice that some of the valves had been replaced at some point (although they looked like the right part, they had the number 10 stamped into them, unlike the others.) Could they have dropped a metal part (nut, or the like) into a cylinder? Seems odd that it would have run so well for so long like this...
Any thoughts?
I'm gonna upload pix later.
ZJ 4.0 AW4, 260k miles. Alright here's the story - The car used to misfire at idle, tested for low compression in one cylinder, used to throw a CEL for misfire in one cylinder, but it ran great like that for a damn long time. But when the waterpump span a bearing, the shaft fell out, and the drivebelt was lost, my brother attempted to drive the car to the nearest autozone. Needless to say the car severely overheated, and it was driven the the point an audible whack was heard, and the car stopped.
After this it would not start and compression was 30psi in all cylinders except the one that had low compression, which had 0. Upon cranking, bubbles appeared in the coolant tank. I tried starting fluid - this caused the oil dipstick to blow out of the car! I figured the piston rings were shot so I tore into the engine to replace them.
After finally pulling the oil pan, I found some metal shavings in the oil pan pickup screen. When I pulled the head, I found that there were six big cracks in it. Worse, one of the pistons was badly damaged, with a good amount of metal missing and unaccounted for. It looked almost like the damn thing had lost timing!
Now I don't know what do do as Ive put like 300 toward parts - bearings, rings, gaskets, etc... and I'm wondering whether to slap in a new engine or rebuild the one that's there. I'll need a new head and one new piston. I'm worried about rebuilding as the engine probably has little flakes of metal in all sorts of tricky spots.
Also, the car has not lost timing and the rod is fine. why the hell would this have happened? Prolonged detonation? I did notice that some of the valves had been replaced at some point (although they looked like the right part, they had the number 10 stamped into them, unlike the others.) Could they have dropped a metal part (nut, or the like) into a cylinder? Seems odd that it would have run so well for so long like this...
Any thoughts?
