Now I know why my engine was sick....

[Dave_M]

As some of you may know, I took my escos off the road a little over a year ago as it was blowing it's oil out under boost - to the extent the oil went from max to min on the dipstick over 1 fill of the fuel tank. Mark Shead did a leak down test on it which showed cylinder 3 was leaking past the piston rings.

I pulled the engine a box out a couple of weeks ago and started to strip it - got the head off and pistons out yesterday. Cylinder 3 piston had a broken oil control ring (the pieces fell out as I removed the piston) as well as the 2nd compression ring being completely jammed in its groove on one side of the piston. Cylinder 4 piston also had a broken oil control ring.

Other than the above, the rest of the engine looks in good condition so far. The broken oil ring in cylinder 3 has marked the bore - though I can't feel the scratches with my fingernails. At the very least it's going to need honing - but I need to get it measured up to see if it needs a rebore.

Any ideas what would cause oil control rings to break? I'm guessing the stuck compression ring may be because the car wasn't used for 5 years before I bought it.

I'll post some pictures up later.

Dave

[mark shead]

Don't bother honing it as it will make bore clearance to large and it will use oil.
A rebore is the only way.

Mark

[Dave_M]

Thanks Mark - I'll get it rebored. Pics of each cylinder below - these are all the thrust side (same side as exhaust manifold). The score on cylinder 3 is clearly visible, with no marks at all on the other 3 cylinders (the engine's done 64k miles, and as far as I know the only previous internal work was a new head gasket at c.42k miles).

Dave