Cylinder wall damage at top, in ring area

thomas682 · 10-12-2019, 07:51 AM

All,

While inspecting a newly rebuilt engine for purchase I discovered, using a Snap-On BK5600-OD bore scope, what appears to be a chipped damaged area in the very top section of a cylinder. The damage appears to be just below the top ring area of the piston at TDC and just above the top of the oil ring. The bottom of the photos, the silver area, is the squish band area of the cylinder head near the intake valve. Based on the photos below can anyone tell me how much of a risk do I have that the cylinder or piston rings will prematurely fail? The engine has not been run, does not even been filled with oil but is fully assembled and ready to be installed into the car.

Just hoping to receive some wise counsel from the engine experts on Pelican.

boosted79 · 10-12-2019, 11:49 AM

That engine was not "rebuilt", it was thrown together. Run away as fast as you can.

Walt Fricke · 10-12-2019, 03:06 PM

No way a gouge like that would be overlooked while the cylinders were being prepped for installation.

I think that typically good used cylinders still show a fair amount of their original cross hatch. Maybe I'm wrong on that.

dannobee · 10-12-2019, 04:06 PM

Quote:

Originally Posted by Walt Fricke

No way a gouge like that would be overlooked while the cylinders were being prepped for installation.

I think that typically good used cylinders still show a fair amount of their original cross hatch. Maybe I'm wrong on that.

No, no. You're right. That cylinder needs to be repaired/replaced. The other bit that concerns me is the wear pattern. Not just the lack of a crosshatch pattern, but also the scuffing. It's likely had enough boost at one time that the piston heated up enough to where there was no clearance.

mikedsilva · 10-12-2019, 08:37 PM

That borescope has taken some very good quality photos.. the one I got from ebay takes rubbish images.

boosted79 · 10-13-2019, 06:55 AM

That bore was never touched with Scotchbrite. Ask to see all of the measurements that should have been taken after the tear down and clean up but before the "rebuild". Like bore diameters (both axes top and bottom), crank journals, saddle bores, piston skirt diameters, etc. Ask to see the new ring end gaps and land clearances, new bearing clearances, deck height on each jug,etc. It will be interesting to see what they say.