Vilhuer

P or N doesn't make difference.

We are going to take a look inside tomorrow with very expensive camera. Owner is loaning it from local camera importer he knows. Will be interesting to see what's inside. It should provide video evidence on what's causing this.

Gretch, finnish names (including mine) are different and difficult to write correctly for english speakers it seems. But no-one in their right mind would name their child as Aut if that's what you thought. Well maybe if labor was really bad. Now some names starting with A would maybe sound close to that to english speakers.

Gretch

What I thought was that I might be interested in thinking through the puzzle you have on your hands. I asked a couple of questions, so that I might be headed in the right direction......

I am sure you will figure it out...............

Vilhuer

Cars owner had loaned Olympus fiberscope with 8mm tip. Great device. Next time when shopping for car similar product is a simple must. Would love to see salesmans face when that puppy comes out It was small enough to fit through injector holes in intake runners for viewing intake valves and through exhaust ports up to exhaust valves. Most importantly it fitted nicely through sparkplug holes inside combustion chambers.

Was easy to see what's the problem. There wasn't any foreign objects visible anywhere. But what there was on sight is really disturbing. On cylinder #3 there is serious sized up down direction scratch. It wasn't there when heads were off. Only logical explanation for it (what we could come up) is compression ring must have snapped and small portion of it must have eaten itself into cylinder wall. Looked like someone had pushed sharp edge agains wall and part of the aluminium had piled up in fron of it preventing piston to go by the pile. This explains why it didn't want to move up beyond certain point. We couldn't rotate crank backwards enough to see how far down scratch extends. Probably little piece is eating its way between piston and cylinder wall also to downwards direction and preventing movement to that direction too.

Basically what was only few crank rotations ago pristine block was ruined because there was something small and sharp loose in piston ring groove. We heard nothing that would indicate this was going on. There was no excess resistance when rotating. Reason for taking heads out was blown head gasket on cylinder #3. I don't believe it was coincidence when both occured on #3. What must have happened is that when head gasket blew some water got inside combustion chamber and it broke one of the rings. For some reason this didn't manifest itself during block cleanup but it only took under 20 rounds in total for it to start making it's mark.

My advise is that whenever head gasket goes, always change all piston rings. It's small job and cost compared to locating different short block. In this case block rebuild would mean either 100mm pistons (if owner is lucky and cut is't as deeb as it looks in fiberscope), replacing entire cylinder tower with new pressed in aluminium tower or putting in steel sleeves. All these are expensive compared to new rings but are available locally.

ErnestSw

OUCH!!! Bummer. Deep respects for the ingenuity show in the diagnostic process.

Lagavulin

I agree, that's exactly what happened; hydraulic-lock occurred and the ring lost. I wonder if the top of the cylinder ballooned out too?

Vilhuer

Owner didn't notice hydraulic lock before he parked it. Heads were fine and only needed smallest possible amount taken of just to clean the surface. They weren't twisted at all. That's why it was so unexpected when problems arose.