Rust...in cylinders.

[vtl]

I've added a picture with a better angle. The corroded part is felt up and down, it's on the piston thrust axis I believe.

If this won't keep wearing down or even destroy the rings I will run it as is.

In fact I am thinking of attempting to start and run the car like this. If the engine dies at least I'll know and be certain and scrap it.

If it runs and compression is adequate I will use it like that.

This one is pretty bad. Not sure what happened? A piston melted onto the sleeve? A sleeve started to crumble? What caused that? Is it above the surface of the sleeve or below?

I would pull at least this one piston and inspect it.

[dikidera]

Corrosion from staying without a head for too long.

Yes I can catch my fingernail on it. Buuut...it is what it is.

The cylinder was fine when i opened the enginr, it just stayed too long without a head.

I'm assembling the engine as is. Whatever happens , happens.

[cn90]

You will be fine.
Just do the usual break-in procedure to be safe.
For the first 200-300 miles, keep rpm low like 2000 or 3000 rpm.

[Krons]

Can always pour a little engine oil in the cylinder for when you fire it up to help lubrication.

[dikidera]

I plan to, yes. I have heard many situations of people being unable to start the car, as the lack of oil around the piston doesn't help seal the combustion chamber very well, but a drop of oil, helps in this regard.

Within 2-3 days I will know for sure what will happen. First procedure is cleaning out the bolt holes of the block, as any debree in there can do damage when torquing down the head.

[jonesg]

thats way down in the cylinder, not exactly up in the compression zone.

[dikidera]

Sadly the extent of the damage was not the little blotch you see in the pics, as soon as I rotated the crank I saw more stuff and this time it went around the piston. As a last resort, I will use the 1200 grit sandpaper and very very very lightly give these places a few touches so as to not be so rough and not kill the rings immediately.

I have nothing else to lose. The damage is already there. If I am lucky and see compression at or above 11.5 I will be somewhat relieved. If the piston(s) seize, then they seize.

We did some tests. We poured some kerosene on the pistons, to observe and also loosen up any piston rings that may have seized as well as the bolt holes so we can blow them out later.

Interestingly, pistons 1 and 2 which have this extensive corrosion held up just fine while in their middle to near bottom travel, but it's one thing to do this with a non-running engine, it's another thing entirely when the engine is operating at 5000 RPM.
But pistons 3 and 4 in their TDC, had the kerosene drip down within 5 minutes. This is interesting as before all of this, before my headgasket blew my radiator, I measured compression around 205 psi in cyl #4.

I was running 5w30 oil before, but I plan to use 10w40. Thoughts on this?

[vtl]

I was running 5w30 oil before, but I plan to use 10w40. Thoughts on this?

I was running 10w40 and topping up with 15w40 since I started overlanding on XC70, till the engine died and got rebuilt. At times, it worked heavily 9-10 hours a day, week+. No problem.

[dikidera]

15w40 sounds about what I might need. Still, it's unclear what will happen. I will post back soon on the results. I will be the first Volvo owner to ever run an engine like this, with a ported head no less.

The irony is, my old S40 1.6 had a heavily worn engine, we're talking about 8 psi warm and 6 psi cold.

[vtl]

Nothing will happen because of heavy oil. Well, I lie: mechanical wear will almost stop.

Your old engine had worn compression rings. Volvo's natural aspiration engines are known to operate till they loose compression due to excessive thermal gap in rings, which typically happens at around 600-700k km.