Rust on inside of cylinders

[ajgaines]

I received this engine with some water in the cylinders. It sat that way for about 1-2 weeks before I was able to open it up and clean it out. It is currently seized and this is what the inside of the cylinders look like. Pictures are in reply.

What do you guys recommend for taking care of the rust? I've been spraying it with PB blaster continually, and been wiping it gently with blue paper towels, but it doesn't seem to clean it off. Does it only require honing? Full reboring? Total scrap??


Cheers!

[ajgaines]

[Al Schober]

Ugly stuff..
The seizing is most likely due to the rings corroding to the bore. The bore is a high nickel alloy, resistant to corrosion and wear.
Time is your friend in getting things loosened up. If you get impatient, you can remove the crankshaft then tap the pistons - block of wood and a hammer. If you hit it too hard, you can break a land loose on the piston. Then you're looking at a replacement piston.
If this is part of a rebuild, you'll be removing the crankshaft anyway so you can get a hone in there. Should clean up nicely. New rings and you're on your way.
How are the valves/seats?

[ajgaines]

I think the valves are just fine. I think I can't get them out though if the pistons aren't moving? The issue is I want to do all this in the boat, I'm not certain how I can get the crank out just working in the boat. The 1st cylinder actually moves a little when I pry on the flywheel, but I've had them sitting in oil and that cylinder just started draining out when I fill it, is that a concern?

[joe_db]

If only ONE piston moves then there are issues

[Al Schober]

Got it - no rebuild now, just get it turning. Then see if the valves go up and down too.
The piston that's moving a little could be free. Leave oil in there.
Perhaps a more effective penetrant than oil for the other three? A long time favorite of mine is a 50/50 mix of kerosene and ATF. PB Blaster is also good.
How's access to the engine? Remove/reinstall may not be that big a deal. Could be as little as 3-4 hours for removal, 3-4 hrs for reinstall.

[ajgaines]

The access is decent but I'm terrified of connecting it to the boom the raise it, it seems like such a heavy engine to lift out with the boom. And I don't fully know what to connect to where as I've never done it before. You think just honing the cylinders in enough to move the rust on the sides?

[ndutton]

You don't use the boom to do the lifting. Connect a Come-Along (cable winch) to the main halyard for the lifting. The boom comes into play by positioning the halyard with a line from the halyard bottom to the outboard end of the boom. All the load on the boom is in compression pushing from the clew end toward the gooseneck.

[ajgaines]

I tried to draw a picture to clarify your description for myself. Is this what you had in mind?

[ndutton]

Yes, exactly. For safety, no snap shackles should be used in the lifting operation. Snap shackles are designed to be able to release under load so are dangerous in this application.

CAUTION - - Engineering geek alert
The only load on the boom is at the clew end and its force vector is parallel to the boom toward the gooseneck.

[Al Schober]

You've already done a lot of the work, having the head and manifold off. Still to go are the flywheel and the starter. The casting around the flywheel has to stay in place until you can get access to the two lower bolts. Total lift will be a bit over 200#.

[Al Schober]

I do not recommend putting a hone into the bores until you remove the pistons. The stones will leave abrasive residue that you won't remove in its entirety and the residual abrasive will not be good for the engine. In addition to becoming imbedded in the pistons and scoring the bores, some will wash down into the oil sump and find its way to the bearings, scoring your crankshaft and cam.

[tenders]

You are getting world-class advice in this endeavour, ajgaines. Please stick with this project!!

[joe_db]

Can we revisit one piston moving? Unless the crankshaft broke, I don't see how just one of them is going to move