My main concern is that with water in the oil, how concerned do I need to be about the moving parts in there rusting? The block can rust all it wants, Im not too concerned about it anymore as it is suspect number 1 at this point, but I want to be able to salvage everything in it, obviously. It's a VERY fresh build. I think it has maybe 3/4 of a mile on it plus the cam break in at this point. I caught this well before any obvious damage cropped up and my oil pressure was still a healthy 45 psi at idle at the last shutdown, but of course I'll be keeping a close eye on things as I tear it down, AGAIN.

I've been keeping a close eye on the oil during break in and the preliminary runs to watch out for this very problem, and I never noticed it before, so it only ran like this for at most a couple of minutes. I think some kind of crack somewhere just finally opened up with that last heat cycle. I was just trying to let it warm up a little so that i could get started tuning the carb to get it drivable... I guess fate had other ideas.





If it's the block, do you guys think it would be a good or bad idea to reuse the main and rod bearings? I figure they're wearing into my parts at this point, and since it didnt run very long at all with the water in it, they should all be fine (barring rust issues) but I am concerned about tolerances and clearances in a different set of main journals. I'll probably grab a new set of piston rings, but, again, is that a good or bad idea? These rings havent even seated yet, but my rotating assembly has been balanced. Will a new set of the same rings be close enough in weight to the ones I have for the balance job to still be okay? My goal here isnt to save money, but to make the switchover as gentle as possible for the moving parts. I've spent enough money already to make this thing work as well as possible, $30 bearings and $30 rings aren't going to break the bank. I'm just trying to figure out what's best for the motor.

Is rust a valid concern here? What precautions should I be taking? Should I be tearing this thing apart ASAP and coating everything in oil?

 

I personally wouldn't put the block as suspect number one. If this is a .030" overbored block, with just a few heat cycles on it, I highly doubt it's the problem.
If it were me? I'd want to know exactly where the leak was before I tore it down. I'd put new intake gaskets on, RTV it down. Drain the oil. Refill. Check to make sure it's clean.
Then remove the thermostat, hook up a cooling system pressure tester to your rad, and pressurize it up. See if it's leaking, and where from. Listen for the hiss, use a piece of hose and your ear.

If you want, you can tear it completely down, and bring the block in for a magnaflux. Get new bearings, but i'd reuse the rings. Once you get some load on the rings they will seat, I wouldn't worry about that. But once I torque down bearings I consider them used up, so after removing I toss them.
You can get the summit house brand aluminum bearings for $12 a set. $25+$10 fee and you're done. That's less than a tank of gas. Well, after you get all the gaskets and fluids you'll need, it'll be more, but still...

 

I would suspect the heads or head gaskets. I have seen many head gaskets get crushed during install and cause this leak. You should be able to narrow this down. Have you tried pulling the plugs yet? If you pull the spark plugs and one or more of them dumps water out then that would signify a blown head gasket.

 

It's a .060 over block with two sleeves in it.

 

oh. Well still, a machine shop that does sleeves should know how to do them. Your choice though, try to find the leak while it's assembled, or hope you can find it when it's in a million pieces.