to rebuild or not to rebuild

[medic0079]

So I got this parts truck with a supposedly rebuilt 302 in it. Now of course I have no idea who rebuilt said truck, nor has this truck been running for years. likewise it was stored outside under a tarp, and had about 1 qt of water in with the 5 qts of oil when drained. So here is the question. I ripped off one of the heads and the engine does look as if it has had a recent refresh. looks to be new valves, and there is still honing (spelling?) marks on the cylinder walls. so what I'm thinking is that I might be able to rip it apart, take it to the machine shop have everything mic'ed and reassemble assuming all is well. the other option is to put the head back on roll it over pull the pan make sure there is no catastrophic problems with the lower end, put the pan back on oil, and try and fire it up. obviously either way its getting a bath and repainted. there was a minor rust spot at the top of one of the cylinders in the wall. I scratched it with my finger nail and it seemed to come off. I have a pic of this, and think it will go away if I hit it again with a hone (spelling once again?) I am tight budget right now as I'm trying to save for other components so I really don't want to go back over someones work assuming there are no problems with it.
please tell me what you guys think, as you have FAR more experience in the field than I, and let me know if there is anything else you can spot with any of the pics.
Thanks a bunch for the help guys. This place is great.
Noah

 

[lincolnuT]

That water in the pan is the biggest problem I see with what you have posted. That water could have come from the 10 years it was stored. If you don't see anything wrong with the other side of the engine I would be tempted to put it back together and give it a try. Your only out some oil and time that way.....Take the other head off and look because you will need a headgasket set anyway.....

My .02
Mike

 

[Wild Mango]

What lincolnuT said. Check the inside pan bottom for rust if she's had water in there for an appreciable time. Check the head and deck sealing surfaces to make sure the oil in the pan didn't come from a blowed head gasket. If she's been leaking water into the oil while running the water and oil tend to emulsify with a light grey milky appearance, but if its a rainwater incursion from storage the water just lurks in the bottom of the pan. Button her back up with fresh oil and filter and give her a run, nice and gentle while she warms up. Those bores look pretty good from the photos. After a good run and a cool down, a leak down test will tell you all you need to know.

 

[Mike]

Rust = pitting. No way to get around that fact. And because of that, I would really be wanting to see all eight bores, top to bottom, to see just how much rusting has taken place. Even light surface rust in ring travel is unacceptable.

It's impossible to say how you need to proceed from there. It really seems like a simple question, but the truth is there is not a simple answer. If you see more rust that what your images show, then you have a really big problem. If not, then you might be able to touch hone the block and be in good shape. But that is assuming piston to wall clearance will allow you to touch-hone. If piston to wall is already at the wide side of things, then it might be time to regroup. Things are going to have to be measured, to know for sure.

If that block was honed for a cast ring, it looks to have some miles on it. If it was honed for a moly ring, then it might not have many miles on it, at all. The pictures provide some really good clues, but they cannot tell the entire story. The type of ring being used determines the honing finish the machinist will give you. With a chrome ring, you can nearly hone the block with a handful of gravel. I've seen people achieve really good cast ring seal with a 220 stone, although I don't advise it. With a moly-faced ring, honing becomes much more involved and time-consuming. Things like stone designs, stroke counts, load-meter numbers, honing oils suddenly become critical. And the skill of the machinist is even more critical. In the hands of someone who knows how to hone, diamond stones can be a magical thing. In the hands of someone who doesn't understand how they work, the cylinder walls can be trashed.

If you do touch-hone the block, be sure to buy a fresh set of top rings. Have your machinist advise the ring type you should purchase.

Where you are now, you've no way of knowing how much rusting you're really dealing with. And as the walls have pitted from the rusting, those pits have become irregular and sharp-edged voids in the walls. You might get a cast ring to live on that for a few thousand miles. If those are a moly-filled top ring, those sharp edges are going to rip the moly right off the face of the ring and you're going to be pumping oil within a few hundred miles.

Remember, that engine is naught but a hot air pump. The more hot air you can pump with it, the more power you are going to make. Which means piston ring seal and head gasket sealing are extremely important.

When in doubt...

 

[RPM]

I'd pull the other head, and pull the pan. That water in the pan is real concern even if it just caused the pan itself to rust, or has rust in the oil pump, or pick up. Check a few bearings, if all is good button it back up, and run it.

 

[Screaming Metal]

What Mike and RPM said! Also, magnaflux the heads and look closely to the waterjackets on the block, especially your freeze plugs. If all is OK, plug off your upper and lower radiator hoses, regulate airpressure down to about 20 PSI, air up the waterjacket, see if it holds pressure. Don't throw 20 psi to your radiator....

 

[Screaming Metal]

OK, I've had some sleep now. I've been here for years and usually I'm doing about 15 things at one time, trying to get things done on a schedule. Sorry for a not-so-clear answer....
As I said, you were given the best advice by Mike and RPM....but if you decide to start and use this motor, put some time into her and clear her up some. Like, look things over really good since you have the heads off, go ahead and put new gaskets everywhere and check things out Good.
After cleaning up your deck surfaces, degrease/pressure wash things, a vat is good.... but if you decide to button here up after checking the bearings and bores and valves....pressure check things to make sure no cracked water jackets, which I believe Ron was worried about.
No-one ever died because things were too clean during motor assembly.
Rust and pitting in the bores are a bad thing. I've known and seen guys that work in my shop, pull down a 350 Chevy or a 302 Ford, mic things, go grab a bottle hone or a glaze breaker, and go at it, wash it down and go back together with it.
I try and teach them you can't fix a pitted bore with such tools....I have a perfectly good Machine hone that can be loaded in a 1/2 " drill and has 4 stones, has 1/10th clicks on the top wheel. With this, you can get a bore straight, round and true. I also have a Sunnen honing machine for blocks.
As Mike said, it ain't good. Rust in the bores will mess up the rings, pistons, possibly develop cracks if close to thin water jackets....but its all in what you want.
If you spend a day cleaning things, and looking things over....that motor will have a happier life. I've seen one of my friends rebuild a 350 in under a hour, after vatting the block and heads. Thats with the valve job. The ole motor is in his old beat up pickup, drives it back and forth to work, runs good and he has under $500 in his rebuild. I'd say the rering kit which included gaskets, antifreeze, plugs and plugwires was all he had in it, and his time.
If you go this route, just pay attention to details....

 

[medic0079]

I think I'm going to rebuild it it's 150 difference between gasket set and complete overhaul kit. Machine shop will have to see it but that's ok do it once and done right..