The Stovebolt Site Forums The Shop Area Engine Shop Surface rust in cylinder walls?

Looking at this here 350 eng.that sat over at my mother's garage for some 20 years all apart. It is .030" over but as I look at it closer the cylinder walls are rusted. It is really hard to tell how deep the rust is, what would be the best way to determine how deep the rust is and how far can you safely bore a 1969 350 chevy block?

Is the engine fully disassembled, or are only the heads off? I'd suggest a vigorous cleanup with a dingleberry hone and a variable speed 1/2" drill motor, followed by a thorough scrubbing with a stiff bristle scrub brush, dish washing liquid, and HOT water. Also check the cylinders for taper wear after they're cleaned up. The same procedure can be done with the pistons in the block- - - -it won't give the bottom of the cylinders as much cleaning, but if the engine's been siting that long it's going to need a full teardown and rebuild anyway. There's a tech tip on the site for checking cylinder taper with a used piston ring, a feeler gauge, and a calculator. Most 350s will handle 60 over, but ring life will be shorter than usual and you'll need a pretty good radiator. We ran +60 350's on the round tracks at 500+ HP for half a season or so. That's equivalent to several years of street time.

www.ebay.com/itm/276265232246?

Jerry

Here is the “Tech Tip” that Jerry is talking about. [LINK]

I had mentioned in my thread that the block was all apart meaning no crank, rods, pistons and cam.

Ol'55, if the block is a 2 bolt main and nothing real special as far as the serial number, you might not want to put much money into it, 350 engines are a dime a dozen. If it happens to be a 4 bolt block with high tin and high nickel content, you may want to build it but that would certainly warrant a good inspection. If the block, crankshaft, rods, and heads check out ok, you can probably put the engine together for less than $3000.

It is a 69' 4 bolt main out of a chevelle with a steel crankshaft.

I would take the whole thing to a good machine shop and have them check it out.

I hate wasting anything as much as any of you do but with these gen 1 350 four bolt motors, a fully machined and prepared bare .030 block can be had for like 1300. Sometimes the effort to deal with an old rusty but profoundly common block is just not worth the effort.

https://acceleratedraceparts.com/products/350?variant=43958242345114

I can build a complete short block for the same money, using parts and pieces I've stashed away for the past 50 years. I'm sitting on six- - - -count 'em- - - -4 bolt main bearing 350 blocks people have given me that can be honed and rebuilt, or maybe bored for the next oversize. Buying somebody else's junk for more than scrap iron price just never occurred to me.

That is because you can do your own work, lol! Me, I need access to a machine shop and truth be told, those are getting hard to find these days in some parts of the country.

For someone who does not have a local machine shop handy, might be stuck having to purchase a machined bare block. For a more than common 350 motor, I don't think it pays to try to salvage a block that is already .030 over, especially a rusty block. First you would have the shot blast cabinet charge to derust the block unless you are dunking it in evaoporust yourself. Then a mag to confirm no cracks. If it all checks out, pull the cam bearings, freeze and galley plugs and into the caustic bath and/or oven. Then the fun begins with all the nice machine work to square the decks, align the mains, bore, freeze plug and cam bearing purchase and install. As you know, machine shops charge for all of that. I have purchased a machined block in the past and it was not terrible. Its not nhra superstock level work but its not awful either. Kept a truck of mine on the road for quite a few years, even longer as it was still running when I sold it so, its an option.

The used block may not need all the fancy work if it checks ok as far as main alignment, deck accuracy, etc. The last small block I put together cost me about $3000, that included the stroker crank and lower end parts, I used the original truck 5.7 rods. Hypereutectic flat tops, and of course all new cam, lifters, chain and gears, oil pump, bla bla bla. I didn't build it for high RPM and intended it for a swap in my Vette that has 3.08 gears. I decided to keep the Vette stock so I have the 383 all wrapped up with all the ports capped/plugged/taped and sitting on the engine cradle. Someday I may use it, it wouldn't take much to put it in my '57 2 ton if needed.

What????? Doesn't everybody have 65 years' experience and $50K worth of machinery to play with? I can assure you I wasn't born with either of those things! I helped out with the rebore job on a flathead Ford V8 for my first car in 1962- - - - -been at it ever since!
LOL!
Jerry

Edit- - -just a suggestion on that stored 383- - - -drain the crankcase and store it upside down. The residual oil will creep past the piston rings and keep the combustion chambers wet- - - -no rusty cylinders that way. Loosen up all the rocker arms so all the valves stay closed. A salvage yard where I used to buy a lot of used engines stored them that way. The first few minutes of run time created an epic cloud of oil smoke!
Jerry

It still has the assembly lube on all the bearings, never filled it with oil. Once in a while I pull the spark plugs and shoot some marine fogging oil in the cylinders and turn it over by hand. I suppose I could loosen the rockers to relax the valve springs and close the valves.

Anywhere the engine stops, there are a few valves in the open position. Those are the cylinders that are prone to rust because of temperature change and humidity. I had to sleeve one cylinder of an otherwise zero-wear Oldsmobile 350 engine (less than 20K miles) after it sat for less than six months. The piston in that hole was rusted tight to the bore because of humidity- - - -and an open exhaust valve.
Jerry

Ya, but you have to know that up hear in the desert dry southern Michigan weather, we have no humidity, no mosquitos, tics, or deer flies, Hà ha. I feel pretty good about the storage environment, it's in my insulated pole barn with concrete floor, my tools very seldom sweat. I have all the ports, openings, and holes plugged or taped over and after the fogging oil I turn it over with a 1/2" rachet on the crank snout. It probably would be a wise thing to peep in the plug holes to look at the cylinders. I do appreciate your knowledge and advice.

Good points by others, but if you decide to bore it, yes you can go .060 over. .060 over on a 350 would be 4.060, and a small block 400 bore is 4.125, although the 400's suffered from overheating issues.

Casting is not the same from the 350 block to the 400 block, the 400 block has no water between the cylinders, the cylinder casting is siamesed or joined together, that is one of the reasons the cooling was more difficult. The 350 block should be cleaned and inspected and Magna-Fluxed to confirm its usability.

So how much would a guy have to spend these days on a Goodwrench new 350 crate motor?

LINK
$4700 from GM