rusted engine blocks

[BTR69]

Good evening. I just became the owner of 2 old sbc blocks, (freebies). one has crank, rods and pistons still. They've been outside for a few years and look like good candidates for boat anchors. I'm curious if it would be worth a try, to clean them up and possibly use them. What would be the best somewhat low buck way to try to clean them up? Thanks.

[Tony Corley]

There was a time that I used to read about guys purposely leaving blocks outside to rust to "condition" them before they would completely clean and machine them. I have no idea if it actually made a difference or not. As far as cleaning and machining, I would think a shot blast cleaning oven would take care of all of the rust, and then just a matter of doing the machine work. Obviously, if the rust really got to it, you will probably be machining mains, cam journals, lifter bores, along with cylinders and decks, but if it's an all out race piece, you should be doing that anyway. Otherwise, it may be more cost effective to start with a non rusted block.

[Alan Roehrich]

In an open area, with plenty of ventilation, and away from everything else, you can use muriatic acid, commonly found at hardware stores, known as "brick acid" to remove the rust. Apply with a paint brush, wearing gloves and goggles. It WILL eat clothes and shoes.The vapors are hazardous, wear a mask, and they will rust exposed ferrous material. You must immediately flush the parts with water, and you must dry them and use something to prevent them from rusting again. It will even clean the water jackets.

[BTR69]

Originally Posted by Alan Roehrich

In an open area, with plenty of ventilation, and away from everything else, you can use muriatic acid, commonly found at hardware stores, known as "brick acid" to remove the rust. Apply with a paint brush, wearing gloves and goggles. It WILL eat clothes and shoes.The vapors are hazardous, wear a mask, and they will rust exposed ferrous material. You must immediately flush the parts with water, and you must dry them and use something to prevent them from rusting again. It will even clean the water jackets.

Thanks. Looks like I have a plan for a project for next weekend.

[Glenn Briglio]

Better and cheaper to buy a brand new block!

[Steve Stasko]

Originally Posted by Tony Corley

There was a time that I used to read about guys purposely leaving blocks outside to rust to "condition" them before they would completely clean and machine them. I have no idea if it actually made a difference or not.

Petty Enterprises used to do this.

That being said...I agree with Glenn.

[Mike Taylor 3601]

Originally Posted by Tony Corley

There was a time that I used to read about guys purposely leaving blocks outside to rust to "condition" them before they would completely clean and machine them. I have no idea if it actually made a difference or not. As far as cleaning and machining, I would think a shot blast cleaning oven would take care of all of the rust, and then just a matter of doing the machine work. Obviously, if the rust really got to it, you will probably be machining mains, cam journals, lifter bores, along with cylinders and decks, but if it's an all out race piece, you should be doing that anyway. Otherwise, it may be more cost effective to start with a non rusted block.

I hear people talking about seasoning blocks, by letting them rust or even burying them for a year or two, that comes from back in magazine engine build days they would say the engine builder would start with a well-seasoned block, that means a used block, ran thousands of miles, ran through heat cycles of everyday use and somehow people not knowing any better turned that into the same process as seasoning wood/lumber leaving them outside or burying them.
letting a block rust serves no purpose that improves anything, that comes from ignorance, not an insult, ignorance by its definition. When I read ND ads at about 7 years old and it listed a car with strange axles, I thought it meant some kind of strange axles, IDK it was a brand of axle...I was ignorant, now I'm just dumb LOL

To season an engine block, you run it 100K miles, the heating, cooling "seasons" the block stress relieves the metal and settles, shifts and then when it is machined after that it doesn't shift and move, settle as much or you do some method of vibratory or cryogenic stress relief.
If you plan on using rusted up block, take it and have it thermal cleaned at machine shop,baked,blasted and tumbled then magnafluxed. the correct shot(.020 or smaller) will not damage anything

[Dwight Southerland]

Relevant and interesting story. When I was constructing my '67 Z28 in 1979, I came across two identical '68 small journal 327 blocks that were removed from city dumptrucks. (These blocks were unique in that they had fully machined crank bulkheads and used longer main cap bolts like on 350 4-bolt blocks.) Having heard about Grumpy "curing" blocks by burying them, I decided to give it a try. I first had both blocks Brinnell tested on the deck surface and the pan rail. I stored one in the corner of my heated shop and the other I buried under the frost line behind the shop. In the spring after the chassis work was done and the body had been prepped and painted, I dug up the "cured" block and had both of them tested again. The "cured" block was indeed 4 points harder than the "uncured" block. What was surprising to me was that both blocks had been run 75K miles in dumptrucks before I got them!

[Tony Corley]

Originally Posted by Mike Taylor 3601

I hear people talking about seasoning blocks, by letting them rust or even burying them for a year or two, that comes from back in magazine engine build days they would say the engine builder would start with a well-seasoned block, that means a used block, ran thousands of miles, ran through heat cycles of everyday use and somehow people not knowing any better turned that into the same process as seasoning wood/lumber leaving them outside or burying them.
letting a block rust serves no purpose that improves anything, that comes from ignorance, not an insult, ignorance by its definition. When I read ND ads at about 7 years old and it listed a car with strange axles, I thought it meant some kind of strange axles, IDK it was a brand of axle...I was ignorant, now I'm just dumb LOL

To season an engine block, you run it 100K miles, the heating, cooling "seasons" the block stress relieves the metal and settles, shifts and then when it is machined after that it doesn't shift and move, settle as much or you do some method of vibratory or cryogenic stress relief.
If you plan on using rusted up block, take it and have it thermal cleaned at machine shop,baked,blasted and tumbled then magnafluxed. the correct shot(.020 or smaller) will not damage anything

Was just simply stating what I used to hear, decades ago. It never made any sense to me, and I also never tried it. But there were some well known names that did it. And after reading Dwight's post, maybe there was something too it.....

[Alan Roehrich]

Dan Dvorak used to "loan out" engines to commercial use.


Kubota once allowed their castings to sit for a year before machining.


I can tell you that the ovens people use to clean parts will make cast iron as soft as the day it was cast, and it will "move" significantly.


For some people, a new block is no option at all, and for others it is at best an extremely expensive option.


Y'all take the free advice and information for what it is worth.