rusted engine blocks
 

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.

Re: rusted engine blocks
 

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.

Re: rusted engine blocks
 

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.

Re: rusted engine blocks
 

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

Re: rusted engine blocks
 

Better and cheaper to buy a brand new block!

Re: rusted engine blocks
 

Petty Enterprises used to do this.

That being said...I agree with Glenn.

Re: rusted engine blocks
 

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

Re: rusted engine blocks
 

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!

Re: rusted engine blocks
 

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.....

Re: rusted engine blocks
 

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.

Re: rusted engine blocks
 

Thanks again for the info y'all. I'm much more optimistic that they're useable now. Hopefully I'll get to spend some time with these soon. I'll try to take the time to document everything.

Re: rusted engine blocks
 

What about media blasting?

Re: rusted engine blocks
 

Have seen many (youtube videos), of people doing plastic drum anode electrolysis on rusted blocks and other cast iron parts/pcs. (You would need/ o watch a few vids to get the chemical and electrical choices that they use, but I have seen amazing results (the water and chemicals they use may be a hazardous materials issue later as the drum is usually pretty mucked up once the process is completed). Have seen them use Welding machines to battery chargers for the DC current as it flat boils the rust away.

Then maybe an immediate hot tanking and bead blasting & then full machining at a machine shop), as soon as it is
removed from the drum. Torch all exterior surfaces w/ Propane or Map gas torch to remove (quickly cook away all grease and oil on exterior surfaces after that, mask and paint ASAP after short block assembly). Personally I like Dupli-Color Engine or Caliper Enamel with ceramic as it withstands up to 500 degree temps and oil and other fluids, resists chipping due to the added
ceramic.

Have seen some pretty rusted cast iron blocks, pans (as in cookware), look like new once done. Just make sure you do it outside in open air as it creates an acid during the process.

Re: rusted engine blocks
 

https://youtube.com/shorts/h_rXSqb_w...IxYM21m4f7DhWc

Pickling...or an acid dip of entire rusted block in HCL Acid really does the job. Looks like new and is pretty fast in comparison to the above method I called out using DC electricity.

Re: rusted engine blocks
 

Check out Dave's auto center on facebook they specialize in diesel engines. They put rusty blocks, heads in a machine and it shoots stainless pelets at the rusty part, comes out like new! Luke

Re: rusted engine blocks
 

Another great Tech thread with a special shout out to Dwight, Steve and Alan.

Petty Enterprises rough bored wedge blocks are legendary. A very close friend had one, regrets not using it in his Max Wedge car, however sold it for largese.

We don't know if it was was exhumed from their cylinder block cemetery though. LOL!

Too cool!

PS; Cast Iron intakes and cylinder heads included in this "dirt nap" process?

Re: rusted engine blocks
 

Could you share the brinell readings.

Re: rusted engine blocks
 

One of the main problems with the rusted blocks is the degradation of the threads in the block, Especially the head and main bolt threads. Corrosion eats away at the threads then they pull out when the proper torque is applied. I would shy away from a severely corroded block for this reason. Blasting and chemical cleaning only removes more metal making the problem worse.