I had some engine blocks cleaned in a big tumbler with zinc shot the other day. They came out looking really nice. This is the first time I had gone with the tumble process. A shop near me added the equipment so I gave it a try. This is a 1972 440 HP block. Looks really nice for being almost 50 years old.

Wow.........that is a big part to tumble.
It turned out really nice.
What is the $$ to have something like that done ?

Not sure I would call it a deburr process. What is up with that one driver side lifter bore.

Never mind on the lifter bore.

A large Reman facility down in Missouri used to tumble them, back in the 90’s.

Most everybody I know is using a Wheel-A-Brator now - more intense blast and does a much better job, gets inside nooks and crannies.

When you say tumbler, do you mean the block is loose and tumbles like a rock in a polisher or the method where the block is fixed in a jig and it turns and tilts while a steel shot paddle throws steel beads at high velocity and blasts it clean. My shop used one of those for years after they cooked ii in a big oven for 45 minutes. It came really clean. It was such a high maintenance piece of equipment, they got tired of fixing it when it broke.

The block is secured in a cage and turns in the shot blaster. My shop has offered this for years and the blocks come out looking freshly cast. Keep in mind the block needs a complete machining afterwards.

Yes, Best Machine did this for me with my 360 block about 20 years ago now. First they cook it then into the rotissory and bead blasted. They no longer do this. Make sure you get all the shot out of the block coolant passage ways thou. I must have had a lot left in mine and it chewed up water pumps for awhile. Just a heads up. The block comes out of the blast tank looking brand new.

Make sure you get all the shot out of the block coolant passage ways

YES, and the oil passages

The Wheel-A-Brator I mentioned does exactly that - picture a rotisserie inside a cage with shot being thrown as the part rotates.

Never had issue with blast media left in the engine - rifle brush the oil passages, run water through the coolant passages.

I always knock out the core plugs and remove the gallery plugs before getting a block blasted.

The machines I have used did nothing that required getting the block machined again, just honing the bores. I think it relates to the media being used.
I have seen some blocks with mild peening of machined surfaces.

Can’t see the advantage of this unless you want a pretty block. My concern would be getting the water jacket and oil galleries clean.

We have a big oven and cook them for a while, then put them in the shot blaster/tumbler....They look like new when done...

I would send the block out and have it "dipped" rather than blasted. When I say "dipped" I mean the same process for dipping bodies. This gets every bit of crud, rust etc. from every nook and cranny whereas the blaster can't possibly get into the water jackets. The dipping won't harm machined surfaces but by the same token, won't peen any casting flash either. I have sandblasted my own blocks a couple times. I made wood plates to cover machined surfaces and plugs for the lifter bores. What a PITA. Dipping would be the way to go. On a recent episode of Nick's Garage he sent out a Charger and a whole sh!tload of parts including a block.to the dipper. He was quite impressed with result.

I had a bead in my oil passage to the head so it was a good thing I checked.

Old school hot tank with caustic soda is 10x better at cleaning a block.

They charged me $150 for two blocks. These are both 440 HP blocks that I had sitting under the bench. Figured I'd get them cleaned up and ready to sell.

Thats not a bad price really since some shops charge 65 to bake and rinse a block and then its two more hours of self cleaning the oil passages.

What do they do if its say like a 70s smog gunked up pasty block, power wash it first or bake it? Cant see anyone putting a block with 5 lbs of sludge buildup in a tumbler.

Lifter valleys look great and could be painted/sealed without much prep.

Seems like a bargain.
I just spent 85.00 having a block and set of heads baked , and they came back cleaner than I expected.
I believe the EPA has some issues with the caustic soda soaking process.
I don't know anyone that does it anymore , but the problem was what to do with the residue inside the tank after doing a bunch of parts.
At the tech school I went to , they drained the tank , then shoveled the remaining goo into a 55 gallon drum.............this was early 80's and no one cared much how you got rid of the sludge.
Now , you could probably still do it , but the permits would not be cheap.

These blocks were hot tanked before they were tumbled. They came out of the hot tank fairly clean, but they had some surface rust which the tumbler took care of.

Exactly. The shop I used had to stop because they could not find anyway to legally get rid of the wasted vat chemicals. The EPA started coming in shops and fining people for even having it on the premises. They bought a Hugh oven that really cooks the parts and turns the gunk into powder. They used the shot machine after that. They cleaned the blocks really well and I always clean and brush every hole. I never had a problem. His shot machine kept breaking so now he sends them out to be blasted.