How do they get blocks this clean!
 

As part of 4 previous engine builds, I used different machine shops for each. Each shop vatted the block and they all cleaned up fine. All of the blocks wound up with some traces/patches of rust staining on the outside. I’m not talking about flash rust that appeared on the block days after picking it up from the shop. This stuff was already there the day I picked these blocks up, so it appeared to be surface rust that was on the block but did not get removed by whatever method the shop used. Now, I compare my experience to what I see in every engine rebuild article in every car magazine I’ve ever seen. All the blocks in these articles are spotlessly clean and look like virgin cast iron. How is this look achieved? Shot peening? Some other product/process?

In the past I've had them put in a tumbler for lack of a better word, I think it used steel BB's and came out brand new. There is a name for the process that escapes me at the moment, someone will know.

Shot blasting

steel abrading............the use of small steel balls to clean the cast iron with friction.

Thermal cleaner.... Heats the parts up and pelts it with steel shot.

Well there ya go, all kinds of names for it :D

If you wanted to do it yourself at home, get your 12 GA shotgun and a couple of cases of #4 steel shot! OH.......and a 6 pack of your favorite beer.

Uh, I don’t think so…

Lol... Not really. Tumbling is usually done with an abrasive material rotating in a drum, usually used for cleaning valves. Shot blasting is similar to shot peening but not controlled and won't remove grease, works great for cleaning rusty cranks and cast rods. Steel abrating is one of my favorite but won't work well on an oily block, the best process I've found for cleaning rusty parts like exhaust manifolds. Thermal cleaning heats up the block and is the only process mentioned that will remove rust, corrosion and sludge.... In short

Just trying to be informative.

I can tell you how a guy I know tried to shoot a cast iron frying pan with a 12 gauge.

That didn't work out so well. I think beer was involved with that one too :D

Seen the new Laser rust cleaning??? Prob not used on blocks, most are bathed, then put into a shot blasting cabinet with steel BB's. But man, the new Lase tech is wicked!

Tie a rope between 2 trees, then hang the pan off rope off that. Then got a nice game of plinky plinky with the .22!!! Or 50cal black powder!! That's more fun. Yes, there are some in Canada who LOVE shooting too

:thumbup: It was an added process I've had done in the past that I do remember involved steel shot. It was also tanked with chemicals and all the other usual stuff. I just can't remember what he called it and I haven't had it done in a while. I really like how the block looks when it's finished.

It started with "hold my beer" He propped it up with a rock, point blank, and ended up with dozens of shot imbedded in his skin pretty much from his shoulders to his feet. :pound:

Ummm OUCH!! and Ya, point blank. Kinda says whats gona happen

Not one of his best moments, funny looking back though.

The thermal cleaning equipment my school uses was purchased in 1998. So it's 24 years old and has cleaned several thousand blocks, heads, sheet metal and crankshafts. Minimal maintenance, reliable equipment. Our system has a slow rotating drum that the parts are fastened into. Iron and steel like crankshafts are baked in the oven at 600-625 degrees F for an hour. Aluminum blocks, 275-300 degrees F. Overhead cam aluminum heads can't be baked. Ruins the cam bearing journals and tiny shot gets caught in all the teeny, tiny passages. Ultrasonic cleaner is the best we can do with that stuff. From oven, directly into the blaster/tumbler. Ours uses .030" chopped stainless steel wire. It works great but you MUST get all the tiny wire shot out of the castings and all the passages. Looks like new metal when it comes out. The crud and sludge acts as fuel in the oven. The dirtier they go in, the cleaner they come out. All machined surfaces need to be restored when the castings come out of the oven. So every block cleaned this way MUST be line honed, surfaced and cylinders honed. Crankshafts also must be ground undersize if cleaned in our system.

The process per Post #17 is fantastic, making the old Pontiac castings look real good.

It is certainly a less aggressive process than the Kolene process we used. I have scars on my arms and hands from Kolene residue. The mineral salts used in the Kolene process are caustic.

Nah, chopped wire has sharp edges, which requires more machining, especially an Aling hone, which should be avoided. Steel shot is round, and blocks don't require the extra machine work. So method similar, Media is Not.