Bead blasted engine case question
 

Guys, I've been offered a dismantled 2.7 engine in lieu of cash and though the seller has sent pictures there is little clarity on some of them. I highly suspect the engine case has been bead blasted. The prior owner tore the motor down and did the cleaning, not the current owner.

I myself have seen three situations with other brands of engines which failed due to abrasive material stuck in crevasses even after aggressive washing. In one case they reused the block twice with all new rotating components each time yet succumbed to identical failures before tossing the entire motor and starting fresh.

For the above reasons should I avoid the case or have people been successful in blasting and cleaning?






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Although I expect that bead blasting is common practice.......I personally clean the case/parts by hand and never media blast the case or anything that will be internal to the case.......This is not as the result of any failures I've experienced, but it may be the reason i've experienced no failures..... i do not believe that you can clean all the media out of there...and abrasives and tightly toleranced engine bits don't mix well.

I hope that others will chime in with their experience.

regards,
al

Take the cash...
Bruce

Excellent advice,...........:)

Thank you for the qualified feedback, Al, Bruce, and Steve. respect your advice. Al, I've always been of the same opinion as you, no blasting of ANY internals, don't even want them in a blasting cabinet if doing the outside but some minor exceptions like small parts with no hidden areas, ie valve covers. Easy to scour the oil side afterwards.

Though I sound like I know better I still wanted others opinions since this is currently the only alternate to cash.

Engine cases and internals, I can see the reasons for not doing bead-blasting. But what about the external thermostat on a 1980 911SC? With the thermostat completely disassembled, there are no crevices or internal oil passages. Is it safe to bead blast and then clean well?

Real world question -- I get the car back from the painters in a couple of weeks and the thermostat is cleaned up, reassembled, and in a plastic bag awaiting reinstallation!

Brian

I don't see an issue as long as you scrubbed it out with soapy water and a tooth brush, rag.

Glass grit breaks down upon impact and to a small extent embeds itself on the surface of the soft aluminum. Aluminum looks clean after blasting when in fact all you see is a uniform surface, but it's actually contaminated with glass particulate.

On items similar to a T-stat housing I pack paper towel into ports then tape the heck out of them. Blow it off, remove the tape and packing then scrub the device out. You will see some grit stuck to the edge of tape residue. Brake clean or solvent... before washing. Simply be thorough.

Thanks Jim,

I didn't stuff the ports nor tape them off -- that is a good idea. I recall, during the cleanup (hot water, soap) that there were areas of grit embedded in the AL. The objective was to clean up the exterior, but I must have run the blaster down the ports because I found some grit there. I think I was thorough, but it will worry me forever. I think I'll take it apart and clean it again, in the name of thoroughness and longevity.

Brian

Soda blast only on blocks and cases. Rinse well with a pressure washer, no worries.

Update... I made the drive three hours each way to have a look at the parts and inspect the case. As it ends up the outside of the case has some silver spray paint on it though the inside was still coated with the factory black magnesium treatment. Everything looked good! P&C were smoked though.