Topic: Assembling an engine after vapour blasting

[drumstyx]

As I get ready to get my head back from MRieck, I'm checking over the loose bottom end assembly I've done, and I just wanted to ease my paranoia about something...

So I had everything vapour blasted when it was apart, then after getting them back, I soaked the parts in hot water as recommended (to loosen anything stuck to oil in the passageways) and then took my pressure washer to each piece (most concerned about the cases) flushing out the passages from every which way for many minutes.

But I noticed, as I was threading some things in, that blind threaded holes still had some grittiness to them. Now, in fairness, I didn't pay special attention to those holes, since I was focusing on the oil passages, but it made me wonder if there are just perpetually glass beads that I can't get at. And that makes me paranoid.

Did I not do enough? What did you folks that got your cases blasted do?

[grcamna2]

bump

[Steve_K]

I glass bead blasted my fork lowers after I taped all openings.  I used solvents and a brush.  Still dirty.  Hot water and soap three more times and THEN I was sure it was clean inside.  On engines,  I would not be comfortable with out a lot of cleaning.  That said,  I am not familiar with vapor blasting.  The glass beads and oil seem to stick together very well.
Good luck cleaning.
BTW,  I do like how the cases look after glass bead blasting.
Steve

[PeWe]

Cases still open?
Soak cases with nafta to remove all old oil with eventual parts in it. Acetone might be too tough for eventual rubber o-rings sealing some oil passage ends.
I use dishwasher powder (for machine wash) in hot water when cleaning my cases. Last time with transmission still in it. Nafta used before to remove most of the oil. I guess the cases were clean before blasting them

The blind threaded holes have no contact with the engine inner life and oil flow. Some of the threads for cylinder studs are going all the way thru.

Soda will not blast enough?
No worries about sharp stuff inside if a soda will be lest in smaller amound. Water will solve it.

I had worries of too long 6mm case bolt that might have cracked the inside the blind hole. Especially one close to the front sprocket, bolt will end up very close to a gear in transmission. I became cool after check of the little bit too long bolt and found its thread covered by old oil. That thread was open before, no popping this time with alu parts from case inside. Not fun to get when cases are mounted, tightned and sealed with Permatex Aviation stuff.
I have an set of extra cases where the inside of a blind hole is cracked (bottom broken) by a most likely too long bolt.
This is a must to worry about, check the total depth of the threaded hole before monting and tighten the bolt.

[pjlogue]

Any oil film, however thin, attracts the glass beads like a magnet.  I used a hot phosphate detergent to clean the engine parts I vapor blasted.  I then got a few cans of carb cleaner and stuck the tube down any threaded holes and gave a good blast followed by an air blast (thin tube attached to the air gun to get to the bottom of the hole)  Run a tap down the threaded holes while carb cleaner is in them and air blast them.  Oil galleys I used a set of brass gun cleaning brushes and carb cleaner followed by compressed air. 

Be sure to blow compressed air using a tube to reach the bottom of blind holes.  If you have any junk/fluid down the hole you can hydraulically strip the threads.   Even with all the effort I did I still had a few thread holes that felt gritty.  If you feel any gritty threads stop and re-clean them.  I also ran the engine the first time for a short while and then changed the oil and filter. 

-P.