Issue after sandblasting

[Figoulu]

Hi gents

I had my rocker arm cover sandblasted to make it nicer
The thing is that a lot of small pieces of sand are blocked inside the oil vapor compartment… (dark grey assembly underneath the cover)
Sure that sooner or later those thousands of small particules will gently flow inside the engine…

Now… what should I do ? I already cleaned it with under pressure water, but no way to eliminate all the small pieces of sand… cause the access is terrible
If I remove the entire compartment wall I will have holes on the top of the cover, and I’m not sure I can aesthetically change the little rivets…
Il f only remove the upper rivet, I would be able to bend the wall and probably have a better access to clean everything. I think I won’t be able to put new rivets… they are not going trough the cover

Any idea / suggestions?

[DaveB]

I would just keep going and going with the cleaning. Maybe not under pressure but filling the compartment then turning upside down and draining  through the breather hole. You probably already did that though..
That is quite a rough blast, it might collect more grime than the original finish.

[Kevkeller]

Someone else did the same and had a post on here how they took apart the cover to clean it.  Maybe you can find it by searching.

[teahead]

OH man, I wouldn't chance it.

Buy another valve cover and have it vapor or ICE blasted; NOT sandblasted!

[cabrioletturbo]

I would understand you blasting from outside, but from inside? I know it is too late now to talk about it, just for a next guy contemplating the same - don't do it.
Have you maybe considered another shot at blasting but with smaller granulate? As small as you can get?
If you have visual access to those clogged spots, can you pull them out mechanically (wooden or metal pick)? 
It also depends what granulate you used the first time. If it was something that it is not chemically inert, you may have a shot at dissolving the residue with an appropriate chemical. 

[Figoulu]

I would just keep going and going with the cleaning. Maybe not under pressure but filling the compartment then turning upside down and draining  through the breather hole. You probably already did that though..
That is quite a rough blast, it might collect more grime than the original finish.

Did it several times but the small particules of sand are really hard to get cause they are like pasted by I guess some oily residue… I sent a endoscopic camera to see that a significant quantity was still inside…

[Figoulu]

Someone else did the same and had a post on here how they took apart the cover to clean it.  Maybe you can find it by searching.

Good lead, thanks

[Benz Dr.]

None of those ideas are required. Take it to an automotive machine shop and have them put it into their parts cleaner ( cyclone ) and it will knock all of that crud out of there. Any other method is not effective compared to the relative ease of a parts cleaner. These machines use heat and a cleaning agent to degrease parts which is the real problem you have. The grit is sticking to all of that goo under the baffle and you can't wash it off.

[Figoulu]

OH man, I wouldn't chance it.

Buy another valve cover and have it vapor or ICE blasted; NOT sandblasted!

That’s a possibility yes… one is for sale for 70€.. might be the better solution

[Figoulu]

None of those ideas are required. Take it to an automotive machine shop and have them put it into their parts cleaner ( cyclone ) and it will knock all of that crud out of there. Any other method is not effective compared to the relative ease of a parts cleaner. These machines use heat and a cleaning agent to degrease parts which is the real problem you have. The grit is sticking to all of that goo under the baffle and you can't wash it off.

Thanks ! I will try first, I wanna keep my original (clean) cover 😅😅
I can double check afterward with my endoscopic camera if needs another round…

[Figoulu]

Someone else did the same and had a post on here how they took apart the cover to clean it.  Maybe you can find it by searching.

Found it : https://www.sl113.org/forums/index.php?topic=25653.msg183759#msg183759

[DaveB]

I would understand you blasting from outside, but from inside?

I'm sure the sand got in from outside, it wasn't blasted on the inside. That would be dumb
But yeah definitely something to remember not to do..

[DaveB]

None of those ideas are required. Take it to an automotive machine shop and have them put it into their parts cleaner ( cyclone ) and it will knock all of that crud out of there. Any other method is not effective compared to the relative ease of a parts cleaner. These machines use heat and a cleaning agent to degrease parts which is the real problem you have. The grit is sticking to all of that goo under the baffle and you can't wash it off.

Yep best 'solution'

[Figoulu]

I'm sure the sand got in from outside, it wasn't blasted on the inside. That would be dumb
But yeah definitely something to remember not to do..

Of course… no sandblasting inside, just sand going everywhere…

[BobH]

If you're satisfied with the finish on the outside then go ahead and get it cleaned inside, but the finish looks to me to be quite rough, and may attract dirt very quickly. it looks suitable for a painted finish, but not to leave bare.  I would take it to a specialist and see if a finer blast would give a smoother finish, before you start cleaning the inside.  May be more expensive then simply replacing it, but i'm all for preservation where possible

Bead blasting seems to be a good method, perhaps take a picture of the correct finish to a specialist and see if they can achieve the same look, have a look on here

https://www.sl113.org/forums/index.php?topic=1105.msg5428#msg5428

[rwmastel]

Some sand blasting v ice blasting videos.

How dry ice blasting works in auto. detailing https://youtu.be/iTilpcYBmM0

On iron & rust. https://youtu.be/ukDyKJW1_6g

On Porsche underbody and aluminum engine case. https://youtu.be/fHy_JpRI4lw

[Cees Klumper]

I would buy a good used one (€70 is not bad) and throw this one away, it doesn't look right with that coarse finish even if you would go through the trouble of taking the sand out.

[MikeSimon]

The proper way to do these parts now is to vapor blast. Sand- or any other media-blasting is too abrasive for surfaces that are not being painted or otherwise finish-treated afterwards. I had my valve cover, cylinder head, intake manifold and even the exhaust manifolds vapor blasted.

[Figoulu]

The proper way to do these parts now is to vapor blast. Sand- or any other media-blasting is too abrasive for surfaces that are not being painted or otherwise finish-treated afterwards. I had my valve cover, cylinder head, intake manifold and even the exhaust manifolds vapor blasted.

Vapor blasting or ice blasting are quiet attractive techniques... The thing is to find a good pro already equipped with those quiet expensive machines...

[stickandrudderman]

I would also strongly recommend you bin this part and get another one then have it vapour blasted.
You do not want even the tiniest bit of that sand getting into your engine.

[MikeSimon]

Vapor blasting or ice blasting are quiet attractive techniques... The thing is to find a good pro already equipped with those quiet expensive machines...

The process was relatively hard to find up until 5-8 years ago. No it is quite popular and many shops that do powder coating or surface blasting have the equipment. I have two places in my vicinity.

[mdsalemi]

The proper way to do these parts now is to vapor blast. Sand- or any other media-blasting is too abrasive for surfaces that are not being painted or otherwise finish-treated afterwards. I had my valve cover, cylinder head, intake manifold and even the exhaust manifolds vapor blasted.

I had not heard of vapor blasting before so I looked it up. From the places that do it that I found, most of which have a description of the process, it too uses an abrasive media albeit mixed with water, so it would not be an appropriate cleaning method if residual abrasive is going to be a concern.

I would probably suggest the dry ice blasting which leaves no residue of any kind; it just evaporates. More and more firms are doing this as the equipment cost is coming down.

Since this initial thread was started regarding a valve cover, wouldn't it have been prudent to simply block off the underside, plug the holes, and just do the top side? In any case the natural finish on the valve cover is not rough, but smooth. I don't know that any abrasive blasting of any kind would have been the proper protocol.

A good thorough cleaning of the outside could easily be done (once the valve cover is removed from the car that is) with degreasers followed by aluminum brighteners, to bring back that fresh-cast look.

[rwmastel]

I would probably suggest the dry ice blasting which leaves no residue of any kind; it just evaporates.

See my video links above!