Glass Bead Blasting a Twink Head

[JonnyPlus2]

Hi All,
Dave Bean (California Elan supremo) recommends NOT bead blasting one's head (or the car's for that matter) because the beads tend to get stuck in the alloy, only to come out later and get into the engine. I can see that if this happens, when the beads break up it will be approximately like sand in the sump.

My machine shop guy (well known as a Formula Ford builder) says that glass bead blasting should be OK, "we've done it to Jaguars with no problems".

Has anyone had any experiences with bead blasting, good or bad. On the other hand, what would you recommend to clean the crud off the face of the head, chambers and ports ? Thanks.

Best Regards,
Jonny

[512BB]

Common sense tells me that blasting almost any media at an alloy or ali head is a no no. Think about it. What is harder? Glass, which is quartz, or the head. Obviously, the glass. So it stands to reason, that blasting glass beads at a head, some will stick, no? And when will those beads drop off? When the head gets hot, and into the oil!!!!!!!! Not on my rebuilds, thank you.

There might be other media that is safe to use on an ali head, but the only safe way to clean one properly, is either vapour blasting, or chemical cleaning, and you have to be careful with that. I am sure others will have an opinion.

Leslie

[cliveyboy]

Blasting with grit or glass beads is not a good idea the beads will tend to embed into the aluminium and take a lot of cleaning to get them out. Also too many crevices for the beads to build up in and there is no real way of checking internally that you have removed it all.
Are you sure your engine builder was talking about blasting internally with beads or grit.
You can blast internally with certain mediums. One type is made up of crushed walnut shells (or equiv). The idea being that any residue left over will break down and dissolve. Although too much left over will sludge up and block oil ways etc.
Best advice is avoid blasting internally when ever possible.
Clive

[rgh0]

My engine shop only soda blasts alloy heads to remove built up carbon.

cheers
Rohan

[CBUEB1771]

When I was young and stupid I let the owner of a well known shop talk me into glass beading the head from my +2. The result was two ruined cams and a set of followers.

[JonnyPlus2]

Hi All,

Thanks for this. I am really glad I asked.

Since I am going to get the body shell soda blasted to remove all the various colours (white, red, black) I'll have him do the heads as well. Thanks again.

Best Regards,
Jonny

[rgh0]

The shop only soda blasts the ports and combustion bowls. When doing the bowls it masks off the rest of the head face surface with an old head gasket to avoid affecting the surface finsh on the face. The rest of the head it cleans by hot tank cleaning with alloy suitable chemical solutions. I normal clean the combustion bowls and the rest by hand with degreaser and bush and just get them to do the port cleaning which are hard to clean by hand.

regards
Rohan

[RichardHawkins]

Blast cleaning is potentially tricky. There is a large range of media and systems available. I expect it can be done successfully, but basically I agree with the other people who advise against. Blast cleaning is usually horrible filthy rough work, and most blast cleaners are inclined to be rough. I have seen blast cleaning successfully used on gas turbines, and aircraft structures. There are proprietary cleaning liquids that will remove carbon and paint from a head, I purchased from The Walsall Chemical Co, and have not risked blast cleaning.

Richard Hawkins

[JonnyPlus2]

One of my heads has a fair amount of crud on the face. I suspect that I shall have to have a blond one taken off the face after it is soda blasted. Does this sound like a reasonable plan ?

The ports are also pretty filthy although the bowls are not too shabby.

Best.,
Jonny

[rgh0]

The crud on the face should come off with gasket stripper and careful use of a plastic scraper to avoid damaging the surface. Once its cleaned you may need to take a small cut to restore the surface finish if its needed depending on the corrossion or other damage you find.

cheers
Rohan