Hi has anybody got any experiance on repairing small areas of pitting on alloy engine casings?

Thanks.

Are they too deep to be media blasted?

If they are going to be painted you could try a liquid metal and then a dremel to sand them flat.

Yes quite deep pits, it looks like the casing had a weld repair along time ago, but I've only just noticed it after having the casings blasted, I may have to consider re painting them or try and find replacements on Ebay.