How often should you remove the access plate?

[msauntry]

How often should the side access plate be removed for cleaning?

I took mine off in 2007 and blasted a lot of stuff from around the cylinders. There was a fine black sediment that settled in the bottom (Chesapeake mud?) as well as a lot of brittle red "flakes" that look like rusted metal. Most had a curved surface, so I'm thinking they're from the cylinder walls or engine block internal surfaces.

I took the plate off again in 2008 and noticed a lot of the same stuff in there. Is there a recommendation for how often this should be cleaned out?

Anecdotal evidence shows that some people get a lot of black junk out of their engines with the first few moments of an acid flush, but I'm doubting that it'll break up the rust flakes.

Is there anyone that's been doing regular acid flushes and still found flakes when they remove the access plate?

[Kurt]

I actually do at least one acid flush and a couple of vinegar flushes annually on my engine. I just removed my water jacket side plate last week right after doing an acid flush and found metal flakes as well as black muck. I'm in San Diego, CA and lots of salt crystals were also accumulated around outside edge of the side plate. I am in the process of doing a conversion to fresh water cooling so I don't have to keep doing these flushes and to hopefully prolong the life of the motor. So, my experience would tell me that acid flushes don't doing anything with the flakes in the block. They are effective in breaking up deposits in the cooling passages, but will also not get rid of that mysterious black muck, which is not composed of hard deposits in need of breaking up. The only thing I have found that is more effective in getting some of that muck out of there is a power flush of the block and manifold using plumbing adapters screwed into the block and then manifold drains (I use the kit from Moyer).