should i be worried about the marks on the housings? are the housings usable?

 

First, those coolant passages look NASTY! Hope the irons are good and not too rusty!

Those dark points are where the apex seal lifted and left a carbon deposit behind. The surface of the housing may not be 100% flat any more. It most likely would be a good candidate for refinishing, I know there are a few shops out there that can clean and refinish rotor housings for a reasonable price (Goopy I think is one).

As it stands, it would definitely work, but you may not have as good power and compression. But, you could definitely use it.

Dale

 

Take a look at the picture below, I've circled in red an area that looks like the coolant passage wall has rusted through to the O-ring groove. If that is the case don't use the housing.

 

due to his location, i think it is far from worthwhile to pay the ungodly shipping charges overseas for a refinishing job. better to find a good used housing and pay for shipping only one way and port to match the old one.