Split my block and found some small spots of discoloration on one of the main journals. What are these?(It's not grease) Something to worry about? Please don't say it involves milling. Thanks

Discoloration is oxidation. Once it starts it will continue.

So is this block junk or can I squeeze another couple hundred thousand out of it? Thanks.

Its questionalbe. Do what you feel is right, and you will never go wrong. I think that Emily will have the right answer tho...from CCR.

You need to put the case back together, without the crank or bearings or anything in there. Torque all the bolts to spec. leave the heads off. Take it to a machine shop and have them measue all of the main bearing bores in three places each. If this measurement is off, the case will need to be line-bored. In the case of subaru, porsche, and VW, you need to check the availibility of oversize "line-bore bearings", due to the engine's construction, the only way to be able to align-bore the block is to supply special bearings that are oversized in their outer diameter. Find these before any machine work takes place.

 

It looks to me like hot spots from main bearing movement, or loss of bearing crush. You NEED to have it measured before you spend any money on it.

Its not corrosion if its on the main journal surface, its aluminum and won't rust it will corrode a bit but thats only places that are not exposed to oil, its a hot spot, thats not good but its not particularly bad either, call emily at ccr and she'll help you out, they are cheaper than trying to rebuild it yourself