Lots of carbon in cylinders??

[S10K5]

I bought this TBI 350 out of a '95 Tahoe to drop in my project. Owner said it was running when it was pulled (truck was wrecked). I figured I would inspect it before I dropped in in just for good measure. There are large amounts of carbon deposits on all of the piston heads and the valves. Also on the #2 cylinder there is a small amount of surface rust twards the top of the stroke.
My question is what could have caused the carbon build up in the cylinders, and what should I do about the rust?
Any info would be great!

 

[James670X]

Carbon build up can be caused by a number of things, engine running too rich, blowby, weak spark/no spark, leaking/cracked valve seals, etc, etc...., as far as the rust on the cylinder wall??? goes I would think honing it should clean it off.
If you want to remove carbon without tearing into the engine you can use GM combustion chamber cleaner.

 

[S10K5]

Can I get that at my local auto parts store or do I have to get it from the dealership? Also is that something I would use prior to assymbly or is it a fule additive type of product?


Thanks again for the help.

 

[Fierospeeder]

Top clean is a dealer item.

You can also buy Seafoam in a can. Find a vacuum hose and rev the motor up while you let the hose suck seafoam out of the can. This will make a lot of smoke out of your exhaust.

Seafoam is found mostly at small auto shops, and i do believe nappa carries it.

 

[James670X]

You can buy the GM combustion chamber stuff at any of your local auto parts stores or any GM dealership (at least you can up here in Canada anyways).
A person could use it one of two ways, either spray it down the throttle body or carb or you could soak your pistons, valves, etc.... and use it that way as well.