Engine Aluminum Oxidation - How to Clean

[chesnut]

My 1992 ZR-1 engine is showing some black spots.

Is this oxidation?

How to clean without tarnishing?

Thanks in advance for your all's help.

Gary
....:flag:

[secondchance]

Looks more like original paint degradation. Over the years, many owners tried various methods with varying levels of limited success.
Most of us eventually had the intake plenum, injector housing, throttle body and the cam covers repainted, powder coated or stripped and polished.

[WARP TEN]

Yun may be correct that the paint is shot but there also have been quite a few posts over the years on how to clean an engine without permanently damaging the finish. So Search could be your friend. But be careful, as using strong solvents will definitely give you much darker paint. The original engine paint does not respond well to many cleaning solutions.--Bob