IS THERE A COATING?

[Slow Ride]

Rebuilding 1999 Yamaha ox66 200. I cleaned these water jackets and other parts of motor with aluminumoxide blaster to remove 19 years of salt water corrosion. The areas that were not so badly corroded appeared to have a coating on the aluminum. I'm not sure if it was a coating or perhaps just a discoloration of the aluminum. Does anyone know if yamaha (or any other maker) has an internal coating and if so, what is it?

 

[Scott Danforth]

probably anodizing when the parts were first cast.

 

[robert graham]

Some of the manufacturers are starting to paint the interior cooling surfaces....more easily done at the factory before assembly.....

 

[Slow Ride]

Do you think it's a good idea to paint the inside of the cooling surfaces? Thinking of using a high heat engine paint but I'm concerned about having an effect on the ability to disipate heat. Do you think the paint would add a measurable amount of insulation that might insulate the heat into the motor?

 

[dingbat]

The green color point to an Aluminum chrome conversion process, i.e Iridite or Alodine

Provides corrison protection and enhanced adhesion of subsequent coatings such as paints and primers.

 

[dingbat]

Do you think it's a good idea to paint the inside of the cooling surfaces? Thinking of using a high heat engine paint but I'm concerned about having an effect on the ability to disipate heat. Do you think the paint would add a measurable amount of insulation that might insulate the heat into the motor?

What happens when a chip of paint comes off and gets stuck in a cooling passage?
If you want to do it right, strip the components and send the housing off to be stripped and iridited. Anything this else is a bandaid fix