corrosion around aluminum motor plate coolant holes
 

Racers,

any suggestions to limit this corrosion?

Re: corrosion around aluminum motor plate coolant holes
 

It appears you are experiencing Electrolysis.

1. Use distilled water, not drinking or tap water.

2. Check the grounding of the engine to chassis and chassis to battery.

3. Add some Royal Purple - Purple Ice to the distilled water.

4. You can also have the plate anodized.

Re: corrosion around aluminum motor plate coolant holes
 

Back in my flathead days, anti-freeze was the answer.

Re: corrosion around aluminum motor plate coolant holes
 

Adding a zinc anode in a radiator bung used to be SOP when aluminum cooling system components were used in a cast iron engine environment. Adequate engine grounding is a must. As long as the water is potable (clean tap water quality) and the ph is around 7.0 we never found it necessary to use distilled water to prevent electrolysis.

Re: corrosion around aluminum motor plate coolant holes
 

I see it occasionally on cars in the shop. Usually can be traced to no or inadequate engine grounding. the motor plate should have a ground also.
A little cooling system conditioner dosent hurt either , helps with the Ph level.

Re: corrosion around aluminum motor plate coolant holes
 

Hi Guys,

Just my 2 cents..................

Zinc plates have been welded to the hulls of ships to prevent damage to the steel hull and brass screws by galvanic reaction.....

The more active metal is sacrificed to protect the less active.....

Zinc is a less active metal and unable to protect aluminum....

To prevent galvanic damage to aluminum a magnesium anode should be used....

For additional info I will post a link speaks to galvanic action...

http://www.performancemetals.com/anodes/AnodeFAQs.shtml

Bob