frost plugs

paul c · Post by **paul c** » Sat Jul 19, 2008 12:26 am

Any reasons why brass frost plugs cant be used in an alloy block, I am not a fan of steel ones but wasnt sure if brass would be compatible either due to corrosion or expansion rates?

RoverP6B · Post by **RoverP6B** » Sat Jul 19, 2008 12:47 am

I would imagine that there would be an unacceptable rate of galvanic corrosion between the brass plug and the aluminium block, especially so in the presence of an electrolyte.

Ron.

paul c · Post by **paul c** » Sat Jul 19, 2008 2:32 am

worse than steel ones, I think they are zinc or galv coated arent they?

kiwicar · Post by **kiwicar** » Sat Jul 19, 2008 6:55 am

Brass is an alloy of copper and Zinc, attached to ally the copper will come out of the brass quicker than the zinc (similar thing happens to the nickle in stainless steel fittings if you use bronze screws to fit them to a boat) net result they get micro perforations in the brass. They can be used however if you use alot of antifreeze in the water /antifreeze mix, still happens but it slows right down so the engine will have atleast 10 years life. I would make sure you put copper slip on all the steel bolts that go into the water jacket before fitting if you want to get them out again.
Mike