Protection of galvanization. Old vs new.

[livi]

The SC and Carrera are galvanized and should offer a pretty good protection against corrosion. At least if not damaged. And at least when new.

At one time I had a Toyota Corolla ´89. I got lazy with the washing and that car just fell apart from rust attacks in less than three years.

My question: How did the galv. process and quality of our 20 + years old cars compare to newer cars. I would speculate that the anti rust protection were improved over the years but my own experience seems to point to the opposite.

Further I have read several testimonies, not least from England, of owners using they old Porsche´s as daily drivers with no rust what so ever.

Is this all anecdotal or is there a general truth somewhere ?

[turborat]

I would venture to say that rust protection improvements have more to do with materials used and the build quality of cars as opposed to galvanizing process itself.

If moisture is allowed to penetrate the internal cavities of a car, corrosion will eventually dissipate the sacrificial zinc coating on the steel and begin to rust the steel out. Newer cars seem to be built better in these areas using plastics instead of dissimilar metals, and either sealing hidden areas of their chassis or designing them to drain water more efficiently.

[wholberg]

In the late '70's, US cars became much more rust resistant with the widespread adoption of hot dip galvanizing my the major auto manufacturers. Galvanizing is a sacrificial protectant. It oxidizes more slowly than steel, so it protects the steel from rust as long as it is there. A thicker galvanized coating lasts longer than a thin one, so my guess is that your Toyota Corolla had a thin coat of galvanizing, either intentionally or accidentally. Even with older non-galvanized cars, if you can prevent water from pooling under gaskets and trim and rinse salt off before it eats through the paint or undercoating, theoretically the car should never rust (much more difficult in practice, though).

[blucille]

and my question is, if I buy a new fender or door skin from the factory for an early 911, is the new piece galvanized???

-Lewis

[Dan in Pasadena]

Originally posted by livi
The SC and Carrera are galvanized....

Actually, fully galvanized bodies from Porsche began with Mid Year cars in 1976.

There was some earlier use of galvanization but I am not certain the years/parts. Others with more knowledge will probaby post.

[livi]

On the other hand I have driven my Grand Cherokee every day threw six winters with only sporadic washing - no rust what so ever.

There ya go - American quality!