Topic: car electronic rust protection question

[2wheels]

A question about those gismos they put on you car to electronically control rust.
Has anyone got an opinion on these?
Even better, has anyone who lives in a rust belt (winter weather with lots of salt on the road) have any experience?  More than 10 years old is preferred.

[HondaMan]

They were popular [to sell] in the 1960s and 1970s. The general idea behind them was to offset the [slight] electrical covalence that salts can cause on the surface of steel by adding an electrical current to it. But, it is up to you to then figure out which polarity to use: for example, where steel bolts against aluminum, the steel has the higher voltage on it as compared to the aluminum when corrosion happens, so the (-) terminal must then be applied to that structure.

Mostly (back then) it just made the car battery go dead when the car was parked a lot. The cars just rusted somewhere else!

[2wheels]

Right.  The rust just finds a spot on the car that is not protected.
Recently my daughter in law bought a 2 year old Toyota from the dealer.  To get the extended warranty they forced her to put one of these gismos on.
Just a money grab by the dealer.  I think.

[seanbarney41]

When I was much younger my dad used a 1949 Ford to haul pianos for his restoration business.  It had the flathead v8 and the associated positive ground 6 volt electrical system.  This was in the 1980's and the big old F6 was still damn solid and most everything else in Michigan from the 50's, 60's and 70's had rusted into oblivion.  My Dad believed it was the positive ground electrical system that kept it intact.

[2wheels]

Interesting Sean.
I vaguely remember other cars had the positive connected to the chassis.  Am I right?

[seanbarney41]

I am sure there were some others...but that '49 Ford is the only one I have personal experience with.  Interesting idea, yes.  Whether there is any science to it?, I don't know.  My dad is rather famous for exageration!

[HondaMan]

When I was much younger my dad used a 1949 Ford to haul pianos for his restoration business.  It had the flathead v8 and the associated positive ground 6 volt electrical system.  This was in the 1980's and the big old F6 was still damn solid and most everything else in Michigan from the 50's, 60's and 70's had rusted into oblivion.  My Dad believed it was the positive ground electrical system that kept it intact.

Now, there's an 'angle' I never heard before! I do know those old trucks lasted forever, though.
Come to think of it, I've never seen WHY the negative ground system was adopted in the end. Might have to research that one, hmm...

[dave500]

old british cars into the 60s are pos ground,it was changed as the neg ground was thought to better handle that rust issue?

[Tim2005]

It's difficult to compare, the underbody sealant on old brit cars was pretty poor or minimal, but on the other hand the metal was much thicker than today's cars.

Another similar approach for rust prevention is attaching some pieces of magnesium or certain other metals, sacrificial corrosion, presumably this works (or doesn't) in a similar way to these gadgets

[dave500]

these days basic metal prep is so much better aswell ?

[BenelliSEI]

these days basic metal prep is so much better aswell ?

......some of the old stuff was pretty good too, at 0.250” thick!

[Stev-o]

I am sure there were some others...but that '49 Ford is the only one I have personal experience with.  Interesting idea, yes.  Whether there is any science to it?, I don't know.  My dad is rather famous for exageration!

Apparently there is some science to it. Dont think your Dad was BS'ing on this one!

"The advantages of positive ground lie mainly in the sacrificial anode being the vehicle itself. A few grams of lost iron is less devastating than the loss (or corrosion) of the brass or copper connections in the vehicle."