Aussieveedubbers - Powered by GaiaBB

stainless steel and radiators

subawee - January 10th, 2007 at 05:03 PM

Hi All,
I seem to remember a post about using different types of tubing to hook up a radiator but can't seen to find it.
Maybe it was on Baja wes's site (can't remember)
Anyway I used stainless steel tubing and have been very pleased with the outcome. Anyone had any problems when useing this material?
thanks,
Bob J.:alien

[ Edited on 1-10-07 by subawee ]

MickH - January 10th, 2007 at 07:55 PM

Custom Offroad did mine in stainless...a bit over the top...but woteva makes them happy. Was well done.

[ Edited on 10-1-07 by Mick H ]

Baja Wes - January 13th, 2007 at 02:19 PM

It was here;
http://forums.aussieveedubbers.com/viewtopic.php?tid=29154&page=4#pid255297

Quote:

Originally posted by Baja Wes
I mentioned that in the 10+page EJ20 post

Quote:

Stainless steel itself is a noble metal, as it it doesn't like to corrode. That simply makes it a fantastic cathode. It therefore tries to use other metals as an anode. This is galvanic corrosion.

There is a thing called a galvanic series. surf the net and you will find it.

The further two metals are apart in the series, the worse they will react with each other in the presence of an electrolite. Stainless steel and aluminium are further apart than steel and aluminium.

So stainless steel radiator pipes will try to corrode your aluminium engine. This will happen if your aluminium engine and stainless pipes have a common earth, and your not using the most expensive radiator fluid you can buy.

I have rubber mounted my stainless radiator pipes from touching anything but the rubber radiator hoses (they don't touch the chassis or body). This should keep the galvanic circuit open and stop the corrosion.

When my last radiator died, it was corroded from salt water on the outside so that was the obvious cause of death. But I did wonder if the stainless pipes were earthing somewhere and adding to the problem, as stainless will also try to corrode normal steel (my radiator) via galvanic corrosion.

Theoretically if your radiator fluid is good enough it won't matter, but it's probably best not to test how good your fluid is.

here is the galvanic series;
http://www.corrprev.org.au/Galvanic.htm

The further two metals are apart, the worse they are together. The more negative material becomes the anode, and is corroded. The anode material tries to migrate onto the cathode.

I'm sure we all know aluminium head / cast iron block cars have problems with corrosion with poor quality coolant. Well that gives the following;
aluminium: -0.76 to -1.00
steel / cast iron: -0.60 to -0.72

So that gives a potential range of -0.04 to -0.4 trying to make them corrode.

Now we look at aluminium and stainless steel (passivated 316 pipes are fancy, but bad);
aluminium: -0.76 to -1.00
316 SS passive: 0.00 to -0.10

So that gives a potential range of -0.66 to -1.00 trying to make them corrode. Much much worse than the traditional cast iron block alloy head engines.

So you can see why new car manufacturers use plastic and rubber pipes.

gerrelt - January 13th, 2007 at 06:32 PM

Here's a site on this topic:

http://www.rjes.com/html/material_choice.html

subawee - January 16th, 2007 at 03:07 PM

Thanks for the link Gerrelt,
I checked out the page ang here's a quote;
" You can prevent galvanic corrosion by making sure that there is no electrical contact between the two different metals, but to rely on this is not good engineering practice."
Don't see why it's not a "good engineering practice" though. Seem like a more of a question of keeping stuff maintained than poor engineering.
I used a piece of rubber radiator tubing around the out side of the stainless then I used a strap around that and then bolted the strap to the frame. It seems to me that the set-up should last for a long time with the rubber being the only thing that will neeed to be replaced.
Stainless steel seems like an obvios choice to me, it won't corrode like steel, won't puncture like rubber and doesn't look like a plumber installed it (copper).
Just my opinion though, hope more people get in thoughts about this topic.
Thanks
Bob J.

MickH - January 16th, 2007 at 04:39 PM

Quote:

Originally posted by subawee
....................Stainless steel seems like an obvios choice to me, it won't corrode like steel, won't puncture like rubber and doesn't look like a plumber installed it (copper).
Just my opinion though, hope more people get in thoughts about this topic.
Thanks
Bob J.

What the link is suggesting is that the potential is there for the stainless to be fine while the engine dissolves.....USE A GOOD COOLANT....If I was to do mine it wouldn't have been stainless.I would have used alloy tubing or rubber hose.

subawee - January 16th, 2007 at 05:25 PM

I have to disagree, yes the page does make the point that different metals cause a galvanic response, my point is that it also states
" You can prevent galvanic corrosion by making sure that there is no electrical contact between the two metals"
Take a look at an older home that has copper pipes, chances are that the supply line that enters the house is made out of galvanized pipe and between the two is a union with a rubber/plasic washer that isolates the pipe.
I also think that using high quailty coolant is the norm for most people
I havn't had the head off the engine yet but I have changed the thermostat, the passage and outlet looked normal to me. I guess time will tell.
Buy the way I'm not trying to argue, just discussing things
Thanks,
Bob J.

ratbug - January 16th, 2007 at 07:43 PM

I am using stainless and rubber hose in my current ej20 setup and will be doing the same for my new one. As stated, just make sure its not electrically (metallicaly) connected or touching the chassis of the car. You shouldn't be doing this anyway as over time the constant heating and cooling is going to wreac havoc with the stainless steel to chassis anyway. Where my lines go through or attach to metal it is through rubber bushes or rubber spacers like what Bob (subawee) has done. If in doubt, get the multimeter out and measure all the resistance of all the bits of stainless to the chassis, should be infinity.

MickH - January 16th, 2007 at 08:01 PM

Quote:

Originally posted by subawee
I have to disagree, yes the page does make the point that different metals cause a galvanic response, my point is that it also states
" You can prevent galvanic corrosion by making sure that there is no electrical contact between the two metals"..........etc etc.

You forgot to finish the sentence with the rest of the "important" quote..."but to rely on this is not good engineering practice."....... I would interpret this as "sure you can PREVENT" this happening (coolant),or to not use stainless in the first place would "STOP" this probability of corrosion occuring. Using coolant is the bandaid fix for a preventable occurance. I do NOT think you are argueing,I see this as a healthy discussion with a lot of likeminded people doing conversions getting different, equal sides of the coin....This is a good thing..:thumb People can make up their own minds.

RENNWAGEN - January 16th, 2007 at 09:24 PM

Boof used rubber for mine. Looks good, alloy block heads and radiator almost no opportunity for galvanic corrosion.

Baja Wes - January 17th, 2007 at 08:28 AM

Quote:

Originally posted by subawee
Thanks for the link Gerrelt,
I checked out the page ang here's a quote;
" You can prevent galvanic corrosion by making sure that there is no electrical contact between the two different metals,

That's what I said in my post too. I think that page copied me :P

I changed my thermostat recently after 3.5yrs of running and it looked perfect, as did the alloy cooling passages. As I said, I have my stainless lines insulated. I changed it because I thought it was probably the original one for the motor and that it must be getting old, but looked just fine.

GeorgeL - January 18th, 2007 at 09:18 AM

A lot of these experts don't seem to realize that copper radiators assembled with lead/tin solder have been used with alloy engines for decades by auto manufacturers.

If we're supposed to be worried about the ill effects of a coolant pipe of dissimilar metal, how do the manufacturers get away with an entire radiator?

I intend to keep my entire cooling system electrically isolated. This isn't poor engineering practice as long as the method of isolation is well designed. The isolators also serve to protect the cooling system from vibration cracks as well as absorbing the strain of heat expansion.

George

Baja Wes - January 19th, 2007 at 08:59 AM

Quote:

Originally posted by GeorgeL
If we're supposed to be worried about the ill effects of a coolant pipe of dissimilar metal, how do the manufacturers get away with an entire radiator?

copper was very popular for the first 70 years of automotive use because it was relatively easy to manufacturer and was far more efficient than anything that could be make of steel or aluminium at the time. The galvanic disadvantage was relatively small, and they could get around it by isolating the radiator and using good anti-corrosion additives in the coolant.

One advantage of the relatively delicate copper radiators is that it if galvanic corrosion does occur, it's the thick engine block that corrodes, not the thin copper radiator core.

GeorgeL - January 21st, 2007 at 09:27 AM

Quote:

Originally posted by Baja Wes

Quote:

Originally posted by GeorgeL
If we're supposed to be worried about the ill effects of a coolant pipe of dissimilar metal, how do the manufacturers get away with an entire radiator?

I think that you're pounding the nail in copper's coffin a bit prematurely! Although aluminum is becoming more common, copper still remains in regular use. Oddly, European manufacturers have embraced aluminum strongly, while Japanese manufacturers have not been so quick to switch.

Aluminum will never be as efficient as copper in transmitting heat. You canna' change the laws of physics! The only material with a higher conductivity than copper is silver, which is a bit pricey.

http://hyperphysics.phy-astr.gsu.edu/hbase/tables/thrcn.html

Now, in some of my research on this topic, I ran across an "expert" who suggested that galvanic corrosion problems could be cured by grounding the heater core and radiator to the engine block! Seems to me that this is backwards, since galvanic corrosion needs an electrical return path to proceed! Isolation, not grounding, is the way to keep things from corroding.

Baja Wes - January 21st, 2007 at 11:18 AM

I never said copper was dead, just that there was no real alternatives for the first 70 or so years. Now there is.

Besides, these days most radiators have plastic end tanks which do a great job of isolating the core.