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Magnesium Fans
Posted by: vairmech ()
Date: January 10, 2018 04:49AM

OK, I can't be the only one that has issues with these fans. I posted pics of another fan and I finished breaking off all of the fins and every one had corrosion under it. I looked for the base to take a picture but it was in the bottom of the trash can!

This fan is from car #2 and is NOT a rusty car at all. In fact it is a pretty nice 64 vert! This is the very oily engine I posted about elsewhere and you would think that the fan would be well preserved with all the oil and crud!

So here is the fan as I first saw it, I had to remove it to get the top cover off which warrants a closer look.



Not a bad looking fan is it? This is after I cleaned off the crud in my wash tank. Then I turn it over and I see a tell tale sign that shows me I need to look farther. Do you see it???????



I am talking about the corrosion spot at the 9 o;clock position. Does that look familiar? It is not as bad as the other one I showed but it is there.
Here is that spot after I bead blasted the area. IF that had been the only issue I would have painted and used the fan. Do you see the crack just above the corrosion?



Now I turn the fan over and start bead blasting the fillet area of the fin. And I find this! It was not visible until I bead blasted.



Here is the other side of the fin, AND I bead blasted a couple more fins where there were some very small signs on the bottom, (that you can see above), and I found more cracks.
Can I use this fan???? It should be pretty obvious that I can't but if I had not taken the engine apart I would have never known.



This is the second fan in as many cars! I can't be imagining this stuff, I know I can't just make it up.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Magnesium Fans
Posted by: Chilly Willy ()
Date: January 10, 2018 05:19AM

I don’t know what you’re talking about, I don’t see any cracks.
There is going to be a little white van pulling up to your shop today to take you for a little ride😆

Next week I’ll buff out one of my west coast fans and see what it looks like.




The Corvair, Keeping Nader Notorious winking smiley


Will
Northern California

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Re: Magnesium Fans
Posted by: gnvair ()
Date: January 10, 2018 05:22AM

Compare them to well stored NOS fans to see what kind of blemishes the unused ones had.
Magnesium does not age well outside in the weather extremes. It is also highly prone to corrosion as you have found.

Lee J

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Re: Magnesium Fans
Posted by: v8vair ()
Date: January 10, 2018 05:36AM

Maybe something to do with the Harsh winters,Road Salt getting sprayed on cars and the mist getting sucked in to the fan ? I dont think ive seen that on southern cars

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Re: Magnesium Fans
Posted by: Spectre ()
Date: January 10, 2018 06:29AM

Kevin needs to get his new fan tested. There might be a market for them.
[corvaircenter.com]

David Clamp


1965 Corsa convertible - 140 4spd/3.55/AM-FM

2013 Mustang GT convertible - 5.0, 6spd auto, Procharger i-1

2003 Miata SE - 6spd manual (wife's toy)

"Victory is mine!" - SG

Oklahoma City, OK

Click for Oklahoma City, Oklahoma Forecast

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Re: Magnesium Fans
Posted by: BobV66Vair ()
Date: January 10, 2018 06:37AM

This is what I think of Ken's fan. I want one but given the impending death of my mag fan, I need one now!

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Magnesium Fans
Posted by: American Mel ()
Date: January 10, 2018 08:19AM

As I was walking through the garage one day last week, I noticed my fan from the coupe that is laying around while that engine is torn down.
I remembered Ken fan thread and picked it up for a quick check.
YEP ! ! !
My seemingly perfect fan has issues too.
The end of one of the blades is swelling up like a piece of MDF that has been left out in the rain!
There may be other problems on it, but I stopped looking at that point.
I'll get pics when I get home. (if I can remember) eye rolling smiley

.
-----------------------------------------------
WA. state, 1 mile south of the Canadian border,
I am not at the end of the world, but you can see it from here.
'66 Monza Coupe - 4spd, 140 Daily driver beater
'67 Monza Vert. - PG, 140 Daily driver beater

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Re: Magnesium Fans
Posted by: davemotohead ()
Date: January 10, 2018 09:07AM

You do realize there are 1000's of mag fans running around with hairline cracks in them and deformities just like that and they are not exploding in droves as you are leading on about, I have piles of mag fans out here in the dry desert climate and a lot of them look similar to yours and have been running many many years with out exsploding, even some of my NOS fans have had irregularities right out of the box.





Email me at: Dave Motohead

1960 4dr sedan caveman car
1961 Rampside (Chetside)
1962 Rampside (Barnside)
1962 Short Rampside (Shortside)
1962 Monza 700 Wagon
1963 Monza 900 coup (General Nader)




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Re: Magnesium Fans
Posted by: kdrolt ()
Date: January 10, 2018 05:53PM

We need input from a specialty welding shop. Mg can be TIG welded in an inert gas bath by someone with the right skills.

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Re: Magnesium Fans
Posted by: vairmech ()
Date: January 10, 2018 06:41PM

davemotohead Wrote:
-------------------------------------------------------
> You do realize there are 1000's of mag fans
> running around with hairline cracks in them and
> deformities just like that and they are not
> exploding in droves as you are leading on about, I
> have piles of mag fans out here in the dry desert
> climate and a lot of them look similar to yours
> and have been running many many years with out
> exsploding, even some of my NOS fans have had
> irregularities right out of the box.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

If this would have been an irregularity or JUST a hairline crack I would not have said a word. I am an ex-aircraft mechanic and I know there are others on here and they should know exactly what I am talking about. I already showed pics of an exploded fan, that DID NOT happen in MI! It was a Florida car.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Magnesium Fans
Posted by: vairmech ()
Date: January 10, 2018 06:47PM

v8vair Wrote:
-------------------------------------------------------
> Maybe something to do with the Harsh winters,Road
> Salt getting sprayed on cars and the mist getting
> sucked in to the fan ? I dont think ive seen that
> on southern cars
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

It has been a long time time since the average person has driven a Corvair in any weather other than getting caught in a rain storm in longer than I can remember.
I don't know the history on these cars or where they came from, as good as they look it could have been from a southern state or even from out west. With as little rust was on either of these cars they have not been driven on winter salt roads!

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Magnesium Fans
Posted by: vairsUPnorth ()
Date: January 10, 2018 08:35PM

Hello Ken,

I have looked at some literature in regard to Mg die cast alloys. This looks like stress corrosion cracking; a method of crack initiation and growth accelerated by a combination of stress and a corrosive environment. The various papers not surprisingly identified NaCl and CaCl2 as corrosive agents but also H2SO4--good old battery acid. One paper also identified the sulfur compounds [additives] in oils that would attack Mg. The chemical mechanism is more than I want to describe on this forum but it involves hydrogen liberated from the reaction of the acid with the Mg causing localized hydrogen embrittlement.

There were also a couple references to surface treatments for Mg alloys. In particular, abrasive blasting with silica or [especially bad] iron shot can set up micro galvanic corrosion from residual embedded media that can initiate cracks. I think it would be good idea going forward to only use plastic media for any blast cleaning of Mg fans.

Acid corrosion may explain why otherwise rust free cars have corroded and cracked fans. There was a reason for the original externally vented cap assemblies to direct acid fumes out of the engine compartment. Often these were tossed aside at the first battery change. Modern batteries may not present much of a problem now, especially the AGM or gel types.

Q: Do any of the cracked fans appear to have been abrasive blast cleaned at some prior date?

I would be interested in detailed photos of any NOS fans with apparent cracks.

Dale Dewald, PhD
Lab Assistant/Foundry Technician/Research Advisor
Michigan Technological University, Houghton, MI

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Re: Magnesium Fans
Posted by: Brizo ()
Date: January 10, 2018 10:39PM

For what its worth, I recently cleaned a mag fan that had several corroded spots and surface cracks like the pics above. After a little digging and scrapping, they appeared to only be cracks in a surface coating caused by corrosion underneath. Cleaning the areas left a divot in the surface about .030 deep. In this case at least, none of the cracks appeared to go through the fan. That fan has been painted, but I have another original condition mag fan that I'll clean and check tomorrow.

Dan Brizendine,
'64 8door Greenbrier 140 PG. "In beautiful Wanamaker Indiana...with one stop light and 5 pizza shops"

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Re: Magnesium Fans
Posted by: vairmech ()
Date: January 11, 2018 04:15AM

Brizo Wrote:
-------------------------------------------------------
> For what its worth, I recently cleaned a mag fan
> that had several corroded spots and surface cracks
> like the pics above. After a little digging and
> scrapping, they appeared to only be cracks in a
> surface coating caused by corrosion underneath.
> Cleaning the areas left a divot in the surface
> about .030 deep. In this case at least, none of
> the cracks appeared to go through the fan. That
> fan has been painted, but I have another original
> condition mag fan that I'll clean and check
> tomorrow.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

I would also use that fan!

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Magnesium Fans
Posted by: vairmech ()
Date: January 11, 2018 04:24AM

Dale, I to did a little more research on the Mg fans but I didn't have the time to go into the detail like you did.
I can't really make up my mind if this starts with a stress crack and then the corrosion starts underneath or if the corrosion starts underneath leading to a stress crack, chicken or the egg?

If you look at the picture above this is an original coated fan.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Magnesium Fans
Posted by: vairsUPnorth ()
Date: January 11, 2018 12:11PM

Hello Ken,

I would still like a detailed look at the root of the vanes of an NOS fan. If cracks like these are present in the as-cast fans, it would point to hot-tear defects, not SCC. This is not to say that SCC could continue and cause failures...

There was mention by Dan that the original fans had a coating. This is most likely a chromic acid picking dip that would leave a matte gray coating. This was commonly done back in the day for appearance and to impart some corrosion resistance to Mg castings. It is not used so much any more [except for Mil-spec] due to the cost of disposing the hexavalent chromium solutions.

Dale Dewald
Hancock, MI

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Re: Magnesium Fans
Posted by: Brizo ()
Date: January 11, 2018 07:02PM

Many guys don't believe / know that the original color of the mag fans was a dark gray. I was tired of seeing silver fans ( that look dirty quickly ) so for the last few years I've been painting them with a Ford gray engine enamel that is very close.

Dan Brizendine,
'64 8door Greenbrier 140 PG. "In beautiful Wanamaker Indiana...with one stop light and 5 pizza shops"

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Re: Magnesium Fans
Posted by: MattNall ()
Date: January 11, 2018 07:16PM

I posted a pic a while back setting in a box in dry garages all these years.







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Re: Magnesium Fans
Posted by: davemotohead ()
Date: January 11, 2018 07:22PM

smoking smiley





Email me at: Dave Motohead

1960 4dr sedan caveman car
1961 Rampside (Chetside)
1962 Rampside (Barnside)
1962 Short Rampside (Shortside)
1962 Monza 700 Wagon
1963 Monza 900 coup (General Nader)




Sign my guest book!
[motoheadmall.com]
-----------------------------------
Rust Free Lancaster Ca

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Re: Magnesium Fans
Posted by: MattNall ()
Date: January 11, 2018 07:26PM

Great... they both look the same!





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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