Chassis Corrosion

[Bram]

Guys,

Now that some of our cars are 22 years and counting. It would be interesting to get some input from Owners that has removing panels and other parts from their cars and are able to comment after seeing the basic structure. I recall reading someplace that the NSX Aluminium chassis have a life cycle of approximately 30 years

- Aluminium stress cracking.
- Corrosion on panels
- Any issue with different metal contact
- Any deterioration of the Aluminium structure
- Spot Wields integrity
- Suspension arms deterioration

Discussion, or any insights welcome

Bram

 

[Hapa88]

I'd be interested to follow this. My understanding about aluminum is that it oxidizes and the resulting material layer is aluminum oxide. It creates a passivation layer that is impervious to air and many chemicals; it also protect the surfaces from further "rusting." Aluminum oxide is also extremely hard.. so I'm wondering if that was taken into account when they gave that 30 year lifespan. Of course most of the car is painted, so bare aluminum is hard to find, and I'm curious if oxygen is still able to penetrate the paint layer and still produce the aluminum oxide layer. I mean after 20 years, I would assume oxygen would eventually get there.. it's a long time to be sitting in the environment.


When I had my two piece forged aluminum wheels that had bare polished lips, it would take ~2days before the lip would being hazing, showing signs of the aluminum oxide layer forming. That's pretty fast in my mind.

 

[shawn110975]

out of all the NSX's I have worked on/ rebuilt I have not seen any corrosion, some white powder kinda stuff on some of the chassis but a simple wipe cleaned it off.

now.......... bolts that are not alum rust out like a plague, tons of parts suspension parts, brackets etc rusted so bad you need to throw them away.

some owners up north ( snow ) have had more powder or it could have been salt but nothing that would effect the chassis.

- - - Updated - - -

but life of the alum is a question how long can an aluminum control arm keep taking hits on a daily driver for 20+ years that is the question

 

[Alas-NSX]

I'm no expert by any means but one thing to consider is real world numbers. There are numerous members here on Prime with 200k and 300k miles on their cars. I have not read or honestly paid any attention to suspension failures, etc. due to aluminium fatigue.

In the absence of any hard data or accelerated life testing, real world field data makes sense.....to me at least.

Does anyone have any literature to support the 30 year number that is quoted?

I would assume the 30 year number is derived from "expected" material properties, loads, driving conditions, overall care and handling of the car and possible many other factors. I don't know what those factors are just speculating. Again where does the 30 year number come from??

I'm not worried based off what I have seen.

 

[heySkippy]

Didn't Hugh have a suspension piece snap recently?

 

[Bram]

Does anyone have any literature to support the 30 year number that is quoted?

I would assume the 30 year number is derived from "expected" material properties, loads, driving conditions, overall care and handling of the car and possible many other factors. I don't know what those factors are just speculating. Again where does the 30 year number come from??

The 30 years number came from the Wiki....but nothing to support that number

Bram

 

[Alas-NSX]

^
Found the link.
http://www.nsxprime.com/forum/showthread.php/168059-Lower-Control-Arm-Snapped!

 

[GECKO]

The whote stuff you see on the cars north of the border is 'snow', when we get caught driving too late in the season :biggrin:

 

[warrenw]

Take a look on NSX Club of Britain
http://www.nsxcb.co.uk/
Kaz has a very good blog on this site that shows how their climate causes corrosion.
Those cars have plenty of corrosion. Always wet due to the climate
They can't say "never driven in the Rain!"

 

[docjohn]

Uhrehara told us at an xpo that they designed the chassis for a 30 yr structural integrity target...I guess after that there could be some decrease in torsional integrity

 

[nikey22]

If there was a way to replicate that greenish tinged spray on the bolts and aluminum parts that prevents corrosion, we'd all be set for another 22 years......
WHAT IS THAT MAGICAL FILM?????????????

 

[NSX2398]

There are numerous members here on Prime with 200k and 300k miles on their cars. I have not read or honestly paid any attention to suspension failures, etc. due to aluminium fatigue.

Well .. I have about 190k on mine and probably 100k of those I put on myself up here in the Great White North ... and about 25-30k of the 100 were winter miles on somewhat salted roads but typically not as much as Ontario. Anyway, I've had no corrosion related suspension issues of any kind that I know about other than my right rear toe link adjustment bolt is currently 'frozen' to the point where the dealership didn't want to risk using additional force. As you might expect, the original exhaust system didn't do as well and was replaced at around 120k but that wasn't because it had developed holes. I had Mark Basch install headers on it in 2008 and I remember him mumbling "I hate Canadian cars" afterward. I've also had some rusty in the area under the battery .. presumably from battery acid issues .. not sure if the tray is aluminum. Oddly enough, the only visible sign of the 'white corrosion powder' I've seen anywhere on the car is on the trunk latch .. not the one on the trunk .. the one it latches onto.

 

[gdae]

On the day my car turns 30, I'm gonna take it for a nice drive, park it, turn around, and wait for it to fall apart like the Blues Mobile.

 

[FF Drifter]

If there was a way to replicate that greenish tinged spray on the bolts and aluminum parts that prevents corrosion, we'd all be set for another 22 years......
WHAT IS THAT MAGICAL FILM?????????????

I thought that was just to mark those bolts and parts as being made of aluminum so you didn't mix it up with non-special bolts.

 

[dablackgoku1234]

I don't think any bolts are made out of aluminum. The bolts are coated (with Dacro?) to prevent corrosion. According to the manual, bolts can be removed and re-installed 8 times before the coating wears off. Then it would need to be replaced.

 

[LuckyM]

I hear a lot more about aluminum chassis issue from lotus cars with spider cracks but that is because they are glue together. Also bmw e36 and early e46 models have crack issues due to stiffness to suspensions. I haven't hear one single issue with nsx with chassis problem (knock on woods). I wouldn't worry a bit.

 

[phryxis]

I'd be interested to follow this. My understanding about aluminum is that it oxidizes and the resulting material layer is aluminum oxide. It creates a passivation layer that is impervious to air and many chemicals; it also protect the surfaces from further "rusting." Aluminum oxide is also extremely hard.

Yes, you're right, when exposed to air, aluminum anodizes itself.

For those interested in the topic, read up on galvanic corrosion, it pertains to this situation, and is why you get the white dust on steel bolts when attached to an aluminum frame.

 

[silver2002]

I Use Ultra-Tef Gel

http://www.jamestowndistributors.com/userportal/show_product.do?pid=546&familyName=Ultra+Tef-Gel

If there was a way to replicate that greenish tinged spray on the bolts and aluminum parts that prevents corrosion, we'd all be set for another 22 years......
WHAT IS THAT MAGICAL FILM?????????????