How do YOU protect your transmission case from corrosion?, What coatings do you use? Options

[Dr Evil]

I am trying to finish my notes to accompany the rebuild video (notes will be free) and I am wanting to pick your collective brains for info on corrosion prevention for the mag alloy case. What do you do? The factory coating only lasted a few years and is long gone now. On most peoples cases, it is the oil that keeps it from corroding (IMG:style_emoticons/default/wink.gif)

[Krieger]

The one sitting on my garage floor is coated in wd-40 and shows no corrosion after 4 years.

[underthetire]

Nickel plating, a little bling bling....

[McMark]

I cover mine with 40 yr old German steel and don't look at it. (IMG:style_emoticons/default/laugh.gif)

sacrifical anode?

[Dr Evil]

I know one can clear coat a clean one. There is this stuff called "Gibbs" or something like that which some have tried with success. There is no shortage of people that will clean these things, but they do not know to coat it and they start to deteriorate.

[bandjoey]

MOTOR OIL and dirt works great! (IMG:style_emoticons/default/lol-2.gif)

[Dr Evil]

I know, I mentioned that (IMG:style_emoticons/default/tongue.gif)

[Dr. Roger]

I try to make sure at least one of my valve cover gaskets are leaking and maybe one other high level oil gasket is giving up a little oil all in the name of protecting my prized 901.

but seriously,


http://www.finishing.com/faqs/magnesium.html
Dow 17 surface conversion coating if it's Magnesium.

[Rand]

Is corrosion a serious issue? Rust on steel is a horrible cancer that destroys, but the transmissions don't really decay. Is this for purely cosmetic reasons?
Please forgive the dumb Qs, just wondering.
I've also seen people paint them... The pros and cons might be worth mentioning in the vid?

Can't wait to add the Evil DVD to my library!

[zymurgist]

I think this could apply to /6 fans too... aren't they magnesium?

Not like 914/6 guys ever see their fans, though. (IMG:style_emoticons/default/wink.gif)

[Gint]

Never bothered. I might want to at some point though (the six resto), so this thread is a bonus.

[Richard Casto]

Mike,

I started a long term test of a few cleaning and protection methods a few years ago. Check this out...

http://motorsport.zyyz.com/project_914_03_14.htm

Last update was early 2008. Part is still hanging up outside and I need to bring it in and take some more photos. I look at it periodically, but in general I would stand by what I said last time I posted and that is...

* Media blasting is the best at cleaning, but it removes the chromate conversion that may still provide some corrosion protection.
* Gibbs Brand Penetrating Oil/Lubricant works, but it's not a miracle product.
* CRC Heavy Duty Corrosion Inhibitor seems to work the best. This is not surprising since Porsche also used a waxy protectant (Tectyl) on the magnesium transmissions parts.

So short of finding a place to buy Tectyl (what the factory used and I can't seem to find anyone who sells it in small quantities), I would go with "CRC Heavy Duty Corrosion Inhibitor".

http://www.crcindustries.com/ei/content/pr...N=06026&S=C

Occasionally I find this stuff at stores, but generally I have to order it. It is somewhat targeted at boaters, so I have yet to see if boating supply stores carry it on a regular basis.

Richard

[Richard Casto]

I should also mention that I was looking to go for "period correct" look/style (I also wanted it to be cost effective) with respect to a method to protect the transmission case. Back in the day Porsche used a chromate finish to provide temporary protection to the parts between the time they were machined and when they were assembled. Chromate finish provides decent, but not long term protection. So it was never intended to really protect the case. What Porsche did was spray the assembled case with a product named Tectyl which is a waxy coating. The CRC product above is similar to Tectyl.

If you are not looking for period specific or a low cost solution, then there are many newer coatings (particularly aerospace based) that can be used on magnesium and aluminum. However some of those may result in oddly colored finishes (such as green). You might be able to find someone willing to do another chromate conversion process on a case if you want to replicate the factory finish (particularly the brassy color the chromate finish gives). However most (all?) chromate conversion processes use hexavalent chromium which is nasty stuff. The movie Erin Brockovich is about people who were poisoned by hexavalent chromium. So the stuff is just about outlawed today and may be expensive to have done.

I have not put much thought into painting a case and if that is a good idea for the long term. However I know that many people do paint their cases.

[tat2dphreak]

30 years of grease and gunk are keeping mine pristine underneath (IMG:style_emoticons/default/smile.gif)

[pcar916]

... would go with "CRC Heavy Duty Corrosion Inhibitor".

I'm about to order something myself so this is a timely discussion. I got mighty frustrated last year trying to find Tectyl. But in addition to Richard's suggestion, which is described as "dark amber" have any of you tried CRC 3-36 product as well?

http://www.crcindustries.com/ei/content/pr...N=10200&S=Y

It's temperature range is up to 300 degrees and it's just plain "amber" which Tectyl is too. I don't know how that compares with the Marine CRC stuff. According to the spec-sheets, the marine stuff appears to be more viscous than 3-36. Here's a newer coating. I don't know anyone using it on one of our cars.

http://www.tagnite.com/video/ and

http://www.tagnite.com/

Links to Tectyl:

http://www.daubertchemical.com/main.taf?p=3,1

http://tectyl2.valvolineeurope.com/index.a...ba0e5105135c4d5

Also, here is a link to an old thread that covers a lot of ground on this topic.

http://forums.pelicanparts.com/porsche-911...-corrosion.html

Good reading!

[SUNAB914]

Eastwood, Aluma blast spray.

[davep]

Pelican was going to sell Tectyl, but ran into problems with shipping it I believe.
The CRC marine HD material seems to be the best alternative, but it is hard to find. It is possible that only marine stores can get it, our FLAPS cannot.
Gibbs brand lube is possibly the next best inhibitor.
Talking to local trans shops they just use a spray on lube like WD40.

[Richard Casto]

I haven't heard of that CRC 3-36. I read that link and it sounds like a non-drying lubricant (much like Gibbs Brand). If anyone tries it out let me know how it works out.

I haven't tried to buy Tectyl in a few years. Everyone I could find was geared up to provide large quanties. Not to mention the fact that Tectyl is a brand name and not a single product. So you have to make sure you buy the right thing. That PP thread is great and it was the source of PP planning to sell Tectyl. Grady Clay had found a source for Tectyl 846 (which he said is what Porsche used). But for whatever reason (maybe shipping issues as Dave said) that fell apart.

I just Googled a few minutes ago and did find a supplier that apparently sells Tectyl 846 in spray cans. They list a case of 12 cans at $76 which I think is reasonable. So I ordered a case.

Here is the link if anyone else is looking for it...

http://www.mil-specproducts.com/productPage.aspx?prodID=446

I am guessing that there is not going to be a huge (if any) difference between the Tectyl 846 and the CRC product.

[turboman808]

Got some exhaust spray from Chris last year that works really good and looks like metal. Wonder how that would work.

[Drums66]

Redline Tranny Juice(no corrosion) (IMG:style_emoticons/default/bye1.gif) (IMG:style_emoticons/default/stirthepot.gif)