911 Magnesium block protection. Corrosion

[Anders.]

Hi. is there a way to protect magnesium after a engine rebuild. I Dont want the corrosion to go any further.
-Anders

[GaryR]

That looks like aluminum, are the mag cases not black(ish)?

[Anders.]

pretty sure it is a mag case. case number is *6373474*

[dg567]

Spray it with Gibbs every so often.

[EC900]

7R is the case identifier…it’s the the strongest and last of the Magnesium cases, engine is 1977 model year. Your case could have at some point been long exposed to the elements. I’m not an engine rebuilder so I can’t comment on what may be the norm, but the casting could just be pitted by mfg. process too.
The amount of heat the engine creates would burn off any “preventative” external coating. As long as the case is true then the pitting is merely cosmetic. A mild, low pressure walnut shell media blasting would improve the looks, but mostly those pits will be hidden.

[Dpmulvan]

Originally Posted by dg567

Spray it with Gibbs every so often.

Gibbs is good or
Try aircraftspruce or any aviation supply house, several products to protect magnesium.

[2.7RS]

Cosmoline.

Coat it with anything that prevents oxygen exposure.

Power wash it and repeat as needed

[Shaun @ Tru6]

I have created a positive pressure sealed case system so that I can safely media blast cases. After that it can be coated with one of Cerakote's heat dissipating coatings. Pitting can also be addressed in the same way I do fans and housings.

I have my own 7R case to do for an RS build as a first test.

[RSTarga]

A couple of oil leaks will help preserve it
Factory sprayed cosmoline on it , Wurth has some products you can use. They will cook on after a while.

[fanaudical]

I gave my case a heavy coat of CRC Marine Corrision Inhibitor following rebuilt. It's lasted ~10 years so far still looks OK.

Shaun, that process sounds pretty neat. Please post pics of results. I've heard of issues with coatings sticking to magnesium and am interested in the results.

[AUSTmike]

I have a magnesium case 1977 2.7 ltre and i use a high grade lubricant spray called "Inox" its an oil based and i use it to clean all my engine and gearbox and stays on for months..its anti corrosive and it protects the engine casing it gives the metal a bit of a polish look as well.

https://www.inoxmx.com/products/mx3-lubricant/

[911obgyn]

Another product is ACF50, used on aircraft landing gear and inside of aluminum wings.
In humid climates it needs to be reapplied every 6 mo or so.

[ClickClickBoom]

Originally Posted by 911obgyn

Another product is ACF50, used on aircraft landing gear and inside of aluminum wings.
In humid climates it needs to be reapplied every 6 mo or so.

Been using ACF50 on aircraft for 35 years. It has a few volatiles that evaporate and leaves the thin coating on the surface. I had a open cup of ACF with a brush for touch ups on drilled holes and after a year it had thickened so much it almost wouldn’t pour.
The stuff is amazing it is dielectric so it can be used on electronics with out fear of shorting. I use it on everything from tool wipedowns to light switches. Smells nice too..
Magnesium is difficult on the best of days:

Fan Shroud

If you go to the pics, you will note the internal corrosion on the grain lines. Magnesium is doomed to return to its most stable state as soon as it’s poured. The aircraft industry keeps that herd of cats under control by rigorous maintenance schedules and life limiting parts made of magnesium. The Dow #19 process uses chromium and is not friendly to carbon life forms. Paint and other coverings simply don’t work long term. Which is why the aircraft industry use chromate conversion processes, prior to paint. Cerakote, powder coating and paint just cover up what is going underneath. Magnesium is maintenance labor intensive, with potentially dangerous processes. It’s still used because it is wicked light and crazy strong in the right application. I can honestly say I have never seen a magnesium propeller or fan blade in the aircraft world, but I bet there is one being used somewhere on something.
So the short answer is anything that will stay firmly attached to the surface of the magnesium that will keep water and air(w/oxygen) away from the unoxidized base metal is the answer. I hit my fan and shroud with ACF annually with a brush and occasionally spray some into the idling fan to protect the hard to get to points of the fan shroud components.
Cosmoline is probably the single best alternative, but it is messy and smells like azz for almost ever.

[Locker537]

I haven't used it on Porsche engine cases, but Fluid Film is a good product.

Easy to apply, easy to re-apply periodically, and not too much of a health concern given how it is made.