Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Galvanised chassis

I nearly replied in the same vein, then, thinking about it he may have been referring to the likes of body cappings, which were just painted during the days of coil sprung models (not at the beginning of coilers though)...
Mine rides on a galv chassis, with most of the other steel body parts (door frames, bulkhead &c. also treated in a similar way ).

Don’t worry too much chaps it’s only a temporary glitch. When the penny drops in a couple of years’ time I’m sure it will be available once again as a 2k upgrade.

Hi surprised no one has twigged how about damp zinc and aluminum electric current and a phenomenon called cell action.use an aluminum bulkhead a zinc coated chassis will probably destroy the bulkhead.food for thought.
David

We're all doomed, I tell thee!

Glad to see you changed your mind.

I have often wondered about that. Wouldn't the zinc actually work like a sacrificial annode?

Absolutely if in direct contact. Galvanic corrosion will occur to a greater of lesser extent were there are different metals with a different anodic index and an electrolyte is present. When the localised zinc on the steel was fully sacrificed I suspect that the ali would then start to rot. Not a big problem as it can be mitigated through good design. Are you listening Morgan!

It occurs all over the place in our Morgans. The pic below shows my engine block rotting away owing to the galvanic action between the Ali block and Cu/brass radiator (the rot is very slow though).

It occurs all over the place in our Morgans. The pic below shows my engine block rotting away owing to the galvanic action between the Ali block and Cu/brass radiator (the rot is very slow though).

Sorry for being thick but surely the block isn't in contact with the rad? Or is it the coolant that does it? In which case isn't the water in the coolant that causes it? (maybe evans waterless stuff would be better)

The block in the pic looks fine to me. My 1962 Singer gazelle has an alloy thermostat housing bolted onto a cast iron block and its over 50 years old and neither has rotted away or needed replacement...yet - but you did say it was slow! ( like the gazelle!!)

Yes the radiator is electrically insulated from the block and chassis via the shock mounts and hoses. Yes the radiator (cathode) and block (anode) are in contact via the coolant (electrolyte solution) which does plays it’s part in the rotting process. The evans stuff is probably better but I’m not familiar with it. Having the correct coolant for the metal combination and changing it regularly is important to limit the corrosion as coolant degrades in this respect. The voltmeter reading probably indicates that my coolant is way over due for a change which I will have to do soon as my rad is knackered (again).

Does it matter? Probably not (at least for a long while) as the internal block corrosion would be very slow on the large metal mass. Long term through it is another good reason to replace my rad with an aluminium rad and eliminate the process altogether.

Keep your fingers crossed re the gazelle

I've been reading this thread, with a degree of interested concern.

As a chemist there is much of interest to me in this thread.

First, stepping back a bit: steel is used to make the chassis as in the 1950s it was the only option in town. Back then the quality of steel available was terrible. Remember how cars rotted?

Galvanizing steel helped reduce corrosion, but saying "galvanising" is like saying "painting", there are many ways to get the zinc on the steel and it is easy to do a poor job. Hot dipping, where the steel is dipped in molten zinc gives a thick, but uneven coat and can distort the structure. Electroplating is slow, but gives an even, very thin coat. Both are virtually impossible to paint, though powder coating is OK if the structure doesn't flex. So no use on a Mog. The only way to protect the zinc is to slap an thick solvent based goo on the structure, something the EC Air Quality Rules seek to discourage.

Today alloy steels are of far, far higher quality than in the past and many are inherently rust resistant. There are construction grades of steel that form a strong oxide layer that protects the rest of the steel. They look a bit naff, though.
Also the quality of protective coatings are light years away from oil based paint of the 1960s. As has been mentioned nanao technology is in the wings: early experimental work suggests that self healing coatings are not far away. So for the next 10 to 15 years I think MMC will stick to a steel ladder chassis, protected by clever modern coatings.

BUT steel is still so "yesterday". Aluminium is the future. It is available in many, many alloy forms, some are effectively corrosion proof as the alloy forms a hard, dull grey oxide layer that heals when damaged. Look underneath an early Aero. There is no corrosion because the grade of alloy used is both tough and corrosion resistant. The only problem is that it can't be welded and isn't easily formed into complex shapes. The alloy used to make the panel beaten body is sensitive to galvanic corrosion, unlike the alloy used to make the thermoformed components.
So the Aero based cars have multiple types of aluminium alloy in their structure, assembled round a very high-tech natural composite structure (wood!) As a result they are are inherently corrosion resistant, without the need for additional layers of goo.

So, I expect that over the next 15 years MMC will move almost all production to an alloy structure, as are all motor manufacturers.

It might even be possible to make a ladder chassis in aluminium alloy, but I doubt they will. Even so it would be interesting to see someone try, using a combination of sheet bending, welding and gluing. Light, stiff and corrosion resistant. Then steel chassis can quietly disappear.....