Air Vent Grill is Nonmagentic...Right? Soooooo

A question for all you Ferromagnetic experts out there:

1. If the MGB air grill vents are nonmagnetic, and covered with chrome (which is nonmagnetic), how are the after market magnetic vinyl grill covers supposed to stick?





I called Northwest Imports and Moss - both of the vent covers they currently sell are non-ferrous, and I guess these are made out of "pot metal" which is why they didn't stick.

What were the original ones made out of? I just asked a guy who is selling one on E-bay that we think is original, and he says that one is non-magnetic as well. Plus, correct me if I am wrong, but chrome is non-magnetic as well, yes?

My magnetic cover just falls right off. How are you guys getting your to stay? Does a steel mesh grill beneath it have enough attraction to make the magnet stick? Do you have magnets glued underneath?

I don't know why but the cover on my (newer) vent grille sticks well enough to leave it on while driving.

me too.

There is some pull on mine. I think....

The magnet must be strong enough to attract to the metal under the air grille.

Greg.

I can't speak for the repro grilles, but the originals have some slight magnetic attraction. The vent cover does not need much as it's in a low pressure zone. The faster you go, the more it is pushed down onto the grille.

At about 95 mph you can see the individual grille openings indented into the material of the cover.

Don't ask me how I know.

K.

I can't speak for the repro grilles, but the originals have some slight magnetic attraction.

Thanks. I spoke with Robert of Clark and Clark (who is a Superfantaboulous guy by the way) - and he alluded to the same thing as you said. His company makes the magnetized vinyl covers as most of you know. That the originals had some magnetic attraction, and as testified here, the do stick.

Robert went over and above to do a custom arm rest and shift boot for me, and I really am grateful to him - more on that later.

But, I even asked a guy on Ebay who was selling an original one to put up a magnet to it. Guess what? No sticky.

So....I don't get it. Is it the hardware? Is it the grill underneath? Do the originals (and only the originals) have enough ferrous metal content to generate the magic amount of magnetic force even though they are not made of steel or something and are covered with non-magnetic chrome? Is it the steel grill underneath?

I dunno.

Clark and Clark also sells a steel grill that goes underneath the vent. I have a mesh grill under there, but now sure what it is made of, and not sure that that steel will generate "The Force."

If anyone has an original that they want to sell me that is in decent shape, then [bplease][/b] PM away! I really wanted this magnet thing to work for me.

Mine is magnetic enough to stay put. I suppose wind pressure helps, too, even though you'd think it would blow away. It hasn't so far. I've often thought that someone ought to make the same kind of grille cover but with some simple metal (or even plastic) clips that would make it even more secure to the slats on the little chrome grille. Pretty simple to do, I'd think.

Greg,

I have an 'original' spare, so I did a little experimenting. Off of the car, the grill has minimal, but some magnetic properties, just enoug to allow the magnetic cover to stay on....... IF I am careful about holding it still. I also took a very strong magnet, and could feel only minimal / moderate pull. Okay...... so it is 'pot metal', with only some amount of iron. I then took the spare grill and held it to the body of the car. The standoffs prevented good contact to the body metal, but the magnetic pull was increased noticeably.... but still fairly weak. I conclude that it is the combination of 1) minimal iron in the grill 2) underlying sheet metal body and 3) aerodynamics, that hold the cover in place. FWIW.

My grill is not in that great of shape. It has some impending rust, scratches etc. If you want this one as a 'Winter' grill that you are going to cover with the magnet anyway, and don't care too much about how it looks, and then put on your 'pretty', non-magnetic one in the summer....... $5 + shipping

Grill photo

My cover sticks to my grill fine, I can feel the magnetic pull. I think there's some steel in it somewhere. However, what I did is purchase some of that magnetic sign material, the flexible stuff, and cut out another shape from that, just slightly larger than the black grill cover with the MG logo. I use both together and it adheres to the grill quite well. Stainless steel, btw, is about 10-12% chrome, which is what makes it "stainless." So, maybe there's a bit of steel in chrome-plating as well, to keep it from being pure chrome, which might not last as long.

Dave

David points out an interesting facet of this situation by saying that "The standoffs prevented good contact to the body metal, but the magnetic pull was increased noticeably." when the intake grille and magnetic cover were placed together and then laid on the cowl. I am guessing, but I think what happens in the case of the "ferrous" or magnetic grilles is that they take the diffuse magnetic field of the sheet vinyl cover and concentrate it as the grille distorts the field along its own footprint. Just a thought.

As stated, the "pot metal" in use today probably has no iron (or very little) in it as most pot metal is zinc with some other metals thrown in. The mix used in the OE units may have simply had some ferrous metals in the mix, and whoever has been making them recently in some other country, perhaps has their own idea of what constitutes "pot metal"

Just wrap a sheet of kitchen foil around the wire grill and put it back on the car.

i have that rubber magnet vent cover and it sticks to my car just fine....and keeps the flood at bay when i get caught in rain...used to soak my leg before i got it.

I got one of these covers (not very magnetic on my grille) and for me its a catch-22 - when it rains here it's usually stifling hot and humid, so ... cover the air intake and you have no defogger :X

I learned to keep a 1/2 roll of paper towels in the space where the gearbox dipstick is - for windscreen clearing in the rain and as an absorber for that damn water leak everyones B seems to have LOL!

~Marco and PLT~

Nice having a company wind tunnel, right Kelvin?<G>

Pierre, I think it was presented to the rest of us in the same spirit as "lighten up, yer getting too technical".

Yes, the kitchen foil does the same job as the magnetic thing that doesn't stick 'cause the zinc alloy casting doesn't have the same metallic structure it used to have and the steel mesh may be too far away to get a good magnetic atraction thing going on despite the undeniable fact that there is some positive pressure helping to keep it in place at even legal highway speeds however it is possible that the inconvenience that the aluminium foil doesn't have an MG logo on it may outweigh (nothing to do with the low density of aluminium) the fact that it will cost close to zero for most of us who like to make a parcel with some leaks and a nice piece of salmon with a little white wine in the oven for twenty minutes...
But I digress.

Yes, thanks. You are going to cook that salmon over the exhaust manifold, right?

I am new to MGs having previously owned/restored 3 TR3s and a TR4. I find it incredible that BMC made the B without a means of closing off the air vent box (or alternatively diverting incoming water to a safe exit and keeping the inside of the car dry). It's amazing they ever sold any in England where it rains about every other day.

From reading these posts it appears that the only solution is to slap a magnetic cover on top of the vent grille. Is that a fair deduction or does somebody have another answer?

Chris

The box can be closed at the bottom inside the car so that cold drafts don't get in. But there is no way to close the top of the box outside the car so MG provided a drain hose (aka Tom's knob). Practical, cheap, but not the best solution. Putting on the little magnetic cover is easy enough to do, though, if you're driving in the rain. Assuming you leave the garage while it's raining and remember to put the cover over the chrome grille. If it begins to rain while you're driving -- or if you just forget -- expect some leaking and keep a towel in the car. All part of the fun of old-fashioned British motoring.

What's inside....

Looks like a good time to seal up the air cavity seam is when the heater box is out, and the defroster panel and tubing removed. The air plenum seams can be sealed when the grill is removed - I used a long brush and Rhino liner, but there are other options.

Mine never stuck very well, so I made this:







Sealed very well and helped warm the interior up quicker, but I found it did not work well in wet weather. Due to not having fresh air come in, all the moist air in the car fogged the windshield up to the point where you could not see out of it.

When you block the opening with any of these things, you need to remember to OPEN the fresh air vents in the dash so the air can go IN through them, through the fan and the heater and back into the car via the screen or foot outlets.

Andrew - thats's a nice little device you built. Ah, the ingenuity of British Car owners......necessity is the mother thereof.

You mean to say you get a little rain there in Oregon? :^>

I tried to find one of these at a swap meet, no dice. A very nice member was going to sell me his old one, but I thought I would try and find one on my own around here - plus I thought I could find a solution (I like a challenge). I bought some little magnets, and thought I could epoxy or glue them to the underside of the after market "pot metal" grill and perhaps that would work.



Well, let me save you all the trouble. No dice. The magnets are not strong enough to make that vinyl magnetic grill stick. The magnets stick like heck to a garage steel door though!