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MG MGB Technical - Rustproofing

One of my winter list of jobs is to try and prevent the sills from rusting.When i try using waxoyl it soon goes hard and makes the job difficult.Has any body tried any other method.I wondered about drilling some holes and pouring the waxoyl in the sill.Has any body used old engine oil in the sills.The sills are known to rust easily and i want to try and prevent it from rusting.
Dennis

Dennis,

The inner sill is quite easily injected through the slots in the castle rail and you will have to drill two large holes 2" dia under the tread plates to allow you to inject the outer. Dinitrol is a better material than Waxoyl as it has much better creep properties ans so gets well into the seams etc.

When you drill the large holes in the sill you can shine a light into one hole and look into the other to get an idea about how well you have covered the surface.
Iain MacKintosh

Iain,

Do you drill the two holes at any reasonable place for better access, or is there a particular location dictated by the need to access two separate compartments?

Boiled linseed oil is commonly used for the steel tubing of tube and fabric airplanes. The tubes were pumped full and then allowed to drain. It might be a good choice for cars as well.

Charley
C R Huff

Dennis,

If you want to use engine oil don't use used oil. Instead use cheap fresh engine oil.

Waxoyl flows better when heated.

David
David Witham

Wrong time of year for injecting Waxoyl in the UK, you need a hot summer's day. Thinning with white spirit helps, but even if you stand the can in hot water as recommended the tubing is long enough for it to go back to semi-solid before it reaches the spraygun. I'm told a proper power sprayer i.e. other than the manual pump works better but I've never tried it.

1/4" holes should be enough for spraying, but larger ones will allow to get something of a look-see inside (but see below). There should be one existing on top of the outer curved sill just aft of the A-pillar, drill a corresponding one on top of the square box section just inside the doors. Drill two more holes at the back of the door opening, just as the B-post starts to curve upwards. On the outer one you will drill through two panels - the outer cover panel and the sill itself, spray between the two panels as well as below the lower one.

But the most important places to protect are the very narrow spaces between the sills and the bottom parts of front and rear wings, as it is almost always these that rot first especially after sill replacement. Sprayed Waxoyl will not penetrate here even with a power sprayer, but simply bridge to top of the gap and allow corrosion to fester away underneath unseen, even though there may well be a nice coating of Waxoyl everywhere else you can see. Take the trim panel off behind the doors, and the splash-panels from inside the front wings, and you will be able to get at the tops of these narrow gaps. I've squirted clean engine oil in both, which of course runs down the gaps nicely, and out of the bottom so you will need paper or cardboard underneath for a day or two.

I've also heard of blocking up the drain holes along the bottoms of the sills and castle-rails and pouring engine oil in to *fill* both halves of the sills, leaving it to stand a while to creep into all the tiny gaps, then draining it out again, much like the old mechanics trick of spraying old engine oil on the chassis etc. after an oil change. Some say you should never do that as used engine oil contains acids, but if it's been sitting in my engine for 12 months and 3000 miles gradually building up acids without doing much harm I can't see it hurting the sills much.
Paul Hunt

Dennis,

Subject largely discussed on during last summer on this side of the Channel. If you have an E-mail I can provide you with à document stating all necessary holes to dig in. Car makers now use a kind of wax to protect internal body rails. This operation is renewable. It's more advisable to achieve this treatment when hot.
Hope that help!

Rgds.
Renou

Charley,

Just drill the holes at as wide as possible centres so that the tread plates can cover the drillings
Iain MacKintosh

Thanks Iain.

Charley
C R Huff

Thanks Renou if you could please send me a document showing all the holes.It must be great fun driving your mg around the french alps.Had any snow yet.Thanks Dennis.
Dennis

Hello Dennis,

Everything OK ? HAve a good job time!
Renou

Iain, surely you don't mean 2 inch diameter holes in the sill? That's enormous and must weaken the panel. I drilled two half inch holes in the bottom of the outer sill at each end of the bit you can see under the door. Then by inserting the Dinitrol probe and angling it forwards and backwards I could coat the entire length. The holes are then plugged with rubber plugs. Even with Dinitrol you need a warm day or a warm workshop.
Mike Howlett

Dennis,

I am not actually in the french alpes ( oversea ), but I confirm snow has arrived, just on time. Nice weather for skiing I hope and drive MG's altogether.

Rgds.
Renou

Renou - I would greatly appreciate receiving the document you sent to Dennis. Thank you - Dave
David DuBois

Hi Renou.Thanks for your document on where to drill the holes and thanks to every body else for the advice.Thanks Dennis.
Dennis

I Waxoyled by car, heated the container with a heater standing next to it, which made it very runny an used a 3hp compressor and spayed with a cavity wax gun and tube, very good coverage, even after 2 years if i park in a hot location will normally get a little waxoyl drip from under the car.
Ian Sanders

I have heard of waxoyl tins exploding when heated, so at least loosen the cap when you do this. I now use Dinitrol 3125 brown on cavities for reasons above, waxoyl on exposed surfaces where it takes longer to wash off when exposed to spray.
Stan Best

Supertrol has the same properties as Dinitrol at a fraction of the cost.

FWIW
Roger

"waxoyl on exposed surfaces"

Finnigans "Underbody seal with added Waxoyl" is usually the one to use on exposed surfaces.
Paul Hunt


Renou,

I too would appreciate copy of your document.


Regards,

John
John U

Renou, could I have a copy too? It seems a lot to ask but you can see your plan has raised a lot of interest. Merci.
Maurice Alston

This thread was discussed between 24/11/2008 and 01/12/2008

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