Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) What Did You Do To Your Morgan Today?

Swapping silencers around today to try and locate something loose in the exhaust. Whilst the exhaust was off I took the opportunity to replace the five steel screws directly below the door that holds the wing to the body with aluminum screws. I’m guessing but these steel screws might be responsible for the bimetallic corrosion that causes the bodywork to bubble just below the doors? I’ve seen this on a few cars. Any water or screen wash run off may run past the wing beading into the joint. I replaced the screws on the other side a while back and those screws were more rusty compared to this hot exhaust side. Anyway no bubbling so far so far, fingers crossed this might prevent it

Solved one problem today. I have an isolator switch on the positive earth which was fitted by the previous owner.
The other day my wife noticed the indicators were very dull, and when I switched on the isolator the horn sounded briefly.
As usual it was a simple fault. The flasher unit was faulty, so a new one is on order.
Haven't yet worked out why the horn sounded though.

I am a little wary of aluminium screws! When i renewed the guttering on the house, I used ali screws on the down pipe clamps to prevent eventual rust marks staining down the wall. However, when I needed to remove them, the heads turned to powder and were devils to get out. Maybe salt air as we are only a couple of miles from the coast, though the Severn is more mud than salt!

Have used stainless steel screws to sheet aluminium without galvanic corrosion problems by applying clear mastic sealant to the screw threads and thin rubber washers under the screw head.

Excluding water equals no electrolyte equals no corrosion.

Doug I would guess that the demise of your gutter screws may have been from atmospheric corrosion unless the gutters were steel? Hopefully these screw heads will be protected to some extent from the atmosphere with a few coats of Dinitrol. That’s not my concern here. My concern is the long term galvanic corrosion between the dissimilar metals where the steel screws pass through the aluminium body skin and then fueled with a regular dowsing of electrolyte that manages to gets past the wing beading.

If you look closely at the original screw the most corrosion has occured at the neck just below the head where moisture has run down the screw (the external portion is not corroded). When I took the screws out on the N/S they were even more corroded. One of those five annoyingly completely sheared off owing to the rust at the neck. So like the steel screws the worst that can happen is the ali screws also shear but at least the risk of any bodywork bubbling might be reduced with the similar materials, that’s my rational….

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I did some degreasing and power washing in preparation for changing the transmission and differential oil.

Yesterday, actually, installed these. I've been looking for some sort of air filters for Little Red since we got her last year. I got measurements from ITG and K&N and made mock-ups to test the fit, but nothing would fit under the bonnet scoop. I saw these on FleaBay and the price was right, so I ordered a pair and they arrived today. It's a tight fit, but they do, just barely, clear the scoop. The sharp bark of the Webers is muted, but there's still that nice throaty growl...

Very smart, I used to have the same ones on my Dell'Ortos. You may find you need to adjust the fuel mixture if you haven't already, they'll probably be running a bit richer now.

Cleaned out the windscreen washer tank. An item that has received little attention over the past 12 years, apart from a very occasional top up. Yesterday, I happen to notice that the top looked a little darker. Sticking my finger in, there was a very thick layer of black sludge all across the underside of the tank top, above the waterline. Rather than take the pipe off, it was easier to simply pull the pump out vertically and stick my thumb over the hole to prevent a mess, whilst extracting the tank.
I threw in a handful of pea gravel and gave it a good swirling. Finished off with a washing up brush.
Quite conceivable that sooner or later the sludge would have blocked the jets.

Mixed metals+moisture = corrosion.
An electrolytic cell is formed with resulting corrosion, usually one of the metal components, depending on what metals they are. Think sacrificial anodes often used in marine environments. The zinc( usual metal) corrodes instead of the steel hull of a ship.
The usual simple option is to remove one of the components ( moisture or change metals) to prevent or manage the effect. Separating the metals with non conductive material also helps.