Britannia

[Oyster 49]

Managed to strip the magneto today. The screw that secures the backplate was a bit stubborn to say the least. The silencer is soaking in paraffin, as it is completely full of oily sludge.

I now understand how the cooling system works, water is forced up the leg and around the cylinders and into the outer silencer, before draining back down the leg. The exhaust gases go into the inner silencer where there is an exhaust baffle. That way no water gets into the cylinder. Clever.

The inner silencer is oily and full of sludge, the outer is non oily but full of corrosion.

I need to drill and helicoil 5 holes in the silencer. Crap steel bolts into aluminium.

[Collector Inspector]

AH!

Another Convert!

Enjoy

B

[Oyster 49]

Very interesting engine. The silencer is a piece of art, a cross between heat exchanger and silencer. Quite clever. The only critism would be the lack of a tell-tale in the coolant system. A great little engine though, good to work on, and some similar components to a 1930s seagull.

I'm baffled there is not more interest in these here actually.

[Oyster 49]

Learning about these engines continues. Both cylinders are cleaning up well, but both have rusted through into the water jacket at the same place. Obviously an internal water trap there. I will make a small blank and secure it with epoxy. Once painted you will never know

Loads of rusty crud came out of each water jacket. Just like a 102. soaking the cast iron cylinders in a caustic solution after wire-brushing seems to be working.

I have found a firm on the south coast who have quoted £101for a coil. Ouch That said I have 2 engines that use identical magnetos, so I could restore 1 mag using the best parts from 2, swap the mag over and run 2 engines for the price of 1 coil.

Great little engines these Britannias.

[Stelios_Rjk]

I like those post of restorations with nice pictures! I saw the coil needed. It has two pads, right? Why don't you try to use one M1361 replacement? It will cost you 1/5 from the price you mentioned. May worth the try to modify one of those coils.

[Oyster 49]

Yes I have thought of that. Perhaps a villiers 1030 coil as used on the marston/SD could be modified with a brass plate to fire 2 plugs at once. The problem could be that the spark will most likely go the path of least resistance which could give a strong spark on one plug and a very poor one on the other. I'm not sure but I think this coil has 2 secondarys, to ensure an equal spark to each HT lead. Hence 2 seperate outputs.

I think similar american engines had 2 coils and 2 sets of points, despite both plugs firing at the same time. I'm not that famililar with OMC engines though.

[Horsley-Anarak]

My old Johnson twins have only 1 coil

Yours is looking good Oyster, could be soon time for a twin run on the Thames.

H-A

[Stelios_Rjk]

Do both strokes occur at the same moment? I don't think so. I believe that when one piston is on BDC the other one should be on TDC. If that is correct, then all the spark is driven to one spark plug each time.

[Oyster 49]

Yes, I just need to cough up the cash for a coil, and work out a little in the gym so I can lift the thing onto a transom

The Archimedes I've got takes two to carry. Bloody great lump. Somebody take it off me!!

[Horsley-Anarak]

The Archimedes I've got takes two to carry. Bloody great lump. Somebody take it off me!!

I can see that on a balcony in Athens. That will get the neighbours going.

H-A

[Stelios_Rjk]

[Oyster 49]

Do both strokes occur at the same moment? I don't think so. I believe that when one piston is on BDC the other one should be on TDC. If that is correct, then all the spark is driven to one spark plug each time.

No it's a boxer engine with a 180 degree crank both pistons reach TDC at the same time.

[Stelios_Rjk]

So the coil may have two secondary windings

[Keith.P]

http://www.amazon.co.uk/Villiers-HT-Coil/dp/B0051NUALA

[Oyster 49]

Tried that one, however nil stock. Too good to be true