Mamod Brunel - Mark 3

[rebelego]

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I have got one of these chunky beasts.
Guess it takes some time to get used to it.
And some modifications are needed.
Looks like the exhaust outlet has threads.
What kind of threads?

[rebelego]

Looks like the exhaust outlet has threads. What kind of threads?

Could it be BSW 5/32" x 32?

(I'm more familiar with metric threads.)

[rebelego]

If the Mamod copper pipes are 1/8", I guess it makes more sense if the outlet is BSW 1/8" x 40?
I can easily push an M3 in without resistance, so a 1/8-40 might be a rather loose fit.

To do test runs indoor I made a condenser. The copper pipe used is 3 mm, just screwed in.

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[rebelego]

Being used to noisy burners, it took some time to figure out that the ceramic burner is totally silent. Only a very small turn of the gas valve is needed. The burner starts with a blue flame and then turn into glowing red.

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Don't look down the chimney!

I don't see any reason to lift the boiler from the footplate with washers. Maybe Mamod has made the holes in the frame larger?

The cylinder was leaking and left a lot of water and oil along the track, so I replaced the o-ring on the piston rod inside the cylinder with teflon string. Now it runs much better and without leaking.

[Old Man Aaron]

The boiler bands really balance the look of the thing. I really do like these little Mamods.
How much are you pulling on that single cylinder, anyway?

[rebelego]

How much are you pulling on that single cylinder, anyway?

Haven't done any explicit pull tests. Load has so far been six small LGB wagons with metal wheels and metal buffer couplings, so heavier than the originals. Running fine at a small layout with very tight curves, ie. Faller e-train track 36 cm radius.

[rebelego]

Old threads about the Mamod Brunel:
https://gardenrails.org/forum/viewtopic.php?t=7945
https://gardenrails.org/forum/viewtopic.php?t=8472
https://gardenrails.org/viewtopic.php?t=11480
https://gardenrails.org/viewtopic.php?t=12907

[rebelego]

I'm no longer able to make the burner glow red. It now burns with a blue and yellow flame, and it is not nearly as efficient.

[Preseli Chris]

I'm no longer able to make the burner glow red. It now burns with a blue and yellow flame, and it is not nearly as efficient.

Not that familiar with the Mamod ceramic burners , but maybe there is some muck on the burner restricting the airflow resulting in a yellow flame similar to closing the collar on a bunsen burner. Is the gas 100% butane or a propane butane mix ?

Chris

[Preseli Chris]

There is some info here about the Mamod Brunel which may be of some help.



https://www.tapatalk.com/groups/modelst ... 97007.html


Chris

[rebelego]

Thanks for the link. I haven't had time to investigate further. Though, I wonder if I have got oil in the ceramic burner. Either steam oil from the exhaust or machine oil spatter from the gears.

[Preseli Chris]

Yes a bit of muck on it. A worst case scenario could be the ceramic burner is cracked. Hopefully not.

[rebelego]

Problem solved.

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A spider had made a nest full of eggs in the burner tube between the air holes and the burner. The gas jet had blown a small hole in the nest causing the gas to light the burner, but without sufficient air to burn properly. I cleaned the tube with a Q-tip and the burner got the red glow again.

[rebelego]

For the records ...

This is what the choked burner looked like:

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This is about what it looks like when burning properly:

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[Old Man Aaron]

You must be relieved to find it was a simple fix. I am!