You may only be using 12 volt configuration but if you have 200 amps reserve power or more you can weld with it.  It wouldn't be good for the batteries but you can see what a dead short in some part of your wiring would do!

I melted a 3/4" ring spanner one day on a 24V starter motor - was undoing the battery terminal and it swung around and touched the block - a small spark that welded it to the block, a yelp from me, and it began to glow. And glow and glow and glow, as two 12V atteriesb with an available cranking current of about 1300amps discharged fairly quickly. By the time I figured out it was the battery isolator stuck on and had wopped it with a convenient sledgehammer that was nearby, all the battery wiring was a bit on the hot and slightly-melted side.

My spanner was banana-shaped after that.... which was actually pretty convenient at times.

I wonder if a drum-within-a-drum setup would be a better solution.

Eg. Weld a smaller drum inside a larger one, knock out the floor of the smaller drum so air can flow up the centre.
Less water, heats to temp quicker, but nearly twice the surface area of a single drum to radiate heat from.
Less heat transferred via evaporation from the top of the tank but that does mean less water used as well.

Would be cheaper for those that are using alternative coolants too.

For topping up, my tank will be connected to our house supply with a toilet cistern float valve in a separate pipe on the side, attached to bottom of the main tank with 1/2" pipe with a heat trap loop in it. This should be able to keep the tank level under control without cooking the plastic float valve.

Should being the operative word there, I haven't put it together yet. 

Hmmm.

I can't seem to see the required two tons of carefully-sized-and-engineered concrete anywhere there. Better get onto that guy pronto, the Lister Police will want to have some words with him.

Apart from that, wot's that gauge there? Water temp?

Mine would/will be supplied by Sam Warne here in Oz, he's imported them from "somewhere" presumably from whereever the wattshop gets them from. I might chat to the wattshop guys over in NZ and see what their personal experience is. I wouldn't mind a bit of feedback from someone who's done a few hours on them.

Reviving this topic -

A little more info and a couple more photos have come to light -

http://www.thewattshop.co.nz/workshop/PMG.html

Hollow rotor shaft for cooling, although how effective that is is anyone's guess.
As the machine will be situated in wet rainforest near the ocean, I'm very interested in keeping the crud/salt/frogs/geckos etc out, so a fully sealed design is a bit of a drawcard.

Price to me works out about $1200 for the 240V(-ish  ) 3kW one , or a little under double what I can get a ST head here for.

*shrugs*

A small catalytic exhaust purifier, positioned directly at the exhaust outlet and well insulated, would likely clean up the exhaust enough to pass emissions. Can anyone point me to the proper specs? I've an exhaust gas analyser at work and a few small diesel engines with and without purifiers there.

Something like (random google search) this page here:

http://www.dcl-inc.com/dieselparticulatefilter.cfm?lg=EN

or these:

http://www.dcl-inc.com/apppg.cfm?pg=mutileng&lg=EN

How much you're willing to spend on the unlikely chance of an EPA visit is up to you.

I'm just glad I live in an environmentally irresponsible country, where I can run pretty much any sort of engine I like off-road. 

Some of your regulators would have a seizure if they saw me mowing the lawn with my old 2-stroke.
"Hmm. A dollop of oil in the tank oughta do it. Jeez *cough* it's a bit smokey! Oh well... better too much than too little."

At some particular speed, your engine and the mount it is on will move in sympathy with an external force, of any size. The longer you stay at that speed, the worse it gets, regardless of the amount of force being put in.

There are two ways to get around this :

1. Move that resonant speed up to where you'll never reach it, by stiffening the mount. After a while, you go from rubber to wood to concrete - each step in stiffening increases the resonant speed. Unfortunately, the stiffer the mount, the more force is passed through it to your surroundings. Some people don't want that. As the mounts get stiffer, it gets to the point pretty quick where you might as well just bolt the thing down solid. If you have extra weight onboard, you can take that off as well to raise the resonant speed.

2. Lower the resonant speed to the point that - while you still pass through it on startup/shutdown - the initial imbalance forces are quite small and the engine is only ever briefly there. This requires either more mass, or softer mounts. Really, really soft mounts. For any average listeroid combination, it requires mounts that are so soft that rubber has a hard time filling that role, and air or extremely soft springs are needed.

My biggest concern is for people (bob, I'm looking at you  ) who want to use "firm" rubber mounts. It's quite possible to find a resonant point that is at 500 or 800 RPM with this mount and the typical lister weight. The 500RPM is bad, the 800RPM one is worse, as you'll never really see that until something is wrong....

For testing, I would do the following:

Spin the engine up with the decompression on. Get it as fast as you can. Use a small motor, your big muscly arms, whatever. For a resilient mount, I would ideally like to see some jiggle as low in the RPM range as possible. If I can't find it by spinning the engine over and the mounts *are* resilient... I'd be concerned as it implies the resonant point is somewhere further up in the RPM range, where all that force and energy starts to get dangerous.

So say if I spin it over as fast as I can and find it jiggles at 120RPM from engine imbalance, that means it will also jiggle at 240RPM from power pulses. That should be fine - you pass beyond 240RPM pretty quickly when spinning up (one or two power strokes at full rack?), and when spinning down on decomp, there is no power pulse.

If I spin it up with a motor and find it jiggles at 300RPM.... that's bad, as it means the power pulses will jiggle it when it's running at 600RPM. Something would have to be done before I'd start that up.