Lister CS power loss

[knighty]

can you extend your air intake out of the bunker ?

a cold air intake should be much more efficient and lead to cleaner running ?


might not be a big deal now, but once it gets really cold and you're going 24/7 it might make a difference / help a bit ?


if it's -10'C outside the bunker and 30'C inside the bunker that's quite a temp difference ?

(just did a quick google, air is about 20% more dense at -10 than at +30)

[jotec]

I have been thinking about doing that. As I am ducting air into the bunker for the fan it should not be too difficult however----------

------ 8 hours running perfectly yesterday, 10 hours today then  ---- down again

This time I can see gas in the hot water outlet, recently modified to translucent silicone tube for this purpose, from the head so it (the head) is off to be skimmed tomorrow in the hope of sealing it. Could that have been the problem all along? Strange it has good compression though but perhaps a load of 2 kW is enough with a small leak to pull the speed down?

Watch this space.

[biff]

there must be some terrible mistake,something awfull,some dweadfull misunderstanding,,,wait,,its not a lister, friend paul says they are bullit proof and go forever,,
     could it be lister-india,?
                                          biff

[jotec]

Def a Dursley Lister not a 'roid. I have got the head off (again) and I can see a very small blow to the water way (or can I?)
Will get it skimmed tomorrow and back together.

Getting the head off now takes less than  20 mins, including draining and removing the PMA.

When the head goes back on the torque goes up on the studs!

[bram]

when its down on power whats the exhaust smoke like on max fueling, blue, black, grey, white any change from the norm, particularly on these older engines the colour of the exhaust gas is one of the biggest indicators of whats happening. 

[biff]

would you need a coat of shelac on the gasket,?? 
                                    it worked for me when wonderweld would,nt.. (now there is real bodging)
                                                                                  biff

[jotec]

On power loss the governor opens fully so the smoke is black. Take the load off and there is little smoke.

After the skim I might try the varnish trick.

[knighty]

any idea how hot the water in/out of the engine is ?

iirc it's setup to thermo syphen ?

maybe it's getting a bit hot and that's what's causes the head gasket to fail ? expanding/contracting etc.. ?

[jotec]

It is thermo syphon and the water out is running at 80 ish C according he the non contact thermometer I use. On very close examination of the old gasket it is clear that it was only in contact less than 1/3 of the way across the fire ring in one area. This could explain the fail

I have had the head skimmed today, it was slightly bowed. The locating dowels have been turned down to compensate and the head refitted with a genuine Lister gasket.

It is again going down and holding the governor fully open but no bubbles in the water now.

I think it must be the PMA going partial short and overloading it but it still gives voltage on all 3 phases that are very close to the same when it is, allegedly, in short?

The Windyboy registers the reduced voltage and wattage output is it possible it could be drawing more current than it is outputting and not registering a fault.

[Heinz]

Seems a bit odd for the PMA to be shorted but still chucking out the three phases in balance??
Can you hook the PMA output direct to a test load of some kind. 2KW immersion heater? That would at least tell you whether the fault is in the engine/PMA or the electrickary department.
Have you checked bearings ? Sometimes get some really odd failures like one ball split in half, bearing runs fine by hand but put some load on it and the halves start to separate and slow the thing down.
Slacken the belt a little ? If the belt starts to slip (on the same apparent electrical load) when the engine opens the gov. fully and starts to slow, the problem is PMA etc. rather than engine.

H

[jotec]

Good idea on the slipping belt. Will give it a go tomorrow before I try anything else.
I will try an immersion as well, that should be within the ability of the engine and not cause an overload.
Thanks H.

I am going looking for a clamp on ammeter as well.

[jotec]

Problem solved.
Despite the PMA showing correct resistance across all phases and delivering voltage within vey low percente of each other the fault was  an intermittent short between 2 wires within the stator windings. Once seperated it is working fine.
The manufactures advises running it at a lower temperature s oI have drilled the end covers and fitted a cooling fan. It now runs at about 75c rather than the 100+c previously.
Another stator has been ordered from Ventura USA for when this one fails again. (the windings show signs of overheating in some areas)

Thanks for all the excellent advice.

Dick