Lister CS power loss

[jotec]

As some will know I run a CS to power and heat the house. Fuel is used veg oil.

Recently I have experienced a power loss. It will not maintain the revs necessary and slows down with the governor fully open. It revs fine when not on load.

I have:-
Cleaned the exhaust
Decoked
Ground in valves
Fitted the new rings the were waiting to be fitted
Had the injector set
Checked the timing.
Checked fuel flow

Any ideas where to go next, it was fine last week!

Dick

[Heinz]

As some will know I run a CS to power and heat the house. Fuel is used veg oil.

Recently I have experienced a power loss. It will not maintain the revs necessary and slows down with the governor fully open. It revs fine when not on load.

I have:-
Cleaned the exhaust
Decoked
Ground in valves
Fitted the new rings the were waiting to be fitted
Had the injector set
Checked the timing.
Checked fuel flow

Any ideas where to go next, it was fine last week!

Dick

Lack of fuel, lack of air or too big a load.
First things I would check/replace are the fuel and air filters. You checked the fuel flow how? I find it often help to bypass systems to try and find the fault, like remove the pipe from the injection pump and fit a tin can fuel tank direct to the pump, fill with diesel and see what happens. I've got a used car fuel injection filter case with one end chopped out just for doing stuff like this. Blow out fuel lines/unions individually with compressed air if you can. Disconnect the air filter, what happens? I'm assuming it has an air filter?
Valve clearances OK? better wide than tight. Generator spins freely on it's own?

H

[camillitech]

Blocked air filter  Had it on HR's with the oil bath type, try it with the filter off. Worn, weak or broken governor springs but I'm sure you've covered that. Not really familiar with the CS Dick, sorry.

Good luck, Paul

[billi]

My generator sucks air into the fuel(line) system  somewhere and does not perform smooth under heavy  loads   , found that out  by constant draining air  at the fuel filter while running ( some diesel as well  )  and it works good then

But have no clue about lister engines  so i keep quiet  now

[jotec]

Tried it with no air filter no difference.
Valve clearance is spot on.
No air in system.
Governor striped and clean and a new spring tried.
PMA spins fine.
I am trying with direct diesel to the pump tomorrow but I am comming round to it being the pump. I will strip it and see what I find, I suspect the element.

[desperate]

How about the compression, is it the same as before, can you check it on your engine?, did you check the ring gap before you fitted them, too big or too small is no good, and the clearance in the ring grooves. Does the bore look okay not glazed but smooth, is there a lip at the top. Loss of compression is usually a gradual thing, but you seem to have check the obvious things. That pump is the most likely I would guess.

Let us know what you find.

Desp

[jotec]

The ring gap is spot on and the bore OK. The fit of the rings in the ring groves is spot on. Compression is good. I can stand in the flywheel spokes, I have not checked it with a gauge (not sure if it is possible).
 

[eabadger]

have you tried it with diesel to eliminate issues with your veg oil production? also temp has changed of late, pre heating veg oil is working or fitted?
do you work it hard to stop glazing of bores? try loading it to max for 30 mins.

steve

[jotec]

have you tried it with diesel to eliminate issues with your veg oil production? also temp has changed of late, pre heating veg oil is working or fitted?
do you work it hard to stop glazing of bores? try loading it to max for 30 mins.

steve

Tried it on diesel no difference. It ran all last winter down to -19 here with no problems. The high pressure injector line is heated  and the bunker maintains a temp of 50C.
I have fitted new rings as the old ones were getting worn and glaze busted it but on 2kW continually it is not running at low power.

I have moved the rectifier to a cooler spot and changed the head gasket as it was blowing into the coolant so I will see how that goes but, after taking advice from the PMA manufacturer, I think I will have to cool the stator. 

It is a challenge!

[johnrae]

Chances are that your injector is "wet"  As the orifii wear the injection pressure lowers and the spray pattern isn't as fine as it should be or the injector dribbles due to soot build-up resulting in slower combustion speed and hence lower engine power.  Note that fuel pump capability or engine compression are irrelevant if the injector is dodgy.

[jotec]

Injector has been tested by a diesel services, sonic cleaned and set. I have also tried it with another injector and it was just the same. Also fitted another pump while I await a new element for mine and the fault returned after 6 hours running well. The first 5 hours with the bunker door open, then shut for the last hour.

I have had the head off today to check if it is cracked between the valves (no) and fitted a better type of head gasket as I suspect it may have been blowing exhaust into the water when hot.

it has been running today now for 7 hours on full power (2kW, 550 RPM) and seems OK but I have left the door open to keep the bunker cool.


I am more and more convinced it is heat related, I am now going to fit forced cooling to the PMA and see what that does.


One consolation I could strip it down to decoke quite fast before ---- now it is almost a speed sport!! (except getting the big end done up!!)

[Heinz]

it has been running today now for 7 hours on full power (2kW, 550 RPM) and seems OK but I have left the door open to keep the bunker cool.

Not sure how your system is set up, what is the bunker? Fuel tank? If so, how is it vented? Fuel starvation due to a vacuum developing in the fuel tank?

H

[jotec]

My fault,
The bunker is the underground 'shed' that the Lister is in. The fuel tanks are well vented.
This is the blog of the setup
http://www.dpks.co.uk/CHP/main.htm
Not updated recently, must get round to it!
Dick

[spaces]

Is the bunker temperature higher when the gen is working at full load? Is the air intake inside the bunker? Also, are the fuel tanks outdoors? Has your fuel mix changed much since last winter?

Just had a quick look at your blog, see the Palm Oil wasn't working as bio feedstock, and that this is a change of fuel. Could it be anything to do with this oil - or the J-cloths?

[jotec]

Is the bunker temperature higher when the gen is working at full load? Is the air intake inside the bunker? Also, are the fuel tanks outdoors? Has your fuel mix changed much since last winter?

Just had a quick look at your blog, see the Palm Oil wasn't working as bio feedstock, and that this is a change of fuel. Could it be anything to do with this oil - or the J-cloths?

Bunker temp is constant as the 'cooling' tank is in there to keep it warm as are both fuel tanks. I must confess that it is warmer than I expected when I 'designed' it but that has not changed and it ran through the summer (4000+ hours in total). Been running on palm now for months and the J cloth filter has been in for months  and the cloths changed. I start and when I have problems run on filtered WVO and that is on a different fuel line and filter.
It ran yesterday for 10 hours, 20kWH, fine and is running fine again today so I am hopeful that it is now solved. I think it was a mixture of things culminating in a faulty head gasket but I will only be convinced after quite a while running.
I will post what I have done and my thinking later for the benefit of anyone else doing the same.

Thanks for all the interest and ideas.
Dick