Lister CS 6/1 running to slow

[ajaffa1]

Hi Guys, a couple of very cold windy days have allowed me to have a bit of a play with my CS. It had a few problems with oil and fuel leaks. These issues have now all been resolved and she runs very well. The heat exchanger also works very well cooling the engine and heating the domestic hot water supply.

Having done all that I fitted the belts that connect it to the Chinese ST5 generator head. Not too surprisingly there was no output from the head, it has been standing idle for years. A quick flash of the windings and hey presto we have an output.

I did the calculations for the driven pulley wheel size based on the diameter of the CS flywheel rotating at around 650 RPM. The problem I have is that regardless of how tight I tension the governor spring the CS does not want to rev past about 400 RPM. It will rev higher if I manually apply additional pressure to the governor linkage. I have taken it up to 650 RPM using this method and the generator will put out 50 Hz, however the force required to overcome the governor weights is considerable and far higher than I would expect the governor spring to be able to overcome.

Thoughts please.

Bob

[ajaffa1]

Hi Glort, this is the same CS I have been working on for the last four years, on and off. I had it running before the fires but had nowhere to store it/run it. It now has it`s own concrete shed to live in. I am now trying to test it, it has still not had any significant load or work. Run time from re-build is probably less than five hours.

The injector is original but has a new nozzle, the injector pump is also original but has a new element. The camshaft was rebuilt using the original governor weights, these were reamed out and new over sized pivot pins fitted. The Governor spring is new but feels like an adequate replacement for the original.

The governor mechanism and the fuel injector pump rack appear to be operating smoothly but it only runs at about 400 RPM. With a little pressure on one end of the rack, it will run at over 650 RPM, once that pressure is released the governor spring pulls the rack back and it returns to around 400 RPM. Just judging by feel, if I fitted a second additional governor spring I might get it up to 500 RPM.

Does anyone know if there were different governor weights for different applications? Judging by the awful sticky sh1t I cleaned out of this unit I would say that it had been in a sugar mill or sugar cane processing plant, perhaps it was intended to run at a lower RPM.

Another possibility is that the new element I fitted in the injector pump is under sized and not delivering enough fuel.

What do you think?

Bob

[AdeV]

The governor mechanism and the fuel injector pump rack appear to be operating smoothly but it only runs at about 400 RPM. With a little pressure on one end of the rack, it will run at over 650 RPM, once that pressure is released the governor spring pulls the rack back and it returns to around 400 RPM. Just judging by feel, if I fitted a second additional governor spring I might get it up to 500 RPM.

The CS has a long threaded rod with which one can tweak the RPM; it basically just pulls on the governer spring to increase the tension. If yours is a 'roid, I don't know if it has the same thing?

Does anyone know if there were different governor weights for different applications? Judging by the awful sticky sh1t I cleaned out of this unit I would say that it had been in a sugar mill or sugar cane processing plant, perhaps it was intended to run at a lower RPM.

Another possibility is that the new element I fitted in the injector pump is under sized and not delivering enough fuel.

As far as I am aware, there are only 3 defined speeds for CS engines: 600rpm (for 3/1, 5/1 engines), 650rpm (3.5/1, 6/1) and 800rpm (8/1 - not sure on the rpm figure for that one). I'm not aware of any factory 400rpm sets; however, it may have been modified by a previous owner...

I've never actually seen a CS governer weight; but if it's maxing out at 400rpm they're too heavy - which is good, because you can lighten them with a lathe/mill/file/axe/spoon (whatever you have handy  ) to achieve proper running speed; then trim with the governer spring adjustment.

It won't be fuel starvation; if it were, the engine wouldn't run any faster & the rack would be pegged fully open.

[mikenash]

Hey Bob just a couple quick thoughts

Am I right in thinking you’re in Australia?  I have dealt with the Old Timer Engine Spares chap there & he has been very good. A couple times playing with CSs & not being sure about the provenance or performance of injector or pump, I have simply bought a new injector, pump & delivery line from him to eliminate doubt about those items - and have had good results. I figure they are good items to have as spares anyway. Just a thought

I have a Chinese “ST” head been sitting in the shed for several years destined to go on my 6/1 or 8/1 one day. Can you tell me how you flashed it please?

FWIW I put a new piston & rings & re-honed cylinder in my 6/1 yesterday. I assembled the rod/piston/rings to the crank & dropped the barrel down over the studs & held it suspended 140mm above the block with a bit of dressed “6X2” and rotated the crank to lift the piston up into the barrel - compressing the rings with fingers & ascrewdriver & exploiting the chamfer on the bottom of the cylinder to lead them in. IMHO SO much easier than from the top if you don’t have a ring- compressor.

Just a comment. Cheers

[ajaffa1]

Thank you guys, sorry I did not reply sooner, been a little busy buying and collecting a Lister ST1 powered dumper. Photos at the bottom.

Thanks AdeV, I did a search of the LEF and found an old post by 38ac about exactly that. A quick check today suggests that I need to shorten the governor linkage by about 1/8". Don`t know when I`m going to find the time but I will report back when done.

Hi Mike, yes I`m in Australia and know Rob at Old Timer Engines well. He has a wealth of knowledge and a lot of experience but I hesitate to call him unless I can not find a solution myself, usually makes me look fu*king stupid!
How to flash an ST head: There are two slip rings; The inner one is F1 the outer one is F2 trace the wiring back to the top box and identify which wire connects to F1 and F2. With the generator rotating, apply 12 volt positive to F1 and the negative to F2.
I have found that having a volt meter connected to the 240 volt output gives an indication of when to remove the flashing voltage. In very difficult situations, using a diode between the positive voltage and F1 will prevent back EMF from preventing a satisfactory flash procedure.

Hi Glort, love the idea of a turboroid, not sure that the purist Lister fans would approve but what the hell, life is too short to worry about them!

Couple of pics of my new Lister toy, going to very useful for building our new house:
 

[listeroil]

Heres  a picture of both weights the 8/1 is lighter.

[32 coupe]

If the linkage is free and the weights travel freely with no binding a heavier spring is the answer.

On my 25/2 I spent weeks playing with springs and weights. Gary sent me a lighter set of weights and
i sent the cam, gear and weights to Butch just to make sure I had assembled it correctly. It was.

You can turn the engine to a spot where the weights will full travel and again make sure you have no binding
thru the entire system. This is without the engine running.

The weights I got from Gary were so close to the originals I dont think they made any difference.
My problem was that I was trying to run the engine too slow.

[ajaffa1]

Hi 32 coupe, if I remember rightly you had quite a thread going about how to govern a CS. Glad you got it sorted.

My problem is that my engine appears to want to run at around 400 RPM, If I apply pressure to the injector rack it will spin up to 700 RPM or possibly more. once I remove that pressure the governor very quickly brings it back to 400 RPM.

I am not certain that my old manual RPM counter is as accurate as it once was so I have ordered a more modern digital laser tachometer. I let you know the results when it arrives.

Bob

[32 coupe]

Bob,

If you have it hooked up to a generator you can measure hz and figure the rpm's
by doing the math. 50hz on a 4 pole head should be 1500 rpm's. Do the math on the pulley
sizes and you will have the engine rpm's.

Gary