Forum for air cooled diesel engines and clones

[Militoy]

Thanks for the reply, 90cummins - maybe I need to set up the system to crank for a set period with repeats as necessary - and only add a compression release solenoid if the auto-start sequence fails a few times. So far- the engine has started right up within a second or two. I just wondered if using the CR lever made it easier on the starter somehow. No hour meter on this 2006 (Izumi) genset - but looks like it has quite a few hours on the clock, judging from wear-and-tear, paint splatter, etc. Still, a good strong-running engine for the paltry amount I have invested...

 

[Ilikeurtractor]

On the Launtop "10hp" engine I have there are times when the starter has difficulty getting the engine to roll over w/o throwing the decomp lever but normally this shouldn't be required with the electric starter. To minimize any problems, I'd keep it hooked up to a decent capacity battery (automotive size) with a trickle charger on it and 2 gauge or better cables to the starter/ground. If it's going to be relied upon in cold weather consider some sort of heater to allow it to turn over and start easier. I retrofitted a Cummins intake heater for a snow thrower application as it became clear early on the glow plug that came with it was insufficient in cold weather (<30°F).

 

[California]

Maybe relevant to starting the little clones - ??

Yanmar's older farm tractors seem to be designed for starting when cold, as follows:


1) preheat intake manifold using Thermostart.

2) release compression, crank until oil pressure comes up.

3) open throttle to Run position.

4) with compression still released, crank a moment to spin up the heavy flywheel (genset armature in this case).

5) let the inertia of the flywheel assist the relatively small starter motor. Engage compression after the starter is spinning the engine, so that both the starter and the flywheel are doing the work. Continue cranking if its so cold that it doesn't fire off on the first couple of strokes, until the engine starts to gain rpm.

I'm not sure how to design an unattended start mechanism to do all this for a modern clone 'Yanmar', but describing this might give some insight into Yanmar's design philosophy. In my opinion releasing compression while beginning to run the starter prolongs life of the battery and starter so I do it routinely on my elderly Yanmar tractors.

 

[Neat 1500]

A retro-fitted intake heater may be the go if auto start is needed. I don't think it would fire too well nor crank in cold weather. I maintained some large auto start gen sets many years ago for pumping stations (V10 and V8 Deutz diesels) which had glow plugs but they were on continuously in cold weather in a reduced capacity. I never really looked too hard at the circuitry but the battery charger that was on it drove the plugs at a reduced voltage and current plus kept the batteries charged. When required the change over glowed it fully and it fired on the second crank no matter how cold it was. In warmer weather the thermostat turned the plugs off and turned the battery charger on and off in 12 hour stints.

 

[Militoy]

Good advice from each of you - Thanks! The engine is going to be permanently mounted in a 40 foot Conex container along with all my solar power equipment. It's a new setup - and keeping it all cool has been my biggest challenge so far, with summer temperatures here well over 100F. It can get pretty cold in the winter here - so I probably should consider just putting in a timed compression release and adding a diesel heater to the system for cold engine starts. Controlling the start sequence shouldn't be too big a deal, since I am already controlling and monitoring the system remotely using LabJacks and LabVIEW (Not that I have it all working smoothly yet...).

 

[California]

I like Paul's comment suggesting a pre-heater left on continuously in cold weather at low output, so the diesel thinks it is perpetual summer. Maybe a 5 watt manifold heater left on 24/7 would be enough to make the manifold warm to the touch and take the chill off the entire cylinder head. Then use the glow plug or Thermostart at full power for actual starting and it should fire immediately same as an ordinary warm weather start.

Summary - In winter using energy to keep the engine perpetually ready for an easy start might be more effective than a complex starting ritual.

 

[Militoy]

I like Paul's comment suggesting a pre-heater left on continuously in cold weather at low output, so the diesel thinks it is perpetual summer. Maybe a 5 watt manifold heater left on 24/7 would be enough to make the manifold warm to the touch and take the chill off the entire cylinder head. Then use the glow plug or Thermostart at full power for actual starting and it should fire immediately same as an ordinary warm weather start.

Summary - In winter using energy to keep the engine perpetually ready for an easy start might be more effective than a complex starting ritual.

Agree that running a manifold heater 24/7 would be less complex. In this case though, there are several other considerations. If my battery bank charge state gets so low that I have to charge back up using the diesel genset, it will likely be because we have had a period of cold cloudy weather - and the batteries will be cold and less efficient as well. So heating the battery bank at the same time won't be a bad thing. We are totally off-grid - and under low-battery conditions, every watt I can supply to the house is precious. My transfer switch is set up so that the generator will supply power to the house as well while charging the batteries. I also use the power station as a workshop - with lighting, a drill press and lathe, workbenches etc. inside. I expect I will be using the generator inside the station to weld with as well - and the military diesel shelter heater is already set up there just for my own comfort.
BTW - I wasn't aware these little engines were set up to accommodate any kind of preheat system (glow plug, etc.) at all. My only experience with diesel cold starting is with the Detroit 353 in my military truck, which has an air box. I have never owned a diesel with glow plugs.

 

[Ilikeurtractor]

The glow plug that came in my Launtop diesel was a regular pencil type glow plug you would find in precombustion chambers found on most indirect injection diesels. However, because it was a direct injection diesel, the glow plug is installed in the intake manifold, apparently to heat the air in it which is a rather odd and ineffective application of this style of glow plug - unless it was meant to be left on continuously which is eluded to earlier. Being only 60 watts it doesn't work very well for an intake air heater. These types of glow plugs are intended to have diesel fuel sprayed on them where their high temperatures can ignite it, not heat air alone. I don't believe any of the recent Chinese single-cylinder air-cooled diesels, which are direct injection, use glow plugs in the firing chamber. In fact, I don't know of any direct injected diesels that use glow plugs but that doesn't mean there aren't any. The ones I've seen all have some sort of intake air heater provision.

 

[90cummins]

I finally finished the repairs on the Chinese Leading generator.
To recap it was brought in because it was smoking, skipping and making noises and would not restart turning over like it had low compression.
The first thing I did was remove the oil filter screen which was completely blocked and showed it to the owner, his response was I didn稚 know that was there!
He said the owner痴 manual was destroyed in his damp cellar.
Inquiring as to how much it may cost I replied it all depends on what I find.
Pressing me for an estimate I said that 10 hours should be a reasonable time plus parts, Was I wrong!
Upon teardown I found a couple dead mice and nesting material that blocked much of the cooling system.
After I removed the engine from the silent enclosure I started to remove the rotor from the crankshaft.
This was extremely difficult. First I had to tap generator rotor the end so I could install a ｽ-20 bolt to push the field off the crankshaft.
It was on so tight I was fearing it was not going to come off without major damage.
I used an impact wrench to tighten/loosen it many times with an occasional sharp rap with a hammer in addition to heating the generator end with a torch being careful not to damage the generator itself.
Showing no signs of releasing I threw caution to the wind and went full tilt with my large impact tightening and loosing several times before it final came off. The only damage was to the crankshaft internal threads which a tap cleaned up.
Opening up the engine cases I expected to find a bad cam bearing but to my surprise it was fine.
Further inspection found rust patches in the cylinder and the valves were seating poorly.
The rod and main bearing had many scratches from contamination in the oil but the crankshaft was ok after I polished it with emery.
I ordered a rebuild kit consisting of gaskets with a rod bearing, main bearing and new rings & seals.
Running the hone up & down the cylinder removed the rust but there was pitting that was of no concern.
The valve seats to my surprise were in poor condition so I cut new seats with a Neway seat cutter.
I also lapped the valve and injector lifters to restore a like new finish.
After reassembling the unit I ran it to check operation and found the output voltage low at 90 volts, further inspection found the capacitor faulty.
A new capacitor was ordered and installed and it was tested again only to have it skip occasionally.
This was found to be a faulty low oil pressure circuit. The control units were sensitive to vibration and position so I attempted to order replacements. I also noticed damage to the wiring from MICE! Replacements couldn稚 be found so I had to build a circuit to keep the low oil pressure system operational.
I cut the old control modules out and used two 12v relays to replace them.
After much head scratching and hours I finally had a circuit that worked properly so I could finally test the generator out.
I have a large 3 element heater to load test my generators with each element being 3500 watts.
I connected the load and started the generator, voltage was now 120/240 so I let it warm up with a 3.5kw load so I could set the engine speed for 60HZ and then let run for ｽ hour at load then shut it down to check the oil filter which was clean. Generator was started again and run for 1 hour with a 3.5kw load. After 1 hour I checked the filter again and all was good.
For the final test I plugged it into my house battery backup system for 1 more run at 4kw+ and it ran flawlessly.
The total hours spent troubleshooting was in excess of 25 however 10hrs was my quote.
The total was $800 with 300 being for parts.
The owner operated and stored this generator in every worst possible way.
It was stored in a wet cellar on the ground which promoted rust and mouse damage.
It was always run during power outages with minimal load which caused a wet stacked condition and cylinder corrosion.
He never removed and cleaned the oil filter screen which may have contributed to the erratic operation.
The air filter was not tightened properly which allowed vibration to enlarge the stud hold down hole so it could not properly seal.
When he picks it up I will go to his house and demonstrate how much load he can put on it and how to keep a reasonable load on it at all times.
A killawatt meter and clamp-on meter are essential to properly measure and manage loads.
Last piece of advice will be to store it in a dryer environment after running it with a good load on it and possibly hang the generator from a beam when not in use so mice cannot get into it again.
90cummins

 

[Ilikeurtractor]

Thanks for sharing. Glad you were able to get it running correctly. I usually underestimate time and cost by about 2.5 times also