Micro CoGen.

Been working on a project. I need to start checking in more often.

The Kubota Z482 runs much smoother in the upper range that Keith71 mentioned. (2800 rpm)

When I was testing a Z482, I found that 1800 RPM's was too low. This was also verified from some acquaintance's I got to know that work for a very well known manufacturer that builds Kubota powered generators for marine, standby, and continuous use.

A Kubota Z482 powered 1800 rpm direct drive generator is very rare. It will not be able to put out anywhere close to 4000 watts.

Over ten years ago, I called Kubota engines in the US and had an opportunity to speak to an Application Engineer. He mentioned that the Z482 engine's sweet spot is near 2800 rpm's. He also mentioned that the engine will live a much longer life due to less vibration and stress. The oil pump will also be operating at full continuous output. Even when the oil reaches high temperatures. The Z482 operates much quieter near 2800 to 3000 rpm. At 1800 there is much more noise. (Combustion and mechanical noise) The engine was just not happy running there.

Peak torque is near 2600 rpm's. One of the things the Kubota application engineer went over was how important it is to stay 200 rpm's past peak torque curve. The reason why is, when an engine starts getting a load, the governor speed will drop and in turn the engine normally not dip below peak torque curve. This is healthy for a diesel engine.

Any time an engine goes below peak torque curve, it becomes much easier to overload an engine. (One terminology is called lugging an engine)

I also built a Z482 powered direct drive two pole generator. The engine seemed stressed. It had a good amount of vibration. I would not recommend running a Z482 engine at 3600 rpm, or 3720 rpm unloaded.

My recommendation is belt drive a Z482 engine equipped with a 3600 rpm flywheel. And, run it near 2800 to 3000 rpm. See where is runs best with the least amount of vibration.

Hope this helps.

I meant to ask what Alternator Or Generator do you plan to use ?

Hi three reefs, I am not a Kubota expert but I do have a Kubota D722 that I still deciding on whether to use my meecalte 7500 watt head and belt drive it or go 48 volt with a pma with a bell housing setup, or regular heavy duty truck alternator. Remove the factory rectifier and diodes and externally rectify the three phase ac windings into 2 150 amp rectifiers. Depending on the voltage output, might run it into a charge controller, or in the case of a pma run it at whatever rpm is needed to output 56-57 volts and 100 amps to directly charge a 48 volt bank of lifepo4 batteries. Enough of me.

As for the Z482 for use at 1800 rpm. They may retard the injection timing, Add more mass to the flywheel. The one you posted looks to have a beefy one.  With 5.5 HP at 1800 rpm You would be doing real good if you were getting 3000 watts continuos. I dont think it would like running like this. A more realistic goal might be 2500 watts, maybe 2700 max cont ? I am not sure. The listing you posted does not describe what the engine is used for. But looks to be generator type.

Henry here on the forum has lots of knowledge and could better answer your questions. In fact I think he actually did build a z482 and if I remember correctly he ran it at 2600-2800 rpm? I think he has a build thread if you search the forum. Or better yet you could pm him... He is a nice guy and is willing to help to the best he can.. Have fun, Keith.

I am kicking off a project to build a generator. It will be a smallish Kubota diesel driving a chunky 48V alternator, which can put energy into my 48V batteries which in turn feed an inverter. I'm going for this approach because the inverter will be my main power source - good output, clean sine wave, versatile - and most of my power needs are intermittent, so having a genny run all the time is not a good fit. Plus, this way is a lot less fussy about alternator speeds.

I think I'm looking at a small Kubota engine like the supermini range, Z482 etc, but Kubota seem to advertise some of these - and their larger 3-cylinder brothers - as "1800 rpm" versions like this :
https://global.engine.kubota.co.jp/en/products/detail/126/
They have derated it in the spec to 5kW / 4.5HP, but is this engine "special" in any other way ? What have they done to it, I wonder, to make it a "1800 rpm" version. Am I going to get different results getting a "normal" 482 and just running it slower ?

I want to end up with a slow-running engine for noise and reliability, so 1800 is kind of a goal for me, and 4kW would be a good-size output... just trying to understand the range here.

Anyone have any thoughts ?
Thanks !
Richard

Learning lots of good stuff.

I'll be making calls tomorrow  and work on getting information.

Wow that is a serious build up Henry.. There is some great thinking goin on there.. Dont even know where to start lol. Going to read your post again..

Quote from: keith71 on February 21, 2024, 05:53:02 AMI bought new in 1999 a chevy S10 pickup truck 2wd 5 speed.. It had the 2.2 LN2 4cylinder engine with a whopping 120 HP @5000 rpm with peak TQ of 130 ft.lbs at something like 4200 rpm (cant remember the tq number exactly.

Anyway drove that truck 100 miles a day roundtrip.. It averaged 18-20 mpg whether my foot was to the floor(which it always was with the anemic 120 hp and 3900 weight of the truck) Or gently cruising down the highway @60-65mph..

So in 2009 with roughly 65-70 k on the odometer..
I Fabricated and built a turbo charger for this truck using a T3-T4 turbo, (little to big) At 75000 miles I promptly broke a ring land on the factory cast piston at only 6 lbs of boost.   (had hoped to raise fuel pressure and add fuel the easy way) It was not enough.
Out came the engine Wiseco forged pistons, Eagle H-beam 4340 con rods and Mls head gasket were all installed..

Now the fun part..   I purchased efi live, (same as hp tuners) It is a tuning software that is used to change 90% of the 250-300 tune parameters that are stored in the factory ecm.  I needed to use and be able to tune factory ecm due to emmission regulations in the great state of CT. An aftermarket ecm would have never passed emmissions.. These are obd2 ecm's that started in 1996.
I started slowly adding fuel to the tune and reducing ignition advance while closly watching my AFR gauge.. At 12 lbs of boost and 5200 rpm the injectors could not give anynore fuel(stock 17 lb/hr) So it started getting lean despite increasing the pulse width a ton. but the engine mechanically was okay with almost double the horsepower.
So I Added 30 lb injectors requiring another adjustment on the injector tables in the ecm to compensate. And a smaller T3 turbo with a smaller exhaust AR housing provided nearly instant boost at 2000 rpm. But would run out of airflow at 20-22lbs and 5700 rpm. (who needs to rev that high in a pickup truck anyway)
At 18lbs of boost and 12.6 AFR I had a little sleeper rocket as I called it At about 300 hp at the wheels it was fun to pick on unsuspecting stock  camaro's and rice burners with those fart can type mufflers. They make alot of noise but dont really do anything.. I had 100% stock exhaust from turbo down pipe to the tailpipe. Very mild mannered and pleasant to drive with boost building slowly with rpm just driving normally. Zero lag from the turbo. The T3 was sized just right for a daily driver.

I also got a few more mpg's with the turbo believe it or not. If I was driving normally. I believe because I only need 1/4 throttle to cruise down the highway at 65-75 mph instead of my foot to the floor with stock engine just trying to keep up with traffic. I drove that truck until last year. It had over 200,000 miles on it with 140,000 miles of those with the turbocharger.  She has finally started getting some blowby enough that the biggest catch can they make was 2 quarts to small.It will puke about 2 quarts right out into a catch can in about 6 seconds at 20 psi. lol. yep she is tired now.
Suppose I could bore it 1mm over new wisecos and drive her for another 100,000 ??  . I doubt it now, it is retired..
I know totally off topic but I was just reading about your adventures with your straight 6 and it brought back some memorys..   

Quote from: keith71 on February 21, 2024, 04:51:43 AMLove to hear the condensed version of what your up to now with your Carbureted (yuck) (joking) lol 300 inline 6 .. I only remember the holley sniper efi, which I know was terrible for economy and performance to a stock holley 390 cfm carb?? Among other issues with the sniper.. I hope you go back to efi with another system instead of any holley type..

Iam sure you are aware of the late 80's early 90's GM ecm's.. People have been adapting those things to lawn mowers to trucks.

Their is also megasquirt, which is ok but getting $$$
Also there is now speeduino ecm, which is adaptable to anything 1 cylinder to 12 cylinder.  Both of these would use all factory ford efi parts and the factory efi harness that came in the ford efi trucks with 300 6 cyl.

Speeduino is open source as well as gm ecm's from the 80's. using gm ecm bins with full open source data logging from tunerpro.. 7747 GM ecm from late 80's I believe is a good one. Have you checked out a forum called Gearheadefi ? these guys have been tuning and installing these ecms on everything for 30 years..   I could go on and on..  Was just wondering what you re doing with your inline 300 ford?  I felt bad when I read all the trouble you had with holley sniper. So knew you were not to happy and did not want to piss you off anymore with any other suggestions cause I know you tried them all..

Actually, the 4.9 EFI (300ci) with the updated ignition and Holley 390 setup is doing quite well for what it is. Average MPG is around 16.9-17.6 when taking it easy. And it has consistently achieved  low 19's with a very light foot at 50-55 MPH.

The engine is tired. Working with the retired Ford engineer and another engines builder, the lower displacement 240 engine will be replacing the tired 300.

The engine is being based on an Atkinson-cycle engine. It's going to have less pumping and friction losses.

• Custom cam is drawn up. And cam blank is ready to sent to be ground when everything else is figured out.

Right now we're waiting for the updated high swirl head to arrive. So we can figure out exactly what the combustion chamber cc's are. Once that is finished. The next step is getting the DCR between 7.0-7.2 . This will be accomplished by piston dish depth and width. So far the piston dish looks like it will only be 0.050" deep.

Compression height on the pistons will be 1.6" this will allow up to 0.020" to be milled off the deck. We are looking to get the pistons close to zero deck so a quench of 0.040" is obtained.

This is the reason why the cam blank was not ground. The camshaft will be the last piece that will get the DCR where it needs to be so 87 octane gas can be ran without worrying about detonation.

Pistons will have thinner 1.5mm x 1.5mm x 4mm rings. Much less friction. The piston tops will be ceramic coated. This will reduce heat soak to the piston and wrist pins and in turn, oil temperature will be reduced to a very safe level.

The bottom end of these engines are already strong, but we went a step further by finding a set of early rods without oil squirter. The later rods with oil squirters fail at around 6,500 RPM's. The earlier rods hold up well to over 7,000+ RPM's on the 240 engine.

The 240 crankshaft has a 3.18" stroke. The stock 240 crankshaft mains and rod journals overlap considerably which makes a super strong and stiff crankshaft. These 240 crankshafts are known to hold up to 9,000 RPM's with very little work.

Here is the kicker of this whole build. The engine long block will be capable to handle well over 300 HP.  But, it's detuned for efficiency. We are looking for 25+ MPG.  The engine will put out about the same hp, or possibly more than the 300 engine. The Ford engineer and the other engine builder been building and racing the Ford big block inline sixes since the 1970's. So I have pretty much some of the best mentors available.

Carburetion is going to be used with lots of HEAT on the manifold. TBI and MPFI will not work best for what we're trying to achieve with today's gas.

A Small Weber 32/36 will be used. There is a trick that we've been playing with. And, it works. Since my truck has an AFR meter installed, I can monitor the exact air fuel ratio at all times. We are using a metering valve to create a controlled vacuum leak that adjusts the AFR exactly where it needs to be. The carburetor is jetted slightly rich at sea level, then the controled vacuum leak will be able to adjust to air fuel ratio up to over 6,000 feet with no problems. We have not tested it any higher because the highest elevation here is about 6,600 ft.

So in a nutshell, what is being built is a long block that is grossly over built that capable of handling 300+ hp and over 300 ft-lbs of torque and able to handle over 7,000 rpm's. But, is de-tuned for maximum efficiency and longevity for every day use. Just a bulletproof, efficient engine that will last as long as I'm able to drive.

Cooling, an active radiator shutter will be put in place to keep the coolant close to a 20 degree temperature differential. The belt driven fan is going to be replaced with an electric fan.

Already have an updated MSD6AL ignition box, but that is also being looked into and might be updated with digital timing.

The distributor will be  recurved again by a friend that has a Sun distributor machine. He's been recurving distributors since the mid 1970's. He's one of the best that I know.

I bought new in 1999 a chevy S10 pickup truck 2wd 5 speed.. It had the 2.2 LN2 4cylinder engine with a whopping 120 HP @5000 rpm with peak TQ of 130 ft.lbs at something like 4200 rpm (cant remember the tq number exactly.

Anyway drove that truck 100 miles a day roundtrip.. It averaged 18-20 mpg whether my foot was to the floor(which it always was with the anemic 120 hp and 3900 weight of the truck) Or gently cruising down the highway @60-65mph..

So in 2009 with roughly 65-70 k on the odometer..
I Fabricated and built a turbo charger for this truck using a T3-T4 turbo, (little to big) At 75000 miles I promptly broke a ring land on the factory cast piston at only 6 lbs of boost.   (had hoped to raise fuel pressure and add fuel the easy way) It was not enough.
Out came the engine Wiseco forged pistons, Eagle H-beam 4340 con rods and Mls head gasket were all installed..

Now the fun part..   I purchased efi live, (same as hp tuners) It is a tuning software that is used to change 90% of the 250-300 tune parameters that are stored in the factory ecm.  I needed to use and be able to tune factory ecm due to emmission regulations in the great state of CT. An aftermarket ecm would have never passed emmissions.. These are obd2 ecm's that started in 1996.
I started slowly adding fuel to the tune and reducing ignition advance while closly watching my AFR gauge.. At 12 lbs of boost and 5200 rpm the injectors could not give anynore fuel(stock 17 lb/hr) So it started getting lean despite increasing the pulse width a ton. but the engine mechanically was okay with almost double the horsepower.
So I Added 30 lb injectors requiring another adjustment on the injector tables in the ecm to compensate. And a smaller T3 turbo with a smaller exhaust AR housing provided nearly instant boost at 2000 rpm. But would run out of airflow at 20-22lbs and 5700 rpm. (who needs to rev that high in a pickup truck anyway)
At 18lbs of boost and 12.6 AFR I had a little sleeper rocket as I called it At about 300 hp at the wheels it was fun to pick on unsuspecting stock  camaro's and rice burners with those fart can type mufflers. They make alot of noise but dont really do anything.. I had 100% stock exhaust from turbo down pipe to the tailpipe. Very mild mannered and pleasant to drive with boost building slowly with rpm just driving normally. Zero lag from the turbo. The T3 was sized just right for a daily driver.

I also got a few more mpg's with the turbo believe it or not. If I was driving normally. I believe because I only need 1/4 throttle to cruise down the highway at 65-75 mph instead of my foot to the floor with stock engine just trying to keep up with traffic. I drove that truck until last year. It had over 200,000 miles on it with 140,000 miles of those with the turbocharger.  She has finally started getting some blowby enough that the biggest catch can they make was 2 quarts to small.It will puke about 2 quarts right out into a catch can in about 6 seconds at 20 psi. lol. yep she is tired now.
Suppose I could bore it 1mm over new wisecos and drive her for another 100,000 ??  . I doubt it now, it is retired..
I know totally off topic but I was just reading about your adventures with your straight 6 and it brought back some memorys..   

Love to hear the condensed version of what your up to now with your Carbureted (yuck) (joking) lol 300 inline 6 .. I only remember the holley sniper efi, which I know was terrible for economy and performance to a stock holley 390 cfm carb?? Among other issues with the sniper.. I hope you go back to efi with another system instead of any holley type..

Iam sure you are aware of the late 80's early 90's GM ecm's.. People have been adapting those things to lawn mowers to trucks.

Their is also megasquirt, which is ok but getting $$$
Also there is now speeduino ecm, which is adaptable to anything 1 cylinder to 12 cylinder.  Both of these would use all factory ford efi parts and the factory efi harness that came in the ford efi trucks with 300 6 cyl.

Speeduino is open source as well as gm ecm's from the 80's. using gm ecm bins with full open source data logging from tunerpro.. 7747 GM ecm from late 80's I believe is a good one. Have you checked out a forum called Gearheadefi ? these guys have been tuning and installing these ecms on everything for 30 years..   I could go on and on..  Was just wondering what you re doing with your inline 300 ford?  I felt bad when I read all the trouble you had with holley sniper. So knew you were not to happy and did not want to piss you off anymore with any other suggestions cause I know you tried them all..

You're welcome Keith.

Been busy for the last 7 months on an engine build with some well known engine builders in the country that built many impressive Ford big block inline sixes.

Lots of learning and fun.