Have a D722 from a onan 7500 watt generator. The flywheel on this engine has no way to incorporate a stub shaft. As the generator rotor is casted as one piece with the flyheel. The part numbers I have are for the Z482 engine. Hopefully they should be the same for the D722. Part numbers I am looking for are- Thanks to Henry for posting the z482 parts book..
From the June 2006 parts book Z482-E2B-DGDE-4
Flywheel 16851-2501-5
starter housing plate 15847-0461-2
OR
From the 1994 parts book Z482-BBs engine
Flywheel 16851-2501-0
starter pate housing 19666-0462-0
Thanks, Keith.
More pics of D722 Onan style.. Even the starter is on the wrong side.
if it was me, and fwiw
i would look to making a stub shaft by cutting out and machining a round plate that would
register with the 3 bolt pattern, and then inset a stub shaft into the plate
i would look at maybe a half inch plate, maybe a bit thicker if you like
and machine it to register in the recess of the oem flywheel, drill the three holes to bolt it up
and then chuck it up in the lathe and bore for a stub shaft of whatever size you like, maybe 1.25" or so
press it in and weld it in place,
alternatively with the machining process
rough cut out the round larger than what the finished size would be, chuck it up and bore the hole for the stub shaft
then press in the stub and weld... then chuck up the stub shaft and turn the OD of the plate to fit the flywheel register lip
and then fit it up to the flywheel, use a little slow drying paint of whatever transfer media you like to illustrate the hole pattern, drill and bolt it up.. the holes would not need to be perfectly aligned, just close enough to allow the bolts to mount the plate as the OD would provide for the perfect alignment.
i think that would work very well in my opinion.
about how large is the diameter of the flywheel 3 bolt register on the ID needed to mount the OD of a plate? looks like maybe ~8" or so?
bob g
+1 on what Bob suggested.
Bob and Tom.. Thank you for the reply. I like the way you guy's think.
I will post a few more pictures. Bob those three bolt holes are there for a plastic fan that cooled the radiator. They are only M6 size bolts. Do you think they will be strong enough? It looks like their might be some room to drill and tap for an M8 size bolt.
Also this rotor is deeper than it looks. With a 3-4 inch shaft, the end of the shaft where the pulley will be mounted will be 9-10 inches from the face of the flywheel. Should I be concerned that it might be to much sideload on the crankshaft and bearings? Also, the register where the 3 bolt holes are 5-9/16'' and the flywheel OD is 10-5/8''.. Anyway I will let the pics explain more.
A few more
Look what I came up with.. Pulley is a perfect fit inside the register of the rotor.. If I could thru bolt it with maybe some threaded rod, would it hold tight enough to keep from spinning?
Quote from: keith71 on April 13, 2022, 04:35:58 PM
Look what I came up with.. Pulley is a perfect fit inside the register of the rotor.. If I could thru bolt it with maybe some threaded rod, would it hold tight enough to keep from spinning?
I think the flanges of that pulley are to weak. A 3/8 or 1/2" plate with a stub shaft should work well.
This is where I got the stub shaft adapter for my Kubotoa.
Hayes manufacturing in the USA.
Give them a try.
See the attached .pdf
Quote from: Tom Reed on April 13, 2022, 09:41:28 PM
Quote from: keith71 on April 13, 2022, 04:35:58 PM
Look what I came up with.. Pulley is a perfect fit inside the register of the rotor.. If I could thru bolt it with maybe some threaded rod, would it hold tight enough to keep from spinning?
I think the flanges of that pulley are to weak. A 3/8 or 1/2" plate with a stub shaft should work well.
Yes I agree. I was just throwing it out there. I got over excited because it fit the flange register so well..
How about the three M6 bolts? Pretty small diameter bolts to hold a 1/2'' plate and a 2 groove pulley with 4L belts driving a 7500 watt head. Those three bolts were just holding a plastic cooling fan to the flywheel hub.. Not doubting anyone's expertise here, just double checking..
Kubota used the super mini series in alot of different applications. There are 3-4 different size flywheels, starter plates, bellhousings, starter on left or right side etc depending on what they were installed in. Thank you..
Looks like there is plenty of beef in the cast bosses to easily go up a bolt size. How deep is the step in the flywheel. The reason I'm asking is that if you're uncomfortable with the 3 bolts holding, you could machine a step in the adapter plate and add some new/extra bolts to the surface of the flywheel. If it was mine, I'd just upsize the 3 bolts and go with it.
giving this a bit more thought, and from what i can see in your pictures
i would think that one could make a stub shaft machined to fit the bore of the flywheel, and make it long enough
to go out through the plate that registers to the 3 bolt flange
then the flange need not be more than maybe 1/4" plate, fit it all up, tighten the 3 bolts, tack weld the stub to the plate
then remove and weld it up from the inside
then turn the shaft plate assembly to clear off the tack welds on the outside so the pulley can slide up as close to the plate as possible, and i would think it would be good to go... just use some high strength m6 bolts and it should last forever.
the shaft would not flex the plate under load either, even with a 1/4" plate.
fwiw
bob g
There are a few ways to skin this cat.. But I have found a flywheel and starter mount plate for the D722. And have also found a stub shaft that is made to fit this engine.. For a very reasonable price as well. Thanks for the good idea's Bob.. As I was probably gonna do what you suggested had I not found these parts.. More pics to come soon.. Thanks everyone.
Quote from: keith71 on April 13, 2022, 02:57:11 PMBob and Tom.. Thank you for the reply. I like the way you guy's think.
I will post a few more pictures. Bob those three bolt holes are there for a plastic fan that cooled the radiator. They are only M6 size bolts. Do you think they will be strong enough? It looks like their might be some room to drill and tap for an M8 size bolt.
Also this rotor is deeper than it looks. With a 3-4 inch shaft, the end of the shaft where the pulley will be mounted will be 9-10 inches from the face of the flywheel. Should I be concerned that it might be to much sideload on the crankshaft and bearings? Also, the register where the 3 bolt holes are 5-9/16'' and the flywheel OD is 10-5/8''.. Anyway I will let the pics explain more.
I would be concerned some about side load. 9" to 10" from the face of the flywheel is way too much.
There is a flat D722 flywheel from a grasshopper mower for sale on eBay. I might have a left over starter plate from a Kubota z482. I'll have to get in the garage and look. The starter plate should fit the D722.
China makes a Kubota clone starter that will work. No reason to spend lots of money on an oem starter. The Chinese starters worked fine on my projects.
Henry
Quote from: Henry W on April 27, 2022, 09:19:10 PMQuote from: keith71 on April 13, 2022, 02:57:11 PMBob and Tom.. Thank you for the reply. I like the way you guy's think.
I will post a few more pictures. Bob those three bolt holes are there for a plastic fan that cooled the radiator. They are only M6 size bolts. Do you think they will be strong enough? It looks like their might be some room to drill and tap for an M8 size bolt.
Also this rotor is deeper than it looks. With a 3-4 inch shaft, the end of the shaft where the pulley will be mounted will be 9-10 inches from the face of the flywheel. Should I be concerned that it might be to much sideload on the crankshaft and bearings? Also, the register where the 3 bolt holes are 5-9/16'' and the flywheel OD is 10-5/8''.. Anyway I will let the pics explain more.
I would be concerned some about side load. 9" to 10" from the face of the flywheel is way too much.
There is a flat D722 flywheel from a grasshopper mower for sale on eBay. I might have a left over starter plate from a Kubota z482. I'll have to get in the garage and look. The starter plate should fit the D722.
China makes a Kubota clone starter that will work. No reason to spend lots of money on an oem starter. The Chinese starters worked fine on my projects.
Henry
See post #12 Thanks.
I missed that post. Thanks.
It may have worked being extended that far but I really did not want to take the chance. The belts should not be that tight anyway I imagine. Not sure how to figure the side load it would put on it anyway. And I did not want to spend a ton of money coming up with a bearing and bellhousing support solution.
Meant to ask you guy's,what oil do you like to use in these small Kubota's? Maybe a grade that is close for all season if that is possible. Might have to start up in the winter when it is 25f or in the middle of the summer when it could be 85-90f for a few day's. Thanks.
For older engines such as your Kubota. I use Chevron Delo 400 SAE 30 mono-grade.
The stuff has a total base number of 10.1. A high TBN helps neutralize acids that build up in the crankcase.
And, it has a bit more zinc than other oils.
Amsoil makes two specific multi-grade oils that work well with small industrial diesels.
They are expensive and they work fine in colder weather.
Note: some older engines have oil seals that might not be compatible with synthetic oils and the seals can start leaking.
Product codes for quarts: (Gallon jugs are available)
ADNQT-EA 10W-30
AMEQT-EA 15W-40
(Open the attachments below for Chevron Delo 400 info)
Keith,
I'm looking forward seeing the project come together.
The Kubota D722 is a great engine. It has the same bore and stroke as the Z482 engine. Peak torque on the Z482 and D722 comes on at the same RPM's. (2600) A person that you spoke to not too long ago mentioned to me about ten years ago that it's best to keep the RPM's over the peak torque curve by 200. The reason is when the generator is loaded, the engine RPM's could drop as much 200. This will keep the engine operating at or just over peak torque. I've also had this discussion with an application engineer at Kubota about the same time. This confirms that 2800 is a healthy speed for the Z482 and D722 engines.
About engine life, Some D722 engines and others have been known to operate 20,000+ hours. The maintenance had to be exceptional to achieve it. That is a long time. So, I feel there is no concern for the engine having a long life when the engine is properly maintained.
The Engine should have no problem pulling the load that your generator is able to produce.
Henry
Hi, Henry,yes that custom generator company told me that 2850 is the absolute sweet spot for the D722 for best effiency. And they run their belt driven generators at that rpm. On the other side of that They said that a D722 puts out enough power to make a little over 5000 watts at 1800. They have many units that are direct driven at 1800 rpm. Main issue is harmonics. The oneissue with the kubota super mini series is balancing, or the lack of it.Not very well done in their opinion. There is now a harmonic balancer that attaches to the flywheel available for these engines. They have seen bad vibration at different rpm levels depending on the load and drive set up. It would be great if these guy's were a member of the forum as they can explain alot better than I can. Maybe they will join in the future who knows.
I have a few different ratio's I am going to try. What I really want to get is a belt drive setup that has been in use for awhile now. It is a cogged style drive belt and pulley setup similiar to a harley davidson belt drive. A 35mm wide belt can handle 125 horsepower harley pretty easily, would be great for a kubota setup.. But super expensive. Stub shaft will be here tomorrow morning. Then it is time to get serious..
Quote from: keith71 on May 06, 2022, 02:16:34 PMHi, Henry,yes that custom generator company told me that 2850 is the absolute sweet spot for the D722 for best effiency. And they run their belt driven generators at that rpm. On the other side of that They said that a D722 puts out enough power to make a little over 5000 watts at 1800. They have many units that are direct driven at 1800 rpm. Main issue is harmonics. The oneissue with the kubota super mini series is balancing, or the lack of it.Not very well done in their opinion. There is now a harmonic balancer that attaches to the flywheel available for these engines. They have seen bad vibration at different rpm levels depending on the load and drive set up. It would be great if these guy's were a member of the forum as they can explain alot better than I can. Maybe they will join in the future who knows.
2850 would be pretty much on the mark when the generator frequency is set up near 62Hz. When the generator gets loaded some the frequency will be near 60hHz.(2800) It sounds right.
I've tried 1800 with the Z482 and I did not feel comfortable running it loaded. Yes it ran but, it exhibited harmonic (Critical Speed) issues. The Kubota application engineer and I spoke about this issue in depth and this was one of the reasons why I started looking at other engine options. And, shortly after, I located the D1005 engine. It took some time to set it up as close as I could to the BG series. It was costly but worth it. What a sweet running 1800 RPM, direct drive generator that was. But it was too large for my needs. Belt driving the D722 at 2800 - 2850 is a great compromise.
A person at the generator company does visit the forum from time to time. They are so busy that they don't have much time. They know about us. And we have helped each other. That is a good thing. They are great people to work with.
Quote from: keith71 on May 06, 2022, 02:20:07 PMI have a few different ratio's I am going to try. What I really want to get is a belt drive setup that has been in use for awhile now. It is a cogged style drive belt and pulley setup similiar to a harley davidson belt drive. A 35mm wide belt can handle 125 horsepower harley pretty easily, would be great for a kubota setup.. But super expensive. Stub shaft will be here tomorrow morning. Then it is time to get serious..
Sounds good! A dual pulley BX belted setup should work fine. Bob G has a Browning hand book. He might be able to help. If a double belted setup is marginal, a triple belted setup is available.
Your right, A cogged style setup will be expensive. But it would work very well.
If your able, please take a picture of the stubshaft.
Henry
A few pics of the stub shaft. it has 1-1/8'' shaft about 3'' long.
more
another one.
last one.
Looks beefy.
Keith,
That is the one I've used on the Z482. It's one nice piece. The critical point from the shaft to the hub has a radius. The radius reduces the possibility of stress cracks. You will be able to mount the drive pulley very close to the flywheel face.
Henry
Same here,
That's the one I used on the Z482.
Bolted directly to the flywheel.
Then... slide your pulley all the way onto the shaft to reduce overhung load.
veggie
Keith, any progress? I'm looking forward hearing how it's coming along.
Quote from: Henry W on May 20, 2022, 02:39:56 PMKeith, any progress? I'm looking forward hearing how it's coming along.
Hi Henry, Project is proceeding although much slower than I would like. I am very busy this time of year with my job. 50 hours a week does not leave alot of time for my projects. Also too many things to do around the house. The darn grass grows about 4 inches a week this time of year, as you know..
I also have some questions on my build that I do not have answers for yet. One of my main problems is that I need to come up with an application to use for my kubota. So I can order parts. Yes it came out of a generator, but many things are different in the way kubota made this engine for onan, or the way onan modified it for their use.
Most generators are a fixed speed engine. Say someone wants to use their fixed speed engine in say a tractor. Now they need a variable speed setup. The issue I have is My D722 is already a variable speed engine as it was used in a invertor generator setup that ran between 1600-3200 rpm . Rpm was varied I assume by the invertor that sent a specific voltage signal to the electronic throttle control. (has 2 wires going to it, and a magnet of some sort to turn the throttle).
I need to eliminate this kind of throttle control and go with a standard kubota throttle linkage setup.The issue then becomes what model of equipment do I use to get parts. The D722 was used for probably 50 or more different pieces of equipment in its 25-30 year production run.
I guess I need the standard throttle setup with the shut off solenoid as well.
What would be really cool is if I could figure a way to just incorporate my original electro magnet to my meccalte genrator head and vary the speed depending on load like Onan originally did. I am going to get the onan manuals for my model generator. I still have the original Invertor controller for the Onan generator. But it may not be needed to control the variable speed but not sure on that yet..
I will try to post some pictures of what Im talking about. I posted some pictures before but not sure where they are on the forum, have not looked yet..
Anyway sorry for the rediculously long post. Not to good at getting thoughts into writing I guess.
My problem is I am not using the invertor part of the generator anymore.
I guess all the pictures I originally loaded are on the first page of this thread. But there is no preview as to what the picture is, so people would have to just randomly click on blind pics to find what they are looking for. I will try to repost the pictures.
Do you think I should just use a reefer unit model number to get parts for my Kubota? Does Kubota have a universal industial D722 engine like Cat does with their C4.4 engine or Cummins with their universal 4BT3.9 engines? thanks.
My Kubota D1005 was a Bobcat spec'd engine. All the internals were the same as Kubota universal spec'd engine. Some external parts like the oil pan, intake manifold and and a few other odds and ends were different but not enough to make a conversion difficult. With your Onan spec'd engine, I would imagine internal parts would be the same. But I cant be a 100% sure.
If your able, post a few pics of the electronic throttle controller on the engine. We might be able to get some info about it. I'm wondering if the rpm's is controlled by variable voltage. If that is the case it might be able to be controlled by Some type of variac or trim pot setup. If you get the manual it should be a huge help.
Oh, Grass. That is what I'm doing at this moment. Trying to beat the heat.
Keith,
I been looking at a throttle control for a Kubota D722 on ebay.
I'm wondering if it would work on your engine.
Here it is: https://www.ebay.com/itm/374098605848
Henry, it looks like it would. And it looks like a fuel shut off solenoid can be bolted to it. Pretty good price as well. I am working on building some engine mounts as well. The original Onan frame is aluminum with rubber mounts. Not going to work for this project. Thanks.