The little CAT diesel

[xyzer]

Been watching the thread and lots of good ideas out there. I picked up a Kubota Z482 with generator already mounted. They set it up like this http://www.nextgenerationpower.com/5kwrad.html . I considered the side load and have had no problem so far but I don't think 35 hours is much to go by. I did notice the type of belt they use is much more flexible and wider than the automotive serpentine belts. It appears to stretch to prevent one from over tightening and exceeding the side load allowed. The belt says flexsomthing or somthinflex on it but the pulleys might be hard to find, I don't know they were with it. They could be shelf items?!
Dave

[roverjohn]

Panaceabeachbum, You could buy the parts new for less than you're spending on the billets which would save you the trip to the junkyard and a bunch of machine time. You and I may have access to solid modeling and machining centers but likely the rest here do not. Mind me asking what you'd sell a few of those bell housings for just for S&G? Likely more than $1400 I'd guess.

BTW, a little legwork and I can guarantee that those bell housing can be bought used for way less than $1400.

[panaceabeachbum]

no matter how much flex or give exist in the belt if it transimits full torque with out slippage the overhung load will exist .  

I think the PTO assembly I am going to build will be cost effective enough that folks needing a well made rugged bolt on Unit can afford it and will be less than half the cost of a commercial unit , I already have need for 5 qty for the engines that have landed here in my area and will run a couple of extra for folks that might be interested .  The material cost for the prototype unit is comming in a lttle over $400 , bearings , bushings , shaft raw materials etc . Unless there is something that creaps up I have not anticipated they will run right around $600 . 

[xyzer]

I don't think I said it would eliminate the side load...I know I didn't say that! I said "It appears to stretch to prevent one from over tightening and exceeding the side load allowed". I have no problem how you do yours I was just passing along the knowledge that a commercial company has been using on there products for several years. Take it or leave it but I believe there are some folks that are investigating the belt route.

[roverjohn]

xyzer, The reason that unit pictured uses a cogged belt is because it is simple, cost effective, and proven to work just fine in that application. Apparently that's not good enough for some who don't trust their ability to properly tighten the belt but feel perfectly capable of making their own bell housing and PTO, like Bob. Panaceabeachbum has a full CNC machine shop at his beck and call so his bell housing and PTO will likely look awesome and work perfectly. The rest of us would be better off building a flex plate drive or just copying the commercial unit that has proven itself effective. I'm pretty sure that that engine comes in versions that have more than two cylinders. It would not be too difficult to find out if the rear bearings are the same on the four cylinder variant and to find out if they belt drive anything off the flywheel. If it is it's likely able to handle a lot more side loads than the 13.7hp version would create if someone had a good handle on how to tighten a belt.

Edit: I just looked closer and notice that the gen you linked to actually uses a serpentine style belt. If it can handle that load and deliver rated power a cogged belt would do it with less static load. Dynamic loads will probably be the same for both belt types.

[panaceabeachbum]

Yep your right , you did not say it would reduce side load, just that it helped avoid over tensioning .  I just wanted to point out that that would not translate into reduced side load while running so there would be no confusion. My apologies if my post was taken the wrong way .

I have been up in the air on exactly what to do with my setup , but have decided considering the cost and the fact that I would like to go ahead and use the PTO , I dont think there is anything wrong with using the direct belt drive method . In fact its the method used by the company that these engines were originaly sold to

 http://www.pdmindustries.net/docs/flyers-a-09-page2.pdf

 Â I believe they are driving all the load in this system off the front of the crank which measures aprox 1.125" where it exits the front cover.

[mobile_bob]

rover:

i don't know you from adam, and quite frankly its probably a good thing

you come in here with your 50 odd posts and seem to be looking for a problem.

after giving you some thought and trying to be fair, i have concluded either you are no engineer
or you are a freshly minted one trying to earn your chops by being a pain in the ass.

you make assumptions based on your limited experiences, and also assume that when i outlined a design
it was complete, both are faulty in my opinion.

the little engine we are talking about here is all of about 126lbs dripping wet, it is advertized at 13.7hp at 3600rpm, but
these engines are setup to run 2800rpm so i would expect maybe 10hp at most.

now you have an issue with tube spacers?  when i mentioned tube i called out DOM which is a very thick wall tube
if you cut and grind the end square and then insert a bolt through into the block and torque it properly you will do well
to get any measurable deflection at the distances we are talking about,, (less than 6 inches total), you use 4 of them
and torque up and it will be dead on and rigid as hell, to say otherwise is showing your inexperience.

if you are concerned with squareing the ends of the DOM, simply take them to an automotive machine shop and have
them chucked into a sioux valve grinder, using the stem grinder they can be made equal length and perfectly square.

now once assembled, there is nothing saying you cannot insert web triangulated truss supports from the outer plate to the outer
end of the tube. a couple such webs would make it near impossible to deflect under any normal circumstances.

this system i have related is not of my own design, but rather own borrowed from industrial equipment of thousands of hp

you claim i have no way to keep things square?

i wish you lived closer, i would love to show you methods that you likely have never been taught.

think about it a bit, the plate is as precision as needed, the standoff dom can be machined to .0005" tolerance
so the outer plate can be positioned near perfectly parallel to the oem plate

and when it is all said and done the lovejoy will tolerate a couple thousands, and the flange mount brg is self centering
and can tolerate several degree's if one is sloppy.

there are hollow dowels as well, that could be used with a bit of effort to perfectly locate the assy, as well as solid dowels
and taper pins to lock down the location of the flange brgs after alignment.

i don't know where you are coming from, but attaining precision can be done without machine tools, given a good eye, and enough
time.

i build this stuff with some regularity, and i repair others products even more regularly

i can't imagine how you think this is an inferior method, perhaps you don't understand the processes involved?

again, no body is forcing you to use any particular method.

maybe you should go get a ton of concrete and have at it?

bob g

bob g

[roverjohn]

Bob, You're making WAY more assumption than I have and you are the one changing what your design would entail, not I. I don't have 2000 or more posts because I usually have something productive, or at least more productive than hearing myself talk, to do. You also have no idea as to my level of expertise or experience. If you really think post count equates to knowledge I really don't know how to respond to that.

[mobile_bob]

rover:

you are right, and i am wrong

there now are you happy?

what kind of precision would you like to have demonstrated to you?

i can hand scrape to 2 ten thousands of an inch, is that close enough for you?

and don't even start with me about your superiority when it comes to tightening belts

see the thing is you are new here, and obviously have no clue as to what happens in the diy'er community
when it comes to belt drives, there are countless examples of folks with chirps, sqeals, and other anomolies
and the fix is generally, "tighten the shit out of it"

if you follow the same logic, the little engines will end up paying the price.

and you are right in regards to not everyone having a machine shop at hand, but
everyone that is a bonofide diy'er has hand and some power tools, and things like files
that can be made into scrapers, micrometers are relatively cheap for the precision needed.

it just chaps my ass big time to be made out like i have no clue and am suggesting an inferior solution.

especially when i have heard of no complete solution from you.

to simply state "just attach a pulley to the flywheel, throw on a belt and then tighten it properly" leaves a lot to the imagination.

you haven't mentioned what size belt, what type of belt, what size or type of pulley, how would you mount it properly, let alone
how would you adjust it when done, and what if it chirps or squeaks?  tighten it more?  what if your suggestions result in a broken
crank or wiped rear main, because someone used a belt or pulley that was improperly sized or applied?

you sit around taking your jabs, and so far have provided no substance

kinda like "float like a butterfly, sting like a feather?"

oh ya,, before i forget, a question

you ever dialed in a flywheel housing? ever done so and got it aligned to a half thousand?

i suppose you haven't, because if you had it would be clear to you how you would go about making up
a system like i described and having it work as planned when you were done.

as for panacea having a superior product because of his machine access, it is not because of his machines that it will
be a good product but rather because of his ability to use them.

machines are like puters, garbage in garbage out!

bob g

[panaceabeachbum]

And lord knows I have produced tons of Garbage in my career as a machinist 

[mobile_bob]

rover,

i would put my wrenches against yours any friggin day of the week

i could care the less about post count, but i do care about content

and i am not about to sit back while you make your over the top jabs at me or anyone else for that matter.

as for modifications?  what? i add a couple of struts/webs to stiffen the design to satisfy your ignorance?

and your plan?

ujoints?  no that was a joke,, i forgot!

junkyard parts, but no specific's

tighten the belt properly?  you are too dense to understand my point obviously.

what exactly have you brought to the table?

oh yes,,
bolt a pulley on the crank, add a belt and tighten it properly, and hope it works as planned?

well anyone that goes down that path, good luck to ya, and if this is your path
at least call your belt manufacture and have them work out the engineering for you
and ask them to minimize side loading as your primary concern.

and don't come crying to me, when it doesn't work as planned

we got an engineer here with vast experience of all that is power transmission, better you take his advise
than some old fart that has had to follow engineers like this piece of work for the last 35 years cleaning up their
messes.

i really shouldn't complain, without engineers like rover here  i wouldn't have made such a good living.



bob g

[Doug]

Hey Rover quit picking on Bob and getting him reved up!!!

I have known him here for years posted on line here, other places and in emails.

Getting Bob all reved up and butting heads well thats my thing with Bob 
But I do respect him and like most people treat him with the respect and dignity he deserves.
We all need to show respect inspite difference of opinion.

And I have over 3000 posts because I try and take the time to help or just banter...

[apogee_man]

I would submit that there is more than one way to skin this Cat...

Perhaps either solution would work just fine?

Food for thought...

Steve   

[panaceabeachbum]

all the above, and its really hijacking the cat diesel thread , I agree there are multiple ways of acheiveing the same thing . Bobs method is simple and straight forward , even if I dont like lovejoys , with the addition of flat bar between the DOM spacers it should work just fine if care is taken during assembly , the lovejoy will eliminate any missalignment problems.

On the other side of the coin RoverJohns thought process is sound also , I read the driveshaft reccomendation as a joke , just as intended. In fact I also considered using the center section from an automotive flex plate or clutch disk as he reccomended .

All decent advice , now to get back on topic

[roverjohn]

I guess I really should be nicer to Bob to keep his heart rate down. However it's just too easy and I'm always intrigued by people who take themselves so seriously and by people who denigrate professionals because they don't like working under them. The engineering manuals Bob seems to be so fond of certainly have chapters about using various belts to transmit power. Well, if he's going to trust them for other things, and I'm shocked he would as they are produced by engineers, why not use them to learn how to properly tighten a belt. He's going to have to anyway once he gets his standoff based bell housing built to keep the belt alive for any length of time.
There is no better engineering than proof in the field and Bob seems to know this based on his experience. The proof is that these engines run belt drives successfully off the crank in thousands of applications.  So, you don't need a brain trust or to reengineer anything. Lovejoys bring on teh suck, to use internet speak, because the more you need them the less you want to use one. If Bob can keep things to within half a thou with a hand file why use a lovejoy?

Bob, Can you honestly tell me that your hand fabbed bell housing would work any better than a simple flex plate drive that wouldn't require a bell housing at all?