The little CAT diesel

[Randybee1]

Hey guys, I have one of the little Cat diesels from the SurplusCenter. I was planning to put a stub out with a 6 inch shaft on mine and attach a pulley from George at Utterpower ( and run it at about 2500 RPM). I know there was talk about the engine being able to take a slight load on the bearing but does anyone see a problem with one of the Uttepower pulleys?.. they are pretty darned heavy. I 'm concerned it might be too much weight hanging off the shaft!...Randy B

[compig]

Dunno what the bearings are in this engine but think about the weight of a Lister electric flywheel on it's non pressure lubed mains !!!

[compig]

We might as well use this thread as the Little Cat forum now I guess so , another question ,
Does the engine come with manuals and parts list etc ?

[mobile_bob]

consider this:

1. remove the flywheel

2. remove the steel plate

3. use the plate as a pattern to make a second plate

4. use 4 dom tubes as standoffs, maybe 6inches long

5. use one of the aforementioned drive plates with the lovejoy half coupler

6. install another lovejoy half onto a 8 inch stubshaft

7. assemble with a flange mount brg into the outer plate

now between the plates (oem behind the flywheel and the outer plate you made) you have sandwiched between
the flywheel, a full lovejoy set w/stubshaft, and an outer flange mount brg.

now you can attach an utterpower pulley and put as much side load as you like
and the engine crankshaft will see almost no sideloading.

if you are careful and use two flange mount brgs, back to back, one on each side of the outer steel plate
the engine crank will see no loading from belt loads.

i know they claim the engine's will take belt side loading, but why would you wanna subject it to this stress if
there is a way to keep from doing it in the first place?

btw, the lower spacer tubes can be used for the rear lower motor mounts as well.
the uppers could be used for accessory mounts also, such as another alternator, pump or whatever.

if anyone wants a sketch let me know, pm me and i will email you one.

as i see it, a properly engineered belt drive need not be very tight or present much stress to the crank
and its brgs, but...
i know the tendancy is to tighten the belts more that usual because of poor drive engineering, and
poor engineering is the result of folks taking shortcuts and/or using what is at hand which might be
a bit sketchy to start with, or worse, just being lazy or thinking they don't wanna be bothered by doing
the several steps needed mathmatically to determine a properly engineered drive.

there you go, my contribution to the new engine and its use.



bob g

[roverjohn]

OK, so just mounting a pulley where it belongs is bad engineering but hanging a cantilevered plate off the back with a lovejoy coupler in the middle isn't? Yikes.
If someone wants a Rube Goldberg arrangement may I suggest a drive shaft stuck off the back with U-joints and extending some length to either a pillow block/pulley or just driving a gen directly.
I still have not figured out why the OP wants to space the pulley out 6" because all he will do is create the bearing problems he wishes to avoid. Why not reduce the chance of runout instead of increasing it?

Maybe this thread should be merged with the 'little Perkins' thread as they are the same engine except for the color.

[mobile_bob]

roverjohn:

i have no idea what your problem(s) is or are, and quite frankly i don't really care, but
what i described is in no way some sort of rube goldberg arrangment, rather it is a builtup
bellhousing that anyone can make with a bit of time in their own garage.

what i described is good engineering, and i welcome you to explain your fault with it, rather
than simply putting "yikes" out there to something you clearly have no grasp of the concept of.

if you would take the time to pencil it out or ask for a sketch what you would see is really no different than
your "ujoint" scheme, it is just a more compact and safe design swapping the ujoint for a lovejoy
and instead of a remote mounted mounted pillow block it uses a much closer mountd flange mount brg.

one of the beauties of this little engine is its compact design, and you suggest ujoints/jackshaft, pillowblock and inline connection
of a genhead,, what are you trying to accomplish? making the little engine into a stretch version of ??

talk about "yikes"

i don't suppose you know anything about proper engineering used to determine ujoint uses? it cannot be straight inline, but
rather must be installed includeing a working angle, so now you will need two ujoints? both with complimentary working angles?
oh yes, and they will need to be timed properly, and you may even find you need a slip joint as well, but wow,,, a slipjoint will
complicate matters with a simple pillow block brg now, surely don't want things to loosen a set screw and have the thing slide apart.

now if you have a ujoint failure? then what? ever seen a ujoint jackshaft fail?  more guards are in order for sure.
and we are not talking about hail screen either but real guards with driveline hoops to contain the damn thing.  oh yes
and 3 more zirks to grease as well.
also we can't just use farm grade pto ujoints and drivelines, they aren't up for 1800rpm for direct drive of anything.

and lastly,,

mounting the pulley where it belongs?  where is it said that the pulley belongs mounted to the flywheel? i will bet you a dollar to a dog
turd this engine was designed to work with a bellhousing, and was never intended to carry much in the way of belt side loading. and i don't give a crap what some cat salesman has to say to the contrary,, they didn't design this engine, and
you will not find a single cat designed engine that has a pulley mounted directly to the flywheel for belt driving any accessory at rated load.

this attitude is exactly the sort that gets people in over their heads, shortens product life, places folks in harms way, and leads to less than acceptable results all the way around.

wasn't a couple weeks ago, you took exception to an outline on engine control, thinking it was not in keeping with your perception of KISS
yet today you find fault with a design that is very simple and easy to make should one sit down long enough to seriously look at it and think it through. should you take the time to sit down and do the same you will conclude that the design is much safer, more compact, less costly and will do the intended job.

btw, no one is forced to use any design or other here, quite frankly i could care the less what people do as long as they don't hurt themselves or others. should you decide to go another route, by all means do so, and may luck be with you.

as for me, i depend much more heavily on good engineering, mainly because my "luck" has never been anything i could count on.

perhaps ymmv?

bob g

ps.. you sure you wanna use the word "yikes" with me again?

[panaceabeachbum]

Thats the same PTO I was descirbing last week in the other thread , but with a fabricated bellhousing instead of the simpler tubing std offs .

[roverjohn]

Bob, Have you ever seen one of these engines in use? The reason I ask is because I have and every time I saw one it was driving a belt directly off a pulley mounted directly to the flywheel. These things are in APUs everywhere driving gen sets and compressor via belt drive. They are also used to drive hydraulic pumps bolted directly to bell housings on things like tiny Bobcats. Did you notice the front pulley is set up for an accessory drive? In fact finding a pulley or a bell housing that would fit the engine directly should be quite easy because of that and you can avoid George all together. How KISS is that? My suggestion of using a driveshaft was obviously a joke. Your suggestion to create some sort of bell housing using standoffs would not work without the lovejoy as a crutch and it would likely cost as much as the motor if it was made beefy enough to hold up. That's your idea of good engineering? And, do you have an Engineering degree?

I would be far more concerned with someone running one below rated RPM not having enough oil pressure but since I've never seen one used that way I have no idea what might happen.

[roverjohn]

Why not just buy a bell housing already made to fit this engine and use that as the basis of your PTO? Why add the lovejoy at all? Why NOT assume that the folks getting thousands of hours of use on their APU's with belt drive aren't overloading the bearings which eliminates the need for a PTO all together?

I'm very curious if Bob has calculated the sorts of loads his four standoffs will apply to the engine block when the vibration from the lovejoy is fed back to the block or done any sort of load analysis at all to determine where the loads are. Yet he suggests that his idea is based on valid engineering principles

The guy in the other thread building gensets looks to have at least $1600 in each engine/gen combo times two. So now is the time to get cheap and cobble together a PTO? Honestly?

I really don't get it but I guess as a real engineer I see no point in reinventing the wheel when it's already been done.

YRMV and, of course, you are free to do whatever you like.

[mobile_bob]

rover:

"Bob, Have you ever seen one of these engines in use?"  yes i have

" The reason I ask is because I have and every time I saw one it was driving a belt directly off a pulley mounted directly to the flywheel."

this is not proof that the drives you have seen were properly engineered!!!  i have seen applications from GM where a cs130 was expected to charge dual batteries on a 6.5 liter diesel driven by a single overtightened 7/16" belt, i can enumerate dozens if not hundreds of examples of
a manufacture misapplying all sorts of stuff in order to make a buck.

"These things are in APUs everywhere driving gen sets and compressor via belt drive."

I am sure that they are, but in every application that has proven successful careful application of the engineering from folks like browning
have been closely adhered to in order to keep sideloading and tensions as low as possible, are you as sure of everyone here will do the same?
i am not!

"They are also used to drive hydraulic pumps bolted directly to bell housings on things like tiny Bobcats."

 i am sure they are, and this makes my point,, they are properly applied with a bellhousing. just like every other engine of this type is mounted to somesort of bellhousing. this is why you see a steel plate behind the flywheel and the holes all around, and the starter mounted to this plate. surely they could have cast the block to mount the starter and saved using the steel plate had the engine been designed to run sans
the hsg and just use belt drives.
 
" Did you notice the front pulley is set up for an accessory drive? "

i certainly did, it is also a common item on engine's like this one, engine's like the c201 isuzu/thermoking have that as well,  but
the accy drive at the front of the crank was not to carry an overhung load (at least a very light one) and not full hp.

"In fact finding a pulley or a bell housing that would fit the engine directly should be quite easy because of that and you can avoid George all together. "How KISS is that?"

its very simple, and i too have no problem with that, however
the manufacture may or may not have spec'd a side load, but say they did and it is 100lbs max.  an oem that uses this engine likely would
have his engineering dept work very carefully with someone like browning, martin or gates, to spec a drive that reduced the belt tension requirments to a minimum... i am not at all sure anyone here will go to that much trouble.  its just too easy to just grab a pulley and mount
it and hope for the best,, later to find out you got problems,, how many reports of listeroids with chirping belts have you read about?
what is generally the fix for that problem?  more tension!  what if more tension reduces the chirping problem but exceeds the side load spec
of the oem?  hell cat cannot even tell you what the side load spec is!!!

"My suggestion of using a driveshaft was obviously a joke."

i have a problem with that claim, its just too easy when boxed into a corner to just say "only joking" problem is unless you make that
clear at the time someone will believe your joke and go build something that might get them hurt.  you may not like my system but it is unlikely to get anyone hurt.

"Your suggestion to create some sort of bell housing using standoffs would not work without the lovejoy as a crutch and it would likely cost as much as the motor if it was made beefy enough to hold up."

the lovejoy is not a crutch! what makes you think it is? it is no more a crutch than it is in the drive system of a cummins fuel pump drive.
where everything is cast and machined to tight tolerances. i know i could build exactily what i described in my shop using nothing more than
a torch to cut the plate, a drill press, hacksaw, and a mig welder. and with a little extra time spent on detail forget the welder, and do it
for about 50-75 bucks sans pulley.

" That's your idea of good engineering? "

damn straight it is an example of good engineering!

"And, do you have an Engineering degree?"

no, however one does not have to have a degree in engineering to follow engineering text and adopt solid engineering principles, and to
use engineers to followup and check your design along with the calculations used to arrive at the design... done that many times over the years, and to date have not had an engineer change one of my designs, and i have proven many times the deffiencies of an engineers design
and had him make my suggested changes to his design. (it doesn't happen often without one hell of a fight, but it has happened several
times over the last 35 years).

"I would be far more concerned with someone running one below rated RPM not having enough oil pressure but since I've never seen one used that way I have no idea what might happen"

me either?  however if one simply watches the oil pressure and finds that it runs for instance at 40psi at 2800 and maintains 40psi
at 1800 he is likely to be ok, however if on the other hand he see's it fall to 15 or 20psi, maybe he is going to have issues.


in closing i would like to go back and talk about the apu's that used these engine's, first of all those oem's paid far more for these engine's
that we bought them for here, likely well over 2 grand each. now they are building for a tight market that has two concerns primarily
"cost" and "weight" and they will compromise longevity to a point in order to achieve a reduction of either and especially in both. if they simply bolt on a pulley to the flywheel and have it engineered to keep the side loads to a minimum then they save making up a bellhousing, outer support, stub shaft etc, which saves time and money invested and reduces weight by maybe 30lbs or so. the main point here is if you are going to follow in their footsteps you better look and see how long did these units run being used in this manner "and" most importantly you better consult the engineering text and do the math or call browning and have them do it for you, unless you are just lucky.  if you are lucky
and don't need the engine to run but once a year during a hurricane, you can probably scab together just about anything and have it work adequately.

if on the other hand you plan on running long hours unattended, why not avail yourself to every advantage afforded by the texts, why do you think that browning includes this in every one of their catalog's?

again ymmv and likely will, maybe your just smarter than i am?

bob g

[panaceabeachbum]

The guy in the other thread building gensets looks to have at least $1600 in each engine/gen combo times two. So now is the time to get cheap and cobble together a PTO? Honestly?

Thats why I am seriously considering buillding a PTO for both the engines.  I have a complete machine shop and will be building units a bit more advanced than the one Bob is describing , but it will be the exact same principle, a spacer plate instead of tubular spacers , and a pair of plates with polyurethane bushed drive pins as my flex coupling instead of the lovejoy . But the principle is exactly the same.

To be honest we are all on the same exact page , Bob was just describing the same layout as I did in post 37 of this thread, midway down the page http://listerengine.com/smf/index.php?topic=4808.30  , but he was describing a method that will appeal to the garage builder without access to machine tools.   I like John dont like tubing standoffs or Lovejoy couplings but they do work and the system Bob describes should work just fine .  The stand offs will provide the needed clearance and the lovejoy will isolate the pto shaft from the crankshaft.


I have some photos and solidworks 3d drawings I will share on my thread later tonight that will make my layout of the PTO more clear

[mobile_bob]

rover:  you posted more before i had a chance to include so here goes

"Why not just buy a bell housing already made to fit this engine and use that as the basis of your PTO?"

too expensive as hwew states, something on the order of 1400bucks, don't see many of those being ordered here.

"Why add the lovejoy at all?"

because it is the cheapest solution for the home shop guy to get adequate alignment precision, and to remove all overhung loading
from the crankshaft, and to allow the crankshaft freedom to move according to its thermal needs and clearance in the rear main brg.

"Why NOT assume that the folks getting thousands of hours of use on their APU's with belt drive aren't overloading the bearings which eliminates the need for a PTO all together?"  

i am sure that they are getting thousands of hours, but how many times do i have to say it??? they engineered the drive system to
reduce the side loading to a minimum and they are not driving st5 heads or god knows what else might be dreamed up here. i would however take a good look at the history of any unit i was trying to duplicate, and make sure that the parts are truely off the shelf stuff
and not some purpose built unobtanium used to make something work that had problems early on in development.

"I'm very curious if Bob has calculated the sorts of loads his four standoffs will apply to the engine block when the vibration from the lovejoy is fed back to the block or done any sort of load analysis at all to determine where the loads are."

there is no reason that the standoff should impart any stresses differing from that of a flywheel housing to the engine block., as for
vibration of the lovejoy? how many of these have you worked with? are you aware that there are many changfa's happily driving st
5, 7.5, 10, 12 and 15kwatt heads with lovejoys?

"Yet he suggests that his idea is based on valid engineering principles"

yes i do suggest just that, however i have seen you suggest no real options other than just grab a pulley and bolt it up
and hope it works for thousands of hours???  i only suggested my system when it was clear folks wanted to use a stub shaft
to get away from the engine,, but i guess you missed that?

"The guy in the other thread building gensets looks to have at least $1600 in each engine/gen combo times two. So now is the time to get cheap and cobble together a PTO? Honestly?"

now your beginning to piss me off, "cheap and cobble"  i would suggest you have no idea of what you speak.

"I really don't get it but I guess as a real engineer I see no point in reinventing the wheel when it's already been done."

no problem, and a good engineer will always use an off the shelf solution rather than reinvent anything, but i guess you already
new that being an engineer and all.

"YRMV and, of course, you are free to do whatever you like."

i will as i expect you will too


now one more time in an effort to get my point through your very closed mind:

i see no reason why one could not simply bolt a pulley to the flywheel, provided it is in keeping with browning/gates/goodyears engineering
to drive the particular load you have in mind.

i only suggested my system based on folks wanting to make up a stubshaft that was in some cases 6" long which would place
undue stresses on the crankshaft.

i did not suggest (and later call it a joke) the use of ujoints and drivelines, which btw if it truely was a joke it was irresponsible on your part.

for whatever reason you have decided to make this discussion a personal one, hopefully i have not written anything that was inflammatory toward you, if so i apologize.

as for you being an engineer?  maybe so, but certainly unlike any engineer i have had the pleasure to work with in my experience.

of course you didn't say what kind of engineer you are?  now did you?

bob g

[roverjohn]

Panaceabeachbum, Your homebuilt bellhousing likely would be every bit as good as a factory one albeit heavier. Bob's would not because there is no way for him to keep everything square no matter how good he is with the tools he listed. Wouldn't it be WAY simpler to simply make a flex plate type drive driving a drive shaft mounted in a pillow block? You would not need any sort precise machine work at all.

Go to a junkyard, find an early eighties BMW 5, 6, or 7 series and grab the center carrier bearing and the part of the drive shaft closest to it. It will have a flange that bolts to a readily available rubber spider that lives in very harsh condition and passes hundreds of HP with ease. Mount the pulley to the shaft on the other side of the pillow block. There, you're done and the fitment could be done via eyeball. We know the bolt circle of those three holes on the flywheel because there is a drawing on Perkins site. If someone wants to measure the bolt circle of the BMW part I'd would probably be happy to whip up a .dfx burn file that anyone could take to any laser of water jet shop. The rest of it could be built from junkyard parts. This would be so much simpler than trying to create a bell housing from scratch and any alignment issues are taken care of because you've planned for a little misalignment instead of assuming that you are capable of eliminating it. This is a very sound approach that has been used for years. If you're capable of machining a bell housing building a flange to couple your pulley to your stub shaft should be a cake walk.

Bob, If you can't figure out that I was joking about the drive shaft idea you must not know who Rube Goldberg was.

[panaceabeachbum]

I dont think mine will be much heavier than a factory built unit, other than my bell housing will be machined from alum billet instead of cast aluminum . I think it would wieght in only 1-2 pounds heavier than a commercial unit.    The used parts , salvage yard approach might be cheaper but in the day lost going to and from plus digging thru the salvage yard I can cnc machine a precision unit , to much higher tolerances than any mass produced unit, althoug as BOB pointed out the flex coupling (or lovejoy) should negate the need for aerospace alignment. Having 4 huge machining centers, surface grinder , wire edm, heat treat oven etc will give me a little edge over the salvage yard approach . Cant wait to get under way and post a few pics . I have the solid models done, just waiting on the chunk of aluminum to land to make the bell housing

[Tijean]

I think I will take the standard industrial parts and stock steel items long before I consider incorporating BMW parts.
 I have used the standoff tube system in mounting things but do like to tie them together with plate or flat bar for unit rigidity. Torsional resonance and side loading create fatigue factors that can really shorten shaft life unless either brute strength or finesse is incorporated.  I saw the crankshaft broken on a VG4D Wisconsin engine because of a stone wedged in the attached pump impeller. The fracture had the classic signs of progressive fatigue failure from the lateral load.