More Slow Speed Changfa Mods

[veggie]

This question is to anyone who has had their Changfa style engine torn down....

My Slow Speed Changfa project was a success in that it allows the engine to run nicely at 900 while driving a 3kw generator.
The engine is much quieter, however there is still some gear lash noise coming from the counterbalance shaft spur gears.
http://www.microcogen.info/index.php?topic=477.0

I am wondering if the engine really needs counterbalance shafts at 800- 900 rpm, or where they installed because of the shaking which occurs at 1800- 2600 rpm ?
I have not seen these gears but I would like to get some opinions on weather this shaft and the associated gear can be removed ?
Or does it drive the camshaft ?

I wonder if the counter shaft and the gear can be removed ?

Thoughts ?

Chears,
veggie

[deeiche]

I haven't looked inside either of my Changfa's but found the following in the manual.  I'm looking at a diagram in the R185 manual and it shows "Crankshaft timing gear", "Camshaft timing gear" and "Counterbalance shaft gear".  Then it states the following, "Counterbalance shaft gear driven.  Which would lead me to believe the camshaft is not driven off the counterbalance gear.  I also found the manual online, here, Changfa 185 manual  where it clearly shows two separate gears on the crankshaft, one for timing gear, other for counterbalance.

Hopes this helps.

[veggie]

Thanks deeiche,

So if the Cam is not driven from the counter weight shaft, and the counter shaft is an isolated item....
I suppose the only way to find out if this idea will work  is to remove it and run the engine.
The crankshaft does have counterweights so there will still be some weight to offset the firing stroke.
And...the slow speed unit does have a heavier flywheel to carry the momentum through to the next stroke.
I may give this a try and report back.

veggie

[vdubnut62]

I just came into another S1100 that was a nonrunner or fixer-upper. At any rate, it was let run with the flywheel loose, and that caused backlash to break teeth off several of the
timing/counterbalance gears. There are two counter balance shafts, an upper and a lower. I'm not far enough into the dis-assembly process yet to determine just what drives the oil pump.  I hope this somehow helps.
  It looks like it will be an undetermined amount of time before I get to finish, I am now full time caretaker for my Wife who had a pretty bad fall last week and suffered a "burst fracture" in her spine. She is not permanently disabled, but she does currently need help with everything.  She wanted to enter a rehab/physical therapy facility, but my insurance was too cheap, and they wanted 5 grand upfront to admit her. Cash. Gotta love free healthcare!
Ron.

[mobile_bob]

fwiw

the balance shaft (lower) drives the oil pump on the 195's

here is my thinking

take for instance a metal lathe headstock and its backgearing
those gears are spur/straight cut and generally are also quite noisey
however if you dribble even a little bit of oil into the gears this film transfers
all around the gears and they go nearly dead silent, so

my thinking is this, you could simply drill a hole in the gear case cover above the upper countershaft gear, install an orifice fitting and route some of the return oil that goes up to the red indicator on the valve cover... just a bit of oil feeding into the gear train would likely reduce the noise associated with the geartrain to nearly inaudible.

yes there is oil in and around the gears, but mostly is is simply oil mist or vapor and in my opinion while that might be enough to keep wear down, it is simply not enough to quite those pesky gears.

another thing

somewhere in my collection of emails, i have a contact in china who's company has manufactured helical cut gears for the 195/1100 series engines. those gears ought to run nearly silent, however i was not sure of our communications as to whether these gears were something new and untested, or whether other machine work and different bearing would be needed to allow for the thrust action given by helical cut gears.  i have no idea where that contact info is, it has been maybe 5 years since i had any contact with the manufacture...  iirc minimum order was 3 sets of gears, at a total cost of something like 120 bucks or so, plus shipping.

me? i would go for the admission of oil to the spur gears first, it would be easy to do and something that could be removed if it didn't work as well as needed.

bob g

[vdubnut62]

Bob, I don't have a clue about your 195, but I don't think axle grease squirted on them would quiet the gear-train on my engine. It is really noisy.
Kind of an intermittent rattle. About like a quarter inch play in the rod journal might sound. I keep waiting for it come apart, and it keeps running.
I inquired about the helical gears and was told it would be a US product, although  I haven't any idea why anyone would think there was enough of a US market to tool up to cut gears for a Chinese single. A set of Chinese straight cut gears are only $25.
 Now just to prove me wrong, what size orifice do you suppose would be appropriate to spray the geartrain? Yes, I think I will give it a try later on.
I am afraid that the lack of thrust bearings would cause as many problems as a set of helical cut gears would solve. Now If the engine was designed for them ok.
Usually in my experience there is a tradeoff when one uses a new and improved product on an old design.

Ron.

[mobile_bob]

because of the rather high oil pressures involved in the changfa type engines, i would expect
no more than maybe 1/16th inch would flood the gears with more than enough oil to quiet the gear clatter.

i know that small engine lathes (atlas and southbend) have spur gears in their back gears and they clatter like hell even at such low spindle speeds, it takes very little motor oil dribbled into the gears to make them dead quiet.

because there really is no oil flow to the gear teeth in a changfa type, relying only on mist and vapor for lubrication, my bet is any addition liquid oil squirted down on top of the top balance shaft gear will feed all around the gear train and go a very long way toward quieting the beast...

in any event it really would be quite easy to fit the engine with such a line and give it a try.

one could make up a longer hollow bolt and replace the bango bolt on the valve cover, add another bango fitting to take off some of the bleed off oil and have ample oil to feed up to an orifice fitting tapped into the top of the gearcase portion of the block.

my suspicion is maybe even a 1/32" would be plenty of orifice

if i had even an afternoon to try it on one of mine, i would go for doing it and report back.
as i have been buried here and have so little time, that project was slated to be put off until such time that i can take the engine completely down.  at that time my plan was to reroute the oil system to provide for a full flow oil filtration system, and also fit a bypass filter after the added oil pressure regulator, so that i could simply dump all the clean regulated oil back into the gear train.  if that makes sense?

after studying the oil passages on the changfa 195 i am convinced they were originally designed to have full flow filtration and that was deleted in order to cut down costs, most especially once they found out the engines seem to run a long time without having the filtration/regulator system.  this suspicion of mine was supported when a few years ago i found on alibaba a manufacture of 195's that had the external oil filter and also a regulator cast into the gear case end housing.

bottom line, at least for me i am convinced that adding oil will do a lot to quiet those rattling gears.

bob g

[Thob]

An easy way to test the oil on the gears would be to drill the hole in the case, pump oil in from a squirt can and see if (how much) it quiets down.  If it doesn't work, plug the hole.  If it does work, then connect up the engine oil feed to a fitting in the hole.

[vdubnut62]

An easy way to test the oil on the gears would be to drill the hole in the case, pump oil in from a squirt can and see if (how much) it quiets down.  If it doesn't work, plug the hole.  If it does work, then connect up the engine oil feed to a fitting in the hole.

I just hate it when someone beats me over the head with a perfectly logical and sensible idea!

Just kidding, Thob. Thanks!


Now I'm sitting here scratching my head wondering why I didn't thunk of it.
Ron.

[vdubnut62]

Uh Veggie, now that I have totally de-railed your topic, what is your take on the gear racket? I guess removing the counter-balance shafts is out unless you want to
build a dummy shaft to run the oil pump. And then you would only eliminate what, just one gear? I'm going to try to post a pic of a set of replacement gears for everyone's consideration. I'm not exactly sure where all of these go, until I get to crack the gear case open on my project S1100.  From what I can find out, an S1100 is just a bored out S195. What I can't figure out is how do they come up with the number system to name these things? Bob? Anybody?

[mobile_bob]

195= 1cylinder 95mm bore
1100= 1cylinder 100mm bore

395=3cyl , 95mm bore

iirc

bob g

[veggie]

vbdubnut62,

I think you are right, the removal of the counter shaft and gears is not possible without having to fab an oil pump drive shaft.

Case closed !   

cheers,
veggie

[mobile_bob]

hey Vdub

is that a picture of the helical cut gear set?  and do you have a set on hand?

you i think, others and myself have had concerns regarding thrust motion and its containment
in an engine that was otherwise not designed to accommodate it.

what i wonder, and no i have not gotten that deep into things is this.

i wonder if the counter shaft brgs, if they are ball brgs have sufficient ability to handle a bit of thrust?  if not i wonder if there is an optional ball brg that is made with deep enough races to take the thrust?

that would take care of counter balance shaft thrust issues. the crankshaft ought to be able to handle a bit without issues, which leaves camshaft and maybe an idler?  i don't have a parts breakdown handy to check this out.

anyway, if anyone wants to try and order a set, i would be interested in going in on the order for one set, provided the price is not extraordinary... last i checked was maybe 5 years ago and three sets were about 120bucks or so,,, and i don't recall if that included shipping.  at the time i didn't think i wanted to buy 3 sets to take a chance on being able to figure out a work around for the thrust issues.

however i might see myself clear to 50-60 bucks for a set of helical gears just to have them around for the day i finally pull my horns in politically  and go back to the shop.

bob g

[vdubnut62]

Hey Bob,
   Sorry, but no these are just plain straight cut or spur gears.

I am "assuming" that if a bearing is available that will stand up to a 12kw ST head being run in the vertical position, that yes, a bearing is available that will stand the side load from a set of helical cut gears in a Chinese horizontal single.
 
What I am doing is contacting a good friend who is a ME to help me figure this out.

Meanwhile,  my  Son-in-Law (The Parts Guy) is going to be digging through catalogs to see what specs he can find on what bearing will hopefully be suited to this application.

What I don't know is what kind of side loads to expect and plan for.

I do know is that without the mass of the flywheel, or just if the flywheel works loose these things will generate enough energy from the backlash of the power and compression strokes, to take the teeth off a spur gear.

That tells me that the geartrain in general has quite a bit of play or backlash or slop, whatever term you want to use.

Could that be helped or eliminated with the use of helical gearing? Is there a way to set backlash? Are any of the idlers movable?  It's a shot in the dark at this point, at least to me. If a helical setup still has a bunch of slop or backlash, I'm not sure that it would help anything. It just may create a worse problem by adding a side load to the already existing problem of excessive backlash. I'm still not deep enough into this engine yet to know just what is possible. The manual for my engine is pretty sad, it's a really bad translation. For example, the front of the manual says SUPPER DONGFENG   S1100 Diesel engine.  I just scratch my head at a lot of it.

The bottom line, I would be willing to pony up 60 or 70 bucks to find out.

So if anyone wanted to join Bob and I as a third party to try a set of helical gears, if Mobile Bob is up for it, so am I .
Ron.

[playdiesel]

For the end thrust problems check out "Angular contact ball bearings" They are generally available in same sizes as deep groove ball bearings. You have to be careful how you install them as they take trust in one direction only. In the case of your balance shafts you would need to install them both so they accept thrust outward. 

Picture helps explain I think? Shows how races are shaped to contain thrust but only in one direction.