Author Topic: Slow rpm Chang fa?  (Read 870 times)

bigbad

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Slow rpm Chang fa?
« on: October 30, 2021, 03:22:54 AM »
I am looking at websites for the Chang fa and related and I only see conflicting info - mostly look at the mfg page.  One part they say 800ish rpm and on another part of the same page they say something like 2,500 rpm.  Is there a Chang fa that is really a slow speed engine?

guest18

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Re: Slow rpm Chang fa?
« Reply #1 on: October 30, 2021, 03:33:53 PM »
I donít know of any Changfa, Chang-Chai (Chinese) diesels that are designed to operate continuous at speeds below or near 1000 rpm.

All the S195 and larger horizontal single cylinder (Changfa, Chang-Chai) Chinese diesels operate, I believe up to 2,200 rpmís. Most work fine direct driving an 1800 rpm 60hz or 1500 rpm 50hz generator head. They are tough engines that proven themselves to take quite a beating and still able to run for long hours. All engines are designed to run at certain speeds and itís best to stay within the parameters the manufacturer specíd the engine run.

Veggie is a member here and on the microcogen.info forum. He has modified S195 engines to operate at lower speeds successfully. He spent hours on his projects and acquired the knowledge to get these engines to run at lower speeds reliably. It does cost money for the average person to do these modifications. I believe Veggie had access, or known people in a machine shop to machine the parts for his engines. His work is beautiful I would recommend checking out some of his builds.

I my opinion, Veggie is an exception to the rule of staying within manufacturerís specíd engine operating parameters.




38ac

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Re: Slow rpm Chang fa?
« Reply #2 on: October 30, 2021, 03:35:59 PM »
Member here Veggie modified one to run at maximum efficiency when running slow and his work is impeccable.
That being said they are all variable speed governed. You can run one anywhere from just off idle to full RPM and have good governor response without doing anything to it other than adjusting the throttle. If you intend to run one at a lowered RPM, AND and at full load AND continuous then it would be beneficial to back down the injection timing a few degree. Other than that don't worry about it. Remember that when you lower the operating speed that the availabile HP also drops. A 195 is probably a 6HP engine at 1000 RPM, just guessing from experience.
Collector and horder of about anything diesel

mobile_bob

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Re: Slow rpm Chang fa?
« Reply #3 on: October 30, 2021, 03:53:17 PM »
i did a lot of testing back around '07-'09 with a changfa s195
it had no problem running and carrying a load at 1000rpm

i didn't back off the timing, and used it to drive a 555 alternator at 2880watts at 28.8 volts

no problems at all, and i think i could have gone lower with as suggested reduced timing, but because the unit was setup to run dual speed 1800 and 1000 i didn't want to alter the timing.

tough as nails engine's that likely could be made to run at lower rpms, and do it well.
i always figured that 1000rpm was a good spot to run at, but i know veggie got one running slower.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

guest18

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Re: Slow rpm Chang fa?
« Reply #4 on: October 30, 2021, 04:02:34 PM »
Yes Veggie did get one to run slower than a 1000 rpm.

On one of Veggieís projects he machined the flywheel to accept  additional weight. The additional weight helps with rotational stability (inertia). +1 on retarding injection pump timing.

Here is a topic of his slow running S195.

http://www.microcogen.info/index.php?topic=477.0

bigbad

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Re: Slow rpm Chang fa?
« Reply #5 on: October 31, 2021, 11:56:06 AM »
Thank you all!  A Chang Fa fits my budget at this point  ::)  Are they as versatile about fuels as the Lister engines, i.e. biofuels, waste oil, etc.?

mobile_bob

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Re: Slow rpm Chang fa?
« Reply #6 on: October 31, 2021, 06:10:14 PM »
here is a list of fuels i tried in the s195

bearing in mind it was built with a closed cooling system, radiator, 7lb cap, running between 205-214deg F

1. pump diesel
2. home heating oil
3. hydraulic oil
4. 30 weight motor oil
5. 15/40 motor oil
6. 50 weight motor oil
7. 15/40 waste motor oil
8. kerosene
9. straight corn oil,(wesson cooking oil)
10. atf (automatic transmission fluid)
11. lamp oil (walmart stuff in the bottle)

at operating temperatures, the engine ran cleanly with very small amount of grey smoke at full load, that on all fuels, there was no difference in visible smoke.

i think the only limiting factor is make sure the engine is fully warmed up, and the fuels are clean, well filtered.

also of note, the engine would start from cold (70deg ambeint) with 50 weight motor oil, but it would smoke for about 30 seconds, then it cleaned right up and you really could not tell the difference between 50 weight and pump diesel.

there is one thing you should be aware of, that is the ash residue burning motor oils, and waste oils.  the ash residue likely will be somewhat abrasive and "may" shorten the lifespan of the cylinder kit.

if you do an analysis, i think you will conclude that the savings in fuel cost burning waste oil stocks out way the cost of repair parts.  so you probably want to put in a stock of replacement cylinder liners, pistons, rings, gaskets.

for my application, i figured to mix the waste fuel sources 50/50 with pump diesel, then filter to 1 micron.   and i would never use any waste oil sources that i did not know the origins of.

at the time i ran a mobile service, so i knew where the waste oils came from, and what they were.  what i did not want was unknown waste oils that might have brake fluid, brakleen, paint thinners, or any other unknown waste that might be a carcinogen.

what i would not run in any engine i cared about would be waste cooking oils, they might be at the very least acidic, likely high in salts and other corrosives. however i might use some from a source that regularly changes their oils, and would put the waste back in the 5 gallon jugs they get the new stuff in.  then i might use the stuff after well filtering, settling out the heavies first.  then maybe i would run some after the engine is warmed up, and then switch back over to pump diesel to clear the injection system (pumps, lines, injector). i would also keep a good eye on crankcase oil contamination, pull the head and check for carbon buildup and any signs of premature wear.

i might also mention my engine is an idi (indirect injection), so in my opinion it will likely burn just about anything flammable, some very well with good lifespan of parts, some well with reduced lifespan of parts.

my bet is the darn thing would run on bacon grease, if it was preheated enough to make it through the injection system.

having reported all this, all testing was done prior to the tier 4 ban on import of these engines.  read whatever you like into this report, however be aware that burning anything other than low sulfur diesel fuel is likely to put you afoul of the US EPA, and probably other controlling authorities in whatever country the reader might be contemplating such use.

just because the engine can burn these alternate fuels, does not mean you should burn these fuels,  so bear this in mind. 

best to use alternate fuels only in the case of emergencies.

and of course let your conscience be your guide.

bob g



 
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

guest18

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Re: Slow rpm Chang fa?
« Reply #7 on: October 31, 2021, 07:02:04 PM »
Bob,
I agree with everything you written.

I would like to add that my Pre-Ban S195ís were DI (Direct Injected) engines. I did not go through to the extent you have to see what the engines would effectively burn, but the DI engines had no problems burning a 50/50 mix of #2 Off-Road Diesel & New 15-W40 Diesel Oil. A matter of fact while testing, it ran much quieter and showed no loss in power. And it Started up with no starting aid @ 40 degrees F. This testing was also done prior to the Tier 4 ban.

I wish I kept one of those engines.

For my current diesel genset I just run #2 Off-Road Diesel I donít go through enough to be concerned.

guest18

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Re: Slow rpm Chang fa?
« Reply #8 on: October 31, 2021, 07:37:54 PM »
Here is some info I dug up and posted on microcogen back in October, 2009

https://www.microcogen.info/index.php?topic=171.0



For those that are not able to log in to view attachments on microcogen click on the attachments below:

veggie

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Re: Slow rpm Chang fa?
« Reply #9 on: November 01, 2021, 05:11:17 PM »
Here is the slow speed changfa.
It runs at 900 rpm and can pull up to 3kw electrical power.
https://www.youtube.com/watch?v=aOhg1Q1rd6E

My neighbour loved it ... and bought it.  :)

So yes, with a few modifications, the Changfa engines make good slow speed diesels.
I have seen many videos of these engines running in China as slow speed power plants.
Many on grain grinders and tractors.

Come to think of it, my neighbour asked if I would like to buy it back. ::)
Hmmm ... how could I sneak a 600 lb  bright green generator into the garage without my wife noticing  ;D
« Last Edit: November 01, 2021, 05:15:03 PM by veggie »
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw

guest18

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Re: Slow rpm Chang fa?
« Reply #10 on: November 02, 2021, 02:10:56 AM »
If you can buy that thing back you should jump on it. :) Give her some money and tell her to go out and get herself something she likes. It works, Iíve had to do it many times.

bigbad

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Re: Slow rpm Chang fa?
« Reply #11 on: November 07, 2021, 06:40:50 AM »
Thank you!  Is the S195 not allowed into the US now?  Can anyone recommend an honest place to buy one - so that I know that I want I am ordering is what I will get?  Does that engine use a removable cylinder sleeve?  It is nice to know that it will run below 1000 rpms.  Initially, I will need an engine to put out more power - use a gen head, compressor and a few other tools.  Once I get my place built, I can revamp the engine to run a 3KW gen head. 

Fred8

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Re: Slow rpm Chang fa?
« Reply #12 on: November 07, 2021, 12:34:32 PM »

despite the Misinformation and ignorance  people spread about running Diesels slow, you CAN run any engine at low speed if you do it right and without problem.  It's a standard practice in industry to over size and under drive/ rev engines.  Many industrial engines have charts to show what power they make at what RPM.
It's simply a matter of matching the engine speed to the power.

If an engine makes 100HP at 2500 RPM, it will make ( say) 20HP @ 1200 RPM.  if you are putting an 18 HP load on it and turning it at that speed, The engine IS in fact working and will work fine.  I have read a lot where people say engines need the ring revved out of them constantly or they will fail which is just poppycock.

For a generator, gear the head to give the desired RPM  at the RPM the engine delivers the required power and thats it.  Will still be working hard but will not be as stressed or wearing out that fast.

You could easily run an engine out a vehicle this way and get slow speed and long life with good economy. I'm negotiating now on a 90Hp 4 Cyl engine that I want to put on a 10KW head.  Will run nice and slow and quite in that setup with an electronic governor  and last a VERY long time.

mobile_bob

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Re: Slow rpm Chang fa?
« Reply #13 on: November 07, 2021, 01:13:00 PM »
the s195 is not allowed for import into the US currently, and has not been allowed since 2006.

it does have a removable liner, and is rebuildable, there are many parts suppliers on aliexpress and alibaba, among other places like ebay from time to time.

if you are trying to get a new one, in the US, it will either be a NOS that someone has set away, or a used engine, or possibly one that someone has managed to get slipped by customs.  of the three options, the first two are legal to sell and own, the third option is illegal to sell and if the seller is caught by the epa it likely would be tracked down by them and confiscated.

i don't know what the fair market value is for an s195 NOS in the crate, but because of the rarity it is likely going to be north of 750 bucks and maybe a lot more?

problem being finding one and getting to an agreeable price between seller and buyer.

used ones come up form time to time, and sometimes you can get a deal, but i would expect them to go for at least 500 bucks for a known good runner, or more.  maybe less for one that has no history or record of how many hours it has on it or what kind of maintenance it has had.  even those are going to fetch up to 500 and maybe more.

like anything else, it is a supply and demand thing.  if there are few engines and there are more buyers, the price goes up, and up.

i would be interesting to see one come up for auction on a forum.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

bigbad

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Re: Slow rpm Chang fa?
« Reply #14 on: November 09, 2021, 01:43:22 PM »
Pardon my ignorance, but what is NOS?