Lister Engine Forum

Slow Speed Diesel Engines => Changfa Engines => Topic started by: veggie on March 11, 2020, 08:04:21 PM

Title: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: veggie on March 11, 2020, 08:04:21 PM
Far anyone who is planning to replace an injector pump or modify the injection timing by adjusting the shim pack thickness you may find this helpful.

https://www.youtube.com/watch?v=a1ZrAAYGt40 (https://www.youtube.com/watch?v=a1ZrAAYGt40)
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: oldgoat on March 12, 2020, 11:29:04 AM
Classy mechanic.  Doing up injection fittings with multigrips and bending injection pipes
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: dax021 on March 13, 2020, 07:11:35 AM
Was also the first thing that i noticed.  What a wanker.
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: glort on March 13, 2020, 09:14:12 AM

Nothing in that vid bar how to undo 3 bolts incorrectly and one fitting, Incorectly, and put them back again.

I thought there was going to be something on how to know when you had the correct amount of shims or how to time the things properly.
So much for that!  :0(
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: veggie on March 13, 2020, 11:06:13 PM
Agreed, very simplistic
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: Johndoh on March 14, 2020, 10:21:45 PM
Page 93 shows how to set up the fuel injection timing

https://static1.squarespace.com/static/5acc429696d45598c5503e72/t/5bebb5594fa51a3bf1527ba1/1542174071442/Service+Manual+-+Yanmar+Engine+L48-70-100.pdf
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: glort on March 15, 2020, 12:25:54 AM
Page 93 shows how to set up the fuel injection timing

https://static1.squarespace.com/static/5acc429696d45598c5503e72/t/5bebb5594fa51a3bf1527ba1/1542174071442/Service+Manual+-+Yanmar+Engine+L48-70-100.pdf

Now there is some worthwhile information!
Saved.

Thanks mate!
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: veggie on March 15, 2020, 02:51:42 PM

So these engine are only running only 12 to 14 degrees advance according to that manual.
I would have thought they would run 18 to 20 like most diesels I am familiar with.
I suppose the short stroke has something to do with it.
It doesn't explain why they knock an hammer so much.

Glort, from your experience, where is a good zone to target in order to quiet them down?
Something like 9 to 11 degrees?
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: hwew on March 15, 2020, 09:52:37 PM
I just looked at this and the specs printed in the Yanmar manual might not work for the Chinese clones.
Iím looking in my owners manual for my clones and it reads as follows:

Initial angle of fuel delivery
170F & 178Fóóó21 degrees + or - 1 degree
186Fóóóóóóó22 degrees + or - 1 degree

I assume its BTDC

It seems like the specs in my manual is more in line with the norm.
12 to 14 degrees seem to be incorrect for the clones. It might have something to do with how the injector pump and injector are set up on the Yanmar engines.

I know most diesels had the timing bumped up 1 or 2 degrees to help with emissions, but 8 or 10 degrees up from 12 or 14 degrees seems excessive. I just donít understand why Yanmar posted these numbers. I just donít know, Iím just guessing. We probably wonít know until both identical displacement Yanmar and clone engines are blueprinted to see what the differences are.

It seems like the Yanmar and clone engine pump pressures are the same. (200 Kafka/cm2)

I guess the safest way is to do a fuel time test on the clones first to see where it is before re-timing the pump.


Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: veggie on March 15, 2020, 11:33:04 PM

Good catch hwew. I personally have only seen numbers in the 18 - 20 range.
(Except for the advanced computer controlled variable timing automotive diesel engines. VW, BMW, Merc)
 
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: glort on March 16, 2020, 12:55:38 AM

Glort, from your experience, where is a good zone to target in order to quiet them down?
Something like 9 to 11 degrees?

You are talking way too edumacated and technical for me mate.
I just made up a stack of cardboard shims, put some in there, ran the engine and put some more in there till it sounded like it wasn't going to self destruct. Would not have the faintest what the actual timing was.

One I did is very quiet ( relatively) and I highly suspect the timing is a bit retarded BUT, it starts easy, runs clean and I wasn't chasing max power out the thing so I haven't changed it in all the years since I did it.

I'm quite big on the " Not too Bright" method.  For years I used to modify and build 2 stroke engines. I always set the points gap by holding the HT lead and giving the motor a spin without the plug in it. When the thing felt like it was going to take my arm  clean off, it was right.
Stupid as that sounds, I came across several engines owned by other people that I set up like that and they said they never went better even though where I put them was often a LONG way from where they should have been.

Thankfully electronic modules came along that eliminated the points and condenser.
 My arm does still twitch a bit for not particular reason!  :0)

Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: hwew on March 16, 2020, 01:38:54 AM

Good catch hwew. I personally have only seen numbers in the 18 - 20 range.
(Except for the advanced computer controlled variable timing automotive diesel engines. VW, BMW, Merc)

Iíve seen numbers from 17 to 25.5 degrees BTDC on stationary diesels. Never 12 to 14.

To be safe, I would pull off the air shroud and do a fuel spill test on the injector pump to see where the engine is timed. If itís at 21 shim the pump to 18 and give it a try. If it starts ok, runs good and seems to have good power without smoking try retarding it more. Eventually you will reach the point where you will notice loss of power, white smoke and possibly rough running. Iím curious, and want to check timing on one of my engines but I wonít be ready until the engine is mounted.
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: glort on March 16, 2020, 11:23:07 AM

One thing with Diesels is they should have that Charismatic Knock when they are right. 
The knock is compression as well as timing and it's pretty clear on these engines although the ones I have had sound like they are being knocked with a sledge hammer.  The flywheels were ringing like bells.

The quite one I have only has a very feint knock which is why I think it's a bit retarded.

On cars I can tell straight away how good the engine is by that sound. If it's crisp and sharp, the compression is good. If it's dull and subdued, Probably worn and on the way out. Cars don't tend to be off on the diesel timing in my experience because very few people touch injector pumps so they are usualy set right and Locked in and they don't move.

 If the sound a diesel makes is metallic and ringing like these China engines were, run.... or on the China diesels, shim the pump out.
A lot.
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: hwew on March 16, 2020, 01:08:49 PM
Iím more concerned about reducing stress on bearings, rods, crank, pistons... Since Iím going to be running the engine below 3100 or 2600 rpm. Iím thinking of a possibility of using the ST-10 head along with the heavy 8 groove pulleys. Iím hoping to get 2400 watts continuous to 3600  watts surge out of the unit. The engine will be spinning lots of inertia while working to keep it at a speed below max rated speed I want to reduce additional stress some. I remember reading in a Kohler/Hatz air cooled diesel engine service manual about 9 years ago. It mentioned that thicker head gaskets are available. Iím thinking that installing a thicker head gasket on engines with high inertia loads should help reduce stress caused by spinning loads that have high inertia at lower RPMís.

One good example of high inertia loads on a piece of power equipment is a small home owners gas powered wood chipper. It takes a long time to spin up to rated speed right after starting. And than the engine is subjected to constant abuse when pushing branches through and constantly slowing down the engine below itís running speed. This is hard on any engine.
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: glort on March 16, 2020, 02:13:26 PM

to help reduce stress caused by spinning loads that have high inertia.

This makes no sense to me at all.
The whole concept of CS listers is a large, heavy flywheel and slow speed. Some people put extra flywheels on to reduce flicker. If does not matter if it's the flywheel or rotating mass of the load, they have high inertia as do all of the traditional type generators like you want to use.  Never heard of anyone saying they cause " additional stress" ?  Additional to what exactly over any other load??

Never heard of anyone complaining about inertia on a generator before. It's the lack of it that gives problems.   That's what gives reactive power and why heavy engines with large flywheels like listers are so well thought of. It is in fact the best thing you can have on a generator.  It's what STOPS them bogging down when heavy loads are dumped on them and voltage sag which the engine then tends to over fuel on when the governor gives it everything to get the revs back up.
And trust me, These engines WILL over fuel when bogged down.  That's what causes stress not rotating mass!

I also strongly question the idea of using 2 head gaskets to reduce compression. That is widely known in engineering/ mechanical circles to be hackery and a very bad practice. No idea why you would want to reduce compression on a diesel? Would only make for harder starting for one thing and have great potential for poorer combustion... particularly if you were thinking of burning veg, Bio or WMO.  They are all harder to light off and the more compression the better.

Also Gaskets are meant for sealing, not adding length to Cylinders.

If you want to reduce the speed of an engine then you have to derate the power as well. What engine are you intending to run?
An ST 10 is an over sized generator for a 178 to a 186 so you would want to be more concerned about limiting the load on the head to stop  stressing the engine rather than the rotating mass.
In any case if you are belt driving the head there is an amount of slip and cushioning in the belt so really not sure what you are concerned about??

Weren't you all Gung ho about some Briggs twin a while back on a generator and thought that was the best thing sliced bread? 
Seem to remember you wouldn't permit a less than glowing comment about it.
What happened to that thing??

Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: hwew on March 16, 2020, 06:00:21 PM
I answered in Blue.


to help reduce stress caused by spinning loads that have high inertia.

This makes no sense to me at all.
The whole concept of CS listers is a large, heavy flywheel and slow speed. Some people put extra flywheels on to reduce flicker. If does not matter if it's the flywheel or rotating mass of the load, they have high inertia as do all of the traditional type generators like you want to use.  Never heard of anyone saying they cause " additional stress" ?  Additional to what exactly over any other load??
Any additional weight/mass causes additional stress.

Never heard of anyone complaining about inertia on a generator before. It's the lack of it that gives problems. Your partly right. Itís also dependent how fast an engine is able to respond to a load. Some generators have aluminum flywheels and they do just fine. Some Fairbanks Morse generators with  Wisconsin engines had aluminum flywheels.  That's what gives reactive power and why heavy engines with large flywheels like listers are so well thought of. It is in fact the best thing you can have on a generator.  It's what STOPS them bogging down when heavy loads are dumped on them and voltage sag which the engine then tends to over fuel on when the governor gives it everything to get the revs back up.
And trust me, These engines WILL over fuel when bogged down.  That's what causes stress not rotating mass!

I also strongly question the idea of using 2 head gaskets to reduce compression. Did I say I was going to use two head gaskets? Iím sorry I was not detail enough. I was referring to a head gasket a couple of a thousands thicker if needed to get piston to head clearance correct. Iíve found some engines with not enough clearance. With the Clones itís probably best to check clearance to make sure itís within spec.  That is widely known in engineering/ mechanical circles to be hackery and a very bad practice. No idea why you would want to reduce compression on a diesel? Would only make for harder starting for one thing and have great potential for poorer combustion... particularly if you were thinking of burning veg, Bio or WMO.  They are all harder to light off and the more compression the better.

Also Gaskets are meant for sealing, not adding length to Cylinders. need to add or delete cylinder length by gasket size to get piston to head clearance correct.

If you want to reduce the speed of an engine then you have to derate the power as well. What engine are you intending to run? Your correct, yes you have to derate the engine to operate at a lower speed.
An ST 10 is an over sized generator for a 178 to a 186 so you would want to be more concerned about limiting the load on the head to stop  stressing the engine rather than the rotating mass. Did you read that Iím hoping to get 2400 watts continuous to 3600  watts surge? 
In any case if you are belt driving the head there is an amount of slip and cushioning in the belt so really not sure what you are concerned about?? Read about my concerns in the very beginning of my post. We all know the Chinese clones have a history of failure in one from or another. Is it too much to make sure the engines tolerances are within spec? One thing I try to avoid is guessing.

Weren't you all Gung ho about some Briggs twin a while back on a generator and thought that was the best thing sliced bread? Does this have anything to do about this topic? What brought this up?
Seem to remember you wouldn't permit a less than glowing comment about it. It must of been some negative comment that someone wrote. Some people can be too abrasive and disrespectful when posting comments about a persons topic. Such behavior is frowned upon.
What happened to that thing?? Donít need it. Gave it to my brother to help him start his ST-7.5 generator project. Itís coming along fine.

Hope this helps clear things up.

By the way, I shipped the Briggs out last Friday.
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: AdeV on March 16, 2020, 07:11:35 PM

to help reduce stress caused by spinning loads that have high inertia.

This makes no sense to me at all.
The whole concept of CS listers is a large, heavy flywheel and slow speed. Some people put extra flywheels on to reduce flicker. If does not matter if it's the flywheel or rotating mass of the load, they have high inertia as do all of the traditional type generators like you want to use.  Never heard of anyone saying they cause " additional stress" ?  Additional to what exactly over any other load??


I think I can see what Henry is getting at - the high inertia will resist the power stroke, which means the rods and bearings are seeing maximum stress - from combustion pressure - for longer, than a lower inertia, free-er revving engine. Which, I suspect, is partially why Listers are built like brick sh*thouses; materials analysis was a new thing back when the CS was designed, if it even existed at all, so better over-built than under...

There is a, possibly apocryphal, story about the development of the RR Merlin engine; during the early tests, they'd run the shit out of an engine until it broke. They'd then beef up the bit that broke, and re-run the tests, until something else broke instead. Then they'd beef up that bit... Rinse and repeat many many times, and you end up with an - almost literally - bulletproof engine, which, as we know, went on to worldwide well deserved fame. I doubt the CS went through much of that; they'd just build it waaaay big enough in the first place.
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: veggie on March 16, 2020, 10:09:11 PM

I would suggest that the RA Lister company did extensive testing to find the optimal flywheel weight and diameter to balance the line between too much resistance to combustion acceleration vs. having enough inertia to carry good power through the next combustion cycle.
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: Johndoh on March 17, 2020, 10:14:34 AM
I have a few of these engines. The Yanmar L48 is a small noisy reliable easy started engine. The 186F engines are very similar to the Yanmar and have been reliable and fairly easily started. They too are very noisy. All are very easy to work at. I'm with Glort on the pump timing, just pack it up or lower it down until it "sounds right". When you buy a car thermostat they are often for many models and come with a selection of gaskets, they can often be adapted as spacers.
Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: glort on March 17, 2020, 12:57:54 PM
Does this have anything to do about this topic? What brought this up?

What brought it up was just wondering why you were now setting up this little diesel when previously you were so wrapped up ( as you still are) in the Briggs. Just wondering why if the Briggs was so great you weren't still using it?.  But not to worry, just a passing thought not a rhetorical question. 

Would seem to me that the logical thing to do if one were so worried about inertial stress on the engine would be to get a smaller and much lighter  gen head that would still be more that adequate for the intended load. That would to me be the proper way to reduce the stresses rather than try and modify the engine in a way that has good potential to cause other problems, but each to their way of doing things.



Title: Re: AIr Cooled Chinese L186 Diesel Injector Pump R&R
Post by: glort on March 17, 2020, 01:22:04 PM

I think I can see what Henry is getting at - the high inertia will resist the power stroke, which means the rods and bearings are seeing maximum stress - from combustion pressure -

I can't, in my mind, visualising it being any different to when the engine was at full load with any other load.
The gen head will have load which is trying to resist the engine.  With a lot of mass or a little, it's trying to slow down.  If it wasn't the load pulling the piston up to compression it would be the flywheel and as the force required will be the same wither way, don't see the difference in which force does it.

What I do see is with a high rotating mass the engine speed is going to be more stable between the firing strokes and therefore the speed changes will be less than if there was a lighter rotating mass used.  The actual load will be the same regardless of the rotating mass attached.

As compression is also the same with  or without a high rotating mass on the engine, the resistance will be the same either way.  The power stroke is going to generate far greater forces than the piston coming up under compression anyway.
i'd be far more worried about getting the timing right so the piston wasn't being slammed into the bore of the engine and the flywheel  ringing like a bell due to being slowed down then sped up again milliseconds later.
The cylinder pressures must be off the charts when that happens.
That's incomparable stress to the piston just coming up to the compression stroke.

As the load is intended to be under the engines power capability, I don't see the worry in stresses there either as the engine was designed to handle more than it's going to encounter in that application so stresses are already reduced.

I got a few thoughts how lowering the compression could create problems on those engines through hands on experience of what I have seen.  Helped a pommie bloke once with his bike he had fitted one of those engines to.  He was riding round the world on Veg oil and was getting a lot of problems which we traced to a new engine he got after the other one got a stone through the crank case.  Worked out the difference comparing it to the engines I had, tried a fix and he no longer had to pull the engine down after every ride.

Anyway...