Diesel engine : Kromhout Gardner 4LW 1940

[minh-thanh]

I make connecting ends as shown
Pipes for lubricating oil , I use tubes with OD-ID 3-2mm
Fuel tube : I use a capillary tube commonly used in the refrigerator

 

[Nerd1000]

What are you guys using for that very small diameter copper tubing & how do you make the connecting ends into a larger body like a housing or injector? I've been thinking about future engine with lubrication oil pump & this is (yet another) uncharted waters consideration.

Like Minh, I used air conditioning capillary tube. There are lots of ways to do the high pressure connections. My prototype injector is silver brazed to its fuel line, the line then connects to the pump via a flare connection much like automotive brake lines.

 

[Roger B]

For the injection pipes I use 2mm dia 1mm bore copper tube. Oil and fuel feed pipes are 3mm dia 2mm bore. These are connected with cone unions. There are various suppliers, I use Regner Dampftechnik:

https://www.regner-dampftechnik.com/kupferrohr-verbinder

 

[petertha]

Very helpful, thanks guys. I don't want to derail the Diesel thread so I'll start a new post on this & related matters because it probably warrants more discussion & exchange of resources.

 

[minh-thanh]

Hi All !
An update:
Injector - First test:
I can't get it to inject fuel, the fuel just drips. , with many adjustments and tightening ( because I think it's not sealed ) so part of the injector is broken . After measuring and checking...I found that the inside diameter of the needle body fit well and that caused the needle to not move freely, so I changed it a little with the inside diameter - as shown in image

Second test: After checking everything is ok, but it still doesn't spray in the form of fuel mist, adjusted dozens of times still doesn't work.
Then I thought "maybe it's the test fuel", it's old oil and it's a mixture of diesel and quite a bit of w40 oil.
So I changed to just using new diesel, and after a few tweaks, the result :

 

[ajoeiam]

Hi All !
An update:
Injector - First test:
I can't get it to inject fuel, the fuel just drips. , with many adjustments and tightening ( because I think it's not sealed ) so part of the injector is broken . After measuring and checking...I found that the inside diameter of the needle body fit well and that caused the needle to not move freely, so I changed it a little with the inside diameter - as shown in image



Second test: After checking everything is ok, but it still doesn't spray in the form of fuel mist, adjusted dozens of times still doesn't work.
Then I thought "maybe it's the test fuel", it's old oil and it's a mixture of diesel and quite a bit of w40 oil.
So I changed to just using new diesel, and after a few tweaks, the result :

Noticed that someone's hand was the 'catch device'. Its many years ago not but I clearly remember being told to never ever use my hand or any other body part around high pressure diesel or any oils. If you manage to inject yourself with any such under the skin - - - - well - - - the warning said that the effect was terminal at weorst and at least would mean amputation. The suggestion was to use cardboard or some other such instead of the body part.

 

[minh-thanh]

My hand is about 12cm away from the nozzle, when the oil vapor reaches my hand, I only feel like a light mist

 

[Mechanicboy]

Noticed that someone's hand was the 'catch device'. Its many years ago not but I clearly remember being told to never ever use my hand or any other body part around high pressure diesel or any oils. If you manage to inject yourself with any such under the skin - - - - well - - - the warning said that the effect was terminal at weorst and at least would mean amputation. The suggestion was to use cardboard or some other such instead of the body part.

In other words: Blood poisoning!

 

[minh-thanh]

Hi All !
An update:
I soldered the fuel pipe
Yesterday, I tried to run the engine, for a short time the engine seemed to want to run, after a few tests I discovered that the fuel pump was not pumping into the cylinders of the engine.
I don't understand why with the fuel pump of this engine I did better than the 1-cylinder engine but it didn't work, I will have to remove the fuel pump and check again

 

[Roger B]

Good Luck

 

[minh-thanh]

Good Luck

Thank you

Hi All !
An update:
I removed the fuel pump and examined it with a magnifying glass. A mistake resulted in the pump not being able to pump fuel
With the pump on the left side, when I set the plunger stroke to about 0.7mm limit, the plunger almost completely covers the inlet port.
With the pump on the right side, the plunger stroke is about 1.5mm, the inlet port is open
This can be easily solved: grind a little above the plunger

 

[minh-thanh]

Hi All !
An update:
With the tests, only 2 pumps create enough pressure to inject fuel into the cylinder at compression stroke, another pump sometimes does not work, and one pump can not even open the injectors - injectors are not assembled into the engine
After testing and comparing the pump system for this engine and with the hand pump and fuel pump in a single cylinder engine, I decided to design and build a new pump body to eliminate all the possibilities that I had suspect
With a lot of testing with the engine , the crankshaft ( my biggest concern ) It is pretty good until now . That gives me more focus on the pump system
I will update more

 

[Lloyd-ss]

Hi All !
An update:
Injector - First test:
I can't get it to inject fuel, the fuel just drips. , with many adjustments and tightening ( because I think it's not sealed ) so part of the injector is broken . After measuring and checking...I found...................................

-- quote snipped for the part I wanted--

Minh-thanh,
This all sounds so familiar. Working with the tolerances needed for a diesel injector is so difficult when the machinery isn't really up to the task and you have to rely on ingenuity and luck.
------- Check-lap-try again-lap- oh darn, too much- start over and repeat-----
But it works out in the end, sooner or later.
A very serious project!!!
Lloyd

 

[Mechanicboy]

The pump parts who are using as diesel pump must be clean and without metal particles or it will scratch the surfaces who lead to leakage. Better to clean up in the ultrasonic cleaner to remove the dirty
particles after working with the pump parts in work shop after the parts is lapped/grinded. Lapped pump piston in steel in the cast iron cylinder is better against abration and the piston plunger length must be longer than the diameter too keep tight without leakage but allow to lubricate the piston and cylinder. As your photo are showing the parts is not clean hence the parts can be damaged by dirty particles who lead to loss of the pressure. Use fuel filter to keep fuel clean before entering into the diesel pump.

 

[minh-thanh]

Hi @Lloyd-ss !
As I said: "I'm not sure the engine will run"
I'm just like you - too hard headed.., Find something new, strange ....build it....
And because this is a homemade forum , so : build if you like , , ... and FUN the results for later .

Hi @Mechanicboy !
The image you see has been magnified so many times - use a 2mm drill and compared to the picture you will see, it also wasn't cleaned when I took it because I decided to take it apart and redo the whole thing.
Trust me, I'm the type of guy who hates engine parts getting dirty when I'm done with it, during assembly, and during testing.

 

[minh-thanh]

If I remember correctly, someone asked me about the surface finish of the my fuel pump cylinder
This is the picture I tried to take

 

[minh-thanh]

Hi All !
An update:

After making a new pump body, as well as changing the size of some pump parts
Everything went according to plan: adjusting the amount of fuel -ok, adjusting the plunger stroke - ok, all pumps created enough pressure to inject into the cylinder at the compression stroke -ok...
attempt : n + 1 : Engine might want to run and then 1 injector gets stuck and it can't open
attempt : n + 2 - after injector repair
I'm adjusting the lobe time - injection time, and after a while...the engine doesn't want to run anymore
I tried starting the engine a little more and I discovered that there were quite a few bubbles in the fuel line
Cause: when the engine starts to heat up, one injector starts to no longer seal
I wanted to make a 4 cylinder engine to know more about fuel pumps and injectors in small diesel engines and the result: I don't know much more than I did with 1 cylinder engines - REALLY CRAZY

 

[Lloyd-ss]

.............................................
I wanted to make a 4 cylinder engine to know more about fuel pumps and injectors in small diesel engines and the result: I don't know much more than I did with 1 cylinder engines - REALLY CRAZY

View attachment 148856

But darn, it is wicked looking, and something that wicked will definitely wear you down.
But we can all wait for it to run. And it will happen !

 

[Mechanicboy]

Does the injection pump lose pressure when the engine warms up? It sounds like you have material with high thermal expansion that the pump loses pressure. What material did you use for the injection pump? The same with the injection nozzle must have at least thermal expansion so as not to lose pressure and keep the nozzle cooled against excessive heat.

 

[minh-thanh]

Regarding thermal expansion, I think it is not a problem because With 4 pumps and 4 injectors only 1 injector does not seal when the temperature is increased.
I think there's a problem with the way I make the injectors