Diesel engine : Kromhout Gardner 4LW 1940

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minh-thanh

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Hard to tell from the picture but is the lapping tool split?
I'm a bit late to reply, sorry.

No, it's not necessary
I sharpened it to the angle of the needle and sharpened it with a file - making a place for the abrasive to stay - it's made of steel
I tried with aluminum, but it's too hard to do and it wears out too fast
 

minh-thanh

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Hi All !
An update

I've done the fuel pump cylinder but haven't lap yet
With some testing, I found a pump cylinder length of about 8 to 10 mm to be fine - because the plunger stroke is very small - about 1 mm, but I wanted the best I could so I made it almost 2 times longer.
The engine only needs 4 but I did 5 and I will choose the best 4 for the engine and the other 1 for the injector testing.
With this 4-cylinder engine, I try to equalize the amount of fuel for each engine cylinder so I have to make 4 cylinders of the fuel pump which must be of the same diameter.
20221121_170825.jpg


Although I have some experience with small diameters, But before I lapping , I need to redefine a few things, so I made several cylinders out of brass, steel and different lengths. for test

Cylinder and plunger for test

20221128_172001.jpg




lapping this small diameter cylinder probably only have 2 options: buy or make it yourself
Lapping it is a challenge
Must be remove all scratches caused by drilling or reaming and to ensure it is relatively straight throughout the lapping process.
With purchased or homemade tools, they only have 2 parts in contact with the cylinder - they actually don't make perfect contact with the cylinder and it can give a lot of shape to the cylinder - so lapping takes very careful and meticulous

20221128_175723.jpg
 
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