Mastiff lc mason engine REDO .

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Dec 29, 2016
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Viet Nam
This is the engine that I will remake it for a friend.
He bought from the son of the person who made this engine, it was not completed .
The cylinder surface is not good, I will rebuild the valve seat with brass material and make it according to valve seat standards, make a new camshaft, A lot of things need to be redone.




Nice puzzle. Please keep us informed.
I have drawings from this engine and will build it sometime.

Merry Christmas
Hi All !
An update
I just finished making the cylinder.
Next to it is a fake piston - it looks like a measure of the cylinder's inner diameter. After completing the cylinders, it will be a measure of thermal expansion: I heat it up to about 150 - 200 degrees Celsius. If it cannot enter the cylinder, I will reduce its diameter a little and check again. The temperature is 150 -200 degrees Celsius, it fits tightly to the inside diameter of the cylinder : Then I will use that diameter to make the pistons - An amateur method ;)

Good Idea, you never know unless you try Minh Thanh Number 1 Mini Motor Repair. 😊 Looking good. 😊

This is funny, what Battalion were u in......I was in 1
Hi All !
With this project :
- I have to convert inches to mm
- Change the piston making to the standard way. I don't understand why the piston is designed and machined like the attached picture
- And must make a part or machine to cut helical gears

Hi Minh,
I built a Mastiff (finished in 2018) and wrote up the build on the Model Engine Maker forum. My description of making the pistons and cylinder liners is in
Len Mason's "Mastiff" - chewed from the solid
I think that Len Mason's reason for making the pistons in two parts is so that the internal shape of the gudgeon pin bosses can be machined. Without the two-part construction it would be necessary to make the pistons from cored castings. If you use the cast iron pistons, then you will not need to adjust the diameters for temperature difference and the liners and pistons can be lapped to a fine finish. If you go for aluminium pistons then, as you describe above, you need to allow for the expansion of the piston as the engine warms up. In my engine the cooling water doesn't get anywhere near boiling, but I haven't measured the temperature, I don't think that the cylinder liner would reach anything like the 150-200 C that you mention. If I'm estimating it correctly then for a 100 C temperature rise a 25 mm piston will increase in diameter by about 50 microns - 0.050 mm. Others should check this!

Hope this helps!
I am not an IC person by any measure, but I was playing around with making a piston for a scaled Galloway, and this is what I came up with.
Not sure if this is relevant/usable or not, but for a first try on a piston, I thought it turned out pretty decent.
Perhaps a bit on the heavy side in gray iron, and could maybe be milled a bit more on the inside with a smaller bit.

That piston build by deltango looks to be a great setup.
I am not sure how he machined the inside of that piston.

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There was some good discussion here about making helical gears, using standard gear cutters.
The topic came up with regards to making the helical gears for the Frisco Standard marine engine.

JasonB came up with a 3D design for the Frisco, and I intend to lost-PLA cast them.
They mesh perfectly, and give a 2:1 ratio with gears of the same diameter.

You could actually get Jason to post how he did it in 3D, because the method would be similar or even the same using gear cutters.


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