Mastiff lc mason engine REDO .

[minh-thanh]

Hi All !
An update :
After thinking about oil rings, ...-...I decided to make oil rings for engine
I redesigned the piston according to the piston size I made

A few tests :

- Sharpen a cutter

- Make rings

Next will be drilling holes, TOO MANY small sized holes

 

[Steamchick]

Wow! I am impressed...
Hope it works as planned.
K2

 

[Scott_M]

Hi Minh Thanh
I concur, drilling a bunch of small holes sucks! Several of my products have small holes. I am calling .0635" a small hole.
I have drilled many thousands of these holes over the years. My advice for your upcoming hole jubilee is to first, make a fixture with a hardened bushing ( drill guide ) and then buy a sleeve of drills. Here in the USA they come in packs of 10 or 12. My preferred brand is PTD ( Precision Twist Drill ) They sell #52 drills by the dozen. My local supplier sells them to me for about $15.00/dozen. I have found over the years that it is far better to start with a brand new factory sharp drill, use a drill guide and change drills as soon as something odd happens. A funny sound, a clogged flute or any other oddity while drilling. I am drilling my holes on a CNC machine with a rigid fixture and a drill guide, drilling in steel. I can get about 200-250 holes to a drill before it will break. If it breaks, it usually trashes my drill guide and the part and cost me about a hour to get everything cleared up and reset. Those numbers above are much less on a manual machine.
For the cost of the drills I would change them out very often. Make a fixture for the rings and another for the pistons. With a replaceable drill bushing ( hardened ) It will be more work but I doubt you will scrap any parts or break any drills in your pistons or rings. And your parts will come out spot on. Overall saving you a lot of time and effort.
Again just my thoughts. But remember, small drills want to wander, especially on a curved surface. And drills don't like to be bent.
Some pics.

And one of my drilling fixtures

Again just suggestions.

I hope it offers some help or thoughts in your upcoming "bunch of tiny holes" marathon.

Scott

 

[minh-thanh]

Thanks for the comment, lots of information that I need to keep in mind
About the small drill bit: I use NACHI's bit
I plan to make a drill guide, but right now I don't have the 0.5 and 0.6mm drill bits, I will when I buy the drill bits.
Below is the part I made a few days ago, it will be used to fix the piston and rings when drilling, with the ring it will have an adapter - like a piston. They will be rotated when drilling the next hole.

 

[Steamchick]

I like the drill guide.
I sometimes have to drill gas jets, my smallest being 0.25mm. I buy drill bits with 1/8in/3mm shanks - makes use of a precision chuck easier, as I use a larger more robust version.
I get anything from 1 to 10 holes in brass before the edge goes off the drill bits. But the smallest ones can sometimes destroy themselves at high speed - e.g. if I use a dremel with collets, due to centrifugal forces... So while these small drills like speed, I end up using the lathe at maybe 1200rpm and very gentle tailstock feed pressure.. feeling the work.
K2

 

[minh-thanh]

Hi All !
I wonder....why not....
And a test :

I need to calculate the circumference and buy another small file

 

[minh-thanh]

Hi All !
I just made an adapter for a small drill bit

 

[minh-thanh]

Hi All !
An update :
After some thought, and a little experience, I decided not to do a drill guide
A short video, in the video have 3 rings set up at the same time

 

[Sprocket]

Minh Thanh,
That's about how I did it.

I shortened up on the drill to make it stiffer, and I think that helped.

Doug

 

[Steamchick]

Been there... used short (stiffer) hand sharpened drills..
K2

 

[minh-thanh]

Minh Thanh,

I suggest a ring of holes at the top of the skirt, just below the oil scraper ring, may also be advantageous to your oil clearing issue?

K2

I just drilled the hole and was nervous
I hate and Thank you for your suggestion.

 

[Nerd1000]

Nice work! I had similar tiny hole issues with the oil ring for my diesel.

For consideration in future, I think it may be possible to replace the tiny holes with slots cut by slitting saw. I did this on my oil ring, and it should be possible on the piston as well, if you are careful about the design of the piston (dont want to weaken it too much). Many older engines actually have such slots cut as 'heat breaks' to reduce expansion of the skirt, along with slots in the skirt that help compensate for any expansion that does occur.

 

[minh-thanh]

I think it's not too difficult, just be more careful when drilling and "feeling"
I drill at 1800 rpm or 2700 rpm, they are fine, drill bit 0.5 and 0.6 mm

 

[minh-thanh]

Hi All !
An update :
Drilled 96 holes
I bought 8 drill bits 0.5 and 0.6 mm Nachi / Japan
And I have 2 drill bits to use and 6 spare drill bits

 

[Steamchick]

Well done Minh Thanh! Once you have the right technique it all goes well! Have a beer and relax now.
K2

 

[minh-thanh]

Hi All !
An update :
This is an idea of mine to make oil rings

After searching and thinking...I decided to buy artificial diamond coated cutting blade, it's quite cheap, and use a hand drill

Cutting the ring was quite easy and after 2 trials, I decided to do it, this is the result :
Just completed 1 set of rings for 1 piston, I'm quite satisfied

 

[minh-thanh]

Hi All.
A small update
I'm a bit busy with some work, the weather is quite hot right now, so the project is a bit slow
I have finished assembling all the rings onto the pistons

 

[minh-thanh]

Hi All.
A small update
I did "gasket" (I don't know what to call it) for Pin piston
And draw a simple diagram of the position of the cylinders, the direction of rotation of the crankshaft...., to determine the lobes of the camshaft.

 

[minh-thanh]

Hi All .
I have a question,
I looked at the plans for this engine, it seems the firing order is not correct, right ? , 2 cll on the same side would fire and after another

 

[deltatango]

Hi All .
I have a question,
I looked at the plans for this engine, it seems the firing order is not correct, right ? , 2 cll on the same side would fire and after another

View attachment 155150

Hi Minh,
That firing order works fine on my Mastiff:
https://www.modelenginemaker.com/index.php/topic,6419.210.html

Also, I've owned three Subarus and they all fire in the same order as used by Len Mason for Mastiff.

David