The LD110 Adventures.

Chainlube

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Can you link to or give a better description as to what you used to polish the head?
Back on page #2.
Akin to this.
 

ImpulseRocket89

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Can you link to or give a better description as to what you used to polish the head?
Yeah, I can link you to what I use. If you order these you will have a supply to last you for many many many engines to come.

I first used these abrasive scotchbrite wheels that start at 180 grit and go to 1000 grit to get it to a state where you can then use polishing compounds. The type that Chainlube posted also work well. I just like these because they also fit into ports rather well. Makes polishing up an exhaust port rather easy.

I then use Polishing compound just like Karl stated, with some felt polishing pads
Pads:

Compound:


I prefer the smaller stuff like this when working on these little engines because it helps get into small spaces better. As Karl also said, there are many types and sizes of polishing wheels and pads, from tiny rotary tool to huge bench grinder sized units. Just depends on what you are doing or wanting to polish. For these tiny little engines, I find this stuff to be more than sufficient.
 

ImpulseRocket89

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Nothing picture wise to share. I've been preoccupied with a new job and a change of schedule that my work has been minimal on this project. I am currently working on removing the lips from the ports that need to be removed and then I can clean it up and take new timing numbers before I attempt to change any of the ports.

Also still trying to work out the best way to get at the upper transfers effectively without spending a lot of money on a right angle tool or a dental drill that will take forever to remove the material needed (also a bit pricey).

My one real observation that I will make about the cylinder is the iron liner itself. As far as iron goes, this is some pretty soft stuff that cuts easily with my single cut burrs. I was afraid of ruining the burrs, but as long as you keep them oiled it cuts rather easy.
 

Chainlube

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With the way that liner fits in the casting, you might want to check those #s before you clean too much up. You could be just smoothing with a file.

I have a handful of those little diamond files, but they are very time consuming.
 

ImpulseRocket89

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With the way that liner fits in the casting, you might want to check those #s before you clean too much up. You could be just smoothing with a file.

I have a handful of those little diamond files, but they are very time consuming.
the way the lips protrude into the ports, and the already pathetic nature of the port timing, they can only improve in this case. I already have the timing numbers of the liner pre-cleanup.
 

Chainlube

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the way the lips protrude into the ports, and the already pathetic nature of the port timing, they can only improve in this case. I already have the timing numbers of the liner pre-cleanup.
Wasn't sure what you did already, but with the way those edges on the ports look, kinda like a poorly sharpened saw, thought it might be hard to get a good number.
 

ImpulseRocket89

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Wasn't sure what you did already, but with the way those edges on the ports look, kinda like a poorly sharpened saw, thought it might be hard to get a good number.
The intake and exhaust ports are more than able to be adjusted for desired timing numbers. It is mainly the upper transfers that really let the whole thing down. With adding a second base gasket and removing the lips I can get the transfer port duration to about 116-117 degrees. I would love to be able to at least get that number to 120 degrees to match the peak power RPM I want to tune the intake and exhaust timing for.

The only thing that kind of lets the exhaust port down is the piston sticking up above the floor of the port a few millimeters which will be a point of turbulence. Much like the lip from the top of the intake port, I am thinking about using some reinforced epoxy (aka JB Weld) to build a ramp to help with reducing that turbulence. I can then re-shape both ports to restore area and improve the timing figures.
 

ImpulseRocket89

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I haven't forgotten about this little project, but I have just been so busy with other things that it kind of took a back seat for a bit. I started to get a little bit more work done on the ports. At this point I am focusing on removing the iron sleeve overhangs on the transfers and exhaust ports. Once that is done I am going to do a little create JB welding on all 4 ports to reduce turbulence and try to shape airflow.

I have decided to aim for the following numbers after doing some measuring, thinking, and evaluation of the cylinder and ports.

Exhaust - Still going for the opening at 100ATDC and 160 total duration. (current work in progress)

Transfer ports - 2 base gaskets and the overhangs removed has given me 116 degrees of total duration. With the transfers opening 122ATDC

This will give me a blowdown of 22 degrees which lands it much closer to the power band of the rest of the port timings and durations.

Intake - I am still undecided. A part of me is considering dropping the floor of the intake port to match the height of the inlet. This will increase my intake timing from 62BTDC to 66BTDC increasing the duration from 124 degrees to 132 degrees which is a bit aggressive. This has me considering a window and reed or third transfer and reed setup.

I am open to criticisms or suggestions. I don't claim to be the most well versed builder so if anybody thinks my numbers could use some tweaking let me know. My main goal is to try and land my power peak somewhere around 6000rpm and to run this motor with a clone pipe with the long header.
 
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