The next 066 top end

[parrisw]

Phew. Damn this internet thingy and it's complete lack of personality

:cool2:

 

[mtngun]

Are you going to position the plug straight up or angled? Just curious if that has any effect?

I insist on having a decomp valve, so the plug will have to be angled. That makes the head much more difficult to design and build.

Cowboyvet, those are good questions, but I don't pretend to know all the answers. Timberwolf is the guy to talk to about theory.

If squish velocity is too high, it can cause detonation. But -- there is no agreement on what is "too high." Saws run squish velocities that would be considered unacceptable in the bike and cart world.

Here's a thread on the subject of squish velocity, I suggest reading TW's posts and ignoring the rest. http://www.arboristsite.com/saw-building-101/67669.htm

 

[cowboyvet]

Thanks Mtngun. The link to TW and then his link to another article cleared up many of my questions. Always a great day to learn something new.

 

[mtngun]

6061, mushy but cheap.

Cutting the dome, aiming for a 6.5 cc dome.

Cutting the squish band. Outer 3mm is flat, rest is 2 degree angle.

Lots and lots left to do. It's going to be tricky putting the angled plug and decomp in just the right places. :msp_scared:

 

[2stroked2smoke]

nice! Is this just gonna be a race saw or will you be able to do real work with this? Will the removable head cool well or not?

 

[mtngun]

This is going to be a milling saw, so it darn well better cool OK. :msp_wink: Compression will not be that high, only about 160 psi (or 188 psi at sea level).

As predicted, putting the angled holes in exactly the right spot was challenging, and they ended up being a hair off. It should work, though.

 

[mtngun]

A little more progress. :msp_ohmy:

Fit under the hood has not been tested yet, so it may need a little more milling tomorrow.

 

[mtngun]

Dimensions of combustion chamber in inches unless otherwise noted.

 

[parrisw]

Dimensions of combustion chamber in inches unless otherwise noted.

Nice work! How do you cut the combustion chamber to a raduis in the lathe?

 

[mdavlee]

Looks great. That is some slick looking work you did.:msp_thumbup:

 

[RiverRat2]

+1 !!!!!

Looks great. That is some slick looking work you did.:msp_thumbup:

Yep!!!!

 

[mtngun]

How do you cut the combustion chamber to a radius in the lathe?

The lathe has been converted to CNC. Works great for this and for pop-ups, PITA for simple jobs like shaving the base of a jug or threading a rifle barrel. Guess I need to buy another lathe ? :msp_biggrin:

 

[parrisw]

The lathe has been converted to CNC. Works great for this and for pop-ups, PITA for simple jobs like shaving the base of a jug or threading a rifle barrel. Guess I need to buy another lathe ? :msp_biggrin:

Ahh, ok. Grrrrrr. How wold one do it manually.

 

[mtngun]

Ahh, ok. Grrrrrr. How wold one do it manually.

You can do it by making a radius attachment for your lathe, Will. Sometimes called a ball turner -- I believe you can set them up to cut either concave or convex.

Pic of one for turning balls.

Different design doing the same thing.

I couldn't find a pic showing how to turn a concave radius, but the same principles are applied. There's going to be a limit on the range of radii it will handle. I've never built one since I have CNC. :hmm3grin2orange:

 

[parrisw]

You can do it by making a radius attachment for your lathe, Will. Sometimes called a ball turner -- I believe you can set them up to cut either concave or convex.

Pic of one for turning balls.


Different design doing the same thing.

I couldn't find a pic showing how to turn a concave radius, but the same principles are applied. There's going to be a limit on the range of radii it will handle. I've never built one since I have CNC. :hmm3grin2orange:

Right, ya I've seen those, didn't know you could do concave stuff.

 

[2stroked2smoke]

Great work! What are you gonna use for a head gasket.

 

[Tzed250]

Super nice work!!!

 

[mtngun]

Great work! What are you gonna use for a head gasket.

Normally this kind of head is assembled with no gasket, but I'll prolly smear a little hylomar for insurance.

 

[greg986547]

A little more progress. :msp_ohmy:

Fit under the hood has not been tested yet, so it may need a little more milling tomorrow.

wow....very cool work! wondering if the thick fins on top of the head will transfer heat quickly enough? great thread!!

 

[MCW]

Love your work MTN. This is some fancy stuff