another Snow engine

[Roger B]

Looking good    Does the Snow engine use rollers to follow the cam? If it has flat followers the cam flanks could do with a radius.

[fumopuc]

Looking good  Does the Snow engine use rollers to follow the cam? If it has flat followers the cam flanks could do with a radius.

Hi Roger, the model is there close to the original engine.
There are 12 mm rollers in the rocker arms, rolling on the cams.
The attached picture shows it at the big one.

[Roger B]

I don't know if it is the light or the angle but that full size cam seems to have an odd notch in the profile  There's also a flange just like yours   

[fumopuc]

Hi Roger, I would say it is my bad picture.
Have a look at 0:40
<a href="https://www.youtube.com/watch?v=JKXqm49c1Qg" target="_blank">http://www.youtube.com/watch?v=JKXqm49c1Qg</a>

[fumopuc]

Hi everybody, here a quick up date were we are today. Some impressions of ongoing manufacturing, but no finished parts at the moment.
The cam shaft brackets are outside for black anodising, so I have started with the valve cages already.
I would like to used some studs for the fixation of valve cages to the combustion chambers.
For the inlet side it seems to be useful, for the outlet side, under the cylinder unit, a nightmare.
I have to find there a more handy solution.
Also some gaskets are already made.
 

[vcutajar]

I think the inner two studs will be a bit of a problem to attach a nut to them.

Can you glue a nut to one side of the stud and use it as a bolt.  I do not know if this makes sense to you.

Vince

[Dave Otto]

Nice work as usual Achim.

I see that you are making good use of your cutting machine for the gaskets. I recently purchased a Silhouette Cameo machine and have been learning how to run it.  My first attempt at cutting gaskets was not completely successful. I was cutting a rubber reinforced fiber material about .017" thick; no matter what I did it just wouldn't cut clear through. I think the rubber in the material allows it to push away from the knife. I was able to get usable gaskets by finishing them with a sharp X-acto knife. Maybe I need to start looking for some different gasket material.

Can you remove the cylinder assembly from the base to install the exhaust valve cages?

Dave

[fumopuc]

I think the inner two studs will be a bit of a problem to attach a nut to them.

Can you glue a nut to one side of the stud and use it as a bolt.  I do not know if this makes sense to you.

Vince

Hi Vince, the nuts at the inner studs are not a problem, but to fit the studs is not so easy. Also the length of the hole unit with the valve and spring will be a no go.
I will try to make some bolts with a similar shape of the small  3 mm nuts, may be the best solution.

[fumopuc]

Nice work as usual Achim.

I see that you are making good use of your cutting machine for the gaskets. I recently purchased a Silhouette Cameo machine and have been learning how to run it.  My first attempt at cutting gaskets was not completely successful. I was cutting a rubber reinforced fiber material about .017" thick; no matter what I did it just wouldn't cut clear through. I think the rubber in the material allows it to push away from the knife. I was able to get usable gaskets by finishing them with a sharp X-acto knife. Maybe I need to start looking for some different gasket material.

Can you remove the cylinder assembly from the base to install the exhaust valve cages?

Dave

Hi Dave, thanks.

0,4318 mm (0,017") is thick in my experience. But never the less, it should be possible with the right adjustment.There are different blades available also a so called deep cut blade.
When I have cut some gaskets from 0,25mm (0,0098") material (http://www.ebay.de/itm/like/281318145007?ul_noapp=true&chn=ps&lpid=106) I have choosen a set up of their software for light carton and the knife has been  followed automatically the outline two times. May be you should play around with some lost material like light carton first to find the right set up. As seen in my gasket picture, the correct contour was cut into paper first to check the fit at the real part.

[Ian S C]

Some times cutting rubber can be helped by putting it in the freezer for a while, with thin stuff like that, probably best to put the cutting board in the freezer too. Rubber would be best cut with a wad punch.
Ian S C

[fumopuc]

Some times cutting rubber can be helped by putting it in the freezer for a while, with thin stuff like that, probably best to put the cutting board in the freezer too. Rubber would be best cut with a wad punch.
Ian S C

Hi Ian, good idea, have to try this.

[Dave Otto]

Thanks for the tips Achim.
Ian, the freezer is also a great idea I will give that one a try.

Dave

[fumopuc]

.... some more impressions from the valve cage story. They are all fitted nicely now and getting their individual identification to the fitted place.
Today I should get a hexagon 5c collet in 4mm, so I will try to make some special bolts for the lower ones.
Before the remaining surfaces for brackets and inlet ports will be machined,I have tried a proper valve seat machining at my sample part.
A lot of tools are used for this operation.
To check if it will be OK I do need a valve next.
After reading all the old MEB magazines, I will try the "step method" from Jerry Kieffer first now.
I will let you know what happens.

[fumopuc]

Hi Everybody, some valve attempts has been made. First attempt was with wrong material, I have had a 10mm bar without  any marking and that was not the 1.4305 SS (X8CrNiS18-9 (DIN EN 10088-1)) I do use normally. Second attempt was a small fight with my carbide insert, was no the best any more. But third attempt went fine. The "step method" is generally working fine, sorry for the bad picture.
Additional to Jerry Kieffers method, I have added a grinding process with a Dremel in the tool post.
I have left stem 0,1 - 0,15 mm overstock at the stem and tried to do a grinding, which worked very well.
Finally some manual sanding with 400 grid, still in lathe.
A quick check of the wear pattern, shows that the valve disk should be a bit smaller.
Generally I think to be at the right way.

[ICEpeter]

Achim,
I noticed you were using a, I presume, 90 degree countersink for making the valve seat. How did that work and what was the resulting valve seat surface quality? did the surface require or will require additional treatment i.e. grinding / lapping to be acceptable?

Peter J.