another Snow engine

[Roger B]

Looking good    That's a lot of parts to make 

How big are the valve stems? You could probably use a tailstock center to stop them deflecting when you are turning them (you could also use M5 screws as the raw material to reduce the amount of turning). The center drilling can be cut off when you making the fixing for the spring cap.

[fumopuc]

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.

Hi Peter, I have still the same questiones. Today I have been concentrated to the valve stem mostly and that seems to work.
Tomorrow I will make another valve with the additional target to check the leakage of valve cage and valve.
As seen in the above pictures with the blue paint, I am not so far away.
A small vaccuum pump for brake bleeding is ordered as test equipment, and some grinding paste is under the bench.
Until now I have used the 90° countersink for both, making the valve seat and valve chamfer and no additional treatment.
I will let you know what will be the final result.

[fumopuc]

Looking good    That's a lot of parts to make 

How big are the valve stems? You could probably use a tailstock center to stop them deflecting when you are turning them (you could also use M5 screws as the raw material to reduce the amount of turning). The center drilling can be cut off when you making the fixing for the spring cap.

Hi Roger, thanks.
The stems are 3,1 mm and the valve disc is 9,3 mm. So im startng with 10 mm bar stock.
My target was to avoid this center drilling story and it seems to work.
Thanks to Jerry Kieffer.

[Don1966]

The valves and guide look good Achim. What did you use the Dremel stone for?

Don

[Kim]

Looking good Achim.  You're out in an area that I've never played in before, but its looking really nice. You do very careful, methodical work.
Kim

[zeeprogrammer]

Still watching Achim. A very fascinating model.

[fumopuc]

Looking good Achim.  You're out in an area that I've never played in before, but its looking really nice. You do very careful, methodical work.
Kim

Hi Kim, thanks.
May be you are closer to that area as you can imagine at the moment.

Still watching Achim. A very fascinating model.

Carl, thanks for watching.

The valves and guide look good Achim. What did you use the Dremel stone for?Don

Don, thanks.
I have ground the last 0,1 mm before polishing off the stem with the stone, see pictures below.

I have written this post yesterday morning already, but than it disappeared in the suddenly interrupted internet connection.
After this I have not been in the mood to repeat it yesterday.

Generally I have been able to repeat and improve my first attempts with the valve machining in accordance with my drawings.
1. Starting from 10 mm bar stock with the Jerry Kieffer step method. This little 15 mm micrometer from Moore & Wright was a very useful tool for all measurements in this case. Very handy.
2. I have left 0,1 to 0,15 mm overstock material.
3. Using the Dremel with the stone and this last 0,1 mm were ground down.
4. Some polishing with 400 grig given a surface like a mirror.
5. Machining the 45° angle as a seat of the valve with the 90° countersink. In my last pictures in the earlier posting it cold be seen, that the contact between valve and valve seat (in the blue area) didnīt match properly. The contact was at an edge only and not at the possible surface. So I have corrected the clamping of the 90° countersink in the tool post very little.
Again, I have tried to make the wear pattern visible with some blue colour. In my opinion it looks much better than the first attempt, because now there is a surface going around on the valve and the valve seat with no paint.
The ordered vacuum pump for brake bleeding arrived yesterday, so at a later point it will let me know if it will leak or not.
I have started to make some more valves.

[fumopuc]

We do have 11 valves now, with a, in my opinion, reasonable wear pattern.
The holes for the pins are made and I am just preparing the first real leakage test.
All valves stems are checked with my sample valve cage.

[Kim]

Very nice looking valves! 
Eleven of them huh?  How many do you need, is it 8?  So you've done 3 for the shop gnomes?
Kim

[fumopuc]

Very nice looking valves! 
Eleven of them huh?  How many do you need, is it 8?  So you've done 3 for the shop gnomes?
Kim

Hi Kim, yes the engine will need 8 valves. I have made 8 valve cages plus one sampe valve cage for any kind of experiments. So minimum 9 valves will be needed. After the final machinng of the valve cages with bore and valve seat I will match the valves to an individual valve cage by best fit. So the remaining ones may be will end as a keyring pendant.
I have told the shop gnomes that valves are not good for them, hopefully they understood.
Today I have done some leakage test already, the first result was not so bad, but improvement is necessary.
The report and pictures will follow soon.

[crueby]

You have shop gnomes too? Still trying to find out where the put my compass and protractor. And the larger dead center too. Pesky buggers! Leaving cookies for them didn't help...

Great looking engine by the way!

[fumopuc]

Hi Chris, thank for checking.


Valve seats next part.
Basically I think I try to be to accurate here, but I am afraid, that at the end at this 4 cylinder engine every single issue, what can be check in advance will decide about running or not.
So I have checked my sample valve cage first, if everything is sealed. First it was not, due to a not proper soft soldering of the flange, I did it in the oven with solder paste, but I think there was not enough paste involved.
Then I have tried a valve like it was coming from the late and did the vacuum test. It toke 5 sec until the vacuum was gone.
Here I do need some help/advice  from the more experienced IC engine builders if this may be is not so bad already ?
The wear pattern is good and if I would build a single cylinder engine, I would try to run it like that, because after some running it will be seated quickly, I could imagine.
But as already said before, in this case with the 8 valves in the engine I would like to go the safer way.
So I made a handle to clamp at the valve stem with a brass plunger and a 3 mm grub screw and did some grinding with a fine automotive valve grinding paste.
Lets say 5 Minutes job.
After this I have got the result, seen in the small video.
[youtube1]https://youtu.be/8VFQPxGbFuM[/youtube1]
It keeps some vacuum for nearly 20 sec now.
Is that enough ?
In my feeling it is more than enough, but I would like to hear the opinion of you guys out there.

[vcutajar]

I did the same thing to check the valves on the Kiwi.  If I am not mistaken, if you can keep some vacuum for 20 seconds than it should be OK.

Vince

[sco]

Looks more than good enough to me Achim.  Still following quietly along,

Simon.

[Roger B]

Good progress Achim  A 20 second vacuum sounds ok to me