Kiwi Mk2 Engine

vcutajar · Jul 1, 2012

Finished the rocker arm pillar.

Gave the column a 5 deg taper in the 4 jaw chuck (photo 1). Then changed to a 3 jaw chuck. Held the pillar from the threaded end to machine the top part. Used a split aluminium collet between the threads and the chuck which can be seen in photo 2).

Photo 3 & 4 are the fully assembled rocker mechanism on the cylinder head.

ProdEng · Jul 1, 2012

Valve gear is looking good Vince, can't be too much left to do now.

Jan

vcutajar · Jul 2, 2012

Thanks Dave and Jan for looking.

Been planning how to do the valves and also the valve guides. I will be using a collet holder in the lathe to work on these items. Problem is that the material, stainless for the valves and phosphor bronze for the guides, that came with the kit, are in imperial diameters. I only have metric collets and although they can be compressed by 1mm, I try to avoid that.

So this morning went shopping for some 304 SS in 10mm diameter and 8mm diameter phosphor bronze. Managed to find he stainless but not the bronze. Smallest I found was 12mm and got some of that.

Before I remove the three jaw chuck I thought I would finish off the valve collars and collets.

tvoght · Jul 2, 2012

Vince,
You're so close. I'm on the edge of my seat. I'm hoping you get to those valves very soon, and that your pictures are good. I'll be watching very closely.

--Tim

vcutajar · Jul 2, 2012

Thanks Tim

For sure this week work will start on the valves but they will be the last items to be done.

This evening located the tool that I will use to cut the groove in the stem. Did a trial cut in 3mm mild steel to check the dimension of the groove. 0.9mm which is close enough.

Did the two valve collets. Fiddly little things. Used a piece of 5mm mild steel. Faced it off and drilled a 2mm hole about 6mm deep. Transferred the piece to the milling vice and after locating the hole under the spindle, used a 2.5mm slot drill to open it up. Then using the y axis, milled the slot (photo 1). Transferred the piece back to the lathe and parted off two collets. After cleaning them up, did a trial fit in the groove I made previously.

idahoan · Jul 2, 2012

I'm still following along Vince,

The work on the head is just great; it really looks nice.

Dave

vcutajar · Jul 3, 2012

This evening did the two valve collars. Actually three of them. One of the first two got chewed up in the lathe chuck so I made another one.

I think I have found a mistake in the drawings. Photo 1 is showing the drawing for the valve collar. If the total length of the collar is 5/32" and the lip is 3/32" then the body is 1/16" as per drawing but I think the lip should be 1/16" and the body should be 3/32".

Machined a 10mm BMS to 8.5mm and then to 5mm (photo 2) and then drilled and reamed 3mm (photo 3) and then parted off. Did the same for the other one.

Then clamped the collar to the chuck and counterbored 5mm for the valve collet.

Photo 4 shows the three valve collars. One of them with the collet and the stem fitted.

arnoldb · Jul 3, 2012

On the fiddly bits now Vince ;D - Good going!

I think I have found a mistake in the drawings. Photo 1 is showing the drawing for the valve collar. If the total length of the collar is 5/32" and the lip is 3/32" then the body is 1/16" as per drawing but I think the lip should be 1/16" and the body should be 3/32".

I agree with your thinking; even the physical plan supports that.

Kind regards, Arnold

vcutajar · Jul 3, 2012

Thanks Dave and Arnold for the support.

Vince

steamer · Jul 3, 2012

I'm watching too Vince! The valves are about the same size as the Wallaby's

Dave

vcutajar · Jul 4, 2012

Thanks Dave (Steamer) for your continued support.

Vince

vcutajar · Jul 6, 2012

Progress has been slow. Managed to finish the two valve guides. Nothing special just turning operations.

I started with the phosphor bronze I bought locally and as the OD was a bit rough, I cleaned it up with the three jaw chuck. Then cut two pieces for the blanks (photo 1). Replaced the three jaw chuck with a collet holder and turned the side that needs to be pressed in the cylinder head. With the same setup drilled and reamed 3mm the part (photo 2).

Reversed the part and machined the other side. There were no dimensions on the plans how thick the lip is. Also there is a shallow taper but no angle indications. So I improvised. Made the lip 2mm wide and the taper of 2 degrees (photo 3).

Photo 4 depicts the finished valve guides.

vcutajar · Jul 9, 2012

During the last two days I have been working on and off on the two valves for the Kiwi. I would like to thank George for showing me how to do them. :bow: :bow: :bow:

He gave me a descriptive run through here: http://www.homemodelenginemachinist.com/index.php?topic=19103.0
and also in radial engine build (page 10) http://www.homemodelenginemachinist.com/index.php?topic=15942.135

I am using 304 stainless for the valves and as long as the tool is sharp I did not find any problems during machining. Hopefully tomorrow they will be finished and I will post some photos.

vcutajar · Jul 10, 2012

Finished the two valves today. They are nice and pretty, but are they functional? Time will tell. I am just attaching some photos of the valve machining but no descriptions as I followed George's instructions.

vcutajar · Jul 10, 2012

And one last shot. Next to press the valve guides in the cylinder head. I will try the shink method first.

arnoldb · Jul 10, 2012

The valves DO look nice Vince :bow:

Kind regards, Arnold

vcutajar · Jul 10, 2012

Thanks Arnold

When I did a similar part having a thin long stem in a previous build (not an engine), I fabricated the part. This time I wanted to do it from solid and with George's help I managed to do a decent job of it.

Vince

tvoght · Jul 10, 2012

Vince,
You and I are making valves at the same time. I must say that one you hold in your hand is beautiful! Keep up the good work.

--Tim

vcutajar · Jul 11, 2012

Thanks Tim

I left the stem 0.05mm oversize and used sandpaper to get it down to size using the valve guide as a gauge. This way I removed all the machining marks.

Vince

steamer · Jul 11, 2012

I like the valves Vince! I really like the tool you made to turn them with!

:bow:

Dave

Kiwi Mk2 Engine

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