Kiwi Mk2 Engine

[vcutajar]

Filed the back and bottom contour and sanded the arms. Removed most machining marks. Some still evident in the main body recess. Just could not remove them. Polished with a dremel to a shiny finish. At one time, rocker arm literally flew from my hand whilst polishing. I am not going to repeat what was said at that time. Took me 30 minutes to find it.

8 days to do two rocker arms.

 

[John S]

8 days to do two rocker arms.

Not thought about doing a twelve cylinder 4 valve then ? ? ;D

John S.

P.S. Nice work though.

 

[vcutajar]

Nice one John. Its more probable that I buy it then make it. ;D

 

[vcutajar]

Today I started work on the rocker arm bushes. E.T. Westbury specifies that these should be made from gunmetal (yellow brass) and not from brass. Now I have never used gunmetal so I do not know how it looks. I have found a piece of hexagonal bar (in the kit) suitable for the bushes but I suspect its brass and not gunmetal. Well, if this engine ever runs, I would be running for short periods so I guess if the bushes are made of brass, it would not make a lot of difference.

I faced of the hexagonal stock and it felt like brass. I then turned it down to 6mm diameter. According to the plans it should be the same thickness as the rocker arm, but I made it a tad longer as I suspect that the rocker arm might bind with the rocker arm pillar. I can always shorten it later on. I parted the part off and faced it.

Hopefully tomorrow, if I manage to find the 3mm reamer, I will drill and ream the bushes. It has to be drilled 1/64" off centre.

Now to continue babysitting the cats and make myself something to eat as I am alone at home (wife and kids went for a 3 day holiday in Rome).

 

[vcutajar]

After a long search this morning for the 3mm reamer I still could not find it. It was made by Master and I love their tooling. Unfortunately the shop that imported them from Italy does not get them anymore because since they have been taken over by Scandvik they could not handle the relatively small orders (very small market locally). So I got myself a Dormier reamer. Hope its OK. We'll find out later on today.

 

[vcutajar]

The Dormier reamer worked out fine. Drilled the hole 1/64" off the centre and reamed it. Trial fit in the rocker arms and all seems OK. Most probably will do the 3mm studs for the bushes.

 

[vcutajar]

Did the 3mm studs. Just took 3mm bar stock and cut it to lenght. There where no dimensions on the plans but it was easy to figure them out. Threaded both ends and that's all. The second photo shows my method of keeping the die straight whilst threading. I just use an old collet chuck in the tailstock.

I was thinking I would do the rocker arm pillar next but I would not be able to complete it before the cylinder head. I do not like to start parts that I cannot completly finish so am trying to see what else I can do. I was hoping that by this time I would have received the timing gears, but they still have not arrived. Last week I sent an email to Kirk at Hemingways to check about these gears but have not received any response. Usually he is quick in answering back. I suspect that Hemingways may be closed due to the festivities.

I guess I am stuck.

 

[vcutajar]

Today I found something else I could do on the engine. I started work on the crankcase breather sytem. I started off with a 12 mm brass bar stock and turned it down to 10.5mm. I then knurled the machined part and then continued turning down part of the knurl to 6mm. I threaded it 6mm Fine with a die. I then made a quick 6mm fine nut out of a piece of brass strip. I cut a shallow groove at the top of the thread (between thread and knurl) and inserted the thin nut I just made to clean up the thread. I left it there and reduced the thread lenght to dimension using the nut to clean the edge of the thread.

And that's when the lathe motor started giving my problems (see other thread). This evening managed to fix the motor and finished the cap of the crankcase breather. I will not part it off for now just in case it needs further machining. Next I will work on the breather body.

 

[vcutajar]

Started work on the breather assembly body. Took a piece of 10mm brass and faced it off (lathe motor still working - keeping my fingers crossed). Took some measurements for the breather holes. Put in dividing head and drill six 1.5mm holes.

 

[vcutajar]

Happy new year to all.

Yesterday and this morning I continued work on the breather.

I cut down the breather body to size and reduced the side that goes into the crankcase to 6mm and then threaded it with a 6mm fine die. I then drilled and reamed the through hole 4mm. Reversed it in the chuck and with a 5mm slot drill increased the bored to the desired depth. Then tapped the first part of the 5mm hole 6mm fine. Yes, I should have drilled it 5.2 mm but brass is a bit forgiving. After tapping I passed again the 4mm reamer and then the 5mm slot drill to clean up the body of any burrs that might have been produced with the tap. Tested the cap and it fits nicely.

I then parted the cap off as it was still attached to the bar stock and cleaned it up.

Also yesterday I received an email from Kirk @ Hemingways that the gears should be available 1st week of January. Looking forward to receive them so I can check the bore and see if I can increase it slightly to a metric bore and then get started with the main castings.

 

[vcutajar]

And here it is nearly finished.

I now need to put a 5mm tufnol disc inside. I ordered a small sheet of 1mm tufnol from ebay (postage cost more than the tufnol but what can I do if I can't find it locally). Now I need to machine a 5mm punch and die and see how that works.

 

[metalmad]

Looking good there Mate
Hope you made a few extra rockers buddy, You can make a Wallaby next :big:
Pete

 

[vcutajar]

Thanks Pete

I am also following your Wallaby build with interest.

 

[vcutajar]

Haven't done anything in particular except machine the 5mm punch and die. Still waiting for the teflon sheet to arrive from the UK.

Have been looking again at the two crankcase castings and plans and been converting dimensions to metric. I am already getting the jitters just thinking of fouling up the castings.

 

[vcutajar]

Today I received the 1mm teflon sheet and immediately went to the garage to try out the punch and die I made. I put the die in the headstock chuck and the punch in the tailstock. It works although the punched out teflon was slightly wider than 5mm. Fixed that by sanding it. The breather assembly is complete and it works.

In the photo is the teflon sheet, the breather parts and the punch and die. Not visible in the photo is a 3mm through hole in the die so that I can push out the punched out teflon.

 

[vcutajar]

This morning I went shopping for some metric ball bearings. The ones I got in the kit were 3/8 x 7/8 x 7/32. The ones I got were 10 x 19 x 5 (61800). I wanted open bearings (without shields) but could not find them, so I got them with rubber shields and removed the rubber. I hope I did not compromise them by doing that.

In the photo the ones on the left are the original bearings and the ones on the right are the ones I bought.

 

[vcutajar]

This evening I plucked some courage to start work on the front crankcase casting. I put it in the 4 jaw chuck and centered it as best I could. It's so difficult with nothing really running true. I trimmed the chucking piece of the casting and then replaced the 4 jaw chuck with a collet holder. Clamped the casting (the part that had been cleaned up) in a collet. Turned the front face and bearing housing face to dimension. Hopefully tomorrow I will turn the front face spigot.

I am not really enjoying working on this casting because I can't exactly take any real measurements. Even the crankcase barrel is offcenter. I have the feeling that I am doing something not right all the time. I will persevere but I suspect that this will be the first and last time I will work on a casting model.

 

[ShedBoy]

Looking good, castings give me the same feeling but I like casting my own so I will go there again. If I paid for some it would be a different story. Enjoying this build.
Brock

 

[vcutajar]

Thanks Brock for the encouragement.

 

[vcutajar]

Continued work on the front crankcase housing. Turned the spigot and with the crackcase barrel being casted off centre it came out not uniform. Drilled and bored the crankshaft hole 12.7mm and then machined the bearing housing for a push fit. Then parted off the casting and cleaned it with the mill.

It's not pretty but hopefully functional.