Part 16 By Vince Cutajar

Before starting the cylinder head, I decided to broach the keyway in the cams. I had been putting it off (even though I have all the necessary equipment) as it is a new procedure for me. Photo 1 is showing the 2 and 3 mm broach set I got some weeks earlier. I took a piece of aluminium and drilled and reamed a 6mm hole for the broach collar. Photo 2 shows the collar in the cam and aluminium piece. Transferred the setup to the hydraulic press oiled the broach and started going down slowly adding oil as the broach was going down (photo 3).

The finished product (photo 4). I did not do the second pass with the spacer as the keyway (I think) is deep enough. Next to make the 2mm key. I did not do the timing gear that sits next to the cam as I will do it when the timing is done on the engine.

Started work on the 2 X 2mm key. I had a piece of steel with a thickness of 2.4 mm and started carving out the key using hacksaw, hand files and the grinder wheel which was turned by hand. (my fingers where too close to use it under power. Well after an hour working on it and getting it close I could not feel my fingertips anymore, so called it a day. Something at the back of my mind was saying - "Go on ebay, Go on ebay". Went on ebay and there it was. A piece of key steel 2mm square and 300mm long .

Well you can imagine what happened next. I bought it. No more fingertip bashing.

The cylinder head casting has bosses for the mounting holes. They should be on a PCD of 1.5" but they are not exactly there. The distances between the holes should be 26.94mm. The distance along the fins between the holes are 26.94mm but across the fins they are 25.94mm. A little compromise had to be made.

I started off by clamping the head in the vice aligning the fins to the x axis of the table and keeping it level as much as possible. I then milled off all the bosses and skimmed a little the fins.

Then using the DRO I marked the holes and drilled and partially threaded 4mm the holes. I have a habit of putting a screw in a newly made thread so that the hole will not get filled with swarf while doing the other ops.

Here is the top of the head after all ops. I have also marked the centre between the holes just in case.

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