Hi everyone,
Jo thanks for looking up the spring wire tension tool.
Well I have finally been able to spend some quality shop time on the Pacific. Within the last week I was able to finish up the cylinder head; another little milestone in its construction.
As I had indicated earlier the internal design was altered somewhat to keep from having to drill and plug holes in the side of the head. I created a cavity which would have been more like the original cored water jacket. This way the holes that connect to the ports on the top surface of the cylinder open directly into the water jacket cavity; I’m happy with the way it turned out.
Here are the castings after machining the chucking lugs.
Starting with the upper casting the top surface is profiled.
I created a 2D sketch of the curved profile and put in an intersection point every .0025”. These dimensions were entered into an Excel Spread sheet that could be printed and used at the lathe. The dome is a little more than ½ done here.
Here is a sample of one of the 3 pages of coordinates used to create the upper curve.
After some careful filing and sanding I’m quite please with the result.
After the top surface was finished soft jaws were bored and the upper casting flipped around to work on the underside.
The chucking lug is cut off and the head machined to the proper thickness.
The head is counter bored both for cylinder clearance and the register for the lower casting.
Using a pair of soft jaws in the milling vise the next part of the cavity is machined; notice the one boss that is a little extra big. This is where the outlet port will pass through and the inlet ports will fall between two of the bosses on the opposite side.
Back in the lathe the internal dome is machined using the same method as on the top.
Starting on the lower casting the baffles are turned to be a slip fit in the cylinder and the larger OD is turned to press into the upper casting.
Transferred to the mill and indicated in; the bolt circle is drilled along with the two water ports.
The lower casting is parted from the chucking lug using an insert type parting tool. Just a little bit of work on a lapping plate removed the tool marks and left a nice flat surface.
Here are the upper and lower castings ready for assembly.
And after they have been assembled.
One more detail to take care of is drilling and tapping the water outlet port. The port is at a 45 deg. angle; so the head was dialed in and the spin indexer used to set the angle.
Here is the finished head installed on the engine; I’m really pleased how it turned out.
Thanks for checking in,
Dave