01-03-2019, 12:01 PM
(This post was last modified: 01-03-2019, 12:04 PM by Scarlet O'Hara.)
What a screamer, thanks for the memory Rory, return to Guildtown (near Perth) pencilled in for 2020.
Hi Chris It was a long and tedious process and I’m sure others will have a quicker way of doing it with the right equipment but this is how I did it.
Started off by making two stepped hollow dowel pins with an outside diameter of 11/32” to suit the stud holes in the head reduced to 5/16” at one end. This was then drilled through ¼” diameter for a clamp bolt. I also turned up a 5/16” drill guide with an 11/32 outside diameter to suit the holes in the head. It’s really only a very thin sleeve to keep the drill central.
After drilling one 5/16 hole in the copper sheet in about the right place I then clamped it in-between two heads using one of the dowel pins to locate the copper centrally with the 11/32 clearance hole in the head for the stud.
Using the drill guide I then drilled another 5/16 hole at the opposite end of the head from the first hole, I inserted the second dowel pin to ensure the copper sheet didn’t move and clamped it at that end.
Using the drill guide I then drilled the remaining 12 stud holes using the head holes as a pattern.
The blank gasket was then fitted onto an old block and clamped in position using a head before drilling from the base of the block up through the valve guides.
The gasket was then removed and hole cutters used to approximately cut out the hole above the piston and the combustion chamber above the valves. The bulk of the combustion chamber shape was then cut out by joining up these three holes.
After that it’s just a lot of filing and scraping using the head as a template to get the right shape.
Apologies if it’s not very clear but I found it really difficult to put into words, hopefully the photos might help.
Hi Chris It was a long and tedious process and I’m sure others will have a quicker way of doing it with the right equipment but this is how I did it.
Started off by making two stepped hollow dowel pins with an outside diameter of 11/32” to suit the stud holes in the head reduced to 5/16” at one end. This was then drilled through ¼” diameter for a clamp bolt. I also turned up a 5/16” drill guide with an 11/32 outside diameter to suit the holes in the head. It’s really only a very thin sleeve to keep the drill central.
After drilling one 5/16 hole in the copper sheet in about the right place I then clamped it in-between two heads using one of the dowel pins to locate the copper centrally with the 11/32 clearance hole in the head for the stud.
Using the drill guide I then drilled another 5/16 hole at the opposite end of the head from the first hole, I inserted the second dowel pin to ensure the copper sheet didn’t move and clamped it at that end.
Using the drill guide I then drilled the remaining 12 stud holes using the head holes as a pattern.
The blank gasket was then fitted onto an old block and clamped in position using a head before drilling from the base of the block up through the valve guides.
The gasket was then removed and hole cutters used to approximately cut out the hole above the piston and the combustion chamber above the valves. The bulk of the combustion chamber shape was then cut out by joining up these three holes.
After that it’s just a lot of filing and scraping using the head as a template to get the right shape.
Apologies if it’s not very clear but I found it really difficult to put into words, hopefully the photos might help.