building the engine block side:
-Take your 4-5" peice of copper and using a vice grip or other means, flatten a good 1" to 1.25" section of the pipe.
-Now take 1/8" of the tip and bend it 90*. You are trying to seal off the end of the tube. Drill a hole just large enough for the bolt in the flattened part of the pipe.
-Solder the 1/2" threaded fitting onto the end of the pipe, and also solder shut the flattened bent tip.
-Take some teflon tape and wrap the 1/4" barbed fitting and screw it into the pipe fitting.
Here is what the engine block side of the det can will look like
run your 1/2" hose through the firewall and into the cabin
Bolt the block side of the det can to the block. Connect the hose to the block fitting.
You have an option here, you can:
-T the 1/2" hose and run two lines, 1 to each side of the ear protectors.
-just run the single line to one side of the ear protectors.
I chose to just run the single hose to one side of the ear protectors for simplicity and to save money.
Drill 1/2" hole in your ear protectors
Shove 1/2" of the tubing into the ear protectors and seal it with duct tape. The tape allows you to disconnect the ear protectors and remove the det can when finished. Another option would be super glue or hot glue. this would seal better than ductape but I'll see how this setup works.
An overall shot of the setup
congrats you have successfully built a det can. You can now listen to detonation to help you tune your timing on the streets