Click here to check out previous "How To's" “Souping” up sprinkler valves 
Step 1: Buying the correct valve The first thing that must be done in order to soup up a sprinkler valve is to buy the valve. There is one major thing to consider when buying a valve, does it or doesn’t it have a guide rod? A guide rod is a small metal bar inside the valve that guides the diaphragm. I have found two different valves that don’t have guide rods and are very simple to work with and soup up. The first valve is a Rainbird 1” inline automatic sprinkler valve. The second valve, the one pictured below and through out this how to, is a Watermaster 3/4" inline automatic sprinkler valve. 
You can purchase Rainbird valves from your local home improvement store or online at http://www.sprinklerwarehouse.com, and you can purchase Watermaster valves directly from the Spudtech order form.
Step 2: Removing the cover
After acquiring your valve you must remove the cover from it. You do this by simply removing the 6-10 screws in the cover and pulling it off. Below is a picture of the inside and all contents of a Watermaster valve. All other valves should look similar. 
Step 3: Drilling hole in cover Once you have removed your cover you need to drill a hole in the center of it. You will thread a 1/4" barbed hose adaptor into this hole. You can either use a 1/4" NPT pipe tap or you can simply drill a 1/2" hole and thread it with your fitting. Make sure that the hole will not be in the way of the spring. If your valve has a guide rod, drill to the side of the cover but make sure that it isn’t in the way of anything. If you plan to use a 1/4" pipe tap, instead of the 1/2" hole, drill whatever size your tap recommends. 
This is what the top of your valve should look like after drilling the hole. 
Step 4: Tapping the hole Now that your hole has been drilled you are ready to tap it for your fitting. If you are using a pipe tap simply tap the hole and move on to step 5. However if you don’t have a pipe tap and are going to be threading the hole with your fitting you will need a drill and a 1/4" male barbed hose adaptor. 
You know want to insert the hose adaptor into your drill chuck like this: 
Now slowly and as straight at possible spin your adaptor into the hole. Once you have gone almost all the way, about 1/16” of threads still showing, stop. Remove the adaptor from the drill chuck and then remove the adaptor with a crescent wrench. Step 5: Threading in your fitting and putting it all back together If you plan on using a barbed elbow like this: 
You will want to wrap the threaded end in Teflon tap before screwing it into your valve. If you are going to be using the same adaptor that you used to tap the hole, you will also want to cover that in Teflon tap and thread it back in. Once you have threaded your fitting back into the valve cover it should look like this: 
Once your adaptor has been threaded into your cover you may replace all parts inside your valve and screw the cover back down. Step 6: Cutting your hose Your next step is to cut your hose to the desired length. I have chosen to use 1/4" id by 1/2" od air hose. This is available at http://www.mcmaster.com. 
After you cut your hose to the desired length you will want to insert one end into the barbed adaptor on your valve cover and the other end into a 1/4" male adaptor. Secure both ends of hose with hose clamps. Next, cover the threads of your male adaptor in Teflon tape and thread it into a blowgun rated for at least 100 PSI. I have used a lever controlled air valve rated to 150 PSI that can also be found on http://www.mcmaster.com. You are now all set to start using your souped up sprinkler valve. Enjoy, and as always, Keep it safe… This How-To has been written by Tim Brown. Please email all questions or comments you may have to HowToGuy@hotmail.com Additional notes: If your now obsolete solenoid is getting in the way you may simply scrap it, however you must fill both small holes in the solenoid port with epoxy. | 
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