This is probably OT, but thought it may be helpful for some. The problem?..How to drill & tap a hole in an engine for a fitting without getting chips in the engine or taking the engine apart. This might be for when a hose barb fitting is needed on a water pump or intake manifold. Recently, I got a John Deere lawntractor which has a liquid cooled aluminum V-twin engine, and needed to tap off the engine for a cab heater connection. Took the radiator and some other fairing off to see where it might be feasible to tap into the engine before the thermostat. The thermostat housing is on the left head, and there didn't seem to be enough room to get a fitting into it. The right and left heads are connected via an aluminum casting; so the right head would do. Drained the coolant down. Had to use a suction syringe because the engine didn't have a coolant drain. Drilled a small hole in the top of the right head and checked for space. Made some adapters to block off the radiator hoses with one having an air fitting. Set the compressor's air pressure down to about 15psi. When the hose was hooked up, there was too much flow, so I found an old flow valve in the misc bin and put that in-line. A simple inline valve would work as well to adjust the flow. Drilled the hole out to 9/16" and using a shop-made tap guide, tapped for 3/8-14 NPT. The airflow kept any chips from entering the engine. Was alot easier than trying to pick them out later....and not being certain they were all removed. Pilot hole in right head. Radiator hoses blocked off. 9/16" drill (carb, etc covered); note flow-control valve ...I also switched fittings around. 3/8-14 NPT tap using shop-made guide....side holes allow chips to come out past the tap flutes. finish 3/8-14 NPT tap for depth head cavity is clean and void of chips, 3/8 NPT to 1/2" hose barb fitting installed with pipe sealant; not Teflon tape. Fairings replaced. 1/2" heater hose attached. The return line from the heater will be Tee'd into the inlet side of the engine's water pump.
Thats a great idea, I will definately use that one. In the past I have packed the flutes of the drill bit and the tap with wheel bearing grease. It usually picks up about 95% of the filings and prevents them from falling in the hole.
This is NEBRASKA... where it can snow quite often, with temps slightly above zero! Not to pick nits, but it's a Lawn Tractor
Nice job. For what it's worth, it's a lot less troublesome to drill and tap into a water jacket than it is to a crankcase or intake/combustion area. A few metal chips in the water jacket is probably not going to cause problems.
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