Saturday, June 9, 2007
OIL PLUGS - II
After posting 'Oil Plugs' on 1 June '07 several people wrote to tell me there were other types of control valve plugs available. Which I already knew... but the fact they thought I didn't means a lot of you might not be aware of what's out there, especially with regard to parts suitable for flying Volkswagens.
So let's take care of that.
Go over and click on the photo. (Don't mind the cat; he always does that.)
The left-most plug is the stock item. Next to it is a plug that has an M12 crankcase nut welded to it. Two of the flats are drilled for safety wire.
The two socket-head plugs in the middle of the picture are typical after-market parts. If you're careful and use the right set-up you can drill these for safety wire.
But the plugs I prefer to use are the hex-head type shown on the right-hand side of the picture. To drill them for safety wire I first open them up with a half-inch Slocum... what folks usta call a center-drill. (I think half-inch is about a #4.) Once you've opened them up axially you chuck them in a drill-vise and drill each of the six faces with a 1/16" drill bit spinning about 3000 rpm. I use a drop of hi-sulphur cutting oil. The drillings are then chamfered so as not to notch the safety wire.
Building just one engine means drilling only two plugs, which is a pain in the ass since it takes longer to do the set-up than to do the work. It becomes more efficient if you do about two dozen plugs at a time - - enough for twelve engines -- since that distributes the set-up across the whole batch. (Yeah, I know... but there it is.)
Mixed in with the friendly messages from people pointing out that other plugs are available was a couple that took me to task for even thinking about safety-wiring the plugs. As they pointed out, they had never had one come loose and that the odds of one doing so was probably ten-thousand to one.
Which is why we want to safety wire the things :-)
A lot of folks will miss that and beating them over the head with it is a waste of time, in my opinion. The truth is, there's a few threaded fasteners for which you can't provide safety wire or a Cotter key. But when you can you always do so even if the odds are 1:10000 because it shifts the odds even farther in your favor.