Paul,
I was able to tap mine to 3/8 NPT which left adequate wall thickness. 

Mark S.


At 09:54 AM 1/12/2004 -0500, you wrote:

Hi, Finn....By the time I drilled and tapped the hole for 1/2 NPT, the remaining wall would be so thin, I was afraid it would break during the tapping operation.  The housing is cast iron, and a pipe tap is tapered, so it tries to expand the hole while tapping. Not a good situation when you have thin walls, expecially if those thin walls are cast iron.  Take care. Paul Conner

----- Original Message -----

From: Finn Lassen

To: Rotary motors in aircraft

Sent: Sunday, January 11, 2004 11:11 PM

Subject: [FlyRotary] Re: Success

I curious as to why you didn't simply thread the housing with 1/2" NPT and used the fitting unaltered.

Finn

sqpilot@earthlink wrote:

     The second item I had success with was the 5/8" heater nipple that is a press fit into the engine, underneath the oil filter.  Mine was missing from my engine. I tried to find a new one, with no success. Finally, Mazdatrix sent a used one, but when I put a micrometer to it, it was considerably out of round (probably caused during removal from the casting).

 

       I found at our local CarQuest auto parts store, a steel 5/8" hose barb to a 1/2" NPT male fitting. I just put it in a lathe, and turned the 1/2" NPT threaded area down to 17 mm, or .160 inches. In the picture, you will see the longer original piece, as well as the new, slightly shorter nipple.