XK6 Engine Education

[Wiggles (Paul Wigton)]

Series 2 Crankshaft Sludge Plug threads

Mike, Check out the archives with the Search function. The consensus there is that the thread is 5/8-14 BSP. That is, the tapered thread sometimes referred to as BSPT, not the parallel thread BSPP. That makes sense, as a tapered thread will seal when it is tightened, whereas a parallel thread requires a sealing washer and a corresponding sealing surface. -David