First thought Brockie is it's a valve and you are adding another possible source of leaking. But I've never used one and it could be bulletproof.
No way. The sump is thin-walled aluminium and it would lead to a sizeable stand-off pipe inside the casing to create a 1-inch thread. Which in turn would ensure that you can't ever drain all the oil. I have not looked either but I expect that the sump only has maybe 5-8 mm (maybe 5 threads) of thickness at that location.I’ve never measured, but memory says it has about 1 inch of nice, clean, well-made threads. Again, I’ve never looked, but I’d expect similar thread length, in the engine casting.
If only 5-8 mm of engine / casting / female threads, then why a bolt with ~25 mm of threads? Not arguing, just wondering…No way. The sump is thin-walled aluminium and it would lead to a sizeable stand-off pipe inside the casing to create a 1-inch thread. Which in turn would ensure that you can't ever drain all the oil. I have not looked either but I expect that the sump only has maybe 5-8 mm (maybe 5 threads) of thickness at that location.
That's part of the problem. People look at the big steel oil drain bolt and apply a correspondingly big torque to it. Yes, the bolt can take it, but the sump threads can't.
For the sake of discussion and entertaining and learning, I am not disagreeing with any comments above, just pointing out alternate views and fun things to think aboutI think some of us are getting their mechanics of materials (a branch of physics) a little bit confused. I’ll just concentrate on the sealing (crush) washer.
- it doesn’t experience any fatigue. Fatigue is a cyclic failure mode (think bending a coat hanger back and forth until it fails). If you use it twice, don’t flip it over. The drain bolt has a smooth face, the engine case is less flat. The crush washer engraves itself into the surface irregularities. Leave it installed the same way, or live like a king and buy several crush washers.
- the sump threads do fatigue. Because you are routinely tightening and loosening the drain bolt.
- Teflon tape is used on straight threads as well as tapered. I have turned wrenches on Harley’s and Teflon paste is what is use. It’s not necessary on Jap bikes.
- it takes some exotic aluminum alloys to even approach the properties of steel. The main one concerning oil drain plugs being steel has very high fatigue strengths and aluminum does not.
Yeah, I know. The next post will be I reuse crush washers for the life of my bike, torque wrenches strip bolts, and any oil is fine in your bike.