Yep, happened to me. I must have flow at least 20 hours with out the cotter key installed.
Landed at Shady Bend where Tracy, Fin and I spent some time admiring each others rig. I remember showing how my new intake manifold inlet could open fully when I shoved the throttle open. So we went in and after spending night at Tracy, we decided the next morning (which was rather cool) to go flying.
Well, forgetting I had left my throttle wide open the evening before, I hopped in and fired her up. Well, with cool morning air and throttle wide open the rpm zoomed to over 5500 in what seemed like a fraction of a second. Yanked the throttle back and all seemed OK. Not much wind, so Tracy and Finn elected to takeoff downwind and did so. Me being a bit heavier and just not like taking off downwind. I started taxing to the other end of the runway. While taxing I noticed my oil pressure seem stuck at around 25 psi where as normally taxing it was closer to 40 psi. Well, I tried to tell myself it was nothing, but just couldn't bring myself to take off. So taxied back to the hanger and shut it down. After several attempts could not find anything wrong with the oil system. So took off the cowling and oil pan and while juggling the oil pan heard a metalitic clink in the pan .... THERE IT WAS the Oil pump cotter pin in the bottom of the oil pan. So during my 20 hours of flying only the nut torque kept the belt turning the pump.
I figured the sudden start with the cold oil was too much for the nut and it began to loosen. Glad I listen to my gut.
Glad your event did not have a bad ending.
Ed Anderson
------ Original Message ------
Date 3/16/2024 12:27:38 AM
Subject [FlyRotary] Re: Oil pump wouldn’t prime cause
As I recall, Ed Anderson had a related incident with the oil pump, he flew to shady grove, and in applying power for takeoff, lost oil pressure, and when they removed oil pan found the cotter key. Glad you found it.
I removed my ‘86 13B from the mount (took two hrs.) and when pulling the pan off, found pieces of a cotter key; so knew I’d screwed something up! Pulled the “front” cover and found the oil pump shaft but the nut was loose, and I’d never bent the locking tab over one flat in the nut. When I spun it up with the starter it immediately tore up and spit out the cotter key, which dropped into the pan. Will do a better job of quality checking my work as it goes back together!
Thanks Dave Leonard for letting me know it should easily prime the oil pump if all was installed correctly the first time.
Doug
Sent from my iPhone--
Homepage: http://www.flyrotary.com/
Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html
|