quote:Originally posted by Cowboy from Hell: The normal shaft removed from a high mileage Ford may have one to two full twists in it.
Several twists are normal? Maybe on junk yard engines. To me it's just a sign of a poorly maintained engine that has survived a couple of near oil pump failures and/or correspondingly one that has had a lot of debris through its lubrication system. They'll usually also have a matching set of bearings and journals that are badly damaged too. Even when considering rebuilding, it raises questions as to whether you can get all the crud out of the oil passages that caused the damage. That's partly why you see all those oil pumps and braided steel lines from the NASCAR teams on ebay. They'll never trust them after they’ve seen a blown up engine and they just pitch'em.
quote:......and over twenty to thirty years of use the shaft slowly twisted into the shape you see.
Looks like every shaft that comes out of an engine with a seized oil pump to me. How do you know those twists developed over 20-30 years and not just as a result of a catastrophic failure caused by debris too large from the pump to tolerate?
quote:…the shafts twisting is a beneficial thing and an intentional design feature.
If shafts really do routinely twist multiple revolutions in use, one could argue that is truly a means of making the engine more tolerant of gear rotor oil pumps intolerance to debris and it would wreck fewer engines and strand fewer people by not failing catastrophically.
One could also argue that the weak link should be the roll pin so an engine that may have just lost it's oil pump is shut down by losing its timing mechanism too.
G, you’re a faithful disciple of the Ford engineers of the day but for me, the design lesson here is gear rotor oil pumps may be simple/reliable but do not tolerate large debris. Faithfully: debur your rebuilds, keep your engine internals spotless during assembly, and change your oil frequently.
Take care,
Kelly