I subscribe to BT member's Samuel Cryer's company, Plane Safe Aircraft Maintenance, Inc.'s FB page, and he posted these pics of the damage of a 421's engine.

I hope he doesn't mind my posting them, they were pretty dramatic.

Ouch, looks expensive...

That will buff right out!

What was the cause?

He didn't say.

By the by, this is Plane Safe Aircraft Maintenance, Inc's FB page.

http://www.facebook.com/pages/Plane-Saf ... 7654717064

+1

glad it wasn't a beech421

Yeah, but that engine is very similar to the engines we run in our Beech's.

I'd love to hear more, obviously the starter adapter was involved.

Rick

I wonder if that is the result of a hung starter motor. If the mag/starter switch is weak then the motor stays engaged and spins around at a different speed than the crank gear and finally gives up teeth. What a mess that must be internally

Not with a properly operating starter adapter, that is the function of the clutch spring, to allow the drive gear to spin faster than the starter motor. If the starter stayed energized, the only effect would be a smoking hot motor and perhaps a dead battery.

Rick

Operating word " Properly working" That is a lot of gear teeth to be floating around in an engine no matter what the cause. I hope someone finds out the real reason so we can learn from it. I take off my alternators at each annual because I dont want a loose gear taking out the engine. I sure dont want to get paranoid about the starter adapter too.

Think that might have been making metal in the filters before it came unglued??

Continental has done a poor job of designing the drives for the starter, generator/alternator and other accessories. This is especiaqlly true of the starters.

Internal gear driven engine starter systems are asking for trouble, as may be seen in the pictures and also seeing the broken gears I have in my collection. Those gears came out of E engines used on the first 4500+ V tailed Bonanzas, but the principle is the same. Unless one understands that the starters are turning a large, heavy engine/ prop assembly from a dead stop using a lever arm only about 1-1/2 inches long or less (the crankshaft gear) and the correct way to push the starter button (at least on the E engines with an E-80 starter) there will be these sort of failures.

Although Continental builds wonderful engines, Lycoming starter and alternator drive designs that use a 12 +/- inch starter ring gear at the prop together with a generator/alternator drive V belt pulley are a much safer and mechanically better system.

All of those gear driven accessories hanging on the back of the engine or at right angles on the front of the engine may look good, but they are the source of a great deal of trouble for the people paying the bills on them! I have no idea why Continental is hanging on to a design that exposes the engines to such failures. Maybe it is pride?

At the ABS/AOPA Convention in Palm Springs I will have the above mentioned broken gears in case anyone would like to see them. I have also had pictures of these broken gears and an explaination of why they are broken in the ABS Magazine several times over the past 30 years and there are still people that just blindly hop in and push the starter button. I think they operate on the principle "it has not happened to me yet so it can not be true." Oh yeah, take a look at this!!

Regards, Lew Gage

Simcom's recommended starting procedure checks for a hung a start prior to anything else. The 421 has a nice volt/battery/L&R amp meter with 4 selectable positions. On startup, you switch to Batt mode immediately to check for the hung start which is indicated by a high needle.

In addition to frying your electronics, I suppose a hung start could do something nasty like this as well. Ouch!