terry.mortimore
Well Known Member
Hi guys, really need some input on this problem.
I have a IO-320 narrow deck engine with a EFII ignition and fuel injection system. I have had the idler gear shaft wear the mounting holes twice.
This engine has a O-320 case which was overhauled by Divco and put together with a new crankshaft and camshaft. I’m using a Sensenich ground adjustable propeller.
At the 191 hour mark the oil analysis showed elevated aluminum levels. Investigation discovered that the two 1/4” bolts that hold the idler shaft had broken and the bore that the idler shaft mounts into had worn.
The engine was dismantled and the case was sent to Divco who welded up the bore and re-machined it. The rest of the case was overhauled and the engine was reassembled with new bearings. I used aircraft grade bolts for the idler shaft that I sourced from aircraft specialties.
The engine now has 386 hours on it and the last oil analyst showed elevated aluminum levels again. The same problem again, this time the bolts held but their holes had worn the case. See the attached pictures.
So, I really need to figure out what is going on. The offending idler gear is only driving the camshaft.
The idler gear has been removed from the right side and the hole covered.
I’m using a 20 amp B&C alternator mounted on the vacuum pad.
Has anyone out there who is not running magnetos had similar problems?
I’d appreciate any input.
Thanks, Terry
I have a IO-320 narrow deck engine with a EFII ignition and fuel injection system. I have had the idler gear shaft wear the mounting holes twice.
This engine has a O-320 case which was overhauled by Divco and put together with a new crankshaft and camshaft. I’m using a Sensenich ground adjustable propeller.
At the 191 hour mark the oil analysis showed elevated aluminum levels. Investigation discovered that the two 1/4” bolts that hold the idler shaft had broken and the bore that the idler shaft mounts into had worn.
The engine was dismantled and the case was sent to Divco who welded up the bore and re-machined it. The rest of the case was overhauled and the engine was reassembled with new bearings. I used aircraft grade bolts for the idler shaft that I sourced from aircraft specialties.
The engine now has 386 hours on it and the last oil analyst showed elevated aluminum levels again. The same problem again, this time the bolts held but their holes had worn the case. See the attached pictures.
So, I really need to figure out what is going on. The offending idler gear is only driving the camshaft.
The idler gear has been removed from the right side and the hole covered.
I’m using a 20 amp B&C alternator mounted on the vacuum pad.
Has anyone out there who is not running magnetos had similar problems?
I’d appreciate any input.
Thanks, Terry