Making metal at 150 hrs

jimgreen · #1 08-14-2014, 12:11 AM

I have an IO 360 from Aerosport. Superior with the roller lifters. Cylinders are ECI Titans which I ordered to get the nickel carbide finish. I knew I wouldn?t be putting many hours on per year, so spent the extra on the cylinders and lifters, hoping to avoid corrosion problems.
Bought the engine Dec/08 and first flight was 11 Jan/2012. I?ve always been very pleased with it; strong, smooth and trouble free.
Now comes the bad part.
A few months ago we found quite a bit of ferrous metal in the filter. After break-in the metal in the filter tapered off but never really went away, Now at around 150hrs it is back with a vengence.
The oil analysis shows fairly normal with slightly elevated copper and nickel.
Borescope of cylinders showed good condition with no corrosion. Since I have the roller tappets we had to pull a cylinder to see the cam. At first sight the cam looked good ? no corrosion. On closer examination we could see what looked like a dimpled surface on the lobes. This shows up better in the photos since it can be magnified.
Have been talking to Aerosport and they agree the engine should be sent back for a new cam.
So what do think the verdict will be? Faulty hardening maybe?

BTW the dry tappet clearance was way too high on all tappets. Averaging about .160.
Should be .028 to .080. Is this related or a separate issue?
Will post pics when I figure it out.

BillL · #2 08-14-2014, 06:33 AM

The failure could have lots of root causes, minor corrosion, hopping of rollers, spalling, heat or hardness treatment, sliding of rollers, many more.

It sounds like Aerosport will make you whole, and provide some assurance of future service. It will be interesting to hear how this turns out, or if RocketBob has some insight to such an early hour failure.

rocketbob · #3 08-14-2014, 07:01 AM

Quote:

Originally Posted by jimgreen

BTW the dry tappet clearance was way too high on all tappets. Averaging about .160.
Should be .028 to .080. Is this related or a separate issue?
Will post pics when I figure it out.

Well if your cam is ending up as shavings in the filter, this will be the result.

jimgreen · #4 08-14-2014, 06:03 PM

Looks like it involves quite a bit more than just the engine. They recommend the prop be flushed, governor overhauled and obviously the oil cooler flushed.
I sure hope Aerosport treats me well.