The International Cessna^® 170 Association

This is an engine question and the engine is in my son's 1960 model 172; sorry, I own a 170B, but I don't have the question.

His airplane is in FAI for annual. It has an O-300. The engine has about 450 hours SMOH. Before he got it, it wasn't flown regularly. He has about 150 hours on it this past year.

I bought the airplane and traded it to him for labor building a house for us in Galena. When I bought the airplane it had been out of annual for two years and as I said, not flown regularly before that. The AI that did the annual was bumb. I got the airplane "home" after annual and did my own annual and found about 15 squawks. I'm not a mechanic, but I've been around airplanes all my adult life and I'm about done building a Glastar. I took the airplane back and he "pulled my punch list". I'm suspect as to weather he pulled the screen.

What the AI in FAI found was about a teaspoon of aluminum in the screen. Number 5 was also down to 58 lbs. He found valve and or seat problems in nubmer 5. From what I know aluminum comes from pistons or piston pin caps. My question is this: How about he fly it around FAI for an hour and pull the screen and if no metal than fly it for 3 to 4 hours and have a look again? He is 2 1/2 hours from FAI to his village so it wouldn't be prudent to take it to Galena until you were pretty certain it wasn't making metal. Does this sound reasonable an prudent to you all?

Best regards, Buck Buchanan, Valier, MT

buchanan wrote: What the AI in FAI found was about a teaspoon of aluminum in the screen. Number 5 was also down to 58 lbs. He found valve and or seat problems in nubmer 5. From what I know aluminum comes from pistons or piston pin caps. My question is this: How about he fly it around FAI for an hour and pull the screen and if no metal than fly it for 3 to 4 hours and have a look again? He is 2 1/2 hours from FAI to his village so it wouldn't be prudent to take it to Galena until you were pretty certain it wasn't making metal. Does this sound reasonable an prudent to you all?

Best regards, Buck Buchanan, Valier, MT

Buck, I had a similar problem about 3 years ago, with a substantial amount of aluminum in the filter. With only about 1000 hours since overhaul, it turned out that one of the piston pin plugs had destroyed itself and distributed aluminum throughout the engine. There were also broken rings in the offending cylinder. In spite of of having a filter, engine dissassembly showed aluminum particles embedded in every bearing insert in the engine. Bottom line, found a good deal on a used engine until I can afford $ for a major overhaul. At least we caught it before the crankshaft, cam, and case became unserviceable.

I'd recommend at least pulling the low cylinder before further flight and check for damage. If you do have aluminum circulating in the engine, further running could completely trash the expensive parts.

Miles

Thanks Miles,

They did pull the low cylinder and found nothing other than a valve (s) problem on the top end. The AI suspected a broken ring but the rings and cylinder wall looked good. There was some pitting on the cam however.

They plan to flush it before they put new oil in it and fly it for an hour over friendly territory and then check the screen. If it is making metal I can bring it down to MT in Sept. and have it overhauled here for probably 1/2 to 2/3 what it would cost in Anchorage. We are hauling a load of household stuff up next month so freight would only cost them one way.

Regards, Buck