Potential Disaster Averted

[Spindrift]

In June I bought a flying RV7 in Michigan and flew it home to Oregon. The pre-buy inspection revealed some corrosion in the cylinders due to the engine sitting for a few years prior to installation in the RV, but the A&P/IA who did the pre-buy didn't think it was dangerous, nor did the A&P/CFII who flew it back with me. I negotiated the price down dramatically in anticipation of an overhaul this winter.

At the first oil change, ~25hrs after purchase, we found shiny metal flakes in the oil screen, and a pinch of metal in each fold of the filter.

Pulling the cylinders revealed nothing beyond the expected corrosion. Long story short, it wasn't until we pulled off the accessory case that we found the source of the metal -- loose bolts/nuts on both magneto gear mounts, one of which was flopping around enough to shave a significant amount of metal off the case. Luckily the accessory case kept it in place enough to keep it from falling off completely!

Once we cracked the case, we found that the metal flakes had made their way into some of the bearings, causing significant scoring, although it appears to my untrained eye that the damage is just to the bearings, not the crank.

Now the question is what is the next step? Reading through some old threads, it sounds like the steel parts should go to Aircraft Specialties, and the case to Divco or Crankcase Services. Any suggestions on where to send the cylinders? They were already overbored .10 at the previous overhaul (only about 200hrs ago), so I'm afraid they may be just scrap metal now.

I'm nervous about the idea of overhauling the engine myself even with A&P supervision, especially since the previous overhaul was done by a homebuilder who obviously didn't do a good job (btw, not the builder of the airplane). Any recommendations on overhaul shops in the NW?

Here are some picts:
http://www.flickr.com/photos/1224546...7624471891425/

Glad I wasn't planning to fly to Oshkosh this year!

Thanks,

[kentb]

http://www.premieraircraft.net/

I had the engine in my 172 done there. Top quality work. Talk to Norm.

Kent

[Jerry Cochran]

Bill,

I will ditto what Kent just said, Premier is first class and local.

They did a $3K teardown and inspection for me including testing the crank and cam for damage as well as the gears, cases, and accesory case. The Crank and Cam were fine, as were the main and rod bearings but had to have new bearings because that is mandatory on any tear down, so I have that engine for sale $19k and I could give you core value for yours. It's a zero time Aeorosport O-360 hollow crank. Well, that is it has a half hour TT... Remember, the guy tipped it over on first flight. I have all the inspection tags from Norm. He will probably remember it cuz it was all red with an Aerosport data plate. Mention I referred you to him, if you want.

Glad to hear you're back in business. I sold that nice Silver/Blue -6a to a fellow 105 member.

Give me a call anytime, maybe I can help

503 702 2663cel

[Pat Stewart]

You have the right folks identified. Both Aircraft Specialties and Divco in Tulsa have been considered the very best for many years. They are both very respected companies with top notch reputations and will not let you down.

Pat Stewart
Tampa Florida

[Radomir]

Out of curiosity... who assembled that engine?

[Spindrift]

Originally Posted by Radomir

Out of curiosity... who assembled that engine?

It was a homebuilder, not a shop. According to the log book, it came out of a Mooney at TBO, was inspected, overhauled, and flown in a Pitts for 60ish hours, then sat for a while before the guy who built my plane bought it.