Cylinder Overhauls
We are a Transport Canada certified cylinder overhaul facility. We're able to overhaul and repair all types of cylinders, including Pratt & Whitney 985 and 1340 cylinders and antiques no longer made.
Because we overhaul cylinders in-house, we can often save you a lot of money if you experience a cylinder problem. While many shops practice simple "plug and play" techniques by replacing faulty cylinders with brand new expensive ones, we offer our customers a choice.
If your damaged cylinders are "first run", more often than not, we can overhaul and re-certify them to serviceable specs. In most cases we can do it at a fraction of the cost of new ones.
We also stock a selection of previously overhauled cylinders so if you're in need of a fast turn around, we can often get your airplane back in the air very quickly.
And, if your engine is a rare antique with cylinders that are no longer made, we can often overhaul and refurbish your existing ones, to keep your antique bird flying. If your antique cylinders are beyond servicable specs, we'll do our level best to find salvagable units through our large network of antique parts sources.
The Cylinder Overhaul Process
Our overhaul process is very thorough and technically precise. We carefully inspect each cylinder for cracks, flaws or signs of stress that would render it unsuitable for another round of service. If we have even the slightest doubt about a cylinder's ability to make TBO after overhaul, it's off to the re-cycle bin.
For the cylinders that make it through the inspection process, we re-bore as required the valve guide bosses and replace the guides. To ensure perfect valve seat alignment we either re-grind or replace the valve seats. And, where necessary, we re-face or replace the rocker arms to ensure perfect surface to surface contact with the top of the valve stem.
The cylinders shown at right are awating cleaning and inspection. Only about half of them will make it through our rigorous re-certification process. The ones that don't are sent to the metal recyclers.
Each cylinder overhaul also requires careful working of the cylinder barrels. They're honed or bored oversized as required. And then the cylinder barrel is honed to a perfect cross hatch pattern which ensures maximum lubrication of the rings. Our carefully controlled honing process makes for fast break-ins, minimum oil consumption and maximum compression.
This Pratt & Whitney R-985 Wasp Jr. has just had an overhauled cylinder installed; it's the one on the right side in the picture.
Unlike modern horizontially opposed engines, radials are very complex machines.
Valley Aero is one of the few shops still capable of working on these big radials. It takes a lot of specialized tools and engine stands, and a whole lot of engine specific knowledge and experience to do so.
This R-985 is from a De Haviland Beaver that makes daily, scheduled passenger flights on the west coast of Britsh Columbia.