Bringing a 1-1/2 HP Aero-Type Sattley to Life Again
The March 2004 issue of Gas Engine Magazine contained a very informative article on Montgomery Ward's air-cooled engines. As I periodically looked through it, I was reminded of the one that had been sitting on my workbench for a couple of years, not running and needing unknown work.
Last winter found me running out of indoor shop projects, and it was still too cold in March to play outside. So, this 1-1/2 HP Aero-type Sattley made by the Nelson Bros. in the early- to mid-1930s was brought in from its "cold storage" to be evaluated. It was lightly stuck and had some rusty-colored liquid in the gas tank. Getting it to turn over was just a matter of some penetrating oil and a few light taps on the piston. Once I got it free, I removed the flywheel to clean the points, replace the split-open condenser and make a new spark plug wire. At this point I had good spark and some compression.
Cleaning the gas tank was the next step. These engines have two separate compartments in the cast iron base. One part holds the lubricating oil, about 3/4 of a quart. The other compartment holds the gas, nearly a gallon on this size engine. The gas tank cleaned up all right at the time - so I thought - but would come back to haunt me soon!
Then I put the flywheel and shroud back on and changed the oil. I poured some fresh gas in the tank and primed the overflow-style carburetor through its primer hole. Someone had put a rope-start pulley on, as apparently the crank had been lost, broken or declared unsafe. After a few pulls it started, but soon ran out of gas. Looking into the carburetor, I could see that no gas had been pumped up from the tank. The supply line was unobstructed, so I knew the fuel system needed more work.
The fuel supply is a force-feed system, where a spring-loaded pushrod driven off the crankshaft through a cam and rocker pumps fuel up to the carburetor. Looking in the pump chamber drain hole, I saw nothing but rust. When I acquired this engine the previous owner said he never had it running, so the last time it ran was anyone's guess.
My next step was to lift the engine assembly off the base. This only revealed an open sump for the oil and the spring-loaded pushrod for the fuel supply. This pushrod was stuck, and I mean really stuck! Furthermore, there was no fresh oil in the connecting rod dipper tray. There is a short plunger rod attached parallel to and driven by the fuel pushrod to supply oil to the dipper tray from the oil sump. Obviously, I had no oil pressure in the minute or two the engine was running.
The fuel pushrod is made of hardened steel with about half of it passing through a brass sleeve, which is surrounded by the cast iron base. The only access to the stuck area was through the fuel drain fitting or the small fuel filler plug - no way to get direct heat on the affected area. It is such an inaccessible area that you can only get a flexible mini-light in there to see what's going on.
After intermittently working on it for many weeks with all kinds of penetrants, both commercially available (call them over-the-parts-counter medications) and various concoctions of homemade mixtures (call them Grandpa's special elixir), that pushrod was still stuck. I made some progress as I opened up the fuel passages in the base, only to find a check ball in the bottom of the pushrod channel. Since there are no Montgomery Ward's stores to obtain a new pushrod from, this one had to come out un-damaged if this engine was to be saved from its impending lawn ornament status. Direct heat was obviously needed, but how to get it to the affected area would be a challenge.
If two dissimilar metals go through several heating and cooling cycles they can often be separated or freed up without damage. Here I had a hardened steel pushrod and a brass sleeve, two dissimilar metals. Remembering occasional comments about "baking" parts to remove scale or free up severely rusted pieces, I decided this was possibly my last resort to save this engine. The kitchen oven was definitely not available, as some of New York state's finest chocolate chip cookies come out of it.
The best plan turned out to be placing the base with its stuck piece about 2 feet away from a 150,000 BTU salamander-style heater; you know, the ones that sound like a jet engine for about 15 minutes at a time. This was long enough to make the hardened steel pushrod too hot to touch but not hot enough to change its temper. I allowed the unit to cool back down to room temperature, then repeated the cycle four or five times before some oil was applied. Then I left it alone for a week.
The following weekend I proceeded with the heat-ing/cooling process. After the first heat/cool cycle, I gave the pushrod a series of tugs with a slide-hammer and felt a little movement. Two more tugs and the pushrod was out, with no damage. I lightly sanded it with some crocus cloth and it was ready for re-use. Since that particular operation was a success, all that remained before reassembly was a thorough cleaning of the oil sump.
Another surprise was finding a piece of piston ring in the sludge in the bottom. "Well," I thought, "I might as well pull the piston and see what's going on." A few minutes later I had the piston out and discovered the rings were complete, just stuck in their grooves. Someone had obviously put rings in it a long time ago. That broken ring led me to the stuck rings, so in reality, some further damage was avoided by finding it.
I took one last look before reassembly and did my final acetone rinse of the gas tank. I saw no more surprises or waiting challenges, so back together it went. It had much better compression now, fuel and oil pumps that pumped, and a good spark. It just doesn't get any better than that, even for an old air-cooled Sattley. Now it starts easy and runs smooth.
Old engine restorations can certainly be a valuable learning experience, no matter how many we've accomplished. During this particular restoration, I was reminded of two valuable concepts: First, patience is always needed. As mentioned previously, no Montgomery Ward stores are around to buy Sattley parts from, so I had to work slowly and carefully to save any reusable parts. Secondly, I had to develop problem-solving methods such as heating an inaccessible area in order to make every effort to save another piece of old iron.
Contact engine enthusiast Bob Naske at: 2059 State Highway 29, Johnstown, NY 12095.