Back to Basics
Peter Rooke’s 1931 2 HP Stover CT2 restored to its original look.
A moment of impulse on eBay resulted in the purchase of a 1931 2 HP Stover CT2, mainly because I have not seen one in the United Kingdom despite this being a common engine in the United States. Undoubtedly, having purchased one I would suddenly see several.
The engine that arrived was something of a strange looking beast having been mounted on a large cart with a non-standard fuel tank, and the cast iron fuel tank from an old Petter engine being used as the basis of a pot muffler.
The Stover Mfg. & Engine Co. of Freeport, Ill., introduced the CT range in 1928, initially the 1-1/2 HP CT1, and the 2 HP CT2, with the 3 HP CT3 and 4 HP CT4 being introduced over the next two years. Some 25,000 CT2s were produced and sold under the Stover name, with further engines being produced, modified and looking different for Sears Roebuck and sold under the Economy name.
This engine is number TB 213534 and research on the Internet indicated that it was built in the early part of 1931. It is throttle governed and designed to run on kerosene with the mixer having a reservoir to be filled with gasoline to start the engine, with a separate fuel adjustment needle purely for starting.
While the engine turned over freely, no attempt was made to start it until all moving parts had been examined. It was clear that at a minimum it would need to be repainted as the paint had been roughly applied and was peeling off in places.
The non-standard exhaust and the fuel tank were removed before the mounting bolts were unscrewed. Then an engine crane was used to hoist the engine onto a small workbench so that it could be given some attention.
The magneto was the first thing to be taken off before trying to move the flywheels so there was no chance of having an accident and damaging it.
It was clear that I was going to have a problem in removing the flywheels as the gib keys had received some rough treatment in the past and little of the key heads remained.
Before trying to remove the flywheels the pulley was removed. Both ends of the crankshaft were badly marked with holes drilled in them and part of the keyway widened for some unknown purpose in the past. A little time was spent with a file, cleaning them as much as possible before emery cloth was used to remove remaining rust and nicks in the steel. The shaft and the area around the flywheel hub were given a dowsing in penetrating fluid, which was then given time to soak in.
The first attempt to remove the gib keys was welding some threaded rod to them in order to then use a nut to pull them off. A lot of care was necessary to ensure that no weld was stuck to the crankshaft, either covering it or using anti-splatter spray. However, the weld did not stand the strain of trying to pull out the key and the rod sheared off.
The second attempt involved a piece of 0.375-inch steel as a drill guide through which an accurate pilot hole had been drilled through the center. This was clamped to the crankshaft, and a long series drill was used to drill a pilot hole through the gib key. Only light pressure was put on the drill so that it did not wander off course and plenty of lubricant was used so that the drill could do its work. The drill bit was frequently removed to clear the swarf, again so that it would not bind, which would make it wander off course.
Once the pilot hole had been drilled, the hole was then drilled out to 0.344 inch, at which point an attempt was made to twist the flywheel to break the remains of the key. The flywheel was still stuck tight so there was no option but to bolt on the hydraulic puller to remove it using a large plate behind the flywheel to spread the load.
Stripping the engine
After removing the flywheels the engine could be stripped. This was followed by the cylinder head since the pipe work from the fuel tank had already been taken off.
The bolts holding the crankcase cover in place were removed, which was a bit of a struggle as a silicon sealant had been used rather than a gasket. A sharp knife had to be used to remove all traces of the sealant so there would be no problems when later fitting a new fiber gasket.
The crankshaft, con rod and piston were removed. The bearings were examined and were satisfactory, and no adjustment was needed to any of the shims to tighten them up. Similarly, the piston rings were in good condition, with plenty of spring in them, so there was no need to replace them.
The bore and all the internal components were then given a good cleaning with kerosene being used to wash the bits down.
There appeared to be relatively new springs for the cylinder head valves, which similarly appeared in good working order.
There appeared to be few problems with the engine, apart from a broken spring on the trip finger and half the advance lever missing. There was a worn taper on the mixer’s kerosene adjustment valve and the throttle butterfly did not fit well as it had been bent at some stage in its life.
There were of course some missing items including a full set of gaskets, fuel tank, filler and muffler, so a lengthy list was sent to Hit & Miss Enterprises. While waiting for these parts the paint was removed from the engine and the minor repairs were carried out.
The advance lever was broken so a replacement was shaped from a piece of .062-inch thick steel using the remains of the old one as a partial template. I only needed to find a similar spring to the old one to finish the trip finger and this was managed by rummaging through the spares box.
As a result of its condition, the throttle butterfly was not fully effective in closing the flow of the fuel/air mix to the engine. The screw holding it in place was removed and the old one used as a template to fashion a new one from some sheet brass. The new one was cut slightly oversize before drilling the center hole for the mounting screw. It was then a case of filing it to size and chamfering the front and back edges on alternate sides so that it opened and closed without catching on the wall of the mixer.
The fuel needle was redressed by setting it to run true on the lathe before giving it a very fine skim to smooth up the surface. Some fine grinding paste was then applied to it with gentle pressure before it was bedded in, taking care not to over do it and badly mark the soft brass.
The crankcase breather is bolted to the top crank cover. This has a leather washer supported by a metal disk and was cleaned to ensure that it worked properly with the old weak spring replaced. The breather operates as a check valve, and it should let pressure out easily but not allow any air to be sucked in. This creates a momentary vacuum in the crankcase every time the piston is on an up stroke and tends to keep the oil “pulled in,” reducing the chance of leaks around the gaskets.
The new fuel tank was supplied with two hangers that had to be soldered to the top of the tank. The tank had been supplied covered in galvanized paint that had to be first cleaned off. Once cleaned, the area for the straps was ready for fluxing and soldering.
The check valve and pipe were fitted to the mixer. When fitting the pipe from the mixer to the check valve, it was necessary to make sure that the check ball was able to move. The test was scientific - seeing if it rattled when shaking it! The pipe compression fitting was tightened then unscrewed so the end of the pipe was filed back to the “olive,” which is the brass ring that is compressed in the compression fitting.
Clearly the cart the engine arrived on was not original, and some red wood that had been left over from some other project was near enough the size to make a replacement. Based on a catalog print of an old engine, this was planed down to a 2.75- by 1.75-inch section and a 2 by 36 inch lengths cut. The engine would be mounted on two cross pieces of 1- by 1.5-inch timber, secured to the long spars by the engine mounting bolts.
The ends of the long spars were shaped and after sanding they were given several coats of varnish.
Examination of the magneto consisted of taking off the side band by removing the two pair of cover screws, dusting off the coils and checking that there was no excessive wear or damage to the points. It had been tested for a spark by turning over with the spark plug removed before the engine was stripped. After assembly a drop of oil was applied to the oiling point.
Searching the posts on SmokStak.com identified that the green paint needed was described as Brewster Green, which is not available over here. However, one post mentioned that British Racing Green was nearly the same, so I mixed some green and black enamel paint to match this color.
Before starting the painting, all traces of old paint on the engine were removed to get to a solid base. The original finish had been covered in a coat of thick paint that also had patches of rust underneath it so that it was peeling off.
After a good wire brushing, the water hopper and crankguard were given a coat of zinc oxide primer mixed to a thick creamy paste by adding powder decorators filler. This was later sanded down to a smooth finish and some of the rough areas were given a second coat. When these areas were smooth, the whole engine was sprayed with a couple of coats of red oxide primer.
While the paint used was reasonably fuel proof, the mixer was not painted.
On this occasion the engine was painted using my small spray gun to give a first-class finish, and after allowing it to harden, any minor blemishes were rubbed out using a rubbing paste or very fine wet and dry paper. The engine was now ready for lining.
Assembling the engine
Once happy with the coverage and smoothness of the green paint the engine was partially assembled before starting the lining.
The piston, con rod and crankshaft were re-fitted, taking care to ensure that the timing marks on the gears lined up. This was followed by the pushrod because the governor had not been removed and all nuts were carefully tightened. When assembling the piston, care was taken to ensure that the hole in the piston was at the top so that oil would drip over the little end bearing.
The valves were assembled in the cylinder head before fitting the cylinder head, using a new gasket to seal it. Finally, the mixer was fitted to the cylinder head. The remaining parts, including the magneto, would be fitted later.
Shelby Babcock was good enough to e-mail me a copy of a page from a brochure setting out the lining scheme for the CT2. This would be one of my first attempts at lining so I first needed an hour or two of practice on a piece of scrap sheet metal. Mack striper brushes and 1 Shot Sign Painter’s lettering enamel was used.
Normally, before lining the surface to be painted it would be degreased but as this was new paintwork that had been untouched it was just given a wipe with a clean cloth. The first task was to mark out the lines using a wax crayon, which if not correct, could be easily rubbed out and redrawn. As the majority of lines were straight, except for the flywheels, some flexible masking tape was used to mark them out to make the job easier. When marking out the lines, a clear line was drawn at right angles to mark the start and finish of the line.
To accurately mark out the line on the flywheels, a washer was found that would hold the pencil the required distance from the rim while the washer was moved around while resting against the flywheel rim.
The lining out was to be in red and yellow, although some say that gold was used in place of yellow. The 1 Shot paint was mixed in a small cup to the shade that looked right against the green base coat of the engine, ready to paint the lines.
After setting up the masking tape on the crankcase cover and water hopper, the first color, red, was readied in a small mixing cup and a small amount of reducer was poured into another cup. For the mixing palette, a page from a glossy magazine was used. Onto this a small amount of paint was dabbed with the mixing stick, then the brush dipped in the reducer and worked into the paint, adding reducer until the lining brush glides through it. Charging the brush by rolling it in the paint, the first line was drawn in a smooth continuous movement, adjusting the pressure on the brush to thicken or thin the line. If you get the right consistency, the paint flows easily, does not run and covers in one coat. This was easy when working within the tape.
When it came to the flywheels, the lines had to be drawn freehand. Resting my painting arm on the workbench, the other hand was used to slowly turn the flywheel while trying to achieve an even width line over the mark. If a mistake was made the paint could be wiped off with some paper towel and the marking line re-drawn before starting again.
Once the lines had been painted for one color the engine was left alone for a day so the paint could harden before starting the second color.
Highlighting the lettering on the flywheels was a simple process, but took time, again wiping off the paint and re-applying it if a mistake was made.
New decals had been obtained from Hit & Miss Enterprises and their position was first marked out using chalk before they were applied.
Final assembly and setup
Once the lining had been allowed to dry the rest of the engine could be assembled, and as a first step the fuel tank was bolted to the underside of the engine casing before it in turn was fitted to the new sled. The fuel lines were then connected to the tank and the mixer.
The flywheels were slid on to the crankshaft and new keys fitted. To be fully effective, a key should engage with the flywheel and the shaft for as much of its length as possible. The normal taper of a key is 0.125-inch per foot. A new key that is well over size can be milled or ground until it is near the correct size, but still a few thousands of an inch too large. While time consuming, the best way to fit a key is to coat it with engineers blue, press it lightly into position, remove and then draw file the high spots where the blue has rubbed off. This process should be repeated until the key is a press fit to just over a half an inch of the head. When adjusting the key do not keep driving it home; just tap it with a piece of wood so it is easy to lever out again.
The timing of the valves should be checked after the rocker arm has been fitted to the cylinder head. The exhaust valve should be open approximately 35 degrees before the crank reaches its bottom dead center and should be closed after the crank has reached 5 degrees beyond its top dead center. Assuming that the gear wheels have been correctly assembled, minor adjustment can be completed by adjusting the screw on the exhaust rocker arm.
To adjust the governor, the speed of the engine is increased by lengthening or decreased by shortening the throttle rod by loosening the lock nut and turning the throttle rod coupling. The rated speed for the CT2 is 575 RPM.
Care is needed when fitting the crankcase cover so that there is a good oil seal and oil is not sprayed all over the exhibition field. New felt strips were obtained from Hit & Miss, and these were given a coat of heavy grease in order to make a complete seal before they were fitted between the crankcover and engine casting.
The crankcase was filled with oil when it was on a level surface. The correct amount was reached as soon as it started to drip from the test cock at the end of the crankcase. It is important not to overfill the engine with oil as this could lead to leaks from the gaskets and fouling of the spark plug. All moving parts were then oiled.
The water hopper was filled with water to within three inches of the top and the engine was then ready for starting.
This engine was designed to run on kerosene, and to start it the mixer reservoir should be filled with gasoline and the kerosene needle closed. The starting needle valve for gasoline should be opened, in this case by half a turn.
The choke was closed, and the lever on the trip finger was moved up to retard the spark. The starting wrench was used, holding the inlet valve open for the first few revolutions to enable the engine to get up some speed. As soon as the inlet valve was closed the engine fired so the choke was opened and the advance/retard lever closed. When the engine had warmed up, the gasoline needle could be closed and the kerosene needle opened.
The WICO magneto should trip when the mark on the governor side flywheel is lined up level with the valve push rod. If adjustment is needed then the trip finger bracket should be reset on the pushrod with only a very slight movement generally being required.