The Dragonfly

Last Update-03/13/2010 01:43 AM           

Here is a little loader I found on Craigslist one day while browsing for parts for the Case loader.  This little loader has a 20 HP Kohler engine that was in need of some serious attention when I received it.  The previous owner mentioned that he had problems keeping it running.  I grabbed the flywheel and it turned like a pinwheel in the wind.  Hmmm I thought, does this thing even have pistons in it?  I knew there was some problem with compression. 




I received a spare engine for the loader.  After some investigation it seems to be a Kohler K482 18 HP engine that is in the same family as the K-532 20 HP engine that is in the loader know.  Looks like should be able to rebuild this one as well with a few spare parts obtained from Craigslist and eBay of course.

All the pins and bushings appear to be in great shape.  The loader looks as though it was fairly well taken care of minus the engine of course.



The engine was in pretty rough shape.  After disassembling it, I discovered the reason for the lack of compression.  Two of the screws that normally hold down the bottom of the air cleaner to the carb had come loose and were now holding open the intake valves on each side.  The valves were fine, but the seats were beat to hell and back.        




The engine came equipped with the incorrect filter. The correct filter for the Kohler K-532 is the FRAM PH3600.

The item to the right of the carburetor with the tube coming out and into the carb is the PCV valve.




Here is the electrical setup as received.  There are three item bolted below the seat.  The one on the left is the voltage regulator/rectifier.  In the middle is the starter solenoid and of course the item on the right is the ignition switch.

The rectifier/regulator take the alternating current produced by the alternator and converts it into direct current (DC). It then regulates the voltage to roughly 13.5-14.5 volts. This alternator can provide up to 15 amps of current or if you like, 180 watts of power.  So basically,the alternator could \provide power to 3 55 watt lights without running down the battery over time.


The item at the end of the crankshaft is a coupler that ties the 1 7/16 crankshaft to the splined input shaft of the piston pump assembly that feeds through into the engine compartment.





This engine uses a pressure lube plain bearing on the flywheel end and a huge ball bearing on the PTO side.  As you can see, the flywheel end bearing was pretty worn.  The photo actually makes it appear worse than it was.  I was able to purchase a New, Old Stock bearing on eBay for 20 bucks instead of the $45 as listed elsewhere.




As I was saying earlier , the intake valve seats needed to be worked on due to small screws being lodged into the opening preventing them from closing but trashing the seat/  If you look closely at the picture to the right, you can see the damage at about the 10 oclock position on the seat.  The shaft you see inserted into the valve guide is the pilot for the coolest tool ever made, the Neway valve seat cutter!




These little cutters are produced by Neway MFG. located in Michigan.  Each cutter is made to a specific angle and most have an angle on each side as you can see on the cutter in the picture.  This seat requires a 46 degree cut for the main seat and a 15 degree top cut to bring the seat width to the correct measurement which in this case is .037-.045.  The cutter uses tungsten carbide inserts to cut the seat with extreme precision.  It only takes a nice easy turns on the wrench to cut the seats.




Here I have almost complete the seat cut.  The damage was a little deeper than I had figured, but as you can see in the pic on the right, the seat came out looking good.  My cameras battery died before I had a chance to take pictures of the 15 degree top cut.  That cut kind of counter bores at at angle down to bring the seat width into range.  I love this tool.  I will be buying more from Neway MFG. for sure!




The valves and springs.  One thing I noticed as I dismantled the engine, was that someone had the intake valve in the exhaust side and of course the exhaust was in the intake side.   The valves will interchange as they are the same size, im just not sure how the intake valve survived the exhaust heat since it is a different material than the exhaust valve.  Someone really didnt know what they were doing.  You have to get the manual and follow it people!




Again, I got caught up in the building frenzy and failed to take pics of the actual rebuild.  Here she is almost complete.  You can see the stator mounted to the front of the timing gear cover.





You can see the starting point for the baffling system attached to the bottom of the gear cover.  The starter gear will protrude though the large hole in the lower baffle.

At right, all the baffling had been installed.  I had to buy two pieces of shroud that cover the top of the cylinders and make one lower shroud that I couldn't find. This little beast should stay nice and cool now that its actually wearing all its metal.  I will need to get or build a grass screen that covers the flywheel to keep foreign objects out of the engine.


The coil and plug wires are in rough shape but ohm out ok.  The two yellow wires shown are the ac lines coming from the stator.  The green line is the negative lead running from one side of the primary winding to the points and coil.

I know she doesn't look to pretty since I didn't take the time to paint it, but paint don't make an engine run any better.


To the left is the heart of the drive system, a Sundstrand Series 15 tandem piston pump assemble.  It consists of two model 15 piston pumps back to back with a common shaft.  Each pump drives its own motor on each side of the loader. 

The input power shaft extends through the assembly allowing a standard hydraulic pump to be atached to the unit.  Here you can see the casting on the end that the gear pump for the boom and bucket attaches to.



The left side drive on the loader would not move when I purchased it.  I initially suspected a  relive valve was missing, but after discovering that is wasn't, I dug deeper and found this, a busted drive pin on the charge pump for the left side drive.  There is one in each piston pump.  This pump helps preload the piston assembly with fluid and most importantly replenishes the fluid lost through internal leakage of the pistons and seals inside the pumps.




It was very cold (3 degrees) when I drained the fluid and found this.  I could not believe the amount of ice in this fluid.  Someone must have left the cover off while the unit was stored outside for this much water to have accumulated.  Needles to say, I think I found the reason the drive pins in the charge  pump broke. 




This is alot of ice.  The entire bottom of the loader was covered with about 1.5 inches of ice.






This is what makes a hydraulic piston pump a "piston pump".  The input shaft runs through this little cylinder block rotating it. The pistons ride against a highly polished movable "swash plate" that can be tilted to increase or decrease the amount of fluid that is pumped into its closed circuit to the motor.  The swash plate can be tilted in either direction providing forward and reverse flow to the motor.




This Webster Press gear pump attaches to the end of the tandem piston pump and provides hydraulic power for the boom, bucket and auxiliary circuits.  This particular pump is a .58 cubic inch per revolution pump.