Stihl 180 Oil Pump Performance
Affordable Solutions for the Home Master
Any owner is pleased with the good technology, proven in practice and more than once justified itself. The latest technology is always surprising and alarming with its characteristics that exceed the characteristics of a very old equipment, which is still in use by many.
Some masters always try to acquire the technique of well-known firms of a certain brand for their business and incline their friends and acquaintances to this, others are guided by the price and buy for themselves only expensive, but the manufacturer does not interest them.
Where is the guarantee that any equipment we purchase fully complies with the quality certificate under which it is sold? Where is the durability promised by the manufacturer, if we use their equipment in our conditions, and moreover, we feed it with our fuel and according to our recipes?
Nowadays there are a lot of equipment that can be sold at different in different outlets. No one will say where and who collected the very lawn mowing or chainsaw that you purchased. A well-known brand, and assembly can be carried out in a nearby garage for components, possibly even in a makeshift way.
A big problem that causes most budget chainsaws of various types of breakdowns is their poor assembly, incompatibility of components, and even a careless attitude to the entire assembly process by unprepared assemblers.
Many owners of chainsaws noticed an oil stain at the place where their chainsaw was resting or stored. Oil under the saw does not start to leak immediately. And with poor assembly, more precisely, with poor assembly of the chainsaw, an oil stain may appear immediately after refueling.
Excluding mechanical damage to the oil tank and oil supply system, there are not many reasons for oil leakage.
- Poor connection of the oil supply line to the input channel of the chainsaw oil pump and poor tightness between the opening of the oil tank and the line.
- Technical compliance with the dimensions of the plunger and the discharge chamber of the oil pump.
- Loose connection of the supply line to the output channel of the oil pump to the lubrication point of the saw chain.
- Violation of the tightness of the plunger chamber of the oil pump.
I will dwell on the latter option in more detail, since it is in the case of loss of tightness of the plunger chamber that oil leaks, and in the saw designs, where the oil tank is located above the oil pump in level, the oil flows out after a couple of days of idle chainsaw.
Eliminate oil leakage from the chainsaw oil pump it’s possible and all this happens quickly, if someone is good at using a screwdriver and wrenches. If your chainsaw has passed a small working resource, then the problem is solved simply.
As I mentioned earlier, the guarantee of the failure-free operation of your chainsaw is provided not only by observing the optimal operating conditions for it and using the recommendations of the manufacturer, it is also ensured by the appropriate quality of components, and most of all by the highest quality assembly.
Let the part be manufactured on high-precision equipment, but when it is installed incorrectly or not fixed with the same effort, the promised warranty from the manufacturer will disappoint you.
Like plunger type oil pump, installed on most models of budget chainsaws, simple in design. The principle of its operation does not differ from the operation of some plunger oil pumps of other categories of chainsaws.
I will briefly describe in my own words the principle of operation of the plunger type oil pump of similar models, which would be a little clearer when familiarizing myself with my method of correcting oil leakage through the chainsaw oil pump.
Work oil plunger pump on a chainsaw.
The oil pump on the chainsaw is valveless and mounted on the crankcase of the chainsaw from the side of the chain drive. The role of the valve in these pumps is performed by a segment cut at the end of the plunger. The plunger is driven in rotation from the clutch by a drive coupled from the worm hub. It turns out that the plunger of the pump rotates in the same direction and at the same time it blocks the input and output channels of the oil pipe in a cycle, combining the function of the valves.
Stihl 180 Oil Pump Performance
When the segment cut-out at the end of the plunger opens the inlet channel of the oil supply line, the plunger extends slightly from the working chamber of the pump, thereby capturing oil from the line through an open hole.
As the plunger rotates further, the inlet channel of the oil chamber of the pump is blocked and the opening of the discharge channel opens. At the same time, the plunger slides inward and pumps the trapped oil into the oil supply channel to the lubrication point with a piston.
With one rotation around its axis, the plunger performs one reciprocating motion along its axis, the stroke value of which is regulated by a screw with an eccentric transversely installed at the end of the plunger shaft. Some people like to call him a cam.
The eccentric abuts against the central protrusion at the end of the plunger shaft, and the greater the angle of deviation of the adjusting screw, the further the eccentric located on it will push the plunger shaft away from itself. In the greatest deviation of the eccentric, the oil cannot be pumped by the pump. No chain lubrication.
In addition to the central protrusion at the end of the plunger shaft there is an annular protrusion with a profile surface that determines the size of the plunger stroke along its axis. That is, the level of capture and injection of oil.
A metal spring is mounted on the plunger shaft, which, abutting one side against the oil pump housing, constantly presses the plunger shaft towards the adjusting screw.
The profile surface of the annular protrusion is in contact with the cylindrical body of the adjusting screw. In the place of their contact, a mate is formed, which, when the plunger shaft rotates, sets a value that limits the movement of the plunger along its axis and affects the process of oil capture and injection by the plunger.
The oil pump will operate at maximum efficiency, provided that the eccentric of the adjusting screw is not in contact with the central protrusion on the end of the plunger shaft. As the adjusting screw rotates, the eccentric will approach the protrusion and push the plunger shaft away from itself. In this case, the amount of oil supplied by the lubrication pump will depend on the position of the eccentric relative to the protrusion on the plunger shaft, and in this example, the volume of oil supplied by the pump is regulated.
Malfunctions of the plunger oil pump of the chainsaw and their elimination.
It often happens that the oil does not feed to the saw chain, even when the adjusting screw is in the maximum oil supply. There are not many reasons:
- After disassembling the oil pump, the adjusting screw is set in a 180 ° position relative to its original position.
It is enough to rearrange the adjustment screw or leave it that way. Then the screw positions for maximum and minimum oil supply () will be interchanged.
- The profile surface of the annular protrusion is worn out and no longer looks like a profile, but flat. The plunger does not move along its axis.
Change the oil pump or form a profile and grind the central protrusion at the end of the plunger shaft. In this case, the volume of the pump chamber will increase slightly.
When adjusting the profile and the protrusion, it is necessary to maintain the same maximum dimensions in height with respect to each other, so that when the adjustment screw is in the minimum mode, the plunger will slightly pump up oil. The new pump has a central protrusion at the end of the plunger shaft above the level of the annular profile somewhere by 0.3. 0.6 mm and in the position of the adjusting screw with a minimum oil supply, the oil pump does not work.
- Depreciation of the inner surface of the plunger chamber of the pump and the outer surface of the plunger.
This, as a rule, manifests itself with a previous defect or with what I will describe further. We change the oil pump or sort out the sets in size from used.
- Violation of the tightness of the working plunger chamber.
Oil can be supplied a little to the lubrication point, but there is a lot of oil on the saw case from the side of the chain drive.
The last example speaks of a cuff of the plunger, which in many cases is installed in the opposite direction, with the collar facing out. Some craftsmen claimed that it was a cuff that traps oil into the pump chamber. But how does this cuff behave when pumped? Will the oil pass through itself?
Some people choose rubber rings instead, but believe me, this is not easy and very caring for not experienced. This method is good, but the density of the seal ring must be considered. If the ring sits tightly in place, you will need to replace the plunger spring, and there is increased wear on the interface of the adjusting screw and plunger shaft. The wear of the plastic hub of the worm pair of the pump drive will also be added.
The ease of movement of the plunger is maintained by the use of a cuff, which does not interfere with the return stroke at the moment the plunger traps the oil and maintains sufficient tightness of the working chamber when pumping oil.
At the first opportunity, for chainsaws coming to me, I always disassemble the oil pump to be completely sure of the condition of the plunger and its cuff. In the case when the cuff is installed with the collar outward, then reinstall it on the contrary, with the collar towards the working plunger chamber of the oil pump.
This is my method, which always justifies itself provided that no one interferes in the design of the oil pump and the oil is fed into the pump through the oil filter.