The pistons and connecting rods
Details of the piston
| || 1 - piston pin |
2 - piston
3 - the piston rings
4 - Connecting rod bolt
5 - rod
6 - rod bearing shells
7 - a cover of the connecting rod bearing
8 - a nut of the connecting rod bearing
Details of the piston shown in the illustration above. To remove the piston motor must be dismantled and the cylinder head removed. Sump must also be removed to get to the connecting rod bearings. Check with the relevant sections.
The pistons and connecting rods are pushed hammer handle on the inside of the cylinder after the cap will be removed and the connecting rod bearing shells. Before performing these studies should be familiar with the instructions below regarding the designation and direction of installation:
Each piston and connecting rod should designate an appropriate number of the cylinder from which they are taken. This is best done by writing the number on the bottom of the piston cylinder. Also applied to the piston of an arrow pointing to the front side of the engine. When the piston is later cleared of oil carbon, the arrow should be applied again.
When removing the piston rod to observe the exact installation position of the connecting rod bearing cap and immediately after the check, and the connecting rod bearing cap room for the presence of the cylinder on one side.
The bottoms of the pistons have a notch on the edge (injection engine) or the arrow (petrol engine), which should be turned forward. Cranks are masloraspylitelnye holes. When installed parts oil holes marked connecting rod bearings and direction of "forward" should be shown in the illustration below position. The illustration shows the parts of the injection engine. On the carburettor engine on the contrary, that is. E. The number of the connecting rod and the lid is on the same side as the masloraspylitelnoe hole.
Properly assembled piston and connecting rod injection engine. In the carburettor engine label (4) and masloraspylitelnoe hole (2) shall lie on the same side
| || 1 - Before |
2 - hole masloraspylitelnoe
3 - the size of the piston
4 - the number of cylinders
- Mark the connecting rod bearing shells with respect and covers. Also mark the upper and lower liners color on the reverse side.
- Remove the cover and bearing shells.
- Push pistons and connecting rods by the hammer handle on the inner side of the cylinder upward. If you want to remove the oil carbon ring on the top side of the cylinder bores using a scraper.
- Remove the piston rings in order using forceps through the piston head, as shown below. If the ring will be used again, they should be marked. If no special forceps for piston rings, metal strips can be inserted under the ring on opposite sides of the piston. One strip is required to enclose a joint ring in order to avoid scratches.
| || Removal and installation of the piston rings using special forceps. |
- Press out the piston pin from the piston and connecting rod. For this purpose the piston heat to a temperature 60 - 70 ?° (hot). Remove the two locking lugs of the piston rings, put the piston appropriately and press out the pin from the piston and connecting rod eye. Gather together all related to one of pistons and rods details.
Check of pistons and rods
- Carefully check all the details. If the items show signs of rust scratches or wear, they must be replaced. Measure the vertical gap in the piston ring grooves of the piston rings alternately inserting into the corresponding slots, as shown below. Using feeler gauge define a gap between the surface and the inner surface of the ring groove. If the clearance rings is more than 0.20 mm, or worn piston rings or replace complete. The required clearance given in the Specifications.
Vertical dimension of the piston rings in the grooves of the piston. The probe must be inserted in accordance with the image on the lower left figure
| || 1 - flat probe |
2 - piston ring
- Alternately, insert all the piston rings with the top side of the crankcase into the cylinder. Insert using an inverted piston rings about the height of the piston. Because of this they will sit in the hole exactly. Insert a flat feeler gauge into the gap between the ends of the ring as shown at right in the illustration below, to measure the end gap. Mi one ring should not be a gap greater than 1.0 mm. The required values are listed in the Specifications.
Check gap piston ring. Push rings upside-down piston and then measure as shown in the right figure
| || 1 - the piston |
2 - piston ring
3 - Flat probe
- When the gap is too small (for example, new rings, which are also to be measured) can undermine the ends of the ring. To do this, hold down the file in a vice and undermine the ends of the ring. If the gap is too large ring must be replaced. If you only want to replace the piston rings, cylinders not rastachivaya end gap should be measured on the bottom side of the cylinder. Upper and middle piston ring of the upper side are labeled (not all engines). All rings should be set so that the item (if available) can be read from above. Check the piston pins and bushings rods for rust and wear. If in poor condition is only one connecting rod, replace the entire set.
- The landing place the piston pin in the piston must be such that the finger at room temperature, it was possible to push in the piston of the hand (see. Graphic below). The clearance in the piston pin is 0.004 - 0.00 mm, but it is difficult to measure. Therefore inspection should be carried out on the eye.
Check the installation of the piston pin
| || The piston pin at room temperature must be pressed with the thumb. |
- Check cranks using a special device on the twisting and bending. If you can use such a device, the limit values for rolling 0.15 to 100 mm, 0.30 to bend.
Measure backlash rod bearing
This work is described in Section crankshaft and crankshaft bearings are in connection with the crankshaft. It is made using polymer hairs "Plastigage" or you can measure the inner diameter of the connecting rod bearing and the outer diameter of the neck of the crankshaft.
The assembly of pistons and rods
Heat the eye of the connecting rod to a temperature of 60 - 70 ?° C (lower in hot water). Prepare a suitable rod, which is inserted into the interior of the piston pin.
Well lubricate the piston pin and connecting rod eyelet hole.
Insert circlip piston pin from one side to the piston. Make sure that it is well into the groove of the village.
Fitting the finger suitable mandrel in a hot rod.
When you build must meet the following guidelines:
- The arrow on the piston crown (or painted or embossed on the new piston - see. must point to the front of the engine.
- Designation of cylinders on the rod and the bearing caps should be the same Consider the difference between injected and carbureted engine.
The assembly of pistons and rods
- Well lubricate the cylinder bore.
- Insert the connecting rod bolts and connecting rods, insert bearing shells.
- Place the connecting rods according to the numbers of cylinders. Masloraspylitelnye holes should be on a given side of the cylinder. In the shows how should be placed pistons and rods in the fuel-injected engine. The illustration below shows the position of parts at the carburettor engine.
Correct assembly of the piston and connecting rod on the carburettor engine. The arrow is facing the front of the engine
| || 1 - the size of the piston |
2 - Mark "before"
3 - hole masloraspylitelnoe
4 - the number of cylinders
- The marks on the piston crown, t. E. On the edge of the label (injection engine) or the arrow (petrol engine) must point to the front of the engine.
- Place piston rings around the circumference by 120 ?° to each other. The illustration shows how to lock rings are offset from the piston pins. On engines of both versions are in the same ring.
Location piston rings. The large arrow indicates the front side of the engine
| || 1 - lock expansion element oil scraper ring |
2 - the lock top rings and oil scraper ring of the upper element
3 - lock the second ring
4 - Castle Lower oil ring element
- Apply the tape to shrink piston rings and ring grooves Squeeze. Check that they are properly falling into place. If the shrink tape is not possible to use a large hose clamp or put thin metal strips around the rings and squeeze the ends so that the rings into the slots. The piston insert after will be checked again that foreign objects on it do not. If you use a hose clamp, it can be installed around the ring until the ring will not enter into the cylinder. Then move the clamp ring to the next and enter it into the hole. Then do the same with the upper ring.
- Put on a short section of rubber or plastic hose to the connecting rod bolts to avoid scratching the hole.
- Rotate the crankshaft until the two crankshaft journals occupy the position of the BDC.
- Insert top connecting rod in the hole. To do this, put the engine side to the connecting rod can be mounted on the neck and will not scratch or crank pin hole. Inserts connecting rod bearing should already be in the rod, the projections in the recesses and two oil holes aligned.
- Push the plunger until the ring will go into the hole as shown in the illustration below, and the end of the connecting rod will be on the crankshaft journal.
| || Installation of the piston. Installed shrink tape (1) slides when retracted, the piston |
- Insert the second bearing, well lubricate the insert and push the cover to the connecting rod bolts and gently hammer. Sections of rubber hose must first be removed. Be sure to follow the numbers on the rod and bearing cap were on one side and matched since the last time you can make a mistake.
- Grease the contact surface on the nut connecting rod bearing caps.
- Tighten the new connecting rod nuts alternately with effort 14-16 N ??? m. To withstand the torque, the cylinder head must be installed on the sealing surface. Ask the assistant to hold the unit and tighten both located on top of the connecting rod bearing. In the same way, re-tighten the nut with a force rod bearing 40-45 N ??? m for injection engine or a 23 - 29 N ??? m for gasoline engines.
- After installing the connecting rod, crank a few times to immediately detect jamming.
- Recheck the designation of rods and pistons, check to have been turned in the right direction.
| || Measurement of an axial backlash set on the crankshaft connecting rods. The probe is inserted between the rod and the working surface of the crankshaft. |
- Use the stylus to measure the gap between the side surface of the connecting rod and crankshaft, as shown in the illustration. This axial play of the connecting rod bearing, which should be no more than 0.50 mm. Exceeding replace the appropriate rod or crankshaft.