Removing and Installing Pistons
Removing and installing pistonsTools
Preliminary work
1. Remove engine.
2. Support engine on engine carrier.
3. Remove cylinder head and take off cylinder head gasket.
4. Remove oil pan.
5. Remove oil pump.
Component information
Component Overview For Piston:
Tools and materials
Special Tools For Installing Pistons:
Removing pistons
Note:
^ The pistons are removed in turn.
^ The pistons, connecting rods and connecting rod caps are marked with a felt-tip pen so that they do not get mixed up.
^ Pistons and connecting rods are laid on a clean surface in cylinder order.
^ Con-rod bolts must always be replaced.
^ If being reinstalled, used bearing shells must not be mixed up.
^ Connecting rod bearing shells should always be replaced.
Note:
^ Note the association between the connecting-rod big end and the connecting-rod bearing cap.
^ The retaining lugs of the connecting-rod bearing shells are always located on the same side in order to prevent the bearing shells from turning.
^ The connecting-rod bearing cap and the connecting-rod big end have cast lugs which must lie above one another. These cast lugs lie on the same side as the twist lock (retaining lugs) of the bearing shells. --> Component arrangement
Component Arrangement:
^ The cast lugs, twist locks (retaining lugs) and the flat side of the piston crown are on the same side. --> Component arrangement
^ The flat side of the piston crown always points to the centre of the cylinder block. --> Component arrangement
1. Turn the crankshaft so that the crankshaft journal of the piston to be removed stands vertically upwards.
2. Remove one piston after another, mark them and place them on a clean tray. The flat side of the piston crown always points to the centre of the cylinder block. --> Component arrangement Remove the piston of cylinder 1 by unscrewing the connecting-rod bolts. Remove the connecting-rod bearing cover and place it on a clean surface. Press the piston downwards out of the cylinder, using the handle of a hammer for example, and receive with the other hand. Refit connecting-rod bearing cap immediately on the connecting-rod big end together with the bearing shells (Caution: retaining lugs point to each other) --> Retaining lugs of connecting-rod bearings and place the entire piston on a clean surface. Mark piston with No. 1 (with a felt-tip, not with a prick punch or other sharp-edged tool).
Retaining Lugs Of Connecting-Rod Bearings:
Component Arrangement:
3. Remove all remaining pistons in the same way.
Installing pistons
WARNING: Danger of cutting oneself on sharp metal edges!
--> Wear suitable protective clothing (e.g. gloves).
ATTENTION: Damage to sensitive engine components!
--> Conscientious and precise work
Note:
^ The pistons must already be pre-fitted (pistons, piston rings, connecting rods and fastening material) before performing the next step.
^ Note the association between the connecting-rod big end and the connecting-rod bearing cap.
Retaining Lugs:
^ The retaining lugs of the connecting-rod bearing shells are always located on the same side in order to prevent the bearing shells from turning.
^ The connecting-rod bearing cap and the connecting-rod big end have cast lugs which must lie above one another. These cast lugs lie on the same side as the twist lock (retaining lugs) of the connecting-rod bearing shells.
Component Overview And Allocation:
^ The cast lugs, twist lock (retaining lugs) and the flat side of the piston crown are on the same side.
^ The flat side of the piston crown always points to the centre of the cylinder block.
^ Refit pistons according to removal markings (if being reused).
^ If new connecting-rod bearing shells are used, there will be a red marking on the upper shell and a yellow marking on the lower shell.
1. Note that the piston-ring gaps are offset by 120° with respect to each other.
2. Cylinder barrels, piston bearing surfaces, bearings and the tool funnel T10147 must be oiled with engine oil. Pre-fit the upper bearing shell in the connecting-rod big end. Ensure that the retaining lug fits into the appropriate recess of the connecting-rod big end.
Note: A new funnel T10147 must be deburred with an old piston: i.e. draw the old piston with fitted piston rings a couple of times through the funnel to remove all plastic burrs and residues. If the piston used is to be reinstalled then the plastic shavings will have to be carefully removed.
Funnel:
3. Place special tool funnel T10147 on the appropriate cylinder so that the stud -arrow- always points to the centre of the cylinder block. A new funnel must be deburred with an old piston: i.e. first draw the old piston with fitted piston rings a couple of times through the funnel to remove all plastic burrs and residues. If the piston used is to be reinstalled then the plastic shavings will have to be carefully removed.
ATTENTION: Damage - danger of piston ring fracture!
--> Do not install pistons against resistance and do not use force! Break off the installation attempt, examine the components and try again!
Note: If the piston rings get caught or jammed in the funnel T10147 during insertion into the cylinder, it may be necessary to press the piston rings back into the ring grooves with a soft tool through the slits in the funnel or break off the installation attempt, free the piston and try again.
4. Press the piston very carefully with both thumbs through the funnel into the cylinder. Always keep a close watch on the pistons rings. If necessary, press the piston rings back into the ring grooves with a soft tool through the slits in the funnel or break off the installation attempt, free the piston and try again.
5. Push piston into the cylinder until the connecting-rod big end is positioned just in front of the corresponding connecting-rod bearing of the crankshaft. Push the piston with one hand further into the cylinder and with the other hand push the connecting-rod big end onto the connecting-rod bearing of the crankshaft.
Note: Oil the bearing shells and bearing with engine oil.
6. Place connecting-rod bearing cap fitted with the correct bearing shell on the connecting-rod big end so that the retaining lugs of the bearing shells are on the same side.
7. Insert connecting-rod bolts. Then tighten to the specified tightening torque. Tightening torque 22 ft. lbs.. Torque angle 90°
8. Turn the crankshaft further so that the crank pin of the next piston to be removed stands vertically upwards. Install other pistons in the same way.
Subsequent work
1. Install oil pump.
2. Install oil pan.
3. Install cylinder head.
4. Install engine.