BMW 3 Series E30

since 1983-1994 release

Repair and operation of the car

+ 1. Maintenance instruction
+ 2. Maintenance
- 3. Engine
   + 3.1.2. Specifications
   - 3.2. Dismantle and capital repairs of the engine
      3.2.2. Specifications
      3.2.3. Capital repairs – the general instructions
      3.2.4. Check of a compression in engine cylinders
      3.2.5. Capital repairs – general comments
      3.2.6. Diagnostics of the engine by means of the vacuum gage
      3.2.7. Capital repairs – alternatives
      3.2.8. Dismantle of the power unit
      3.2.9. Removal and installation of the engine
      3.2.10. Order of dismantling of the engine
      3.2.11. Dismantling of a head of the block of cylinders
      3.2.12. Cleaning and check of a head of cylinders and details of the valvate mechanism
      3.2.13. Repair of valves
      3.2.14. Assembly of a head of the block of cylinders
      3.2.15. Removal of pistons and rods
      3.2.16. Dismantle of the crankshaft
      3.2.17. Intermediate shaft (only M20 engine)
      3.2.18. Cleaning of the block of cylinders
      3.2.19. Check of a condition of the block of cylinders
      3.2.20. Honningovaniye of cylinders
      3.2.21. Check of a condition of pistons and rods
      3.2.22. Check of a condition of the crankshaft
      3.2.23. Check of radical and conrod bearings
      3.2.24. Engine assembly order
      3.2.25. Installation of piston rings
      3.2.26. Installation of an intermediate shaft
      3.2.27. Installation of the crankshaft and check of gaps in radical bearings
      3.2.28. Installation of a back epiploon
      3.2.29. Installation of rods and pistons, check of gaps in conrod bearings
      3.2.30. Launch of the engine after repair and a running in
   + 3.3. Engine electric equipment
+ 4. Cooling system
+ 5. Heating and ventilation
+ 6. Fuel system
+ 7. Exhaust system
+ 8. Transmissions
+ 9. Coupling
+ 10. Brake system
+ 11. Running gear
+ 12. Body
+ 13. Electric equipment
+ 14. Useful tips


3.2.12. Cleaning and check of a head of cylinders and details of the valvate mechanism


Careful cleaning of a head of the block of cylinders and its details with the subsequent check will allow to estimate amount of works on repair of the valvate mechanism.


If the engine often overheated, then most likely the head of cylinders could warp, carefully check existence of signs of deformation of a head.


1. Clear the demountable planes of a head of cylinders of the consolidation remains.
2. Remove a scum from channels of cooling liquid.
3. Clean all openings.
4. Banish all carving openings.
5. Wash out a head of cylinders solvent and blow compressed air.
6. Remove massive deposits of a deposit from valves. When cleaning do not mix valves from different sets of the removed details.


Before drawing a conclusion on need of regrinding of details, surely perform all checks described below than the procedure.

Wear of the valve

1. End face

2. A pro-point under crackers

3. A core (part with the smallest wear)

4. A core (part with the greatest wear)

5. Facet

6. Corbel

Head of cylinders
1. Attentively examine a head, check existence of cracks, traces of penetration of cooling liquid and other damages. At detection of cracks replace a head of cylinders (previously consult in car service).
2. Check deformation of the demountable plane of a head of cylinders. If it is revealed that the curvature of the demountable plane is more than norm, then the head should be proshlifovat. If deformation of the demountable plane such is that head height after grinding will become less standard, then replace a head.
3. Check a condition of saddles of valves. In the presence of pitting (poles), cracks, traces of a progar repair of a head in a workshop of car service will be required.
4. The indicator check a gap of valves in the directing plugs. For this purpose insert the valve into the corresponding directing plug so that he acted on 2,0 mm from a saddle, and shake here and there. Divide the size of a total side play in half. If there are doubts concerning a condition of plugs, then the head should be handed over in car service for more detailed check.
5. Check existence on valves of cracks, traces of a burn-out, zadir and the fillet formed owing to wear on cores. Turn of the valve check its bend. Check development of end faces. At detection of any signs of wear the valve should be repaired or replaced.

6. Measure width (1) of a corbel of the valve. If width is less limit, then replace the valve (2).
7. Check existence of wear at spring end faces. A rough inspection of a condition of a spring can be carried out by comparison of length of a spring in a free state from standard.

8. Check a spring deviation from a vertical by means of a square.
9. If at least one of springs is damaged, has the raised deviation from a vertical, or lost elasticity, then replace all springs in a set. Check existence of cracks on crackers of valves and plates of springs. Replace a detail at detection of the slightest damages.
Yokes (M10 and M20)
10. Yokes of final valves are exposed to the greatest wear, they should be checked especially carefully.
Check those places which adjoin to cams of a cam-shaft and an end face of the valve on yokes.
11. Check a side play of yokes on rollers. If the indication of the indicator when rocking a yoke exceeds norm, then replace the plug of a yoke or the roller (or details both these, – it is possible to check it, having placed a yoke on obviously not worn-out part of the roller).
Rollers of yokes (M10 and M20)
12. Check existence on the roller of wear tracks, zadir and other damages. At detection of a fillet in the places corresponding to edges of yokes, replace the roller.
Hydropushers and levers (M40)
13. Check a condition of working surfaces of levers, existence of traces of deep development for them. At detection of signs of wear on pushers and a cam-shaft, replace pushers and a cam-shaft.
14. Check a condition of the rubbing surfaces of hydropushers. If the increased noise from at least one pusher during the operation of the engine was noted, then replace all pushers in a set. Pushers change also at any signs of a doubtful state.
15. Check existence on cams of a cam-shaft of traces of deep development, zadir and poles. Check height of each cam. If the sizes of cams of inlet or final valves differ more than on 0,08 mm, or at detection of any signs of wear, replace a cam-shaft.
16. Check a condition of basic necks, existence for them deep development, zadir and poles. At detection of wear of necks replace a head of cylinders as beds under necks will be obviously worn-out.


If the only reason for which the head of cylinders is subject to replacement is insignificant wear of necks of a cam-shaft, then address to BMW car service behind consultation concerning a possibility of repair.

17. Define gaps in basic necks of a cam-shaft, having measured diameters of basic necks and diameters of beds under necks in a head of cylinders (on the M40 engine for this purpose establish covers of basic necks). If the gap differs from norm, then replace a cam-shaft or a head of cylinders (previously address to BMW car service behind consultation).