E30 series BMW 3

since 1983-1994 of release

Repair and car operation

+ 1. Maintenance instruction
+ 2. Maintenance
- 3. Engine
   + 3.1.2. Specifications
   - 3.2. Dismantle and major maintenance of the engine
      3.2.2. Specifications
      3.2.3. Major maintenance – the general instructions
      3.2.4. Compression check in engine cylinders
      3.2.5. Major maintenance – general comments
      3.2.6. Engine diagnostics by means of the vacuum gage
      3.2.7. Major maintenance – alternatives
      3.2.8. Dismantle of the power unit
      3.2.9. Removal and engine installation
      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 klapanny 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. Crankshaft dismantle
      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 shatunny 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 shatunny bearings
      3.2.30. Engine start-up 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. Good advice


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


If the engine often overheated, 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 the 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 repolishing of details, surely execute all checks described below procedure.

Wear of the valve

1. End face

2. A pro-point under crackers

3. A core (a part with the smallest wear)

4. A core (a 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 a head of cylinders replace (previously consult in car-care center).
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, a head it is necessary прошлифовать. If deformation of the demountable plane such is that head height after polishing becomes less standard, a head replace.
3. Check a condition of saddles of valves. In the presence of a petting (poles), cracks, traces прогара head repair in a car-care center workshop is required.
4. The indicator check a gap of valves in directing plugs. For this purpose the valve insert into the corresponding directing plug so that he acted on 2,0 mm from a saddle, and shake here and there. Size total люфта divide half-and-half. If there are doubts concerning a condition of plugs, it is necessary to hand over a head in car-care center for more detailed check.
5. Check existence on valves of cracks, burn-out traces, задиров and a 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 it is necessary to repair or replace the valve.

6. Measure width (1) corbel of the valve. If width less limiting, the valve (2) replace.
7. Check wear existence at spring end faces. Rough check of a condition of a spring can be carried out by a way of comparison of length of a spring in a free condition with 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, 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 (М10 and М20)
10. Yokes of final valves are exposed to the greatest wear, they should be checked especially carefully.
Check on yokes those places which adjoin to cams of a cam-shaft and a valve end face.
11. Check люфт yokes on rollers. If the indicator indication when rocking a yoke exceeds norm, replace the plug of a yoke or the roller (or both these details, are it is possible to check, having placed a yoke on obviously not worn-out part of the roller).
Rollers of yokes (М10 and М20)
12. Check existence on the roller of wear tracks, задиров and other damages. At fillet detection in the places corresponding to edges of yokes, the roller replace.
Hydropushers and levers (М40)
13. Check a condition of working surfaces of levers, existence of traces of deep development on them. At detection of signs of wear on pushers and a cam-shaft, replace pushers and a cam-shaft.
14. Check a condition of rubbing surfaces of hydropushers. If the increased noise was noted from at least one pusher at operation of the engine, replace all pushers in a set. Pushers change also at any signs of a doubtful condition.
15. Check existence on cams of a cam-shaft of traces of deep development, задиров 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, a cam-shaft replace.
16. Check a condition of basic necks, existence on them deep development, задиров and poles. At detection of wear of necks replace a head of cylinders as beds under necks will be obviously worn-out.


If the unique reason on which the head of cylinders is subject to replacement, insignificant wear of necks of a cam-shaft is, address in BMW car-care center for consultation concerning repair possibility.

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, a cam-shaft or a head of cylinders replace (previously address in BMW car-care center for consultation).