Engines B3, B5, B6
The engine uses a valve timing mechanism with an overhead camshaft, which is driven by a toothed belt from a toothed pulley mounted on the crankshaft. Belt tension is provided by a mechanical tensioner.
Camshaft
The camshaft is tricycle. The shaft is fixed against axial movement by a thrust shoulder made on the front neck of the shaft.
Valve timing
Camshaft characteristics
Neck diameter, mm:
- front: 43.44-43.465;
- medium: 43.41-43.435;
- rear: 43.44-43.465.
Neck ovality, no more than, mm: 0.05.
Non-straightness of the necks, no more than, mm: 0.03.
Camshaft axial clearance, mm:
- nominal: 0.05-0.18;
- maximum allowable: 0.20.
Gap between camshaft journals and bearing holes, mm:
- front bearing: 0.035-0.085;
- middle bearing: 0.065-0.115;
- rear bearing: 0.035-0.085.
Height of camshaft cams, mm:
engines B3 and B5:
- intake: 36.378-36.528 (36,23) *;
- graduation: 36.378-36.528 (36,23);
B6 engine:
- intake: 36.811-36.911 (36,66);
- graduation: 36,811-36,911 (36,66).
* The minimum allowable height is indicated in brackets (when worn).
B6 EGI engine
The engine uses a valve timing mechanism with an overhead intake and exhaust camshafts, which are driven by a toothed belt from a toothed pulley mounted on the crankshaft. Belt tension is provided by a mechanical tensioner.
Camshafts
Camshafts - five-bearing. Shafts from axial movement are fixed by thrust collars made on the front necks of the shafts.
Valve timing
The beginning of the opening of the intake valve to the TDC of the exhaust stroke with the lead: 5°.
Closing of the inlet valve after the BDC of the compression stroke with a delay: 51°.
The beginning of the opening of the exhaust valve to the BDC of the working stroke ahead of: 69°.
Closing of the final valve after TDC of a step of release with delay: 1°.
Characteristics of camshafts
Neck diameter, mm: 25.940-25.965.
Neck ovality, no more than, mm: 0.05.
Non-straightness of the necks, no more than, mm: 0.03.
Gap between camshaft journals and bearing holes, mm:
- nominal: 0.035-0.081;
- maximum allowable: 0.15.
Axial clearance of camshafts, mm:
- nominal: 0.07-0.19;
- maximum allowable: 0.2.
Jaw height, mm:
- intake: 40.888 (40,688) *;
- graduation:40,889 (40,689).
* In parentheses are the minimum allowable wear height.
Camshaft drive belt
Belt brand: Unitta.