Volvo Penta MD7A User Manual

39
Technical Data MD7A
General
Type designation
Output at flywheel (DIN) at 43 rev/sec. (2600 rev/mm.)
Number of cylinders
Bore
Stroke
Capacity
Compression ratio
Compression pressure at starter motor speed
Direction of rotation, viewed towards flywheel
Idling speed
Oil pressure, full speed, hot engine
Oil pressure, idling, hot engine
Cylinders
Material
Bore, standard
0.25 mm (0.010”) oversize
0.50 mm (0.020”) oversize
Pistons
Material
Height, total
Height from gudgeon pin centre to piston crown
Piston clearance in cylinder
Pistons, standard diameter
0.25 mm (0.010”) oversize
0.50 mm (0.020”) oversize
Gudgeon pins
Diameter
Gudgeon pin bushing, diameter
Clearance, gudgeon pin - bushing
Piston rings
Compression rings, number
Oil scraper ring, number
The upper compression ring is chromium lined
Piston rings are available for standard size, 0.250 mm
(0.010’) and 0.500 mm (0.020”) oversize
Piston ring clearance in groove, axially:
Upper compression ring
Lower compression ring
Oil scraper ring
Piston ring gap in cylinder
Upper compression ring
Lower compression ring
Oil scraper ring
Crankshaft
Material
Crankshaft axial clearance
Main bearing radial clearance
Big-end bearings, radial clearance
MD7A
10 kW (13.4 h.p.)
2
76 mm (2.9921”)
82 mm (3.2283”)
0.744 dm
3
17:1
2-2.5 MPa (20—25 kp/cm
2
) (284—355 lbf/in
2
)
Clockwise
11—13 rev/sec (650—780 rev/min)
0.35-0.40 MPa (3.5-4.0 kp/cm
2
) (50-57 lbf/in
2
)
0.08-0.15 MPa (0.8-1.5 kp/cm
2
) (11-21 lbf/in
2
)
Cast iron
76.00—76.03 mm (2.9921—2.9933”)
76.25—76.28 mm (3.0020—3.0032”)
76.50—76.53 mm (3.0118—3.0130”)
Light-alloy
76.4 mm (3.0079”)
51.4 mm (2.0236”)
0.073—0.118 mm (0.0029—0.0046”)
75.912—75.927 mm (2.9883—2.9893”)
76.162—76.177 mm (2.9985—2.9991”)
76.412—76.427 mm (3.0084—3.0090”)
28.000—28.004 mm (1.1024—1.1025”)
28.0125—28.0225 mm (1.1029—1.1032”)
0.0085—0.0230 mm (0.0003—0.0009”)
2
1
0.070—0.102 mm (0.0028—0.0040”)
0.050—0.082 mm (0.0020—0.0030”)
0.030—0.062 mm (0.0012—0.0024”)
0.30—0.50 mm (0.0120-0.020”)
0.30—0.50 mm (0.0120-0.020”)
0.25—0.50 mm (0.010-0.020”)
Nodular iron
0.080—0.313 mm (0.0032—0.0123”)
0.026—0.075 mm (0.0010—0.0030”)
0.026—0.075 mm (0.0010—0.0030”)

Volvo Penta MD7A Specifications

General

Engine Type	Diesel
Number of Cylinders	2
Cooling System	Raw water cooled
Type	Marine diesel engine
Rated RPM	3000 rpm
Compression Ratio	22:1
Fuel System	Indirect injection
Displacement	0.8 liters
Weight	150 kg
Max Power Output	13 hp