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Cylinder head

The cylinder head is made of aluminum alloy, and the saddle valve guides false.

Characteristic	Value
The height of the cylinder head, mm
M 115
Rated	84,8-85,0
minimal	83.8
M 102
Rated	98,5-98,4
minimal	97.8
M 123
Rated	84,8-85,0
minimal	84.0
M 110
Rated	93,9-94,0
minimal	93.1
Warping plane coupling head to the cylinder block in a longitudinal / transverse directions, no more, mm
M 102	0.10
M 115	0.08
M 110	0.08
M 123	0.08

Basic specifications

Model	Bore x stroke mm	Displacement, cm3	Rated power "net", kW (hp) / at crankshaft rotation, rev / min	Maximum torque, Nm (kgs.m) / at crankshaft rotation, rev / min	Compression ratio
M 115,938	87x83,6	1997	70 (94) / 4800	158 (16.1) / 3000	9
M 102,920	89x80,25	1997	74 (100) / 5500	160 (16.3) / 3000	8
M 102,939	89x80,25	1997	80 (109) / 5100	172 (17.5) / 3500	9
M 102,980 *	95,5x80,25	2299	100 (136) / 5100	205 (20.9) / 3500	9
102.982 M *	95,5x80,25	2299	92 (125) / 5000	194 (19.8) / 3500	8
M 115.954	93,75x83,6	2307	80 (109) / 4800	185 (18.9) / 3000	8
M 123,920	86x72,45	2525	74 (100) / 5200	183 (18.7) / 3000	8.4
M 123,921	86x72,45	2525	103 (140) / 5500	196 (20.0) / 3500	9.4
M 110,923	86x78,8	2746	115 (156) / 5500	226 (23.0) / 4000	9
M 110,984	86x78,8	2746	125 (170) / 5500	224 (22.8) / 4500	8
M 110,988	86x78,8	2746	136 (185) / 6000	240 (24.5) / 4500	9

* Engine model M 102.980 and 102.982 M have the same factory index (M 102.E23) and different compression ratio and grade of fuel used.

Longitudinal section of the engine M 102

The cross section of the engine M 102

Valves

Characteristic	Value
The diameter of the engine valves, mm
M 102,985
inlet	41.0
graduation	37.0
The roughness of the plane coupling head to the cylinder block, m
M 102	0,005-0,020
M 115	0,012-0,020
M 110	0,012-0,020
M 123	0,012-0,020
The length of the cylinder head bolts, mm
M 102
Rated	119.0
maximum	122.0
M 115
Rated	119.0
maximum	122.0
M 110
Rated	160.0
maximum	162.7
M 123
Rated	160.0
maximum	162.7

Valve seats

Saddle valve plug.

Characteristic	Value
The angle of the bevel, hail.	45 0 -15 0
The angle of the upper cone, hail.	thirty
Lower cone angle, deg.	60
Width of a working facet, mm
M 102
intake valves	1.8-2.5
exhaust valves	1.5-2.5
M 115
intake valves	2.0-2.1
exhaust valves	1.5-2.5
M 110
intake valves	2.3-2.5
exhaust valves	1.5-2.5
M 123
intake valves	2.3-2.5
exhaust valves	1.5-2.5

If you use unleaded petrol must be installed stronger valve seats.

Characteristics of the valve seats

Saddles intake valves

Size, mm	Engine model
	M 115,938	M 102,920, 102,939 M	M 102,980, M 102.982	M 115,954
Hole diameter valve seat
nominal	48,500-48,516	46,000-46,016	46,000-46,016	48,500-48,516
oversize (max)	49,000	47,000		49,000
The outer diameter of the seats
nominal	48,590-48,600	46,090-46,100		48,590-48,600
oversize (max)	49,80	47,30		49.0800
The inner diameter of the seats
	-	37.0		-
Seat height
	10,29-10,40	7,980-8,000		10,89-11,00
Preload for pressing saddles intake and exhaust valves
	0.08-0.10	0,074-0,10		0.08-0.10
Size, mm	M 123,920, 123,921 M	M 110,923	M 110,984, 110,988 M
Hole diameter valve seat
nominal	42,700-42,716	47,000-47,016	47,000-47,016
oversize (max)	43,700	48.018
The outer diameter of the seats
nominal	42,790-42,800	47,090-47,100
oversize (max)	44.0	48.30
The inner diameter of the seats
	-	-	-
Seat height
	10,89-11,00	8,51-8,6
Preload for pressing saddles intake and exhaust valves
	0.08-0.10

Valve guides

Plug valve guides pressed into the cylinder head.

Characteristic	Value
Interference mm	0,012-0,013
Pressing force, kgs.m	300,0-350,0

Features valve guides

Option mm	The guide sleeve of the intake valves
	nominal size	1st oversize	2nd oversize
Color label	Gray-green	Red	White
	Gray
	Taupe
Outside diameter	14,03-14,05	14,21-14,23	14,41-14,43
Inner diameter	9,00-9,015
The diameter of the holes in the guide sleeve	14.02	14,20-14,22	14,40-14,42
Length	55.0
Wear limit	9.025
Option mm	Guide bushings exhaust valves
	nominal size	1st oversize	2nd oversize
Color label	Gray-green	Red	White
	Gray
	Taupe
Outside diameter	15,03-15,05	15,21-15,23	15,41-15,43
Inner diameter	11,000-11,018
The diameter of the holes in the guide sleeve	15.02	15,20-15,22	15,40-15,42
Length	45.0
Wear limit	11,030