M40 - Revision history

Grrrmachine at 10:15, 16 February 2013

2013-02-16T10:15:18Z

2012-09-12T05:39:03Z

2012-09-10T21:35:03Z

2012-09-10T16:58:41Z

2012-09-10T16:34:38Z

2012-09-10T16:31:56Z

2012-09-10T16:16:02Z

2012-09-10T06:02:08Z

2012-09-09T20:25:24Z

2012-09-09T15:33:14Z

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 The E30 was equipped with both versions, powering the [[316i]] and [[318i]] respectively, and continued to use those engines until the end of production in 1994. Both were available with or without a [[Exhaust#Catalyzer|catalyzer]].
-The M40B16 was also fitted to the [[E36]]. The M40B18 was also fitted to the [[E34]] from 1988 to 1994, and briefly the [[E32]] in 1992-1993.
+The M40B16 was also fitted to the [[E36]]. The M40B18 was also fitted to the [[E34]] from 1988 to 1994.
 The M40 formed the basis of all BMW's four-cylinder engines over the next decade. While its direct successor was the M43, it also spawned the 16-valve [[M42]] used in the [[318iS]], which shares many compatible components. Considering the success of these subsequent engines, it is unfortunate that the M40 itself has proved to be the worst of the E30 engines, with many documented [[M40#Common_Problems|problems]] and little scope for improvement.

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 ==Noisy Tappets==
-The [[M40#Tappets|tappets]] in an M40 are known for ticking over time. This is usually due to wear from oil starvation. The first thing to do is remove the [[M40#Rocker_Cover|rocker cover]] and inspect the [[M40#Cam|camshaft]] for signs of wear. Each love should be smooth; any scratches or ridges indicate a worn cam which makes it uneconomically viable to replace the tappets; you will have to refresh every part of the valvetrain.
+The [[M40#Tappets|tappets]] in an M40 are known for ticking over time. This is usually due to wear from oil starvation. The first thing to do is remove the [[M40#Rocker_Cover|rocker cover]] and inspect the [[M40#Cam|camshaft]] for signs of wear. Each lobe should be smooth; any scratches or ridges indicate a worn cam which makes it uneconomically viable to replace the tappets; you will have to refresh every part of the valvetrain.
 If your cam is in good condition, first try an oil change and a new oil spray bar. This will help keep the tappets lubricated. They will continue to tick on cold start but will hopefully quieten down as the engine warms up. If that doesn't solve the issue, consider replacing the tappets, followers and thrust pads with new items; DO NOT use second-hand parts, considering how common this problem is with M40 engines.

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 The [[BMW]] '''M40''' is a 4-cylinder engine, fitted to the [[316i]] and [[318i]] after 1987. It replaced the [[M10]] as the standard 4-cylinder engine in 1987.
-[[Image:M40Engine.jpg|thumb|600px|right|M40B18 engine]]
+[[Image:M40Engine.jpg|thumb|600px|right|M40B18 engine with [[M42]] radiator]]
 __TOC__
 =History=

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 The [[BMW]] '''M40''' is a 4-cylinder engine, fitted to the [[316i]] and [[318i]] after 1987. It replaced the [[M10]] as the standard 4-cylinder engine in 1987.
 __TOC__
 =History=

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 The M40 flywheel is a single mass wheel which keeps the engine spinning long after you take your foot off the throttle. It is also the flat surface to which the [[Drivetrain#Clutch|clutch]] mates, ultimately transferring power from the engine to the [[Drivetrain]]. The edge of the flywheel is toothed. Known as the ring gear, it is what allows the [[M40#Starter_Motor|starter motor]] to bite onto the engine to start it. The flywheel bolts to a pulley at the end of the [[M40#Crank|crank]].
-Two types of flywheel were fitted to M40 engines, depending on whether the car had a manual or automatic [[Drivetrain#Gearbox|gearbox]]. For manual engines, the flywheel contains a spigot bearing to centre the input shaft of the gearbox to the tail of the [[M40#Crankshaft|crankshaft]]. These parts are essential when [[Auto_To_Manual|converting from auto to manual]].
+For manual engines, the flywheel contains a spigot bearing to centre the input shaft of the gearbox to the tail of the [[M40#Crankshaft|crankshaft]]. These parts are essential when [[Auto_To_Manual|converting from auto to manual]]. For automatic cars, the flywheel is little more than a ring gear with a plate to which the torque converter is bolted.
 ===Starter Motor===

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 ===Flywheel===
 ===Starter Motor===
 ===Engine Mounts===
 =Servicing=
 ''Main article: [[Basic_M40_Servicing|Basic M40 Servicing]]

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 __TOC__
 =History=
 The M40B16 was also fitted to the [[E36]]. The M40B18 was also fitted to the [[E34]] from 1988 to 1994, and briefly the [[E32]] in 1992-1993.
 =Versions=
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 ==Block==
 ===Crankshaft===
 ===Piston Rods===

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 ===Piston Rods===
-===Piston Head===
+===Pistons===
-===Piston Rings===
+The two M40 engines share the same piston design. They differ in their stroke due to their different [[M40#Crankshaft|crankshafts]].
 ===Crank Pulley===