E-Class (W124) 1984-1995: E 260, E 300, E 320, E 420, E 500 (Includes CE, T, TD models)

m103 head mods

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Old Jan 17, 2008 | 12:46 AM
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1989 190E 3.0L 5speed
m103 head mods

Has anyone heard of (or better yet tried) shaving the cylinder head down slightly to increase the compression in the engine? I am in a machining class so since tools needed are available I wanted to try it out. Also if anyone knows the stock compression for a 1990 m103 I would really appreciate it.
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Old Jan 17, 2008 | 02:32 AM
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Old Jan 17, 2008 | 08:34 AM
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From: REHOBOTH BEACH DE
88-300CE TWIN TURBO, 99-C43, 05-G55K, 71-280SL, 94-E320 CAB, 08 CLK63 BLACK SERIES
Originally Posted by Wolf190
Has anyone heard of (or better yet tried) shaving the cylinder head down slightly to increase the compression in the engine? I am in a machining class so since tools needed are available I wanted to try it out. Also if anyone knows the stock compression for a 1990 m103 I would really appreciate it.
Compression for a stock M103-12V is 9.2:1.

Milling the head will increase compression, take too much off and you may have pistons hitting valves.

Best to CC each combustion chamber in the head to make them equal with machining.
Porting and polishing the intake runners along with a competition valve job will also be beneficial
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Old Jan 17, 2008 | 09:56 PM
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1989 190E 3.0L 5speed
So any idea on what would be too much to shave? and what do you mean by "competition valve job"? high performance springs or what?
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Old Jan 18, 2008 | 09:41 AM
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From: REHOBOTH BEACH DE
88-300CE TWIN TURBO, 99-C43, 05-G55K, 71-280SL, 94-E320 CAB, 08 CLK63 BLACK SERIES
Originally Posted by Wolf190
So any idea on what would be too much to shave? and what do you mean by "competition valve job"? high performance springs or what?
Competition valve job means how the seats angle and valve angle are cut.

"Too much to shave"....varies from head to head as there is a manufacturing tolerance, so all heads not equal.
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