Once I heard a story that an engineer told someone it was because the combustion pressure in the cylinder was causing the head bolts to stretch and then after the pressure went down the head slammed back on to the block and thus you got the pinging.
Of course this is not true but funny to think about. Trampas -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Marshall Booth Sent: Friday, February 03, 2006 3:59 PM To: Mercedes Discussion List Subject: Re: [MBZ] what IS the "diesel noise"? Christopher McCann wrote: > I'm talking about a perfectly healthy purring engine. I'm thinking: > > 1. Injection pump getting fuel up to pressure (BTW, what pressure does the fuel inject at on an OM617? OM603?) > 2. The detonation under higher compression New injector injection pressure for a non-turbo OM61x/60x Mercedes diesels is 115-125 bar (1667-1812 psi) and 135-145 bar (1957-2102 psi) for turbos. The noise you hear from a diesel engine is the sound of combustion. It can be made VERY quiet if the interior of the prechamber is very very precise. As it accumulates residue or if the injection spray pattern and pressure isn't precise, the noise increases. The properties of the fuel also contribute to noise. Using noise as a tool to measure the condition of a diesel is foolish. A perfect Cummins or Ford diesel makes one heck of a lot of racket at idle while a Mercedes diesel shouldn't, but it takes only a tiny flaw (a little soot in the prechamber, a little nozzle coking or some air or water in the fuel) to make the Mercedes sound as bad as the Cummins or Ford. Marshall -- Marshall Booth (who doesn't respond to unsigned questions) "der Dieseling Doktor" [EMAIL PROTECTED] '87 300TD 182Kmi, '84 190D 2.2 229Kmi, '85 190D 2.0 161Kmi, '87 190D 2.5 turbo 237kmi _______________________________________ http://www.striplin.net For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net
