This is a good example of why it is pretty hard to reply to your
rantings, err I mean insightful inputs, you often change the original
thread title and never quote who you are answering, below are three
different bits, or parts thereof, who wrote what?
Hendrik
who thought he had it there for a while
On 16/06/12 13:49, relng...@aol.com wrote parts of this, I think:
.... M104 has three coil packs, each firing two plugs
simultaneously.
A common arrangement on sixes--the V-6 in my '93 Isuzu Trooper is the same
way. During any given crankshaft revolution one plug is firing at the
start of the power stroke and one at the start of the exhaust stroke. I
don't really understand the point of the latter unless it helps emissions
by igniting some leftover hydrocarbons that would otherwise hit the cat
unburnt.
In the M104, I think it's just cheaper since no harm is done by firing the
other plug. The M112 twin plug 3-valve V-6 (early W203) does not have
variable valve timing (not with one camshaft per bank) so the lower plug must
have
some emission role.
The M272 4-cam V-6 in my C300 with variable intake and exhaust timing has
six coil packs for the six plugs.
RLE
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