In my line of work (valet driving) I've noticed something unique to V12 engines (4 stroke, 60 deg. between banks);

unlike straight fours and sixes, v6s,v8s even horizontally opposed mills in subarus, the engine starts like:

rR-rR-rR-rR
or
chu-chu-chu
or some other familiar grinding noise.

However, the V12s from Jaguar, BMW, and Mercedes Benz all sound like;

zzzZZZIP!!!

Smooth, seamless starts.

What is it about V12 that starter motors like?

Don't use dead dinos for fuel:
let 'em rest in peace!

Let's start with a worst-case - the single cylinder engine. The starter motor simply spins it through about a turn and a half, with no real resistance, before it has to push the piston against compression. Coming up on compression slows it down (1/4 turn), then it speeds up as the piston goes over the top and starts back down. Speed up for a turn and a half, slow down for a quarter turn, pick up for a quarter turn, zip along for a turn and a half, repeat...: rrrrrrrrRRRrrrrrrrrrrrrRRRrrrrrrrrrRRChugChugChug....
A 4 cylinder has compression resistance every rotation, but again only for about half of that turn. The starter speeds up a little during half a turn, then slows during the compression stroke. Sound is:
rrrRRrrrRRrrrRRrrrRRPutPutPtPtvroom.....
The V-8 has even less gap between compression peaks, so it sort of sings with a vibrato:
rrRRrrRRrrRRrrRRrrRRrrRrrRRrRrrRrRVroooooom....
A V-12 has almost no gap between compression peaks - one cylinder is coming up on peak compression just as another is coming off compression, so the starter motor just sees a steady load.
A rope starter on a v-12 would feel like no compression, just a steady load.
Does that make sense?
Cheers
JohnO

[This message was edited by johno on 30 June 2003 at 09:56 AM.]

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more likely. DD GM 71 diesels were supplied in 2, 3, 4, 6, 6V, 8V, 12V and 16V- the 12 and 16 cylinder units are much like two 6's/ 8's joined but I believe sharing a common crank.

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Thats an engine, 1136 cu". There was a surplus landing craft recently for sale with twin 16V71 Detroits. What a grease gobbler that could be! Expect in a pinch one could drag large sea mammals aboard, flense and render them into fuel.

The V 12 and V 16 were integral engines using the same heads as V 6 and V 8- engines were sometimes ganged up in series, even in industrial 'quads'