pining,twin plugging,etc...

[Shannen Durphey]

Gary Derian wrote:

> Sorry guys, my turn for the cone shaped hat.  I wrote "undersquare allows
> higher revs..." when I meant oversquare.  By the way, how many angels can
> fit on the point of a cone shaped hat?
>
> The McLaren F1 I referred to was the $1 million road car with a 6.2 liter
> BMW V-12 not the Formula 1 racing car with the 3 liter Ilmor V-10.
>
> In my opinion, longer stroke engines make better road car engines whan all
> is taken into account.  A 377 Chevy (3.75 inch stroke) is a lot better in a
> Camaro than a 302 (3 inch stroke).  It has more power, more torque, is more
> flexible, weighs the same, costs nearly the same.
>

That would be a 383, at .030 over bore.

> Gary Derian <gderian at cybergate.net>
>
> >> A bigger bore is more sensitive to detonation.  Thats why really big
> >engines
> >> are always diesel.  The bigger the bore, the more leakage past the rings.
> >> Also engines are smaller and lighter when they have a smaller bore and
> >> longer stroke for a given displacement.  The European BMW M3 engine
> >(which
> >> by the way is 1/2 of the McLaren F1 V-12) is undersquare and delivers 321
> >hp
> >> from 3.2 liters.
> >>
> >> In theory, undersquare allows higher revs, bigger valves
> >
> >How can you put bigger valves into a circle that is a small diameter?  The
> >larger the bore the larger the maximum valve sizes are, think about it.
> >Intake valve area is limited to roughly 34% of the bore size on a 4 valve
> >race engine.  A smaller bore would limit the size of the valve.  FWIW, F1
> >engines are around 100 mm bore for a 3 litre engine with 8 cylinders and it
> >is estimated that the3 litre V10's are running around 92-94 mm bores.  This
> >means that they are highly oversquare engines.  The only advantage for a
> >small bore on a street car is the smaller crevice volume which lowers HC
> >emissions.  This is also why the piston to wall clearance has gotten much
> >tighter lately and why the top ring is moving up the piston.  Some engines
> >are down to .002" piston to wall clearance stock on a 86mm bore.
> >
> >and more power per
> >> liter which is good only for racing classes regulated by engine
> >> displacement.  Everywhere else power per weight, specific fuel
> >consumption,
> >> and cost are the main constraints.  Near square engines have a better
> >> balance.
> >>
> >> >---------------SNIP------------------
> >> >
> >> >> Certain Chrysler engineers believe that pistons over 4" dia. waste
> >fuel.
> >> >> Too much ends up collecting around the sides of the piston.  They were
> >> more
> >> >> interested in complete burn for emissions, hence the V10.  Ford has
> >> tagged
> >> >> along and released a V10 of their own, around 420 ci, I think.  Have
> >you
> >> ever
> >> >> noticed anything like this?  Maybe as more power for a given fuel
> >> consumption?
> >> >
> >> >
> >> >What's the story on this one--I've heard that a bigger bore is more
> >> >efficient and the opposite side that more, smaller cylinders is better?
> >> >I got into a discussion about "thumpers" in a motorcycle mail list one
> >> >time and nothing was every really resolved.
> >> >
> >>
> >>