Re: [DML] PRV6 Variations

["BRUCE BENSON" <delornut@xxxx>]

Chris,

I was a bit hasty in my response. If cost is no object, and the Venturi was
quite expensive considering it didn't look all that exotic, a crankshaft
with a separate journal for each cylinder would make an even firing engine.
99% of the worlds 90 degree V-6's are odd firing because of the simplicity,
cost , and reliability of making a crankshaft that has three journals with
every two cylinders sharing one. Many modern V-6's now have their cylinder
banks at 60 degrees which makes an even firing engine when six cylinders are
involved. Many early V-6's were derived from 90 degree V-8's which are even
firing when cylinders share crank shaft journals. Lopping off two cylinders
makes the math come out different and the result is odd firing. My wife's
Taurus SHO with a 60 degree V-8 is just the opposite. It was derived from a
60 degree V-6 and it now is an odd firing engine with a balance shaft
installed to smooth things out. That shaft rotates opposite of engine
rotation and offsets any engine shake associated with the odd firing
scenario. It's very smooth and pretty high in performance. A couple of
months back I wrote a description of what odd firing actually is in the
mailing list and that should be in the archives.

Bruce Benson




> Bruce,
>
> I was looking at what I though was a Renault specialist site, I assume
they
> knew what they were talking about??? I cannot remember the source as this
> was little while ago now. A beakdown of the 2.85 Venturi PRV was listed
and
> I remember the 'even firing' standing out as I remembered that the PRV in
> the DeLorean is odd-firing.
>
> Are you saying that there is no way at all that an even-firing PRV is
> possible???
>
> Any comments from you more technically minded individuals are most
relevant.
> Am I right in saying that odd-firing is less desirable because it limits
> performance modifications????
>
>
> Chris