Larry Widmer's "Soft head" swirl technology

[Kurek, Larry]

FWIW....

I just received a new set of Chevy 4.3 Vortech heads to do some porting
on.... Well, I was somewhat surprised to see quite a bit of material in
the intake bowl. Upon further inspection, it is actually a cast in
"ramp" that starts at the long side of the port, and rises almost
parallel with the valve seat about 108 degrees or so later. I assume
this is where the "Vortech" monicer comes from...and the "high swirl"
capability of these heads. IMO, nice for low speed work, but kind of a
pain for higher RPM power production....lots of cutting needed to get
those ports down  (up) to size :)

TTYL!

Larry

> -----Original Message-----
> From:	dave.williams at chaos.lrk.ar.us
> [SMTP:dave.williams at chaos.lrk.ar.us]
> Sent:	Monday, June 29, 1998 6:06 AM
> To:	diy_efi at efi332.eng.ohio-state.edu
> Subject:	Re: Larry Widmer's "Soft head" swirl technology
> 
> 
> -> the first engines to use a narrow valve included angle  to induce
> -> swirl about a horizontal axis parrallel to the crankshaft. Because
> of
> 
>  Normally (at least on this side of the pond) "swirl" refers to motion
> parallel to the cylinder axis; "tumble" refers to motion parallel to
> the
> crankshaft axis.
> 
>  Narrow-included-angle four valve heads are usually very good at
> tumble
> and poor at swirl unless something is done with the valve timing or
> shape of one of the intake ports.  Some engines use valves or
> deflectors
> of various sorts in one port to induce swirl.
> 
> ==dave.williams at chaos.lrk.ar.us======================================
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