<VV> 110 vs 140 Heads

[MarK Durham]

Yes, everything is getting old. That has to be a big factor. And you are
correct, heat is heat, and small valve heads will experience the same
issues if they get warn enough, its just harder to get them there in
average coupé or sedan driving.  Since my heads only have 72k mikes on
them, and I still have the original seats, I am probably OK. I only drive
the car 1500 Miles a year. Mark Durham Hauser Idaho.
On Mar 24, 2014 9:30 PM, "Frank DuVal" <corvairduval at cox.net> wrote:

> I've worked on enough small valve Corvair heads with dropped seats that
> I no longer consider them less prone than 140 heads.
>
> Hot is hot, whether from running hard racing, climbing hills,
> pre-heating (A/C condenser) or air flow restrictions.
>
> I think the 140s suffered first because of the larger opening and
> spirited driving. The same expansion rate would open the larger hole
> larger than a smaller hole, and conversely shrink the large seat more
> than a small seat (% of expansion vs thousandths of expansion). Since
> the actual size of the interferrence fit is the same for both size
> seats. But, this is just my opinion. Now, after so many heat cycles,
> they all are suspect.
>
> Frank DuVal
>
>
> On 3/24/2014 8:37 PM, MarK Durham wrote:
> > Its just that the small valve heads have a lot less problem with dropped
> > seats than the hotter running 140 heads. I do not know the dynamics of
> why
> > that is other than the 140 heads have a larger intake runner and larger
> > valves and larger exhaust tubes so they can flow more air/fuel mixture
> and
> > produce more power and the result is its easier to put them over the edge
> > when less than ideal hot conditions exist.  Mark Durham Hauser Idaho
> > On Mar 24, 2014 3:07 PM, "corvairduval at cox.net" <corvairduval at cox.net>
> > wrote:
> >
> >> I undrstand the flow of the 95 HP heads and better low end torque, but
> how
> >> does faster air fix the issue of valve seats falling out from cold air
> >> rushing through hot seats?
> >>
> >> Frank DuVal
> >>
> >>
> >>
> >> Original email:
> >> -----------------
> >> From: MarK Durham 62vair at gmail.com
> >> Date: Mon, 24 Mar 2014 14:06:04 -0700
> >> To: hmlinc at sbcglobal.net, virtualvairs at corvair.org, maxspeed at juno.com
> >> Subject: Re: <VV> 110 vs 140 Heads
> >>
> >>
> >> To avoid the valve seat issue, take a 95 head and add the 4x1 Clarks
> >> conversion. The smaller intake runners flow a faster air mix than the
> 140
> >> heads that gives better low end torque. Mark Durham Hauser Idaho.
>
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