6pack
[Top] [All Lists]

Re: Bypass Valve

To: Timothy Holbrook <tjh173@yahoo.com>
Subject: Re: Bypass Valve
From: Don Malling <dmallin@attglobal.net>
Date: Sat, 10 May 2003 14:07:52 -0400
I am replacing my original "boxy" TR250 intake manifold with a later
model TR6 "swept" intake. My original TR250 ZS carbs have the external
manifold bypass lines, so I purchased later ZS carbs with in internal
bypass to match up with the later model TR6 swept intake manifold. 

>From this thread on bypass valves, I would assume I can simply block off
the external bypass lines on my old TR250 original ZS carbs and use them
with the later "swept" TR6 intake manifold.

Just a sanity check...

Don Malling     


Timothy Holbrook wrote:
> 
> I too have my bypass valves "bypassed" by blocking them with gasket
> material.  The purpose of these valves, as others have noted, is simply
> an emissions control to help reduce certain emissions that occur in
> high vacuum situations on "overrun", when your foot is off the gas but
> the engine rpm's are high.  It allows air/fuel mixture to continue to
> get to the engine by bypassing the throttle butterfly.  Unfortunately,
> this also slows engine deceleration, so you lose some engine braking.
> This is even more apparent when you rev the engine in neutral, as the
> engine rpm comes down a bit more slowly than I would like (and it
> becomes more annoying when you add a third carb, since there are now
> three bypass valves working).  Blocking off the bypass valves will have
> no impact on anything other than "overrun" situations.  I have not
> experienced the "popping" that may occur by blocking off the bypass
> valve.
> 
> Tim Holbrook
> 1971 TR6
> 
> --- Gary Fluke <res0s0t7@verizon.net> wrote:
> > Listers,
> >
> > Now I have discovered that each of the bypass valves on my Z-S carbs
> > have been
> > blocked off by the placing of a solid gasket between the valve and
> > the carb
> > body.  The rebuild instructions say the valves are there to stop
> > exhaust
> > popping when backing off the throttle at high RPM.  I don't recall
> > any
> > popping.  Does anyone have thoughts, pro or con, about blocking off
> > the
> > valve?
> >
> >
> > Gary
> > '73
> 
> __________________________________
> The New Yahoo! Search - Faster. Easier. Bingo.
> http://search.yahoo.com

<Prev in Thread] Current Thread [Next in Thread>