68, bad idle

["Dick Benjamin" <DickB@xxxxxxxxx>]

I see I had a typo in my last response here - if course I meant heat riser,
not head riser!   Yes, you can try to tighten the intake manifold bolts, but
if they are already at 35 ft lb., I don't think that will help much.

I'm not sure what you mean by lower gasket - there is only one gasket
between the intake manifold and the heads.   If you are referring to the
lower portion of this gasket, you should still be able to flood the area
with WD-40 and hear a difference in idle if there is a vacuum leak, as this
stuff will find it's way down under the manifold runners.  But the best way
to determine if you have a vacuum leak is to put a vacuum gauge on it!  You
should be showing around 20-21 In. Hg. at sea level, at idle.  If you
aren't, there's a problem somewhere!

Dick Benjamin
----- Original Message -----
From: Dick Benjamin <DickB@xxxxxxxxx>
To: <mailing-list@xxxxxxxxxxxxxxxx>
Sent: Saturday, July 06, 2002 9:58 PM
Subject: Re: IML: 68, bad idle+multiplex stereo


> I think a stuck head riser would certainly affect how the car runs when
hot,
> but my main reason for suggesting it was the difference in exhaust pipe
> temperature between the two sides of the car.  The gasket that would
affect
> only one side of the car would have to be the intake manifold gasket - as
a
> leak at the carburetor base would affect both sides of the car.  Another
> item that would affect mostly one side of the engine would be a serious
leak
> into the intake manifold from the large vacuum fitting that supplies the
> brake booster etc.    This would certainly give a very low reading on your
> vacuum gauge, however.
>
> Since your car already has the 5 speaker setup, you can easily splice into
> the individual speaker leads and drive them from the 4 speaker lines out
of
> your modern device.  The only problem is that the car's speakers share a
> common ground return from some of the speakers (I think the front 3) and
> this is incompatible with most transistorized modern electronic devices,
> they require floating grounds, and if you were to connect to the existing
> harness, you would damage the new equipment.  You'll need to investigate
the
> requirements of the device you want to install, and try to find one that
> tolerates common ground returns.  The other way to accomplish this is to
> rewire the car's speakers so that each speaker has two independent wires,
> and such that none of them are connected together or grounded to the car.
> Then you can hook them up to your new radio and it will work just fine.
I'd
> not try to incorporate the front center speaker, just use the 4 in the
doors
> and rear shelf.  If you are planning to run your sound system really loud,
> you will probably find the original speakers can't take it, though.  Back
in
> the 60's, anything over 100 dB was considered torture (and I agree!).
>
> Dick Benjamin
> ----- Original Message -----
> From: D. Dardalis <dardal@xxxxxxxxxxxxxxx>
> To: <mailing-list@xxxxxxxxxxxxxxxx>
> Sent: Saturday, July 06, 2002 9:34 PM
> Subject: Re: IML: 68, bad idle+multiplex stereo
>
>
> > At 08:43 PM 7/6/2002 -0700, you wrote:
> > >Your problem is more likely a vacuum leak at your intake
> > >gasket, or a plugged heat riser valve.
> >
> > Dick, wouldn't a plugged heat riser valve make the car run poorly when
> > warm?  The car runs pretty strong, especially at WOT.  Also, the poor
idle
> > occurs even when cold (actually, its even worst then).  If you agree,
then
> > it must be the gasket.  I can do the WD-40 test, but if the leak is in
the
> > lower gasket, that wouldn't show right?  Can I just try to tighten the
> > manifold bolts?
> >
> > Also, I was looking at the imperial site where you describe the
multiplex
> > stereo and tape deck installation on your 68.  The LeBaron has the
> > multiplex stereo radio (which does a very good job, almost as good as
you
> > describe) but I do not have the tape deck.  I was curious, is there an
> > "easy" way one can plug a modern CD player or walkman to these old
radios?
> > D^2
> >
> >
> >