Fw: [Vwdiesel] idle switch, diesel leak, oily engine block

[Dana Morphew]

I've always been happy with the "braking" of my diesel when I'm off the 
pedal.  It "compression brakes", if that is the phrase, well because my idle 
rpm is set at a smooth 700 (love the balanced rod/piston/pin sets).  It also 
"brakes" well because each piston pulls in an unhindered gulp of air before 
each compression stroke and the Total Seal rings seem to be seated.   It is a 
1.9 which will, all things being equal, give more braking effect than a 
smaller diesel.

A gas engine must contend with manifold vacuum when attempting to fill its 
cylinders.  This vacuum, (@ 25 lbs. or a bit less than 2 atm.), causes some 
resistance to engine rotation.  If the cylinders were able to get all the air 
their capacities allow, they only have 1/3 to 1/2 the numeric compression my 
diesel has.

Dana
 
>  ----- Original Message -----
> > From: Scott Alexander <salex at dsl.cis.upenn.edu>
> > To: Mark LaPlante <laplante at mac.com>
> > Cc: vwdiesel list <vwdiesel at vwfans.com>
> > Sent: Friday, January 02, 2004 4:21 PM
> > Subject: Re: [Vwdiesel] idle switch, diesel leak, oily engine block
> >
> >
> > > On Fri, 2004-01-02 at 17:13, Mark LaPlante wrote:
 
> > > > I have noticed the upshift light coming on when coasting around a
> > > > downhill 270 degree offramp. I usually put it into third gear, which
> > > > brings the rpm up, but I guess I don't really get the engine braking
> of
> > > > a gas engine in a diesel, right? Or does the compression help slow the
> > > > car?
> > >
> > > I'll be interested to hear other answers on this since my car is a
> > > recent acquisition and has spent more time getting stuff fixed than on the
> > > road.  I did, however, do a quick experiment on a steep hill with the
> > > clutch in and out and concluded that I didn't feel any engine braking. 
> > > (Of course the speedo gear was missing from the trans when I bought the
> > > car, so I was going buy seat of pants rather than a gauge.)
> > >
> > > Best,
> > > Scott