Date: Mon, 14 Apr 2008 22:00:34 -0700
Reply-To: neil N <musomuso@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: neil N <musomuso@GMAIL.COM>
Subject: Re: Vanagon/Jetta timing issue. Use RPM sensor hole to find #1
TDC mark?
In-Reply-To: <48042832.8040308@earthlink.net>
Content-Type: text/plain; charset=ISO-8859-1
Thanks for the reply Mark.
So ok......
If I'm understanding this correctly, as long as #1 is at the top of
its' stroke, whether or not it is an beginning its' exhaust or
compression stroke, is determined by how I set the cam?
FWIW, I'm treating this engine as if the cam, intermediate shaft,
crank and distributor are out of sync with each other.
Currently it's timed so when #1 is at TDC, the cam is at its' correct
mark, and the distributor is at #1 mark. I confirmed TDC using wood
dowel in spark plug hole. Crank pulley mark lines up with mark on
plastic timing belt cover.
But.......
In Bentley it says that if the RPM sensor is faulty, the engine won't
start. I'm not assuming it's faulty, but my concern is that if
(ignoring cam now) I have #1 set to the "exhaust" stroke in relation
to the gap on the crank gear, that this may be fouling up the RPM
sensor, therefore keeping the engine from starting.
Neil.
On Mon, Apr 14, 2008 at 8:59 PM, Mark Drillock <drillock@earthlink.net> wrote:
> You have a 4 stroke engine, also called a 4 cycle. (I don't mean 4 cyl
> though yours is that too)
>
> With a 4 stroke engine it takes 2 complete revolutions of the crank to
> complete a full cycle. With a 4 cylinder 4 cycle that means the crank timing
> mark will line up for 2 different cylinders at TDC at the same time. One
> will be lined up in its compression stroke TDC and the other will at the
> same time be lined up for its exhaust stroke TDC.
>
> The firing order of the VW inline engine is 1-3-4-2. That means that cyls 1
> AND 4 will be at TDC at the SAME time, but at different phases of their
> valve timing. VW provides a cam timing indicator so the valve timing phase
> can be checked against cylinder #1 TDC. Once timing for #1 is correct the
> others must also be so.
>
> Mark
>
>
>
>
> neil N wrote:
>
> > Hey everyone.
> >
> > Haven't got my Jetta ABA 2.0 engine started yet. Timing sounds wrong
> > even though I have timing marks "correct".
> >
> > When engine turned over, it sounds like this:
> >
> > "whir whir whir" (slight pause) "whir whir whir" etc. It sounds
> > labored with very distinct "whirs" if that makes sense.
> >
> > Starter is fine, as is battery.
> >
> > I need to confirm TDC of #1 cylinder, but obviously can't see the
> flywheel.
> >
> > Bentley shows a gear attached to crank, that RPM sensor "reads". There
> > is a factory gap on gear. (2 teeth missing). RPM sensor reads this gap
> > as TDC for #1 cylinder.
> >
> > With sensor removed, and gap on gear lined up with RPM sensor hole in
> > block, crank pulley mark is at 9:00 and distributor points close to
> > #4. This somewhat confirms my suspicions. But i"m not certain.
> >
> > Anyone know if I can use this gap on the gear as reference for #1 TDC?
> >
> > This is an interference engine AFAIK, so I don't want to screw with
> > timing any more than I have! --- :^)
> >
> > Thanks,
> >
> > Neil.
> >
> >
> >
> > --
> > Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
> >
> > http://web.mac.com/tubaneil
> > http://tubaneil.googlepages.com/
> >
> >
>
--
Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
http://web.mac.com/tubaneil
http://tubaneil.googlepages.com/
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