Date:         Mon, 29 Apr 1996 10:15:00 -0700 (PDT)
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         "Maher, Steve (SD-MS)" <SMAHER@gi.com>
Subject:      RE: loss of power on hills


>a new problem has developed:   there is a noticeable loss of power when
>driving up hills.  We need to downshift to keep up our speed.  It
>doesn't run rough, it doesn't smoke, and on level roads we can maintain
>65 (we may just be paranoid, but there may also be less power on the
>highway also.). We know that we are talking about a VW Vanagon, but this
>is a new problem, as we said, it is noticeably different from driving it
>when we first bought it.  The timing is right on, it's not burning oil,
>it idles and runs smoothly, just loses power on hills.


I have no experience with Type-4 engines. But if I had this happen to
an older baywindow bus with a type-1 engine, the first place I'd look
would be the distributor. Specifically, the centrifugal-advance
mechanism.

Most (Type-1) distributors had two advance mechanisms operating together:
a vacuum advance that retarded the spark when you floored it, and a
centrifugal advance that advanced the spark as the rpms increased.

Don't know how well this applies to the type-4 distributor in your
Vanagon. Anybody know?

>From your description, my first guess is that the centrifugal advance in
your distributor, isn't advancing as far as it should. Maybe some dirt
in there, or a weight fell off inside the distributor, or etc.? If this
is the case, it would cause a noticable power loss on hills, and maybe
some overheating too. Been there, done that, on my old '69 bus in Colorado
many years ago.


If it were me, I'd do the following:

1.) Disconnect the vacuum line to the distributor, and plug the part
that goes back into the engine so that you don't get a vacuum leak into
the engine while you do this quickie test.

2.) Start the engine and let it idle around 700-800 rpm.

3.) Using a timing light, check where the timing sits at this idle speed.

4.) Rev the engine up to about 3,000 rpm, and check where the timing is
at that speed.

A type-1 distributor usually advances about 20 degrees (varies slightly
year to year I think) from idle speed to high speed. Also, it usually
reaches its maximum advance around 2,000-2,500 rpm. So when you rev it
to 3,000 rpm, the distributor should be advanced all the way.

If your idle timing is set at, say, 10 degrees BTDC, then when you rev it
to 3000, the timing should be around 30 degrees (in an older bus engine).
Anybody know what the exact numbers should be for this Vanagon? They will
be listed in Bentley, I'm sure, and maybe in other books-- or a VW dealer
can tell you over the phone.


Try it-- it's a quick, easy test (my favorite kind!). Good luck!

 ______________________________________________________________________
           _                                            ______________
    ______//________    Steve Maher    smaher@gi.com   //__][__||____\\
   /o _   |  -| _   \   San Diego, CA     75461,1717  (o _-|       _ o|
   `-(_)=======(_)---'                                 '(_)-------(_)-'
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