Great Post Mark!,

I think more people will get curious about their max timing as a result.
 This has got to help other people, as I've heard more that a couple of
people with crossed vacuum hoses and such, which lowers the amount of
timing.  No wonder we're hearing so much about low power.  BTW the
horsepower numbers I crunched seem to suggest that the I-4 people find
so powerful is not really able to produce any additional power over the
waterboxer until it is revving past 5000 RPM.

Sincerely,

Mark Keller
91 Carat.

> Mark Ingalls wrote:
>
> Hello Volks,
>
> There has been some discussion on the list lately about the Digijet
> vans and the 5 degree atdc timing.
>
> I run my van at 2 atdc and it runs fine for me, power is fine and 18
> mpg summer.
>
> I was curious about what the total advance would be with this close to
> stock setting.
>
> So when I found a free hour and 1/2 today I took the spark plugs out
> so it would be easier to turn the engine over. Then I found my plastic
> compass with degree markings on it and marked the very rear pulley at
> 30, 35 and 40 degree's. It had a factory mark on it  already that
> looked to be close to the Top Dead Center . ( I have the power
> steering pulley.)
>
> After I had marked the pulley and put everything back together I
> started the van and warmed it up. I had all vacuum hoses in place and
> the idle stabilizer in service.
>
>  At idle I still had 2 atdc.  At 1500 rpm I had around 7 btdc.  At
> 2500 I had 30 btdc.  At 3000 I had 45 btdc.
>
> My only uneasiness in this report is that it is somewhat difficult to
> find tdc on the rear pulley by using a straight edge and eyeballing
> it, but I wouldn't think I would be that far off. I was only a couple
> degrees before the factory mark on the rear pulley when I used the
> compass to mark the rear pulley. And from my experience building
> engines I would assume the mark on the rear pulley would be TDC if the
> pulley is keyed on the crank.
>
> I had taken my distributor apart a year ago when I had idle surging
> trouble, so I assume the centrifical parts are ok. Springs in place
> and weights lightly greased.
>
> If other people would run this test sometime, it would be interesting
> to hear your results.
>
> peace,
> Mark Ingalls
> Nebraska City, Nebraska
> 85  Vanagon GL    'Aimee Airheart'
> 75  Beetle   'Salvation'