Kelvin Dodd wrote ...
>
> Executive summary:
>
> 1. The late camshaft is slightly advanced from the early. This
> means more
> low end torque, less top end power. Nothing wrong in that if you are
> running the car on the street.
OK, that seems reasonable. If doing an engine rebuild, would it be best to
use the the same camshaft, an early camshaft, or something completely
different? As an aside, my '73 B with it's tired engine pulls way better. I
assumed it to be the combination of camshaft & dual SU's.
I'm not having any particular engine problems, but have a pretty leaky
engine, so all the seals/gaskets need to be redone. And if it's that far
apart, it seems foolish not to refresh the whole motor.
>
> 2. There is nothing wrong with the late distributor either, it just isn't
> designed with performance in mind. If converting carbs it can be
> hooked up
> to the manifold and will operate just the way it was designed to
> do. As an
> aside. We used late distributors for many years on race cars by removing
> the vacuum advance, pining the plate and restricting total centrifugal
> advance slightly, this allowed the use of Pertronix units long before they
> adapted them to the 25D.
The advance on my '80 B is plumbed to vacuum connector at the base of the
Weber DGV. Is this correct, or should it be connected to the manifold
proper? Perhaps a tee fitting where the vacuum line runs from the manifold
to the brake servo?
I thought the 25D was used on earlier cars, with later models getting the
45D, 45DE, or 45DM. By the way, thanks to info researched by Frank
Krajewski, I was able find a replacement ignition module with which to
rebuild my CEI amplifier. The 4 pin GM ignition module inside is available
at most auto parts stores. I was unable to locate the proper module until I
found a suitable part number while browsing the Transpo web site. Ask them
to look up part number D1906 and you should have no problems obtaining one.
It's about $20 to $30 depending on which place you get it from.
Would replacing the 45DM with a 25D or 45D be a sensible thing to do? Or
does it only make sense when changed in conjunction with a suitable
camshaft?
>
>
> In answer to Marc's question. Dual SUs give much better initial
> grunt when
> you hit the loud pedal than the DGV. This because the
> butterflies are much
> closer to the bang bit. This adds up to a much better feel when the light
> turns green, which is what it is all about.
>
> The SUs are also much more forgiving to cam and mixture problems, so will
> tend to be smoother and will mask minor tuning problems. They
> don't tend to
> bog the engine the way an accelerator pump carb can when not set up
> correctly.
Now this is an area that I have no knowledge of. I installed the Weber and
set it for "lean best idle" per the instructions. I know there is further
tuning that could be done vis a vis re-jetting (or is it re-needling???) but
this is beyond my limited knowledge at this time. What's the difference
between an accelerator pump type carb and an SU type carb?
>
> hope this helps
>
>
> Kelvin
>
Yes, thank you, it does, but of course all answers beget more questions!
--
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Marc Siegel, Charm Net LLC eMail: smarc@abs.net
Baltimore, MD http://www.abs.net voice: 410/361-8160
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