On Thu, 5 Oct 1995, Eric L. Van Iderstine wrote:
>
>
> Help,
>
> Situation
> 74 B RD has no power, it couldn't beat a pedestrian...
> it has..
> new electronic ignition (just put on balast resistor, coil still gets
> rather warm), valvetrain adjusted, new plugs/wires, vacuum advance works
> again,
>
> Pluses
> will idle at 1000 rpm
> carbs balanced with SU tool kit (this is something you can build for next
> to nothing, or pay $11.00 for, I wish I would have gotten the Uni-syn)
> no backfiring while revving the engine
>
> Minuses
> Timing at idle (1000 or so rpm) is about 40 deg (any less, and it
> sputters).
With the vacuum advance hooked up or not? That really doesn't sound
right. If that is with the vacuum advance plugged I would say you probably
installed the shutters for the electronic ignition wrong or have the
timing light on the wrong wire or something. Obviously, you have to
increase the idle on the throttle linkage to maintain rpm as you retard
the spark as a retarded spark produces less power at idle. For instance,
10 deg more of retard could lower your rpm a few hundred. You will have
to increase your idle speed to retard the spark to normal. It sounds more
like a measurement problem though
> Runs VERY rich.
> When I drive around the parking lot, it WILL NOT accelerate.
Sounds like you have a very retarded spark. Say you were off with the
shutter or wrong wire with the timing light. You could be 45 deg off in
which case what you are actually reading is not 40 deg btdc but 5 deg
atdc which would be about 15 deg too retarded. then when you try to
retard the spark more the engine can't even run
>
> any suggestions? I'd like to make it to Memphis next weekend in it, not
> my Buick....
With all due respects..
Either your measuring it wrong, installed the electronic ignition in
wrong, or you have not raised the rpm enought to allow you to retard the
spark. Keep in mind that with a static timing of about 10 deg and a
vacuum advance at idle of about 20 your engine gets a total of about 30
deg to idle on, maybe more. But when you step on the gas the vacuum
advance disapears and you are dealing with only the static plus
mechanical advance. Do the timing with the vacuum plugged.
Chris
>
> Eric
>
> Eric L. Van Iderstine - ME senior - Mississippi State University
> Design Coordinator - MSU Formula SAE......Powered by Honda......
> elv1@Ra.MsState.Edu http://www2.msstate.edu/~elv1
> 74 MGB & 85 Buick (until I finish the MG)
>
>
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