Perry I think you should try an MSD ignition. Cap discharge
is supposed to punch through lead deposits. Or build you own.
I think I have one of these I can loan you for test.
Paul Lamar ...No rotor no motor.
--------------------------------------------------------------
Silicon Chip has a new universal high-energy electronic
ignition system that
completely supersedes our previous design.
Main Features
Operates from points, reluctor, Hall Effect and optical triggers,
or 5V signal from engine management computer
5-15V negative earth operation
Selectable dwell period
Coil switches off whenever engine is not turning
Dwell extension with low battery voltage
Minimum spark duration of 1ms
Two points debounce periods
Special operation for poorly operating points
Anti-theft ignition disable switch option
Optional inverted trigger signal operation
http://www.siliconchip.com.au/cms/A_105632/article.html
This is a subscription based site so it will cost you $6.70US
to read the entire article.
--Sandy
Perry, here is the one I have. Send me your address and
I will loan it to you. Keep a set of plugs that have
been fouled by 100LL and reinstall them for test on
the ground.
Paul Lamar
----
I'm on a web-based access, hopefully this isn't an html message.
I haven't burned 100LL for a year, not since my last trip to KS when
I found out TCP doesn't work. I think it doesn't work because the
cylinder head temperature is lower in a water cooled engine. So I
don't have any fouled plugs laying around anymore. I would have to
install the system and then burn 100LL.
I downloaded some manuals from MSD awhile back but it wasn't really
clear how that system installed into an RX-7. Do you think this
system is easily installed and removed?
Send by USPS to PO Box 1553, McMinnville, OR 97128. If you want to
send by other means let me know.
Perry
Ok Perry. There is plenty of data about it on the Internet.
Here is some stuff I extracted from the pdf.
On second thought this is not going to work with the
RX7 ignition system as it fires a single coil twice
per rev and it relies on a distributor to send the spark
to the right one of four plugs. We don't have distributors any
more. However this is a very high performance MSD system.
I think you might need at least four of these circuits.
They are well worth replicating.
If you want to start from scratch here is an idea
I had a while back.
Shown are three capacitors charged to 300 volts switching
a coil in sequence by a CPU. Any number of caps and switches
can be used but the output impedance of the power supply must
be low and the converter frequency higher than 20Khz to
recharge the capacitors rapidly. The sequence can be rapid
or somewhat less than rapid at lower RPMs. In other words
a variable pulse rate multiple spark capacitor discharge
ignition system. The limit is the CL time constant. High C voltage
low L means a rapid voltage rise time with a narrow pulse width.
The chart from Heinze Heisler s book Advanced Engine Technology
showing a cap discharge time or pulse width
of 30 milliseconds which is obviously too long for
an MSD system. Perhaps more than 300 volts is needed
for charging the cap. Most cap discharge systems use
a 1 mike cap and 300 to 350 volts. Evidence is if you go higher
on voltage than this a stock automotive coil may break down.
I was thinking of experiemtaing with a 15KHz CRT fly
back transformer. 15KHz is a period of .01 ms if my
arithmatic is correct.
7000 RPM is 116.7 rev pere second or 42,000 degrees per
second or one e-shaft degree in .02 ms.
Paul Lamar ...No rotor no motor.ne degree in
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