Facet Fuel Pump Install.. 74" Exxe

Turns out, crimp connectors:

*High quality machined barrel or brazed barrel with an outer sleeve for insulator support crimp terminals. The best ones are a machined pin crimped with a four indent crimper (Daniels manufacturing or similar). This type of connector terminal is common in the aerospace and high rel industrial applications.

*Assembled with the proper crimp tools, crimped to the proper dimensions with a pull test is more reliable than solder in many conditions.

I was planning to do a write up on wiring and terminals, but have not had the time to get this done yet.

Some things to consider.

*Solder connections when subjected to high temperatures will cause the solder to crystallize resulting in an intermittent connection (similar to a cold solder joint). This failure mode happens even faster when heat is combined with vibration..

*DO NOT tin a stranded wire before installing it into a crimp or screw terminal. The solder in the wire will re-flow over time and loose all of it's pre-loading from the crimp or screw terminal. This will cause the connection to fail..

Some number of years ago when Hewlett Packard was making series 300 computers. They were experiencing system power supply failures. It turns out the failures were due to tinned stranded wire being installed into screw terminals used for power connections. Tinning the wires made assembly easier, but the connection would loose all of it's pre-load over time resulting in a connection failure.

*Use the proper crimp tool with the specified connector. It does matter. In many manufactured wiring harnesses, the crimp terminals are checked for proper crimped dimension before and after a lot of harnesses. They must also pass a crimp pull out test before the entire lot can pass for delivery.

More on this later..

Bernice


spiggs said:
Bernice - What do you use to do your wiring? Crimp or solder and what type of connectors do you trust?
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This was such a good ideal Paul that I had to use it for the single carb engine that is in the car now.. It reminded me of Detroit V8 Hot Rodder folks who would stack two air cleaner elements together to reduce filter restriction.

Some where there are some images of setting up the cover on the lathe to trim it back.. and the intake snout being sawed off in a band saw..

Thanks for sharing :)

Bernice

Paul Valente said:
:)
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The older x1/9 and FIAT electronic tach requires the pulse input resistor value to be reduced. It was designed to accept a pulse edge in the 200-300 volt range. The MSD tach output is a nice 50% duty cycle square wave that goes from 0 to about 12VDC.. Not enough to trigger the charge pump IC that makes these electronic tach read.

Turns out, the later x1/9 (1979 and later) work with the MSD tach signal direct. These have a differnt circuit and design compared to the older ones.

Like the wire terminals, I'll need to find some time to put this together. The tach can be calibrated after this modification if desired.

On the L-Jetronic. It turns out, the Bosch EI unit generates a tach signal pulse that has a 200 volt rising edge with a pulse width about 10 uS, then it falls to the system supply voltage (about 13.5VDC) for the remainder of the tach pulse duration. The L-jetronic tach input required that 200 volt edge pulse to trigger, much like the early electronic tachs. This is not the waveform generated by the MSD unit and why the L-jetronic does not work with the L-Jetronic.

I posted a simple circuit that could alter the MSD tach output shape some time ago. That basic circut topology can work, but the values and design details need to be worked out for it to function properly.

Another project..

Bernice


olerascal said:
I'm sure several would appreciate hearing
how you solved these problems.
Thank you in advance.


Bernice wrote:
I also figured out how to modify the older style FIAT electronic tach to work with the MSD (this turns out to be quite easy) and why the Bosch L-Jetronic does not work with the MSD tach output. This can be fixed too.
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Last edited by a moderator:
Rupunzell said:
Turns out, crimp connectors:

I was planning to do a write up on wiring and terminals, but have not had the time to get this done yet.

...

More on this later..

Bernice
Click to expand...

I would really be interested in that along with specific recommendations on crimpers etc. Thanks!
 
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