BUBBAS IGNITION
Well-known member
Over the last three to four years we have made up and shipped well over 600 of the chevrolet conversion distributors to a happy group of flathead owners. (672 to be exact)
Over the years as we build these jewels we have made changes as we go along and its good to see one from time to time that has some serious miles on it.
These changes could be finish, paint , machine work , advance limits right down to the contact point attaching screws being switched to stainless ( i hate rust). The way we lube the parts have changed and for the most parts all the changes have been very minor in nature and most changes lately have been cosmetic just because i didnt like the look. Oh well its been a good design for the most part !!!
This unit came in today with some serious miles out of a flathead that the customer had broken something on the engine and wanted the distributor freshened up , recurved and tested for his new engine.
A couple notes based on what i seen when i opened the box...
The basic distributor looked very well, the advance weights still looked very new and the cosmetics looked good.
I noticed that the advance limit ( back then a rubber bushing---today we use a brass bushing) has swollen just from engine fumes etc and i replaced it with the new up graded brass piece. The advance curve was correct but it did change it a little on the lower end and took a couple degrees out of the top end.
The biggest no-no i seen was the primary lead going to the points was cut and a new end crimped on ( see pic) oops that one i hadnt thought about.
I realize why you would neaten up the primary lead but ya can do that !!! The lead is a factory calibrated lead to drop the final little surge of voltage going to the ignition contacts after the coil drops and consumes the final shot of voltage...
We suggest using a 1.5 ohm coil and a 1.5 ohm resistor on 12 volt systems. Using ohms law with 3 ohms resistance and a 12 volt battery would equal 4 amps current flow in the primary ignition system. ( perfect for this system)
Voltage drop is ohms times amps so each would drop 6 volts in a perfect world and the voltage would be zero or close to it at the contact points ( actually approx .100 mili volts etc).
This works well untill you start the engine. Two issues here as the voltage usually goes up to 14 volts and the resistors heat up. This allows the voltage in the calibrated primary lead to increase slightly. The calibrated (finely stranded) lead is our final resistor and consumes the final voltage drop eating up this excess protecting the points.
Its not uncommon to see a street roder replace the engtire lead with solid 14 gauge wire !!!! Bad move for sure.
Moral of the story is "DONT CUT THE FACTORY PRIMARY LEAD ", We install this factory lead for a reason...
Item two is the condition of the contacts with some metal transfer , again pretty normal but maybe a little pre-mature on the example used with cut primary lead.
It changes the capacitance in the system.......clear enough...
????
Over the years as we build these jewels we have made changes as we go along and its good to see one from time to time that has some serious miles on it.
These changes could be finish, paint , machine work , advance limits right down to the contact point attaching screws being switched to stainless ( i hate rust). The way we lube the parts have changed and for the most parts all the changes have been very minor in nature and most changes lately have been cosmetic just because i didnt like the look. Oh well its been a good design for the most part !!!
This unit came in today with some serious miles out of a flathead that the customer had broken something on the engine and wanted the distributor freshened up , recurved and tested for his new engine.
A couple notes based on what i seen when i opened the box...
The basic distributor looked very well, the advance weights still looked very new and the cosmetics looked good.
I noticed that the advance limit ( back then a rubber bushing---today we use a brass bushing) has swollen just from engine fumes etc and i replaced it with the new up graded brass piece. The advance curve was correct but it did change it a little on the lower end and took a couple degrees out of the top end.
The biggest no-no i seen was the primary lead going to the points was cut and a new end crimped on ( see pic) oops that one i hadnt thought about.
I realize why you would neaten up the primary lead but ya can do that !!! The lead is a factory calibrated lead to drop the final little surge of voltage going to the ignition contacts after the coil drops and consumes the final shot of voltage...
We suggest using a 1.5 ohm coil and a 1.5 ohm resistor on 12 volt systems. Using ohms law with 3 ohms resistance and a 12 volt battery would equal 4 amps current flow in the primary ignition system. ( perfect for this system)
Voltage drop is ohms times amps so each would drop 6 volts in a perfect world and the voltage would be zero or close to it at the contact points ( actually approx .100 mili volts etc).
This works well untill you start the engine. Two issues here as the voltage usually goes up to 14 volts and the resistors heat up. This allows the voltage in the calibrated primary lead to increase slightly. The calibrated (finely stranded) lead is our final resistor and consumes the final voltage drop eating up this excess protecting the points.
Its not uncommon to see a street roder replace the engtire lead with solid 14 gauge wire !!!! Bad move for sure.
Moral of the story is "DONT CUT THE FACTORY PRIMARY LEAD ", We install this factory lead for a reason...
Item two is the condition of the contacts with some metal transfer , again pretty normal but maybe a little pre-mature on the example used with cut primary lead.
It changes the capacitance in the system.......clear enough...
????
