I need some help with an old Dodge truck.
Allright let's get down to business on ignition capacitors, back then called "condensers."
VOLTAGE RATING. All capacitors have a voltage rating but that is not generally published for ignition caps because they all see ??up to?? 200V or so peak. They are rated, it's just that the ratiing is not published. So voltage rating for caps between 6 or 12V systems is not relevant.
CAPACITANCE. here are a few random figures.
================================================================
First are from 67 Dodge manual, so "typical" 12V 60's ratings
Capacitance for 6 cyl, 273V8, 318, 383, 440, and 426 hemi, are all shown as .25-.285 mfd (microfarad)
================================================================
Next from 1960 Plymouth service manual
1960 225 6 is ............ .25--.285mfd
V8 318 and 361 ......... .25--.285mfd
=================================================================
Last from an old, tattered, "Motor's" manual, 16th edition, copyright 1953
Under Dodge, the chart all the way from 1936--to 1953 V8 says............... .25---.28 mfd
===================================================================
The cap value depends on the COIL, not the system voltage. Some systems such as Mallory may have used other cap values, and "back in the day" you could BUY different values of caps if breaker points showed pitting on one side or the other---I don't recall-------pitting on ground side you went one direction, pitting on "hot" side, you went the other, etc.
==================================================================
Frazier, 47--48 shows .20--.25mfd
Henry J shows .21--.25mfd
Hudson/ Terraplane shows .20--.25mfd
Desoto same as Dodge
Some Nash shows .18--.25, some shows .20--.25 AND I CAN TELL YOU that is "not" much difference...
Poncho shows .18--.23mfd
Ford all the way from '36 to 48 shows .21--.25mfd
===================================================================
IS A PATTERN STARTING TO FORM HERE???
The correct answer is, "it probably won't make much difference" IF IF the one you use is in good operating condition. Remember that ...........
"New" does not mean "good"
And you CAN NOT check a condenser with an ohmeter
And you CAN NOT check a condenser with a modern solid state cap checker
WHY?
Because almost NO testers check for HIGH VOLTAGE LEAKAGE
The ONLY instruments I have that check for high voltage leakage is the old Bruno tester I have, and an old Heathkit, as well as two (need to be restored) Eico testers These testers in reality are only good for one thing...........LEAKAGE tests. ..........HIGH VOLTAGE leakage tests. The capacitance readings are "accurate enough" but the modern pocket cap checkers are more accurate "for capaciatance"
This is a photo (off the internet) of the same model as my old heathkit. This is so old it uses "octal" vacuum tubes---the ones with the big 8 pin base and "key" in the middle
A stolen photo of the Eico, in many ways similiar to the Heathkit
This is my Bruno tester, and I use the crap out of it on outboards. It tests caps for leakage and value, and tests coils for comparative output voltage
Notice the "leakage" scale is just a "go / no go" deal and right above in red is the capacitance...just reads right out. Outboards run around .22mfd
The next scale up in black says "KV".......That's RIGHT that is KILO volts, for coil output
The ohms scales are good for checking coil continuity which is a joke because if they were open they would not work, and if they are "partially shorted" the meter is not accurate enough.........Neither are modern digi ohmeters....... But it IS useful for "points resistance"
Allright let's get down to business on ignition capacitors, back then called "condensers."
VOLTAGE RATING. All capacitors have a voltage rating but that is not generally published for ignition caps because they all see ??up to?? 200V or so peak. They are rated, it's just that the ratiing is not published. So voltage rating for caps between 6 or 12V systems is not relevant.
CAPACITANCE. here are a few random figures.
================================================================
First are from 67 Dodge manual, so "typical" 12V 60's ratings
Capacitance for 6 cyl, 273V8, 318, 383, 440, and 426 hemi, are all shown as .25-.285 mfd (microfarad)
================================================================
Next from 1960 Plymouth service manual
1960 225 6 is ............ .25--.285mfd
V8 318 and 361 ......... .25--.285mfd
=================================================================
Last from an old, tattered, "Motor's" manual, 16th edition, copyright 1953
Under Dodge, the chart all the way from 1936--to 1953 V8 says............... .25---.28 mfd
===================================================================
The cap value depends on the COIL, not the system voltage. Some systems such as Mallory may have used other cap values, and "back in the day" you could BUY different values of caps if breaker points showed pitting on one side or the other---I don't recall-------pitting on ground side you went one direction, pitting on "hot" side, you went the other, etc.
==================================================================
Frazier, 47--48 shows .20--.25mfd
Henry J shows .21--.25mfd
Hudson/ Terraplane shows .20--.25mfd
Desoto same as Dodge
Some Nash shows .18--.25, some shows .20--.25 AND I CAN TELL YOU that is "not" much difference...
Poncho shows .18--.23mfd
Ford all the way from '36 to 48 shows .21--.25mfd
===================================================================
IS A PATTERN STARTING TO FORM HERE???
The correct answer is, "it probably won't make much difference" IF IF the one you use is in good operating condition. Remember that ...........
"New" does not mean "good"
And you CAN NOT check a condenser with an ohmeter
And you CAN NOT check a condenser with a modern solid state cap checker
WHY?
Because almost NO testers check for HIGH VOLTAGE LEAKAGE
The ONLY instruments I have that check for high voltage leakage is the old Bruno tester I have, and an old Heathkit, as well as two (need to be restored) Eico testers These testers in reality are only good for one thing...........LEAKAGE tests. ..........HIGH VOLTAGE leakage tests. The capacitance readings are "accurate enough" but the modern pocket cap checkers are more accurate "for capaciatance"
This is a photo (off the internet) of the same model as my old heathkit. This is so old it uses "octal" vacuum tubes---the ones with the big 8 pin base and "key" in the middle
A stolen photo of the Eico, in many ways similiar to the Heathkit
This is my Bruno tester, and I use the crap out of it on outboards. It tests caps for leakage and value, and tests coils for comparative output voltage
Notice the "leakage" scale is just a "go / no go" deal and right above in red is the capacitance...just reads right out. Outboards run around .22mfd
The next scale up in black says "KV".......That's RIGHT that is KILO volts, for coil output
The ohms scales are good for checking coil continuity which is a joke because if they were open they would not work, and if they are "partially shorted" the meter is not accurate enough.........Neither are modern digi ohmeters....... But it IS useful for "points resistance"
