positive ground vs negative ground

[motorman8467]

Maybe some of you engine specialist can help me with this. What years were Y block, OHV, V-8 engines manufactured with 6 volt negative ground, and is/can the grounding be changed when converting over to a 12 volt system? Thanks.

James

 

[dmsfrr]

'54 was the first model year for Y-blocks and '55 was the last year for 6 volt Positive ground. There were no original 6 volt Negative ground Y-block Fords that I'm familiar with...
Changing the 'ground' is much easier than the rest of the work to change to 12 volts.

Here's a link to an information page. It was written for '55 T-Birds but 99% of it will apply to other ('54/'55) 6 volt Y-block Fords.
https://www.ctci.org/battery-for-6v-to-12v-conversion/

What vehicle are you working on / asking about?

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[motorman8467]

Thanks for the info. Right now I am converting a 55 Y block 272 to 12 volts. As I remember, these distributors operate at about 7.5 volts by using either a resistance wire, or, a ballast resistor. I want to use a ballast resistor, but can't remember which wire it goes on. The engine is out of a 55 F-150, but I only have the engine, no body. Plan to put in something else later. Any help would be appreiated.

James

 

[40 Deluxe]

Thanks for the info. Right now I am converting a 55 Y block 272 to 12 volts. As I remember, these distributors operate at about 7.5 volts by using either a resistance wire, or, a ballast resistor. I want to use a ballast resistor, but can't remember which wire it goes on. The engine is out of a 55 F-150, but I only have the engine, no body. Plan to put in something else later. Any help would be appreiated.

James

It goes on the primary wire that goes from the ignition switch to the coil. Also, the coil may need the primary wires switched. The primary terminals are marked "+" and "-". On a negative ground system the negative or "-" terminal goes to the distributor. On a positive ground system the "+" terminal goes to the distributor.

 

[dmsfrr]

It goes on the primary wire that goes from the ignition switch to the coil. Also, the coil may need the primary wires switched. The primary terminals are marked "+" and "-". On a negative ground system the negative or "-" terminal goes to the distributor. On a positive ground system the "+" terminal goes to the distributor.

Yes.

... I want to use a ballast resistor, but can't remember which wire it goes on. ...

It goes into the wire from the 'run' position of the ignition switch to the coil.

In this diagram the large right-side terminal of the starter solenoid is shown as the connection for the Positive battery cable. In many/most Y-block powered cars and trucks the large left-side terminal is used for the + battery cable, it makes no difference.
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[motorman8467]

Thanks, Fellows for clearing this up. Used to do this on a regular basis, but too old to remember some of it, anymore. Can't put it down, though. Got to keep going.

James

 

[JeffB2]

Maybe some of you engine specialist can help me with this. What years were Y block, OHV, V-8 engines manufactured with 6 volt negative ground, and is/can the grounding be changed when converting over to a 12 volt system? Thanks.

James

Save this as a guide when converting to 12 volts it covers just about all you will need to know. https://darksidersrealm.forumotion....lt-positive-ground-to-12-volt-negative-ground

 

[JMFL36]

My car is still 6V+ and I could use some of your old 6V+ parts if you'd like to get rid of them. Just PM me. Thanks, John 54 Mercury

 

[dmsfrr]

. . . The engine is out of a 55 F-150, but I only have the engine, no body. Plan to put in something else later. Any help would be appreiated.
James

Just fyi... the '56 and earlier Y-block heads use a larger Temperature sensor than the '57 and newer. They are not interchangeable and effectively year matched to the dash gauge. '56 is one-year-only.
Depending on what vehicle you put the engine in the Temp sensor should match the Temp gauge in the dash.

The threaded bushing near the rear of the left head is replaceable and has two internal thread sizes:
3/8 pipe thread for '56 and earlier or 1/4 inch pipe thread for the '57 & later.