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Old 03-31-2019, 11:52 PM   #2
dmsfrr
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Join Date: Aug 2012
Location: Abq, NM
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Default Re: Overdrive fuse size for '54 Y block 239?

Just assuming for discussion that the 6v '55 OD setup is similar or even the same... (?)
Page 245 of a '55 shop manual outlines a portion of the OD test procedure in paragraph "b." at the top of the page.

(paraphrased here)
Substituting an amp meter for the relay fuse should give an indication of 2 to 2.5 amps with a momentary higher reading during activation.

A 5, 7 or 10 amp fuse in the 6 volt circuit would be a 'safer' substitution than the existing 30 amp version. The 5 amp fuse might be a bit small if the current surge during activation causes it to blow too often, then try a 7 amp fuse.

Quote:
Originally Posted by JimNNN View Post
. . . .
It's 6 volt...but that shouldn't matter for fuses, right?
Yes it can, but not in your car if you're not changing the voltage of the electrical system.

In 6 to 12 volt converted cars that change will technically affect the preferred Current/Amperage values of fuses.
The Current/Amperage value of a fuse or circuit-breaker in a 6 volt circuit can usually be reduced by nearly half if that circuit is changed to 12 volt. (Ohm's Law)

"The fuses may need to be changed to values smaller than original or use the ones rated for the 56 and 57..."
(from this link)
https://www.ctci.org/gilsgarage/6to12.php
.

Last edited by dmsfrr; 04-01-2019 at 12:38 AM.
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