Odd question i guess but thought i would throw it out there for something to talk about...this winter when my 68 Mercury Montego wagon was sleeping in the garage one of the things i did for fun was replace what looked like the original mechanical voltage regulator with a new modern electronic model, the new one looks cooler and modern but ive noticed a difference on my voltmeter when running...both idling, and driving seem to show a lower voltage on the meter by a volt or so...before with the old regulator seems like driving showed pretty close to 14 volts and i dont recall the idiling number but now with the new regulator the volt meter never goes higher than 12.7 volts driving...the battery is not new but was freshly charged so im wondering if the new regulator is off, or defective or what..? has anyone else converted from mechanical to electronic and noticed a difference?
Have you verified 1) voltage across the battery posts, not the terminals that connect to the posts, 2) read voltage at the alternator charging lug, and 3) verified the regulator's base is properly grounded. Yes, a solid-state regulator can replace an electromechanical one, I've done it on several Fords, Mopars, and one pre-internal regulator Pontiac with only one thing to overcome, the solid-state GM one does require adjustment according to underhood temperature. No biggie. So, verify the base has a clean ground path, make sure all your connections are correct and snug (the regulator is plug 'n' play), and use a DVOM to confirm charging voltage. Also, ensure your engine speed is correct; if it's too slow at any point, the alternator will not excite, therefore, no voltage generated.
As always you give excellent advice...thank you! i should have performed those tests yesterday...its just i noticed no matter idling or driving what appears to be a definite drop in voltage from the numbers with the old mechanical regulator, i did insure the base had a clean ground path on the install...i have noticed with the new solid state regulator when stopped and idiling in gear it occasionally drops below 12 volts like its not excited,then it will bounce back above 12 volts, that didnt happen with the old regulator...so i will clean all current paths again, take a reading across the battery, and from the output of the alternator at the charging lug and report back...i will also consider reinstalling the old regulator to document the difference in readings, perhaps theres just a difference in the 2 styles of regulators but i cant help feeling uncomfortable with only reading 12.7 or 12.8 volts max going down the road at 45 mph, i could swear i remember it being close to 14 volts before the swap,..i also realize other factors could be in play such as my old alternator that could possible be the original to the car ( i cant tell because someone painted it) , or its getting time for a new battery ...car sat in storage thru the winter as well but was frequently started, my interior volt meter is a cheepie that plugs in the lighter so i guess since my alternator is externally regulated i could consider adding an amp gauge to test the alternator output...question? driving at road speed what voltage reading would be considered a "normal" range? thanks again, and will report back...Terry
There should be only one difference between electromechanical and solid-state--maintenance. Solid-state is self-controlling, so the old one requires occasional adjustment. It is logical to say that you could have a bad new solid-state regulator. Just so you have the info, on excitation, the system should be 13.5-14.5 volts and fairly steady, amperage varies with load. BTW, does your Montego have a factory ammeter?
Wanted to update my post, i verified a perfect ground path to the mounted electronic regulator, started and warmed up the car, and while the cheepie volt meter i bought on amazon was reading 12.9 volts running and idling at 1100 rpm in park, actual voltage at the battery and alternator roughly turned out to be 14.24 volts , so at this point im blaming the volt meter...thank you Silver for pointing out the tests i should have done before making this post im a machinist by trade, but passed ase school years ago for fun, but electrical has always been my weak subject...thanks for your help! i consider myself good to go now!
Good to hear. And, you're welcome. You'll be pleased with one less maintenance headache. Always remember, though, that the voltage reading inside is usually around 1-1.5 volts lower than the battery terminal readings. So, your dash meter should read 12.75-13.25 volts. Of course, the closer to 1 volt difference you can get it, the better. Look on your fuse block. At some point in the late Sixties, Ford put extra terminals on the block, one each BAT & IGN. So, if they are there, try hooking your meter to the IGN terminal.
Thanks again! my fuse panel is a weak link and i hope to find another one but no luck so far..not on ebay anyway..ive already had mine apart once between the firewall and interior and cleaned the pins and fuse locations, the plastic or bakelite material the fuse block is made from is literally crumbling from age...if one of the fuse clips break then is gets a lot more serious...i dont really, and i really dont want to have to rewire the car with an after market wiring harness, i would like to find an original..will keep looking!
If it comes to pass that the Bakelite, or the clips, break, you can cut the wires and put an inline glass fuse holder in, to keep that function going. So, I know of a '68 Montego at a yard in S. San Antonio, it might still have its electricals intact. Or, they may be falling apart. But, it's about 90% complete, and if you want to try going for just the fuse block and pigtail wiring, I could snag it for you for a labor fee. Trust me, going for a full harness is a task of madness. I did that a few months ago on a '66 Montclair, and man, it was Hell trying to get it all within a three-hour window, as I mainly was pulling the A/C system. The whole dash had to be removed to get all of it, inside and outside!
