number3

last year i had my alternator rebuilt , told the guy to boost up the amps in case i ever wanted to add a/c , he did. this year i looked down and my ammeter was pegged to 40 + , replaced external (solid state regulator ) with old points style , all good pushing out 12 volts .the other day cruisin down the road i get a quick miss ,a while later multiple quick misses, get to the cruise in and stay for a couple hours leave and no issues . Yesterday take the wife out to dinner we go to leave and dead as a doornail ! open the hood move the firewall connectors around and i tighten the battery shut off wheel bingo starts right up ! I get home and wiggle the battery shutoff and get a quick miss do it a couple more times same thing , so i figured the battery disconnect is junk . I disconnect it today and run the cable directly to the battery and no problems starts right up , put my meter on the batt and only getting 11.4 volts , go to alt and same thing 11.4 , did my alternator fail do i need a new one ? if i replace it should i go to just a 2 wire internally regulated ? whats the wiring procedure if i do ? Thanks in advance !

Frankie the Fink

You may have other issues but first thing is to get a knife blade disconnect -- those round **** things are crap....

You can test that round **** do-hickey by throwing it way out in a lake -- if it floats its good; if it sinks its bad...

You'll hear differently from folks but I've had 3 fail in different ways - one came apart, one corroded to pieces and another got to the point I didn't have enough hind end to tighten it sufficiently for a good connection....

And before anybody asks these weren't the cheap ones either...

BTW - your alternator should be "pushing out" 13.8V-14.2V; not 12V with the engine running....
You can measure that across the battery terminals with a multimeter and the engine running...

Make sure your V/R is grounded...

You can swap in a Wells VR-715 solid state alternator (available anywhere for about $28); its plug and play and if it fixes your problem you'll know it was the V/R....if not, it makes a cheap spare for an emergency...

number3

ive got 2 of those spares frankie ! the cover seperated from one because of the heat and the other one got water in it , the cheap plastic covers warped from the heat . Everything was fine till now and yup mine was bad it sank ! Im only getting 11.4 at the batt and the same at the alt , and yes the regulator is grounded would the loose connection to the ground terminal on the batt have fried my alt ?? thanks

Frankie the Fink

Mechancal V/Rs are actually pretty robust and don't have sensitive circuitry - they are basically points and armatures. Its possible to crack it open and look for burned or stuck points or fried wiring... I put a VR-715 under the stock cap and have been running it for 3-1/2 years..

You can have the alternator "load tested" at a bunch of places BTW...for free...

number3

thats why i went back to it . but when i go straight to the alt im only getting 11.4 , before it was putting out what it should but not now , whats the best way to check if alt is good or bad ?

Frankie the Fink

Make SURE that gang connector on your V/R is on TIGHT - I pushed my 66 Mustang 200 yards home because that connector got knocked sideways...

It never hurts to take the leads off the horn relay and clean things up - that's a major distribution point for current to a lot of places.

You could have lost a diode in the alternator...
They will test your components in the car or removed if you carry it to them...

https://www.autozone.com/landing/pag...=in-our-stores

number3

good info frankie thanks for the help !

bj1k

I've had several of the round **** type over the years on different Corvettes and they were all junk . I now have the knife type and they work great .

woodsdesign

When you upgrade the amp output of the alternator they put more windings in the same size case with the same fan. So, it is easier to have internal overheating issues. That will cause internal failures.
I would look at getting a different alternator. JMO

buns

No need to remove the alternator to have it tested, you can do it yourself.


.

number3

Perfect ! thanks buns just what i was lookin for !

USMC 0802

Frankie the Fink

number3

thanks frankie , i just might try using one of my spare vr 715's and see if that straightens things out . i am planning on adding a/c and cooling fan this winter . what amperage alt (if i need one ) would you suggest ?

Frankie the Fink

Are you talking about aftermarket A/C and electric cooling fan(s) - the fans are big current draws ?

number3

yes i ordered a kit from vintage air with the single cooling fan

Frankie the Fink

I would say not less than 70 amp maybe closer to 90, but call the Vintage Air tech line to confirm - those guys are very good about answering such things...a SPAL electric fan sucks down some juice..

number3

I read somewhere that it needs a 20 amp fuse , so i'll call vintage tomorrow and see what they say. I also need to relocate the alt to drivers side , is there an extension harness out there to relocate it ? thanks again for your help frankie

Frankie the Fink

number3

I just checked that number and thats exactly what i need ! many thanks frankie !!