68 Jav 343 Altenator

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   I am adding electric fans and have a sniper efi, so does anyone make a 100+ amp altenator that fits my Jav?
Thanks, 
 Randy

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
RandyB Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Aug/04/2020 Location: Florida Status: Offline Points: 462	Post Options Post Reply Quote RandyB Report Post Thanks(0) Quote Reply Topic: 68 Jav 343 Altenator Posted: Jul/30/2021 at 2:39pm
	I am adding electric fans and have a sniper efi, so does anyone make a 100+ amp altenator that fits my Jav? Thanks, Randy
	Randy B 68 Javelin SST 343 73 Charger Rallye 340 triple Blk

bigbad69 Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jul/02/2007 Location: Ottawa, Ont. Status: Offline Points: 6668	Post Options Post Reply Quote bigbad69 Report Post Thanks(0) Quote Reply Posted: Jul/30/2021 at 2:44pm
	What is the current draw of your fans and the Sniper? It should be in the spec's for those parts. You may not need a 100+ amp alternator.
	69 Javelin SST BBO 390 T10

RandyB Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Aug/04/2020 Location: Florida Status: Offline Points: 462	Post Options Post Reply Quote RandyB Report Post Thanks(0) Quote Reply Posted: Jul/30/2021 at 2:59pm
	2 fans, initial draw is 25a each, efi 4a and fuel pump 10a +/-
	Randy B 68 Javelin SST 343 73 Charger Rallye 340 triple Blk

JGRANTAMX Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jun/02/2017 Location: Maine Status: Offline Points: 1694	Post Options Post Reply Quote JGRANTAMX Report Post Thanks(0) Quote Reply Posted: Jul/30/2021 at 3:25pm
	I asked mostly the same question a few weeks ago. J https://theamcforum.com/forum/alternator-upgrade-question_topic111418.html

tomj Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/27/2010 Location: earth Status: Offline Points: 7544	Post Options Post Reply Quote tomj Report Post Thanks(0) Quote Reply Posted: Jul/30/2021 at 11:15pm
	The 25A startup surge is easily handled by the battery. The starter motor draws hundreds of amps, but only while cranking. A 35 amp alternator will take a few minutes to replace that lost battery charge. The battery smooths out large but short-term loads, the alternator charges at a lower rate, for a longer time. Same logic applies to other high current draw; electric windows, stereos, headlights, etc. Battery handles short term loads, the alternator keeps the battery "full". Edited by tomj - Jul/30/2021 at 11:17pm
	1960 Rambler Super two-door wagon, OHV auto 1961 Roadster American, 195.6 OHV, T5 http://www.ramblerLore.com

bigbad69 Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jul/02/2007 Location: Ottawa, Ont. Status: Offline Points: 6668	Post Options Post Reply Quote bigbad69 Report Post Thanks(0) Quote Reply Posted: Jul/31/2021 at 6:15pm
	Tom made some good points. Honestly, I would leave the current alternator in place if it's being working for you before the fans and EFI. Just monitor the battery voltage regularly. If you find it slowly drops, then you need to look at a bigger alternator. Oh, and if you do find the alternator can't keep up, NEVER go with a 1-wire as a replacement. The controller for Sniper won't tolerate a noisy supply. It may work kinda, sorta, but you will be chasing gremlins in the EFI.
	69 Javelin SST BBO 390 T10

javtopgun Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Aug/03/2021 Location: NV. Status: Offline Points: 342	Post Options Post Reply Quote javtopgun Report Post Thanks(0) Quote Reply Posted: Aug/04/2021 at 8:49pm
	If you want a large amp alt . go with what amc use to use for fleet vehicles that is if your still using a stock 37 amp Alt. you can get 55amp a/c delco for amc pretty cheap from rock auto . less than 40 bucks if i recall . My 68 jav up in till 4 months ago STILL had the factory 37 amp alt . Yep 52 almost 53 years old . lol . The only reason i changed it was that it started puting out 18 volts to the batt . when it started doing that , cant pin pin point when, but when i tried to go to pertronx they would burn out and after a quick bat voltage check when running , i was shocked to see 18.2 at the batt. Dont understand why it was not frying my voltage reg , Guess over the years ( many ) it slowly built to that and the reg, started, soloniod coil , it all just adapted ! But what was weird was i was only getting 5,2 volts at the pos side of coil instead of 10.5 ? go figure . It did burn out 2 elec fuel pumps tho . I changed it All out tho when i discovered it except starter .

bigbad69 Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jul/02/2007 Location: Ottawa, Ont. Status: Offline Points: 6668	Post Options Post Reply Quote bigbad69 Report Post Thanks(0) Quote Reply Posted: Aug/04/2021 at 10:15pm
	With 18.2V on the battery, it's not surprising you fried the electronics. They're not designed to take that much voltage. A car should never be run at that voltage long enough to burn out two fuel pumps. Since the alternator was putting out that much current, it was probably the regulator that failed (or a connection to the alternator). That it could charge the battery to 18.2V shows that "little" alternator was perfectly capable of handling the load on the battery, and more. If it was undersized, the battery voltage would have slowly dropped. I would have the battery tested. It may have been damaged by the overcharging.
	69 Javelin SST BBO 390 T10

javtopgun Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Aug/03/2021 Location: NV. Status: Offline Points: 342	Post Options Post Reply Quote javtopgun Report Post Thanks(0) Quote Reply Posted: Aug/10/2021 at 12:24am
	It was 1 fuel pump , oddly enough from the first day i bought it i never had any problems with the charging system, but i did when i bought it put a new batt in along with hoses and belts and so on . But no issues at all no electrical problems with car electrical interior or exterior or underhood . Never had a reason to check out electrical anything even in zero degree weather back in STL ( in storage but start it once or twice a weeK ) , one turn of the key and instant start up. When that was found , changed every thing , The pump only started when the eng. was rebuilt . so i think the pertronix burning out caused that to start . i really dont know . Batt seems fine as that is the only thing i did not change ( changed coil too ) ???? got me . im just trilled i never had an electrical issues ! I even had a rad fan on it but took it off after rebuild, but untill i figured out my heat issue . i wish i would have left it on . might reinstall it cuz da weather do get HOT here in vegas ! Seen 118 for week last year !
	1968 Javelin SSt 343ci semi restomod .