Originally Posted by sjsingle1

the stud for the batt mount is part of the rectifier assembly..............so you will need a new rectifier

Originally Posted by spintech

My dash voltmeter is intermittently wavering wildly between 8 and 14 volts, usually at startup. This stops after about 2 minutes of running, at which time the voltemeter reads a steady ~13.5v. Battery always stays charged.

I am thinking this could be a developing alternator problem. Based on this thread:

1. I can replace my stock alternator with a junked KG3 truck alternator.

2. It appears the junked truck alternator comes with a 747 pulley. I am assuming that the stock f-body alternator also uses a 747 pulley.

3. 00pooterSS notes that pulley alignment slightly off after this mod, even with the presumed 747 pulley. Is this acceptable? Is this misalignment due to the cases being different, relative to the stock alternator, or is it pulley position due to differing shaft lengths? Is there any way to get perfect alignment?

4. Would changing the wiring harness 4 pin connector to 2 pin connector be beneficial so newer junk trunk alternators (with 2 pin connections) could be used?

Thanks.

Originally Posted by 00pooterSS

I posted a thread a while back about having alternator after alternator fail, one literally lasted about 5 minutes.

Long story short I tested every thing multiple times and even replaced the exciter wire and connector, never could find an issue and it all started when I replaced the factory original alternator with an aftermarket one, and it was all downhill from there.

The fix.... A truck alternator. I got the idea from another board member that the truck alternator actually fits the F body cars, so I went to the junk yard and spent $40 on a used 2003 Truck 145 amp alternator bolted it in and the voltage has never been more stable.

The 145 amp truck alternator only has one simple modification that needs to be made to use it, it does not use the rear support bracket that the F body alternator does so remove the one bolt and bracket, other than that it bolts directly in, plugs directly up, and works good!! So for less money you can have an higher amperage output, more stable, more durable alternator if you go this route. The pulley was even the same, this couldn't be easier.

I am going to add a wire from the back of the alternator to the battery to help carry the extra amperage since it has been stated the factory wire isn't even enough for the puny stock alternator.


I hope this helps anyone else with the same issues, here is the link to my original thread if you feel like reading more details of the problems I was having

https://ls1tech.com/forums/generatio...ders-here.html



Identifying the right alternator:Get a 99-2003 Truck alternator (may even apply to up to around 2005?), 145 amp, 4 pin connector, the code junk yards use to identify it is "KG3". The standard truck alternator is a 105, Escalades and such trucks with a lot of electronics use the 145. When I ordered mine I told them it was a 2003 truck, 145 amp, 4 pin connector, KG3 option and they figured it out. I got mine from LKQ for $43.30 picked up.




Some more info on identifying the alternator


ALSO VERY IMPORTANT Replace the alternator connector, the single wire connector with the plastic plug in on the top, these fail and cause problems as well. Here is some information on the connector.

AC Delco part PN# PT1136 (Oreilly has another brand also for the connector, don't remember the name brand)

I got mine from NAPA so you can try going there or go to Oreilly

http://www.oreillyauto.com/site/c/se...aro&vi=1361450

Originally Posted by sjsingle1

i know the OLDER CS130 had a bearing problems.......which consisted of cooling problems that over heated the bearings ..... and it was identified by GM and fixed in the new CS130 series........never heard of it being a problem since

Originally Posted by sjsingle1

GM made the bearings bigger and put that big funky cooling shroud on f bod alts......have not heard of to many peeps complain about bearing failures............think it is more rectifier failures

Originally Posted by djfury05

I went to Oreilly's and got a 100% new Ultima Select 145 amp alternator. Also got part # PT1136 (4-pin connector)

I've got the alternator installed and looking to wire it up now. Just want to confirm that I only use (1) wire on part # PT 1136 where the connector is labeled (L) on the rectifier? What is the point of getting a new connector for this alternator then? Just to ensure a clean good connection? Do I just cut the red wire from the existing plug on the engine harness and solder it to the new wire on PT1136? Nothing else to do right?