What size battery are you running?

[josh817]

Don't know if it's just because I have a fresh tight motor or if I got too small of a battery but it cranks over slugish like the battery is drained. Bought a 450 Cranking Amp battery thinking it would be enough... I know it's not the starter or anything because when I jump it, it spins quickly and fires up.

 

Curious what everyone else is running because today I was cranking it and after like 3 cranks and no start the battery didn't have enough juice to go anymore.

[philcas1987]

Was running an odyssey pc680mj 220cca I believe

[josh817]

Was running an odyssey pc680mj 220cca I believe

:[ Only 220... Maybe my Everlast Walmart battery sucks.

[ggzilla]

I am using a Group 26 battery, which is the smallest "common" battery in USA (it is stocked by all auto parts stores).

 

Group 26: 6.75 wide, 7.81 in Tall, 8.75 long

$25

31 pounds

CCA: 525

Reserve Capacity: 80 minutes

 

"Racing" batteries like Odyssey PC680MJT

$160

15 pounds

220 CCA

Reserve Capacity 24 minutes

 

Both work fine to start stock Datsun engines. If you have extra high compression (more than 11:1) the smaller one may not be enough

[josh817]

I'm thinking I have stock or less compression. Was a budget build, head wasn't shaved, stock gasket, dished 1mm oversize pistons. I guess I'll find out tonight. I hope Walmart lets me return this sucker. It still has 12v.

[ptown green]

:[ Only 220... Maybe my Everlast Walmart battery sucks.

 

Interstate batteries makes all of Walmarts batteries. Theyre actually pretty good.

[banzai510(hainz)]

have good cables(the ends) and grounded good.

alternator charging the batterey?????

[Wide14u]

i have a wal mart battery but it is the big one 1000 ca and 800 cca it works great

[john510]

Im using a group 27,quite a bit bigger but ive got 13' of battery cable to get to the starter.You sure cables and connections are all good ?

[ggzilla]

So small batteries are fine. They can be half the size -- even a 1/4 -- of the original Datsun battery. Batteries are generally much better today than they were in the 1970s. V8s used to take expensive 325 CCA. Now that is a cheap battery.

 

But some brands are notoriously flaky. And even good brands may be bad right off the shelf. The store will have a load tester to check the battery with, and in most cases it will tell if the battery is bad.

 

I've been buying Sears batteries for 30 years, and never had a problem. I did return one a few years ago after 2 years, and they replaced it under warranty. Auto-store brand batteries I've had many problems with them although they were new.

[Uncle Laulau]

I had the same problem with my 521. Just seemed like the battery was dead or dying. I don't know what size it is, it matches up to the alternator out of a 720. I replaced my starter a couple days ago for about $40 and now it fires up like a brand new truck. Good luck and hope you get it figured out soon.

[josh817]

I know it's not my alternator because it was acting dead the day I first used it. All connections are good. Bought a 650CA and will try it tomorrow.

 

The car I jumped it from was my little Honda Civic, and like I said when I did that it cranked over healthy.

 

We'll see tomorrow!

[I'm BLUE]

I will run Largest CCA's battery I can afford at the moment ,,,

[josh817]

The 650 worked great. Now my deal is that I'm running a Geo Metro one wire alternator however it only reads 12.7V when it's running. The catch is that I guess it's strictly maintaining the charge because I've driven for over two hours now with the headlights on and the battery isn't dead.

 

I think I have to hook up 12v and the IGN light or something as a "tickler" to get it up to 13-14v.

[metalmonkey47]

I have an 800CCA red top Optima that I payed $40 for

 

 

Lets just say, it turns my little A-series over like its a blender.

[josh817]

Now I'm just wrestling this god damn Denso one wire alternator. It's making me wish I never bought it.

[banzai510(hainz)]

always make sure the battery is charging the battery and also ck under a load.Light on ,heater ect... Sometime you can drive home at night and battery wont be charging. best to have a in car volt meter. So you can see the alternator loading down. So the next day you try to start it will have a dead battery as your car was really running off the battery.

 

the idiot light will not detect this soemtimes so a in car volt meter or even a cig light insert meter will still work .

[josh817]

Well Banzai, I'm trying to get some consulting from mike. I have my IGN light hooked to the "L" and a switched 12v to the "S" on the alternator. Light comes on when ignition switch is in run position but motor not running. Light goes out when running. Meter reads 12.35V but it creeped up to 12.4V after a minute of running. I can't figure out what else is needed... Is there suppose to be a resistor or something in the "L, light" wire?

 

I have a third spade on the alternator but the diagram is reading it as a "dummy".

 

This is how I have it:

[banzai510(hainz)]

GGZILLA has a good diagram of the alternator set ups.How to ck out also.

 

My 521 uses a T connector and a red white wire will go to the output post.

and E is case ground (black wire)

very early 521 could use a mutitude of connectors that I seen but most are the common 510/521 T connector Hitachi alternators

 

to me 12.4 with no load is a weak alternator or something wrong

[ggzilla]

Your wiring is fine

 

The cause is one of these:

* Alternator not guaranteed to put out full voltage until 1200 RPM. So rev it up.

* Battery cables/alternator BAT wire or GROUND wire may be corroded

* Alternator may be defective

[josh817]

I'll check to make sure the damn thing is grounded.

 

Is the White/Red wire (prong 9) from your gauge cluster going to the T connector, and the other wire in the connector is a switched 12v? The white/red wire usually goes to the voltage regulator if you were running the stock alternator.

 

I was told that it may take a few seconds, maybe minutes, to "excite" the alternator. Or I may have to rev the motor a little.

 

Damn thing is brand new. Maybe I'm the rare exception to faulty shit. hah

[banzai510(hainz)]

red /wht goes to the output, should be a round lug

 

yes there is a redwhit to the volt reg.

 

I dont know wht year your truck is. but later 521s are same as 510s and there is a simple diagram on the Dime Quarterly site in the electrical section. with colors

[ggzilla]

I was told that it may take a few seconds, maybe minutes, to "excite" the alternator. Or I may have to rev the motor a little.

 

That's a GM "one-wire" setup. On the GM vehicles the factory actually put more than one wire, and they worked like any other alternator. It only takes minutes if you don't rev the engine.

 

If you fit a Datsun alternator you won't have this problem.

[josh817]

I have two datsun alternators, one from the old L16 521 and one from this '78 L20B. I may try the one from when I bought this motor. I think it came from a '78. Basically I need anything that is internally regulated because I rewired the car for that type of system... I don't have a voltage regulator or any of that.

 

Here is a picture of how I have it:

 

Red is to the WR ign light and white is a switched 12v.

 

The case is in fact grounded.

 

WR wire I'm talking about. It is not a heavy gauge wire.

 

Truck is a '71 521

 

I revved the motor once but not very high... because it's midnight. And I didn't run the motor for longer than 5 minutes.

 

EDIT:

Here is the alternator I found in my parts bucket:

 

It came off the motor I bought to rebuild which was advertised as a '78 L20B with a 5 speed. If this is internally regulated I will throw it on instead of trying to be fancy. Luckily I bought the current alternator from my dad so he can just take it back.

 

If this Datsun alternator is indeed internally regulated I have two questions:

-T hook up, which is the tickler and which is the ign light

-how much current does it put out (although I'm sure it is enough for what I need)

 

Thanks guys. :thumbup:

[ggzilla]

That is not internally regulated, it's a stock early-to-mid 1970s Datsun alternator