voltage at starter

[lfdsteve]

Testing my wiring before initial start up. Setup is trunk mount bat. With cutoff switch and ford solenoid. Passes thru bulkhead with bulkhead fittings. Using double ought wire. Only getting 11.78 volts at bulkhead fitting and still have the run up to the robbi MC starter. Is this voltage drop normal. Is it a.concern with such a long run to go? Should I be worried about amps and not volts?
Thanks
Steve

[astroracer]

Are you using 2/0 cable or 2ga wire? There is a big difference. Most of your aftermarket kits sell you 2ga wire. It is about 1/4 in diameter. 2/0 cable will be just under 3/8ths. 1/0 cable is the smallest I would recommend and I have no voltage drop issues with that.
You should see a full 12 to 14 volts at the starter.
Mark

[lfdsteve]

Using 1/0 marine grade. It's huge...

[astroracer]

If that's the case then cable size should not be an issue. The first things I would check are your cable terminations. Make sure they are done correctly, bad terminations are the cause of 90% of all voltage issues.
Mark

[greaser]

It should be reading the same as when you check it at the battery. No real drop unless items are turned on regardless of wire size..

Please dont overlook the ground side. If you are just using a handheld voltmeter in the engine bay, your ground from the meter back to the battery may have resistance.

[David Pozzi]

What is the voltage at the battery? 11.75 is 30% charged.
http://www.rvtechlibrary.com/images/voltchart.gif

[lfdsteve]

Voltage at battery is 12.78. I guess I will check for resistance thru each link, bat to switch,which to solenoid ect. Ground is not.at.play as I was touching battery post.
I used crimp.style connectors with proper tool. The only issue I ran into during setup was the connection points on the solenoid were only 3/8 I think so I had to step down to that size but still kept the same size wire. Hmm.
Thanx for the help.

[David Pozzi]

I would not be concerned about the 3/8" connection. Look at your grounds for a clean connection, ground cable for engine to chassis. Any paint or Annodizing will reduce voltage. The voltage passed by a 3/8" bolt or 5/8" bolted connection should be identical if only a test meter is being used without any load applied.
Once you start passing more amps, then the wire & connection sizes come into play.

[Gandalf]

Use a long piece of (standard size) stranded wire to "extend" the +12v probe on your meter back to your battery terminal (a piece almost as long as the vehicle really speeds up trouble-shooting this stuff). Be sure to protect any connections with some duct tape or similar. This will allow you to move around your car with the meter in-hand and check voltage at different points by using just the ground probe. Start testing at the battery (through the long wire) and check you have the same voltage you mentioned at the battery previously. Use that as your reference. Then move out from there using that long wire to check different points on the chassis, engine etc. See where differences show up and that should help narrow down the issue.

This assumes a ground issue. You can do exactly the same for the +12v side by extending the ground cable.

Let us know what you find.
G.

[lfdsteve]

The test originally performed grounded right to the battery negative post so I am assuming the ground is out. But....
Would it matter if the cable ran off the top positive post of my optima dual post battery but I used the SIDE negative post? I wouldn't think.so but should ask anyway.
I will run further tests tomorrow.
Thanx for all the help

[rocketrod]

...But....
Would it matter if the cable ran off the top positive post of my optima dual post battery but I used the SIDE negative post? I wouldn't think.so but should ask anyway.

No, it doesn't matter, but make sure the side terminals are screwed in all the way and not loose.

[lfdsteve]

Thank you guys for all the help. I will get back to Yall with the results.
Thanx again
Steve

[lfdsteve]

Checked resistance at all cable ends and it was nonexistent thru any of the cables. Hooked everything up and turned the key. My brand new 462 pontiac roared to life. First engine build and so far so good. Now if I could only get the rest of the car finished. Thanx for the help!
Steve

[astroracer]

Kool! Glad it all worked out.
What was done to the engine? I am thinking about building a stroked 400.

[lfdsteve]

It's a stock 455 block and crank, probe forged pistons ans scatt h beam rods. Edelbrock round ports ported and a nice roller cam custom ground. Using Powerjection 3 efi. Sounds mean but will feel better after I het some time on it.