Club Cobra GasN Exhaust  

Go Back   Club Cobra > Manufacturers, Engine Builders, tools, and parts. > ERA---Speak with Bob Putnam

Keith Craft Racing
Nevada Classics
Keith Craft Racing
Main Menu
Module Jump:
Nevada Classics
Nevada Classics
MMG Superformance
Advertise at CC
Banner Ad Rates
MMG Superformance
MMG Superformance
MMG Superformance
March 2024
S M T W T F S
          1 2
3 4 5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31            

Kirkham Motorsports

Like Tree10Likes

Reply
 
LinkBack Thread Tools Display Modes
  #21 (permalink)  
Old 10-03-2022, 07:23 AM
Tommy's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2002
Location: Dadeville, AL
Cobra Make, Engine: Sold my EM.
Posts: 2,433
Not Ranked     
Default

Dan - If your old Corvette is a C1, then I have nothing to add. If it's a C2, it's BATT gauge carries only a very small current and is not as hazardous as gauges that carry the full output of the battery/alternator.
__________________
Tommy
Cheetah tribute completed 2021 (TommysCars.Weebly.com)
Previously owned EM Cobra
"Never attribute to malice that which is adequately explained by stupidity." - Hanlon's Razor
Reply With Quote
  #22 (permalink)  
Old 10-04-2022, 04:55 AM
DanEC's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2009
Location: Little Rock area, AR
Cobra Make, Engine: ERA Street Roadster #782 with 459 cu in FE KC engine, toploader, 3.31
Posts: 4,480
Not Ranked     
Default

It is a battery gage but outside of the Corvette world I wasn’t sure many would understand the term. I wasn’t sure how much juice was sent through it. They have voltmeter conversions for them too, based on the same stories of dangers from the original gage - possibly overblown.
__________________
ERA 782 Running
https://www.youtube.com/watch?v=Cfge...b1-77fqwFRu7c]
Reply With Quote
  #23 (permalink)  
Old 10-04-2022, 05:29 AM
Tommy's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2002
Location: Dadeville, AL
Cobra Make, Engine: Sold my EM.
Posts: 2,433
Not Ranked     
Default

Quote:
Originally Posted by DanEC View Post
It is a battery gage but outside of the Corvette world I wasn’t sure many would understand the term. I wasn’t sure how much juice was sent through it. They have voltmeter conversions for them too, based on the same stories of dangers from the original gage - possibly overblown.
As I understand it, the C1 amp gauges actually carry a lot of current like the Cobra gauge you've been discussing. The C2 gauge connects to the wire between the alternator and the buss in the engine compartment at two different places. The very small voltage difference between those two points is what it senses and displays. It can be disconnected and everything else continues to work normally. . . My C2 is far from stock and I modified my instrument panel to include a voltmeter rather than the BATT gauge.
__________________
Tommy
Cheetah tribute completed 2021 (TommysCars.Weebly.com)
Previously owned EM Cobra
"Never attribute to malice that which is adequately explained by stupidity." - Hanlon's Razor
Reply With Quote
  #24 (permalink)  
Old 10-05-2022, 05:24 AM
Grubby's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Nov 2007
Location: Clayton, IN
Cobra Make, Engine: ERA 838
Posts: 1,064
Not Ranked     
Default

Patrick,

This one of your better suggestions.

I plan to wire it into 838 as part of the initial build.

John
Reply With Quote
  #25 (permalink)  
Old 10-05-2022, 05:16 PM
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2020
Location: Baltimore, MD
Cobra Make, Engine: Everett Morrison FE 428
Posts: 150
Not Ranked     
Default

Could anyone possibly make a schematic for this shunt I have an EM so my wiring is different, I already had to replace my amp gauge because it overheated, or should I just convert to volt gauge? I assume any ignition hot wire could be used for the volt gauge? Thanks
Reply With Quote
  #26 (permalink)  
Old 10-05-2022, 06:47 PM
patrickt's Avatar
Half-Ass Member
Visit my Photo Gallery

 
Join Date: Jun 2005
Cobra Make, Engine: ERA #732, 428FE (447 CID), TKO600, Solid Flat Tappet Cam, Tons of Aluminum
Posts: 21,889
Not Ranked     
Default

Take a nice picture, with a reasonably high resolution, of your engine compartment kind of from overhead, and I'll draw you the connections on it. I mostly want to see the alternator, the starter solenoid if you have one (and I mean the little four post FOMOCO solenoid that mounts to the firewall or fenderwell, not the starter motor) and the battery. The easiest, safest, and for surest method is to run a 10 or 12 gauge wire from the alternator to the battery connection at the starter solenoid.
Reply With Quote
  #27 (permalink)  
Old 10-06-2022, 05:42 AM
CC Member
Visit my Photo Gallery

 
Join Date: Nov 2003
Location: New Britain, CT
Cobra Make, Engine: Size 10 Feet
Posts: 2,993
Not Ranked     
Default

Quote:
Originally Posted by cobragene View Post
Could anyone possibly make a schematic for this shunt I have an EM so my wiring is different, I already had to replace my amp gauge because it overheated, or should I just convert to volt gauge? I assume any ignition hot wire could be used for the volt gauge? Thanks
Your ammeter has two main terminals. Each one has one (or more) heavy wires. All you do is add the shunt wire from one main terminal to the other, leaving all the other wires in place.

If you have male spade terminals on the gauge, each end of the shunt wire must "Y" and have a male and female so that the original connections can be retained.

Last edited by strictlypersonl; 10-06-2022 at 06:15 AM..
Reply With Quote
  #28 (permalink)  
Old 10-06-2022, 07:22 AM
RockBit's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jun 2014
Location: Dallas, TX
Cobra Make, Engine: ERA #812 427/482 FE
Posts: 495
Not Ranked     
Default

Quote:
Originally Posted by cobragene View Post
I assume any ignition hot wire could be used for the volt gauge? Thanks
Correct. A key on 12v wire can be connected to the volt meter, and a good ground.
__________________
Chris
Reply With Quote
  #29 (permalink)  
Old 09-22-2023, 09:14 AM
chucks1's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Sep 2010
Location: Mineapolis, MN
Cobra Make, Engine: SPF, 395 Stroker
Posts: 89
Not Ranked     
Default

Quote:
Originally Posted by patrickt View Post
Take a nice picture, with a reasonably high resolution, of your engine compartment kind of from overhead, and I'll draw you the connections on it. I mostly want to see the alternator, the starter solenoid if you have one (and I mean the little four post FOMOCO solenoid that mounts to the firewall or fenderwell, not the starter motor) and the battery. The easiest, safest, and for surest method is to run a 10 or 12 gauge wire from the alternator to the battery connection at the starter solenoid.

I've been perusing this thread as I have an ammeter issue similar to that noted by the OP and have a question about this shunt wire, which I'll eventually get to.

My SPF ammeter started a constant flickering on both sides of 0 last driving season with no correlation to electrical load. It was just a constant flicker from the time I started the car until the time I shut it off.

I noticed this behavior after having replaced my 11 year old battery, so began troubleshooting there. A load test on the battery says it is good. The battery reads ~14 volts after taking a drive. I have checked and changed battery terminals (they are marine brass) and am confident they are good. The battery ground is good, as is the engine to frame ground. I also added a 12 gauge ground between the VR and the engine block.

After all of the above there is a new symptom; the ammeter needle will occasionally flicker as initially noted, but then read more normal for a bit before taking a nose dive out of sight past 50- and then back to ~0 where it will read normal before starting the behavior all over again.

At present I am running 12 gauge wires from the battery to the cockpit so I can put an analyzer on it to see if there is any change to battery/charging that corresponds to the ammeter dips. Planning to do that test hopefully this weekend.

As to the shunt, am I correct in understanding this is simply a 12 gauge wire from the battery post on the solenoid to the battery post on the alternator? And doing so will route some current away from the ammeter to hopefully get a more normal reading from the gauge (assuming I have no other issues)?

I'm not much with electrical issues, so appreciate any assistance . . .

Chuck
Reply With Quote
  #30 (permalink)  
Old 09-22-2023, 10:01 AM
patrickt's Avatar
Half-Ass Member
Visit my Photo Gallery

 
Join Date: Jun 2005
Cobra Make, Engine: ERA #732, 428FE (447 CID), TKO600, Solid Flat Tappet Cam, Tons of Aluminum
Posts: 21,889
Not Ranked     
Default

Quote:
Originally Posted by chucks1 View Post
As to the shunt, am I correct in understanding this is simply a 12 gauge wire from the battery post on the solenoid to the battery post on the alternator? And doing so will route some current away from the ammeter to hopefully get a more normal reading from the gauge (assuming I have no other issues)?
Well, kind of.... Putting a wire from the solenoid to the alternator will bypass the ammeter, but it will bypass other stuff as well. If you look up at Bob P.'s post with the picture of the shunt wire he has it as just going from one post of the ammeter gauge to the other post of the ammeter gauge -- that's like a three inch wire. That's a true shunt wire. I prefer to run a wire from wherever the first convenient connection is on each side of the ammeter which, for me, happens to be a circuit breaker connection and a fuse box connection both on the engine side of the firewall. But that's on an ERA, every manufacturer is different. OTOH, if my ammeter was really, super-duper easy to get to, like being right out in front of my face, so that I didn't even have to bend my back, much less crawl under the dash like an eel, then all I would have done is exactly what Bob's image shows.
Reply With Quote
  #31 (permalink)  
Old 09-22-2023, 11:43 AM
chucks1's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Sep 2010
Location: Mineapolis, MN
Cobra Make, Engine: SPF, 395 Stroker
Posts: 89
Not Ranked     
Default

Ahh, okay. So it would seem that I mostly understand what is being done here but I, much the same as you just described, try to refrain from under-dash exploits as they generally end up causing more pain than it's worth. Appreciate the response Patrick, I'll have to give it all some thought after I do a road test with an analyzer to see what's really happening with my charging system.

Chuck
Reply With Quote
  #32 (permalink)  
Old 09-22-2023, 12:00 PM
patrickt's Avatar
Half-Ass Member
Visit my Photo Gallery

 
Join Date: Jun 2005
Cobra Make, Engine: ERA #732, 428FE (447 CID), TKO600, Solid Flat Tappet Cam, Tons of Aluminum
Posts: 21,889
Not Ranked     
Default

I see you ran an extra ground to the voltage regulator, which is good, and poor grounding is the #1 cause for a varying voltage which would make for a varying current which would cause your ammeter needle to waver. Just to be absolutely sure though, get a nice four foot long wire with alligator clips on both ends and put one on your voltage regulator case and the other on the negative post of your battery, then see if the wavering is still there. If so, confirm that your voltage at idle is really bouncing around and up in to the 15 volt range, which it shouldn't. Generally when that occurs it's because of poor grounding at the voltage regulator and I'm still suspicious of that.
Reply With Quote
  #33 (permalink)  
Old 09-22-2023, 12:43 PM
chucks1's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Sep 2010
Location: Mineapolis, MN
Cobra Make, Engine: SPF, 395 Stroker
Posts: 89
Not Ranked     
Default

Makes sense. One more item added to the weekend to-do list. Thanks!

Chuck
Reply With Quote
  #34 (permalink)  
Old 09-24-2023, 04:46 PM
chucks1's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Sep 2010
Location: Mineapolis, MN
Cobra Make, Engine: SPF, 395 Stroker
Posts: 89
Not Ranked     
Default

I had a few hours today, so did a little more testing.

I had previously run a ground wire from the VR to the engine block, but this time also ran a temp ground between the battery and VR. The ammeter kept up its' constant flickering even with the extra ground.

Being slightly impatient and better at the shotgun approach as opposed to logical troubleshooting, I replaced the VR with a new one and ran a single new, permanent 12awg ground from the VR to one of the bellhousing-to-block bolts. I then pulled, inspected, cleaned and re-installed the battery to frame and engine to frame ground cables (something I had already done last fall).

With my analyzer hooked up in the cockpit, I started the car to see what I had. For the first time in a long time, the ammeter needle was steady and, after some initial charging from the startup, hovering just to the right of center at a fast idle. The analyzer agreed with that. Going down the road I was getting a constant ~14.5v reading on the analyzer and the ammeter rock solid to the right of center. Running a load (headlights and heater fan) there was a brief dip, but then right back to right of center and ~14.5v.

This was a fantastic turn of events until 10 minutes into the drive, the ammeter dropped to 25- and my analyzer agreed, having dropped to ~12.5v and continuing to decrease in small increments. Things continued to head south for 1-2 minutes, when both ammeter and analyzer went back to right of center and ~14.5v respectively.

The same phenomena happened twice more while out driving. All is working well when things take a 1-2 minute dump before returning to normal.

Any thoughts come to mind with this one? I don't have a new alternator to shotgun into the car, but am thinking about pulling mine and having it tested.

Chuck
Reply With Quote
  #35 (permalink)  
Old 09-24-2023, 05:09 PM
patrickt's Avatar
Half-Ass Member
Visit my Photo Gallery

 
Join Date: Jun 2005
Cobra Make, Engine: ERA #732, 428FE (447 CID), TKO600, Solid Flat Tappet Cam, Tons of Aluminum
Posts: 21,889
Not Ranked     
Default

Quote:
Originally Posted by chucks1 View Post
Any thoughts come to mind with this one? I don't have a new alternator to shotgun into the car, but am thinking about pulling mine and having it tested.
Yep, pull the alternator and have it tested under load for at least 20 minutes or until it fails, whichever comes first.
Reply With Quote
  #36 (permalink)  
Old 10-04-2023, 03:30 PM
chucks1's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Sep 2010
Location: Mineapolis, MN
Cobra Make, Engine: SPF, 395 Stroker
Posts: 89
Not Ranked     
Default

It took a while, but I now know my alternator was failing. I bought a new PowerMaster 7078 75-amp unit, installed my serpentine pulley, installed the alternator and tested the car.

No more flickering ammeter, the battery is in a constant state of charge when the car is running and the ammeter gauge will drop slightly when additional load is added. It's perfect!

Hopefully the really cool weather can hold off until I get a few miles on the thing yet this fall.

Appreciate the assistance Patrick . . .
Reply With Quote
  #37 (permalink)  
Old 10-04-2023, 04:18 PM
patrickt's Avatar
Half-Ass Member
Visit my Photo Gallery

 
Join Date: Jun 2005
Cobra Make, Engine: ERA #732, 428FE (447 CID), TKO600, Solid Flat Tappet Cam, Tons of Aluminum
Posts: 21,889
Not Ranked     
Default

As Mr. Mustang is fond of saying, "I am here to serve others."
Reply With Quote
  #38 (permalink)  
Old 10-04-2023, 07:41 PM
DanEC's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2009
Location: Little Rock area, AR
Cobra Make, Engine: ERA Street Roadster #782 with 459 cu in FE KC engine, toploader, 3.31
Posts: 4,480
Not Ranked     
Default

Quote:
Originally Posted by chucks1 View Post
It took a while, but I now know my alternator was failing. I bought a new PowerMaster 7078 75-amp unit, installed my serpentine pulley, installed the alternator and tested the car.

No more flickering ammeter, the battery is in a constant state of charge when the car is running and the ammeter gauge will drop slightly when additional load is added. It's perfect!

Hopefully the really cool weather can hold off until I get a few miles on the thing yet this fall.

Appreciate the assistance Patrick . . .
Is this with or without the supplemental shunt wire installed?
__________________
ERA 782 Running
https://www.youtube.com/watch?v=Cfge...b1-77fqwFRu7c]
Reply With Quote
  #39 (permalink)  
Old 10-05-2023, 07:55 AM
chucks1's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Sep 2010
Location: Mineapolis, MN
Cobra Make, Engine: SPF, 395 Stroker
Posts: 89
Not Ranked     
Default

I do not have a shunt wire installed, at least not yet. It's still on my list of potential winter projects though . . .

Chuck
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 09:45 PM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
The representations expressed are the representations and opinions of the clubcobra.com forum members and do not necessarily reflect the opinions and viewpoints of the site owners, moderators, Shelby American, any other replica manufacturer, Ford Motor Company. This website has been planned and developed by clubcobra.com and its forum members and should not be construed as being endorsed by Ford Motor Company, or Shelby American or any other manufacturer unless expressly noted by that entity. "Cobra" and the Cobra logo are registered trademarks for Ford Motor Co., Inc. clubcobra.com forum members agree not to post any copyrighted material unless the copyrighted material is owned by you. Although we do not and cannot review the messages posted and are not responsible for the content of any of these messages, we reserve the right to delete any message for any reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold us harmless with respect to any claim based upon transmission of your message(s). Thank you for visiting clubcobra.com. For full policy documentation refer to the following link: CC Policy
Links monetized by VigLink