Author Topic: New Alternator cat 3116  (Read 7795 times)

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Offline inkaroo

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New Alternator cat 3116
« on: February 10, 2016, 04:42:10 PM »
I am on the road and I believe my alternator is not charging 100%.  I checked with Cat and was told the chassis mfg. added the alternator.  I have a Gillig chassis and called them.  They want almost $700.00 plus shipping for a new alternator.  They tell me it's  a Delco alternator but Gillig will only give out their own part number forcing one to buy from them.  I know it is a Delco, but have no idea which Delco alternator it is.  I tried searching Gillig's part number with no luck.  I am on the road in Columbia, SC and would like to buy one at a local dealer.  I don't see a part number on the outside of the old alternator. Any ideas?

Joe
Cat 3116
1991 Beaver

Offline Brett Wolfe

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Re: New Alternator cat 3116
« Reply #1 on: February 11, 2016, 09:13:44 AM »
Joe,

If you have verified that the alternator is at fault, I would contact Delco and get the name of an authorized electrical shop in your area to rebuild it.

If you are not positive that it is the alternator (i.e. could be battery isolator, loose wire, etc, loose or slipping belt), let us know and we can help with the diagnostics.

BTW, suspect there is a Delco part number on the alternator itself. How accessible is your alternator (to both look for PN and to check connections on the back of it?

Brett

Offline ziggyh

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Re: New Alternator cat 3116
« Reply #2 on: February 11, 2016, 09:32:44 AM »
Attached is a Delco core guide that lists and shows pictures of Delco products, as Brett indicated u should be able to find a part number on the alternator many are stamped in the case and dirt hides the number.
ZiggyH

2007 Revolution LE
C9

Offline inkaroo

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Re: New Alternator cat 3116
« Reply #3 on: February 11, 2016, 10:46:10 AM »
I am not 100% it is the alternator.  What I do know is I have a new battery about 30 days old.  I did put my charger on and charged up the batteries.  The charger indicated there was an alternator problem.  I drove it for about an hour and a half today to our next desination.  Started out with full charge.  Now at 12.6V.  That with no head lights or heater or wipers on pulling any extra power.  It sort of appears to me the battery is charging, just below what it should be.

Joe

Offline ziggyh

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Re: New Alternator cat 3116
« Reply #4 on: February 11, 2016, 11:15:01 AM »
What is the voltage with the engine running at idle and 1200 rpm, you should get about 14.2-14.7 volts.  If the temperature is cold when checking the charge voltage SOME alternators can charge as high as 15.2 volts to warm the battery to speed up the chemical action in the battery as the temperature increases the charge rate will come down

Open Circuit Voltage VS. State of Charge.

12.66V     100%     
12.45V     75%     
12.24V     50%     
12.06V     25%     
11.89V     0%     

If the batteries have a removable cap, a hydrometer test would be a better indication of state of charge.

Specific Gravity VS. State of Charge
1.265     100%     
1.225     75%     
1.190     50%     
1.155     25%     
1.120     0%   

To get the most accurate hydrometer reading, you should adjust your hydrometer reading according to the temperature. If the electrolyte temperature is above80°F , add .004  to the hydrometer reading for each 10 degrees above 80°F. If the electrolyte temperature is below 80°F, subtract .004 from the hydrometer reading for each 10 degrees below 80°F.

Check each individual battery cell. If the specific gravity varies more than .050 between the cells while the battery is at a 75% state of charge or above, then the battery is bad and should be replaced. The cells that have a specific gravity of .050  less than the highest cell are bad cells.

A hydrometer reading of 1.265 or greater at 80°F indicates a full charge for most batteries.

A better tool than a battery hydrometer is a refractometer, its readings do not need to be temperature compensated and the same tool can be used to check ethylene glycol and propylene glycol antifreeze for freeze protection.

ZiggyH

2007 Revolution LE
C9

Offline Brett Wolfe

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Re: New Alternator cat 3116
« Reply #5 on: February 11, 2016, 01:58:27 PM »
You will need a digital voltmeter to do realistic troubleshooting-- but this is almost a "requirement" on any RV.  Prices start under $20.

First, verify that all wire connections on the alternator are clean and tight. If external sense wire check it very carefully, as it is small gauge and can be broken by vibration, etc.

With engine running, use cruise to set idle to 1000-1200 RPM.

Check voltage at the B+ terminal of the alternator.  Check also at the battery isolator (if equipped) and also at the batteries.

Offline ziggyh

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Re: New Alternator cat 3116
« Reply #6 on: February 11, 2016, 03:57:04 PM »
It is also a good idea to check the output of the alternator under load using an amp clamp. the alternator amperage output should be a minimum of 90% of rated output with the engine running fast idle and placing a load on the batteries with a carbon pile.

If a carbon pile is not available, run engine with no electrical loads at high idle and measure output voltage, then turn on all 12volt electrical loads and remeasure output voltage.  It should be within .5 volts of the unloaded voltage.

Using a digital meter, measure the AC voltage at the output of the alternator, it should not exceed 500 mV.  Readings higher are an indication of bad rectifier diodes or stator windings.
« Last Edit: February 11, 2016, 05:44:07 PM by ziggyh »
ZiggyH

2007 Revolution LE
C9

Offline inkaroo

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Re: New Alternator cat 3116
« Reply #7 on: February 11, 2016, 06:51:08 PM »
My poor charging problem is now fixed.   It was the alternator gone bad.  It was a Delco Remy alternator and was able to find one at a local supplier.  It was about $480.00 less that what my chasis mfg.  wanted for one.

Thanks for all the responses to my post.

Joe
Cat 3116
1991 Beaver

Offline bullheadbum

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Re: New Alternator cat 3116
« Reply #8 on: February 12, 2016, 02:35:22 PM »
Joe, do you have the part number? I have a 91 Beaver Baronet with 3116, would be nice to have that Delco part number in my book if/when I need it. Thanks Keith