Bad lot of AC60g glow plugs

[K5wrench]

Anyone else replaced their glow plugs lately with AC60g's?

I converted my m1009 to 12 volt.
Replaced the glow plug card, glow plug connectors, glow plug relay, and glow plugs themselves.
My engine is a na 6.2.
I have had 7 of the AC60g's fail in 3 months.
Different cylinders.
They aren't burnt or pitted.
Wipe the soot off and they still look new.
I measure resistance and find them open and replace them.
Measured voltage at the gp connection at 11 volts during glow.
My voltmeter is new and never exceeds 11 volts during glow or 14.8 after glow stops.
Engine is staying cool.
Gp relay isn't sticking on.

Just can't think of why 7 glow plugs would have their element burn out in such a short time frame other than a bad batch.
Bought them on ebay.
Genuine AC Delco.
They measure between .8 and 1.1 ohm out of the box.

What other glow plugs are peeps using in their 6.2's around here?
I am a little pissed at Delco for the $80 worth of wasted glow plugs.

 

[BadDog]

Bought them on ebay.
Genuine AC Delco.

Are you sure? I have no idea how likely, but I would be wondering if they are counterfeit. If you are sure that's not the case, I've got nothin'.

 

[K5wrench]

I know, it doesn't add up.
I've checked everything I can think of.
These were never subjected to the CUCV 24 volt system through the resistor.
Must be I got a bad lot.
AC60g's are the Bee's knees.

Edit;
Maybe I am over-fueling.
There is a severe 10% grade for 10 miles to get up here.
Even though they don't look burnt, they could be getting hot.
Maybe I ought to downshift earlier.
Keep the revs up.

 

[diesel4me]

I've had many 60g's fail,but most didn't burn out,instead the tabs the wires slide on rotted off in a year or so..(and the ones that did that still worked)...

I read AC has them made by Bosch or Beru and are re-boxed,I too am sick of having to throw money away on new ones when they rot away rather than "wear out"..makes me wish I had a gas engine & spark plugs every time the diesel wont fire up on a frigid morning..

I have found my engine often wont start if it has more than one bad glow plug,it seems if one or two burn out,the rest of them fail to get hot enough ..In have one "stuck" GP and its dead,so I have to make sure the other 7 are all working if I want it to start in cold weather..

 

[K5wrench]

I has gotten to where i can tell instantly if one or more has gone bad.
When they all are working, it starts smooth and easy after the glow cycle.
With one bad, it starts fine but I can feel the roughness, like a fouled spark plug in a gas rig, for about a minute after start up.
Two bad, and it takes a second try to get it started.

These were made in Germany it says on the box.

I am thinking it is not a coincidence.
That due to the high altitude and having to climb from 3,800 ft to 9,000 feet in 20 miles, that maybe with the J code engine and high cap Oregon Fuel injection pump that I am pushing too hard climbing.
I don't have a turbo and therefore haven't bothered to put an exhaust gas temp sensor and gauge in.
But maybe at some point on that 10% grade i am cooking the glow plugs.
I just can't believe that 7 could go bad in such a short period of time.
Different cylinders.
I know it is easy to over fuel and get higher than 1100 degrees with a turbo.
But according to Lee Swanger in the Diesel Page articles, it is possible to approach that temp in a NA 6.2 if it is overfueled.
Maybe I need to turn my fuel delivery down.
Or just down shift and keep the revs up.
The dang thing really likes to go uphill though.
And reading others experience with na 6.2's leads me to believe mine might be set above average a bit.

 

[diesel4me]

My truck rarely sees any trips over 30 miles or any highway speeds,and no hills around here to speak of either..
Mine gets used as a daily driver,short trips,around town mostly,and speeds under 50 mph...
Perhaps the fact I cycle the glow plugs often doing short runs makes them fail sooner,but other guys I know with Ford 7.3's and some newer GM trucks with 6.5's seem to not have them failing very often..and they don't do many long trips or high speeds either..

 

[tRustyK5]

I never found a glow plug that lasted more than a year. 60G's, Autolite 1110's, even Kennedy quick heats...all the various brands I'd lose at least one in under 12 months. Once the first one went it was game on...sometimes one a week after that. So I'd order up another 8 and keep the remaining three or four older working GP's in a drawer because I knew I'd be playing this game again and again.

Self limiting, doesn't mean lasts forever. It just means when they fail you'll be able to remove them because the tips won't be swollen.

 

[K5wrench]

I never found a glow plug that lasted more than a year. 60G's, Autolite 1110's, even Kennedy quick heats...all the various brands I'd lose at least one in under 12 months. Once the first one went it was game on...sometimes one a week after that. So I'd order up another 8 and keep the remaining three or four older working GP's in a drawer because I knew I'd be playing this game again and again.

Self limiting, doesn't mean lasts forever. It just means when they fail you'll be able to remove them because the tips won't be swollen.

Yep, about what i figured.
The CUCV had a big resistor bank that restricted the 24 volts from the series batteries so that when all 8 glow plugs were pulling juice, you ended up with about 11 volts per plug.
But when one dies.. the rest get more than 11 volts and so on.. cascade failure.
Which is why a lot of guys swap the glow plug power supply to the 12 volt terminal on the firewall.
Well I skipped the whole program and converted over to 12 volts entirely, batteries parallel.
There is no way I could be over volt on any of these plugs.
I changed all the spade connectors just because.

But I also don't see how my NA 6.2 could even approach a temperature high enough to damage them when the turbo guys run right up to 1100 degrees and don't damage them.
I think my original premise must be true; a bad lot or the JDMTLTUT principal is a work (just don't make them like they used to).

 

[K5wrench]

You know something interesting.
Our 2008 Dodge 3500 with the 6.7 has a solenoid on the Alternator power wire.
I wonder why.
I am going to test it's operation tomorrow morning when it's cold and see if it cuts the alternator out of the circuit while the glow plugs are on.
Why else is it there?
I wonder if the big azz 100 amp alternator combined with 2 healty big truck batteries is over volting my glow plugs during the after glow cycle.
During the first glow before starting up, they get just battery power.
But once that engine starts, if the gp card stays in glow or clicks a few after glow cycles, or i were to use my back up bypass glow button, they would get battery power plus Alternator power which judging by my gauge is 13 volts while running during after glow.
I wonder if a mod is in order.
A continuous duty rated solenoid could isolate the alternator while the gp solenoid is engaged.
Hmmm.
Edit; that solenoid would need to be a Normally Closed instead of Normally open.
Well, i'll test the Dodge system anyways and see what they did there.

The other option is to remove the gp card and only use my manual gp switch and never once the engine starts.
Then see if the failure rate for glow plugs is reduced over time.
I mean, an AC60g can and will burn for 8 hours continuously.. at 10.5 volts.
Maybe the alternator bringing voltage up to 13-14 volts during that brief afterglow period is cooking them.
More coffee.. must have coffee.

 

[diesel4me]

Alternators don't like being run without a load--diodes can pop if there is no battery to accept the output..also it can cause a voltage spike when it starts to charge once the battery is put back in the circuit..

I rather doubt Dodge has it wired that way,but who knows,newer vehicles have the field excitation for the alternator (and output in some cases),controlled by the ECM instead of a 12V hot wire from the ignition and a voltage regulator..

In my case I'm thinking maybe LOW voltage is killing the glow plugs faster--my batteries are very old and marginal,they usually do get it to start,but if I have to make more than two attempts at cycling the glow plugs on a cold morning--they usually croak and crank it way too slowly to start it..

I know low voltage will burn up a starter and many other electrical things ,so maybe that applies to glow plugs too,though I wouldn't think so..one would think they would just glow less brightly or not heat up enough period..

Rene is right about the "self limiting" not preventing them from burning out,it just means they "shouldn't" swell up and be a bitch to remove later on..(I've had a few 60g's "split" and start to swell,but not enough to make removal that difficult)..

 

[K5wrench]

Yea, i was plain wrong about the solenoid being on the alternator power.
It was the glow plug solenoid in the Dodge buried under the air box.
But i measured voltage while it was doing it's after glow cycles.
11.5 volts at the gp solenoid while running for the 6.7 cummins.
Now i'll test my m1009.

 

[diesel4me]

Also I'd never again use an Autolite 1110 in my 6.2 again--maybe it was just a fluke,but one day I had a dead 60g and I took a used Autolite 1110 out of a blown up 6.2 I got for spare parts (crank broke!),and a few minutes after I drove away,the engine started clattering,I thought it spun a rod bearing...

I babied all the way home (3 miles) and once I got within walking distance,I decided to "finish it off" and I slammed it in low,and held it wide open until the govenor kicked in--then I let off and did it several more times...when I reached my driveway,it was idling quietly .like normal again..

I took out the GP I had just replaced,and only about 1/3 of the tip was still there,it had snapped off at an angle,like it had a crack in it--perhaps that engine it was in had water freeze in the cylinder,it was upside down when I found it lying in a friends back yard..but it had the oil pan on it and GP in all 8 cylinders--the J code intake was full to the top with dirt & mud though from laying face down..

But I also read sometimes "mixing" different brands of GP together may result in one getting most of the voltage and prevent the rest from heating up equally..all I know is I am lucky the pieces do not seem to have scored the cylinder,but might still be stuck in the top of the piston maybe..after that happened,I was expecting the engine to have a major malfunction for quite some time--so far no,however..

 

[K5wrench]

Okay, i ran an experiment on my m1009 6.2.
Voltage measured at the gp solenoid output to the glow plugs.
During initial glow i had 11.5 volts.
After startup, voltage climbed to over 13 volts while in after glow.
Then when afterglow was over, 14.8 volts.

I also tested the Dodge with the cummins.
11.5 volts during initial glow, after glow, and 14.2 when all glow was over.

I know it is apples to oranges.
But I did find that my m1009 is supplying significantly more voltage than the rated 10.5 volts during after glow.
Actually both the Dodge and M1009 supplied 11.5 during initial glow which is 1 volt over the gp rating for AC60g's.
But the big difference came during afterglow.
I wonder if this has anything to do with glow plug durability.
11.5 volts / 1ohm=11.5 amps per glow plug.
13.5 volts/ 1ohm=13.5 amps per plug.
That's not an insignificant amount of current considering they are rated at 10.5 volts or 10.5 amps (10.5v / 1ohm = 10.5 amps)
Not sure what to do about it.

 

[diesel4me]

Mine are manual push button operated now,no more "controller"..

I admit I may have left them on too long in frigid winter cold starts,but I find it has a better chance of starting on the first try,if I let them warm up a full 10 seconds at least--if it fails the first time,my batteries usually are sapped out by the glow plugs to crank it fast enough on the second attempt..
I also find leaving them activated while cranking makes it start more often,than letting them heat up and cranking with them "off" will..but having both the starter and glow plugs on at once does sap the batteries down faster,and more..

 

[campfire]

Buying plugs from a random Ebay vendor is a great way to wind up with counterfeits.

Bosch Duraterms come with unique serial numbers on each sealed box, and you can look them up on the Bosch website. This is their way of letting you verify that you have genuine plugs.

I have 3 of these trucks, but I haven't run into this issue. One truck ran the stock GP controller, and the controller failed. So now all 3 are on a manual switch. But I haven't had problems with losing plugs rapidly, aside from when I was running the original CUCV resister bank. I bought the pickup in 2010 and haven't changed the plugs yet. No idea what they are, but they keep working. The Blazer has been rocking six Duraterms and one 13G for a year and a half now (12 volt conversion, though the 13G is the lone abused survivor from the resister bank days). Like you said above, you can tell when plugs start dropping out, and I now hafta hold it for 8 seconds or so before cranking (instead of 4 back when it had 7 good plugs). I suppose the easiest way to fix this is to replace the one that's been broken this whole time. But where's the fun in that?

The 'burb got 8 new 60G plugs 4 years ago, but that was only about 2500 miles ago. So the jury's still out on 60G plugs. I do remember them reading 0.2 ohms when new, though. So 1.1 ohms is a very different signature, closer to the random plugs I have in the stepside. The resistance changes with temperature, so measuring cold resistance doesn't give the whole picture. But you clearly have a different signature than I do. I have a couple extra 60G plugs lying around, and both of them read 0.6 ohms today. These are with the "AC DELCO 0 100 271 107" part number (sometimes there is another number block before that first zero). What part number is stamped into your plugs?

I do give an afterglow if the engine is cold enough. The blazer voltmeter reads about 10.8V when glowing, 8.5V when glowing and cranking, and 14.2V when charging. But even when afterglowing, it's not the full 14.2 volts. I'll watch it next time if you're interested in my exact number.

 

[campfire]

Of course, now that I scrounged up a couple spare plugs, the blazer's engine sounds like a good place to store them.

 

[K5wrench]

This is a slight cross posting.
Bear with me.

So i have a CUCV M1009.
Basically a K5 Blazer.
Converted it to 12 volt but left both alternators in place but wired in parallel, like the batteries.

I suffered a spate of glow plug failures.
Found this online relating to what might have caused it.
Yes, in regards to a superduty.

"rampyJim 12:52 AM 01-12-2006
It has nothing to do with redundancy but everything to do with output. The second alternator is not waiting around for the primary alternator to fail.
The SuperDuty is built, primarily, as a "work" truck and may be subject to higher than normal electrical loads. Part of the reaoning behind the dual alternator configuration is for glow plug protection. Depending on the temperature, the glow plugs will remain "on" for some time after the wait to start lamp goes out.... The secondary alternator will not come "on line" until after the glow plugs have finished heating to avoid high system voltages that could lead to early glow plug failure."

Don't know if that is true.

But it is possible, that my second alternator cut in during after glow and caused an overvolt situation that burned the glow plugs.

I intended the second alternator to do exactly this; kick on when the voltage drops enough such as when using the winch.
I did not intend it to do so during glow plug after glow cycle.
Most of the time the second alt was inert and just like an idler pulley for an extra belt to run the water pump and ps pump.
The unintended consequence MIGHT have been to burn up $80 of glow plugs i short order.
So;

I have removed the second alternator.

Will continue testing regularly.

 

[campfire]

This is a slight cross posting.
Bear with me.

So i have a CUCV M1009.
Basically a K5 Blazer.
Converted it to 12 volt but left both alternators in place but wired in parallel, like the batteries.

I suffered a spate of glow plug failures.
Found this online relating to what might have caused it.
Yes, in regards to a superduty.

"rampyJim 12:52 AM 01-12-2006
It has nothing to do with redundancy but everything to do with output. The second alternator is not waiting around for the primary alternator to fail.
The SuperDuty is built, primarily, as a "work" truck and may be subject to higher than normal electrical loads. Part of the reaoning behind the dual alternator configuration is for glow plug protection. Depending on the temperature, the glow plugs will remain "on" for some time after the wait to start lamp goes out.... The secondary alternator will not come "on line" until after the glow plugs have finished heating to avoid high system voltages that could lead to early glow plug failure."

Don't know if that is true.

But it is possible, that my second alternator cut in during after glow and caused an overvolt situation that burned the glow plugs.

I intended the second alternator to do exactly this; kick on when the voltage drops enough such as when using the winch.
I did not intend it to do so during glow plug after glow cycle.
Most of the time the second alt was inert and just like an idler pulley for an extra belt to run the water pump and ps pump.
The unintended consequence MIGHT have been to burn up $80 of glow plugs i short order.
So;

I have removed the second alternator.

Will continue testing regularly.

A voltmeter reading during afterglow would let you know if you had an overvoltage problem.

I continue to think your 60G plugs aren't the same 60G plugs I've been using. Unless your ohmmeter is out of calibration. For what it's worth, I chucked my harbor freight cheapie after it started reading ~1ohm resistance across a dead short. Bought a slightly more expensive one (that is still in calibration) and measured 0.3 ohms across the spare plugs. Pretty close to the 0.2 that I measured 4 years ago.

Moral of the story...don't trust a cheap & old ohmmeter.

 

[K5wrench]

It's a Fluke meter.
It agrees with my S&W dash mount meter.
But I am inclined to agree; there may be something wrong with the ebay glowplugs i got.
But they were boxed in AC Delco boxes, each one roll marked.
I just can't dismiss the fact that I might have made a mistake leaving the second alternator online.
What I will do, is continue to check the glow plugs perodically.
See if the failure rate decreases.
I am rebuilding the second 27si alternator witb a kit myself.
But I'll keep it in my camper, as a spare.
I have 2 850 cranking amp truck batteries and 1 27 si 100 amp alternator.
I should be okay.

Something else worth mentioning;
At least on my m1009, the passenger alternator had a larger pulley than the driver.
I recall having to rev the engine to get alt #2 (passenger) gen light to go out before conversion.
Did GM anticipate the glow plug issue and use a smaller pulley to keep one alternator off line during afterglow?
Hmmm.
It is interesting.
I will continue to update here.

 

[campfire]

The voltage regulators in 27si alternators have a specific voltage "turn on" point.
That point is different for each regulator.
So cruising down the road, the alternator whose voltage "turn on" point is lowest, does all the charging.
The other alt just spins.
Now i recently went through a spate of glow plug failures.
So i eliminated the spare alternator.
My theory is; the glow plugs were receiving 14.8 volts during the after glow phase because the voltage drop from pulling 100 amps was enough to trigger both alternators to charge.
Instead of 13.8 volts with one alt, i got 14.8 with both alts..

Having 2 alternators does not force the voltage to rise. Having an alternator (either one) with a failed regulator does that. 14.8 volts is high, but it's not high enough that I'd worry about it. Your glow plugs are not seeing 14.8V at their connectors unless you have significantly upgraded their wiring harness. Check the voltage at the actual plug connectors while glowing if you think they're seeing too much. When cranking don't be surprised if the voltage is in the single digits.

And pulling more current does not cause the system to overreact and produce crazy high voltage. It either causes the voltage to drop (if the alternator can't keep up) or the voltage will stay the same (if the regulator is able to match the load). This is true whether you have 1 alternator or 15 of them like the local power plant. You will see a slightly higher voltage at the alternator when large current is being pulled, but that is because the resistance in the wires is causing voltage drop. So the plugs, starter, battery, etc. are not seeing the full 14.8 volts. That is the static voltage on the unloaded side of the circuit, and it's set higher to compensate for the voltage loss at the point of use. That's why your 12 volt batter requires at least 13.8 volts at the terminal to start charging (and more if you want it to charge quickly). You'll always get a lower number when pulling current through a wire, and the effect is more pronounced when you have 8 near-short glow plugs pulling through 14-gauge wires spliced into a 10-gauge wiring harness.

Play around with a voltmeter and see how the voltage varies depending on loading and location. Even though it all starts with a 12 volt battery (if not running) or a 15 volt alternator (if running). The starter motor never gets close to seeing 12 volts at the winding.