Bosch 80034 (Duratherm ?) Resistance in Ohms

[LastFbody]

Had the joy of having my truck barely start at 44 degrees the other day, it's time for glow plugs. Picked out Bosch 80034s based on several different opinions from here and other sites.

Saw a couple reviews mention occasionally having quality control issues with a plug or two, mainly with broken connectors, but still. I want to test them all and make sure they're up to spec before I go through the trouble of putting everything back together.

Does anyone know the resistance in Ohms to test for on these plugs specifically?

----------Edit for future reference: 1.0-1.3 Ohms, cross check the authenticity of your glow plugs (or anything else Bosch, lots of counterfeit parts out there) at http://www.protect.bosch.com/

 

[Tinstar]

Most guys here go with the ACDELCO 60Gs.
Self limiting and a very good and reliable plug.
Glow plugs are very easy to change.

I don’t know what the ohms should be for that specific plug.
Never considered Bosch plugs.

Is your system stock or modified?

 

[Bighorn]

My spare set of AC60G's measure .8 to .9 ohms each.
Your duratherms should be in that range as well since the whole system is built to supply about 12 amps per glow plug.
12 volts/1 ohm= 12 amps
12 amps x 8 plugs =96 amps.
So you whole gp system can pull about 100 amps during glow operation.
Obviously the Duratherms are different and probably have a different resistance.. but they should be in that range as wildly less resistance would pull more current than the system was designed to handle.
The beauty of the AC60G is it's ability to self limit= changes resistance when it gets hot to limit the amount of current it draws.
As I found out myself, the AC60g is not idiot proof.
I installed a resistor bank that had lower than stock resistance and it smoked an AC60G.
Then the rest of the glow plugs received more than normal voltage, and another gp died and so on.
Killed all of them.
I recommend swapping the glow plug power supply onto the 12 volt lug on the firewall.. like everyone suggested I do in the first place.

 

[LastFbody]

The Bosch plugs I got are the other common self limiting choice. Comparable to the 60g but slightly faster heating. Still not anywhere near as fast as a swellman, but I'm not putting that crap in my engine. My old crusty plugs were 13Gs which are also supposedly self limiting, but I read that other users on here had swelling issues with them anyway. Anyway, read about someone torture testing Bosch and Ac60s side by side by running em continuously. The Ac60s gave up the ghost in a few hours, the Bosch one died after a few DAYS of running. I'm not usually rough on my plugs at all, but that kind of durability is impossible to ignore.

Right now my system is 100% stock, eventually gonna go straight 12v for sure. Heard that having GPs fail with the stock resistor pack causes the voltage to go up on the remaining good plugs, causing more failures, no thanks. Not sure about going to a manual switch or not yet, not sold on the idea 100%.

Thought about it earlier and realized I'm being a dummy about this. I have a set of 8 coming, if they're all good they should just read more or less the same as eachother, any bad ones should stick out if there are any. I'll post what they read new for future reference since it's not archived online anywhere.

 

[Bighorn]

Two of my bad 60g's swelled up enough to need channel lock plier extraction.
Ditch that resistor.
Just make a wire with ring connectors; 8 inches in length.
Connect from gp sol to 12v terminal.
Disconnect the resistor bank at the 24v bus.
Done.
Don't wait.
Mine was already converted but i stupidly put it back.
Those resistors; all of them in existence, are 30 years old.
Chuck them in the trash.

 

[gimpyrobb]

Let me know if they come with the hologram on the box. I've heard there is a lot of fakes out there.

 

[LastFbody]

Let me know if they come with the hologram on the box. I've heard there is a lot of fakes out there.

Good intel. Mentioned this to a buddy of mine at work, a speed shop he goes to made a public post warning people about fake Bosch fuel injectors.

I'll make sure they're legit.

 

[rsh4364]

Search Bosch duraterm glow plugs in the archives, some guys were using them back in 2013. Some good information and videos there.

 

[Matt5]

Anyway, read about someone torture testing Bosch and Ac60s side by side by running em continuously. The Ac60s gave up the ghost in a few hours, the Bosch one died after a few DAYS of running. I'm not usually rough on my plugs at all, but that kind of durability is impossible to ignore.

It is easy to ignore because your are looking at something that flat out does not matter in a glow plug... they are on for 30 seconds, not 3 hours. The test shows nothing. Now if you had a test where they were CYCLED... 10,000 times. This is a test that matters in the real world. Maybe they beat the death out of the 60gs when on for a day (never happens in usage) but they fail with heat cycling (what happens in usage) in half the cycles...

Same concept as showing a transmission going 5 million miles... However in the test all it ever does is one set of shifts into high gear. and then never shifts again for the 5 million miles. Pointless test not real world... Same tranny could die in 50k miles under normal usage. Typical advertising, show a test that means nothing but let people assume what they want out of it.

Hope you don't get fake plugs, so sad anymore that everything we buy either may not work or may flat out be fake...

 

[LastFbody]

So they all tested between 1.0-1.3 Ohms, and they all turned out to be authentic. Bosch has unique 18 digit codes on each glow plug box with the aforementioned holographic decal showing the last 6 digits a second time on the packaging.

This is where you cross check the codes: http://www.protect.bosch.com/

It's a tedious process, but it's smart to do.

I can see why some people had broken spade terminals on these, it's a big fat spade spot welded to a small post at the top of the plug. I'd venture to say they're JUST strong enough, and not overbuilt. Gotta finish changing out the truck side terminals for the fatter spades the new GPs have before I can report how well they operate. Read about grinding the terminals down to fit, but after seeing how they're put together and how much material I'd have to take off to make that work, I decided that it was a bad idea.

 

[LastFbody]

Got the truck all put back together today, started like a champ. Though to be fair this time around it was 40 degrees ambient, not windy, and in direct sunlight. I'll have to see how the new plugs handle an actual cold start before I say they're good or not.

The wait light stayed on a lot longer than it used to. With my old super rusty ac13s the wait light would stay on for ~10 seconds and the relay would turn off and back on at about the 7 second mark, and stay on a little after the wait light went out. With the new plugs it stays on for 15 to 20 seconds and the relay completely coincides with the wait light. Judging from a couple different cold start videos I saw that seems more correct, and my truck was running kinda wrong since I had it.

Can anyone confirm?

 

[Bighorn]

I am glad you got her fixed up.

With either my after market glow plug card or my new production stock card, my gp system does the following;
At about 0 degrees.
No block heat.
Key on, wait light and solenoid for 30 seconds.
Then the wait light goes out but the solenoid stays on for another 10 seconds.

Around 32 degrees.
No block heat.
Key on, wait light and solenoid on.
After 15 seconds the wait light goes out but solenoid stays on for about another 10 seconds.

It is this way with either card.
I have learned to trust the wait light and turn to start when the light goes out instead of waiting for the solenoid to stop.
Starts just fine without block heat down to minus 20 this winter.
I have a propane block heater i used a few times but it is a long cold snowmobile ride just to reach my truck, so i usually just run 5w 40 oil and let the gp system do it's thing.
I have AC 60 g plugs in there.

 

[LastFbody]

Huh. That's interesting. Before and after the new glow plugs my relay (solenoid ?) clicks on and off a couple times for ~4 second intervals after startup when its cold. It never stayed on steady like you're saying.

Whatever is making the clicks I hear whether it be relay or solenoid it does coincide with the voltage needle dropping deep into the yellow.

 

[Bighorn]

You mean the after glow cycling.
I get that too.
On particularly cold mornings i get 3 cycles of afterglow with the aftermarket card and a couple of longer afterglow cycles with the stock card.

I do find it strange that my wait light goes out before the actual initial glow cycle stops.
But it does the same with either gp card.
My solenoid isn't sticking as far as i can tell.
But when i follow the light and start just after it goes out, then engine starts perfectly.
Using the instructions on the visor for throttle position.
I have waited the additional time after the light goes out until the solenoid turns off too, but it doesn't make a difference since the engine always starts on the second or third revolution.

 

[LastFbody]

Alrighty, had it parked outside tonight and woke up before sunrise to start it up, was at best 26 degrees ambient temp and it started up like it was 70 and sunny out with no cold advance at all. Wait light ran for 17 seconds and coincided with the plugs recieving power.

I'm satisfied with this result. Last year it just barely got going in almost the same conditions with the cold advance set all the way. I sort of wish I had a colder day to test it harder coming up, but there won't be for the forseeable future. I'm ready for summer anyway.

 

[Tinstar]

17 seconds seems like a very long wait light time.


When really cold outside, mine is on for about 10 seconds.
Starts right up.
Warmer it is, the shorter the wait time.

-6* was coldest start to date and wait light wasn’t on for more than 10 seconds.
Again, cranked right up.

Still haven't used block heater.

 

[Bighorn]

17 seconds seems like a very long wait light time.


When really cold outside, mine is on for about 10 seconds.
Starts right up.
Warmer it is, the shorter the wait time.

-6* was coldest start to date and wait light wasn’t on for more than 10 seconds.
Again, cranked right up.

Still haven't used block heater.

I think so too.
That is why i bought the other glow plug card.
But my wait times are identical.
It bothers me but i can't find anything wrong.
Maybe I'll swap my spare gp solenoid in just for the heck of it but i believe that would either work or not.

 

[Tinstar]

I am still running the stock GP card.
Have 3 brand new spares.
New card does not change wait time.

I have installed new acdelco GP temp sensor.
Recently installed new trombetta GP solenoid.
Recent set of ACDELCO AC60G’s glow plugs.
All stock system

If you count it out, 17 seconds is a really long time.
Seems like the resistor would get hotter than normal.

 

[Bighorn]

Don't tell Rus..

Mine doesnt have a resistor.
I converted to 12 volt.
As for my glow times, the truck sits at 9,000 ft in the snow.
I think the temperatures are warmer where i measure(at my camper) than at the lot 3 miles away.
My longer glow is probably due to the stupid cold and long days between drives of just sitting.
That also explains why i drive the snot out of it every chance i get.
Oh spring.. hurry up!
Still 52 inches of snow here.
Grrrrr...

 

[LastFbody]

I thought it was kind of long too, but I watched a few cold start videos with cucvs specifically, and most of those wait lights stayed on for about 17 seconds as well. I don't think it'll hurt good self limiting plugs unless its shooting more that 12v into them.

Is there any way that the truck can sense when the plugs are heated up enough? Or is it more primitive than that? My truck seems like it may have been refitted by the army sometime in the 90s. It had ac13s instead of the usual ac9s or ac11s or swellmans, they may have changed the electronics around somewhat too. The carc is dated 6/96 in the driver door, thats why I'm thinking they could've done other things in the 90s.

I definitely want to do the 12v bypass, is what Bighorn detailed on page one all I need to do plus a different relay for the lower voltage? That resistor is a huge liability with the threat of cascading glow plug failure. That part of the system seems to still be original from what I can tell.