Hi All,

I bought my 1986 F250 just a month ago and have been working hard to sort everything on it. It came with a manual glow plug switch and the previous owner said the glow plugs were just replaced by a professional mechanic. I have read the issues about bad brands and am thinking about pulling one of them out to see if I can figure out what brand it is. If I do that, will I be able to see any markings to identify it? I would rather not pull out all 8 if they are in good shape. Also, is there any problem with using the manual switch long term? The truck will see some very cold temperatures next year.

Thanks,

h.ubk

 

you should see markings below the Threads

 

Thanks, that makes it worthwhile to pull them.

h.ubk

 

Yessir only motorcraft/beru glow plugs in these trucks. I don’t think there is any downside to manual glow plug controlling as long as you don’t hold them on for more than ten seconds or whatever the controllers timing was. I’m most likely going to do this as my controller which is only like three years old is turning them on while I’m driving. I’ll have to test them to see if there is any burnt out because they were on for quite a while. Paid over three hundred bucks for the controller and I’m not doing it again lol.

 

use a light coating of Anti-Sneeze compound before you re-install it, it will make it much easier to remove next time
and don't over torque it, just snug... 168 Inch Lbs Max...

I'm sure most of us here just snug em with a 1/4 drive ratchet

 

I personally use Autolite 1106 with a spring loaded toggle to fire the Relay, these plugs are 11 Volt plugs and I never hit em more than 3 seconds.

Most Folks here will tell you to use the ZD-1 these are 6 Volt plugs and I'm fine with that when using the Controller..... but I personally do not want 6 volt plugs on a hand Switch JMHO

 

You might consider using PB Blaster on the GPs for a day or two before you remove one. Loosen/snug them a bit each evening. This will hopefully prevent a broken tip if they are cheapies!

 

Definitely a good recommendation with the anti seize, I use that stuff on a lot of stuff and glow plugs especially

Yeah the 6volt plugs heat up QUICK I wouldn't hold them on for more than 5-7 seconds.

If you want to convert to zd-9's you can get glow plug harnesses for a Ford 6.0 powerstroke and they'll fit the plugs well enough. You'll have to do some splicing and move it over to the fender area where your gp relay is.

 

My 86, 6.9 GP controller went bad and I put a momentary switch under the dash for them. I lived in snow country and plugged it in at night and did a slow 3 count and tried it. If it didn't start I'd do it again, and it almost always started on the second shot. I did have to do a 3rd a few times when it got into the - teens.

 

When I was replacing glow plugs I did quite a bit of looking around. My truck came with a button which was fine but I didn’t want to run the same 6v plugs and accidentally burn those up. I ended up finding on eBay for a pretty good price, Napol brand dual coil plugs. The idea is as they heat up they also heat up slower as in there is more resistance to the current and therefore they don’t get so hot to burn out. Had them for a year now and they all still work. When it is around freezing outside you can kinda tell if you’ve held the button for long enough in which case 5–6 seconds isn’t long enough. But a full 10 seconds and the truck fires first crank. The truck also came with a circulating block heater and no matter how cold out, it gets real warm under the hood and it’ll start without glow plugs.

 

welcome to FTE
I think you will find all GP's today are a dual coil design (regulating and heating coil) there may be some exceptions on the Made in China Clones, but most of them that I have disassembled are of the dual design ... it's not that it is actually 2 coils.. it is 1 coil but the thickness of the windings vary.

you may find this useful.... https://www.denso-am.eu/media/corpor...cal-evolution/

 

So, I finally pulled one of the glow plugs and it was labeled Autolite 11.5V. This forum doesn't seem to think too highly of them.

I generally hold the manual button for five seconds to crank after the truck has been sitting. After that, I don't use the glow plugs -- the engine has enough compression to start on it's own.

I can't find it from the part description on any of the sites, but it appears the ZD-1A's are 6V. So what happens if I start running 6V plugs? Would there be a problem? Isn't the manual switch just doing the same thing as the relay -- except that I am using my gray matter to time it?

h.ubk

 

what you need to understand is that with the OEM Controller it calls for a specific Voltage type plug because it uses Feedback from the plugs to "Control" them in a Manual System where you use a switch to energize a Relay "YOU are the Brain" this is why I recommend using 12 volt or 11.6V plugs for a Manual system... you are not using an after Glow timer where current feedback is required...

I use the Autolite 12V plugs right now and looking at my records they have been installed since 2007 I normally pull them every year or 2 just to inspect them .. they are past due for an inspection now... I never hold my spring loaded toggle more than a 3 second count and it is always enough to bust it off first thing in the morning... I never have to hit the plugs for the rest of the day.... I have said it several times here IF you are using the OEM Controller then use the OEM required plugs... IF you have modded to a Manual switch then use 12 or 24V plugs. Autolite makes a Quality Plug... when my 12v plugs show signs of failing I will replace them with 24V plugs Next time..... I think many Clones are out there with the Brand name stamped on them..... just like Ray Ban, Oakley, and Rolex watches.

Autolite would love to hear from you about the quality of their plugs, I have personally sent them links posted in the forums(not always from here) about their Crappy Plugs and none of the Bashing can give evidence of Inferior materials being used .... and BTW I don't work for Autolite other companies make High quality Glow plugs too..... Seems like Motorcraft doesn't make their own Glow plugs they seem to be made by BERU ... but folks get caught up in the internet Hype


EDIT: FRAM Filters will destroy your engine ...... funny they are still in business
I have a 96 Jetta about ready to hit 500K and has had nothing but FRAM filters on it ... and the Recommended Filter by the Vortex Forums is a MANN Filter made in China go figure ????????

The point I'm trying to make is do routine inspections and Maintenance. and you probably won't have a problem.

 

Thanks for that response. It sounds like perhaps I should be staying with the Autolite plugs and just check them regularly. I have a glow plug reamer that I use on my Mercedes. I'm going to see if that will fit for this engine. It basically works out all of the carbon deposits to prevent the plugs from sticking. I think that is more of an issue on the Mercedes because if memory serves me, the glow plugs are mounted horizontally.

Is there a problem with me running the glow plugs for about 5 seconds? I don't think the engine will turn on right now if I just do 3 seconds. I think this is likely because my positive battery cable is corroded and has the insulation trashed by the connectors. I have had a few times where I try to crank the engine and the starter doesn't even turn or click. Usually, if I try to start again after that, the engine jumps on with no problem. I'm actually surprised how quickly the 8 cylinders jump to life as it will start faster than the other diesels I have owned.

h.ubk

 

it's very important that battery cables are in good shape on our diesels..... IF the cables are crappy then it can lead to premature starter failure ... slow crank is not a good thing.... running a glow plug for 5 seconds (a 12 volt plug) should not be an issue but if Cranking speed is too slow then running the glow plug for 30 seconds is not going to help.... the starter need to spin at least 300 RPM

The starter should not draw more than 500 Amps.... the batteries should be in good condition. .... these are the keys to the starting of the IDI diesel