glow plugs - fast vs. slow heat?

[LCAM-01XA]

Those would be for my buddy's 6.9, the local Glendale Auto Supply can get us the Beru ZDs for like $14 a piece, and they can also get the AC Delco 5.7 slow-glows for about $10 a piece. Question is, which ones should we go for? I've read that the slow-glow plugs are damn near indestructible even if left on, but how long do you have to have the on before you fire the engine? Like, I know the Berus should no be working for more than 8 seconds, how slow will the slow-glow ones be compared to those? Truck will have the glowplug system on a momentary-on pushbutton switch, so controllers ain't no issue... Also what about those Borg-Warner "dragon-power" glow plugs, anyone use those?

 

[fuzzy1626]

Don't know about the slow glow plugs, but the big problem with brands other than Motorcraft/Beru, is when they do burn out they swell up and you can't get them out in one piece.

 

[LCAM-01XA]

From what I've read is that the slow-glow units don't swell, cause they don't heat up nearly as much, so they don't distort. Or something like that.

 

[Diesel JD]

I'd buy the 5.7 AC Delcos and use the push button. You could probably leave them on all the time and not have them burn out. Grandfather's 78 Olds had this system, seemed like it took 5 minutes for the glow plugs to heat up when I was little, but in reality it was probably more like 60 seconds. Difference is those are 12V plugs and the ZDs are 6V with 12V going to them, which means they have a relatively short but eciting life, in the words of an engineering professor of mine..

 

[LCAM-01XA]

Well ain't the spade-connector ZDs actually 12V? I did some web-browsing last night and all info I gathered showed that the bullet-style ZDs for the 7.3 and the '87 6.0 (ZD1s?) are the 6V ones, whereas the spade-connector ZDs for the older 6.9s (ZD9s?) are designed for 12V... is that wrong, are all ZDs for 6V?

 

[Mr_Roboto]

All the factory IDI plugs are "quick glow" (6 volt) plugs.

 

[LCAM-01XA]

So for ultimate reliability we should go for the GM plugs, but the downside will be the longer wait-to-start time? Whereas the ZDs will start the engine fast, but are more likely to burn out if accidentally left on for longer period of time? Wouldn't slow-glow plugs work out better for WVO/WMO so they can preheat the cups longer?

 

[Diesel JD]

I really think the AC Delco slow glows are equivalent to the famed Lucas Constant Duty marine glow plugs. Zigg used to buy those from Paul at DAS when he still owned that shop. He said they were an AC Delco part, but when Zigg asked what application he wouldn't say.... I think they might have been very much like the 5.7 plugs. Don't really know about if they'd be better for starting with WVO/WMO but that's kind of a dicey proposition at higher blends even here in sunny FL, I'd not think about it in Michigan.

 

[LCAM-01XA]

We've been having 70F night ad 90F day temperatures lately, so "cold" start should not be much of an issue with WVO/WMO? Winter starts will likely be on straight-up diesel, as I can only imagine how much of molasses those turn into at 20F...

 

[Michael Fowler]

I am confused...
Correct me if I am wrong, but was not the basic idea of the Ford fast glow system to use 6 volt plugs in a 12 volt system, so that they will get hot quicker, but then having to cycle them, to keep them from burning up?

If that is correct, how can a 5.7 Volt plug be consudered slow glo?

I have 11.5 volt plugs on a manual susyem, and have had no failures in 5 or 6 years. I would consider these to be slo glo plugs.

 

[Pipeliner_86]

Ivan, did the truck drive ok going home Saturday?

I hope you guys get good use out of it.

 

[funnyman06]

They are not 5.7 Volt Glow Plugs they are 12 volt plugs for the GM 5.7L Diesel engine they used in a couple of cars.

 

[smoking89IDI]

famed Lucas Constant Duty marine glow plugs.

Off topic but my Range Rover uses lucas for every electronic bit in there, and yes every electronic bit does not work right, dunno if it is the Rover part or the lucas part .

 

[Mr_Roboto]

The early 350 diesels used a slow glow system. The plugs are dimentionally interchangeable with the 6.9 plugs.

 

[LCAM-01XA]

Ivan, did the truck drive ok going home Saturday?

I hope you guys get good use out of it.

Yes sir, it was just fine - I kept it at 55mph (2200 rpms) so it don't burn too much fuel, I have no idea how much I actually went through, but it purred like a kitten (well, more like a tiger) all the way to Livonia. If anything it actually has better brakes and easier steering than my dually, which was needless to say a very pleasant surprise! One thing I learnt tho, Jake sucks at the whole convoy thing, he would speed up miles ahead then pull over on the side of the road and wait for me to catch up

But yeah, truck will not become a backyard paperweight, you can be sure of that - tis already cleaned up and vacuumed out, right now the goal is to get the glowplugs working fine, then next weekend tis the injector return line and over the weekend maybe exhaust (Jake wants it like mine, straight up through the bed) - we got a list of maybe 50 or so things that we want done soon, but many are easy like new heater core hose and vacuum pump belts. I have a camera so I will keep you updated with pics as work progresses.