Manual glow plug rules

[DB2]

Hey all, my truck was getting harder and harder to start and naturally I checked out the glowplugs. I converted mine over to the ford solenoid a while back and was getting perhaps a bit overzealous on the push button inside. I pulled the plugs and this is what I found:


Here are three old ones and one new one. Notice a difference in length?

I figured I would ask what some basic rules should be so I don't get trigger happy again (how long is ok? Is it ok to glow while turning the engine over? can you glow then glow again right after or do you have to wait? etc). I once had heard that 60G's were self regulating but evidently they are not to a point.

 

[ak diesel driver]

see my post here http://www.thetruckstop.us/forum/showthread.php?33850-Cured-hard-starts-from-glow-plugs

 

[WarWagon]

Ether used? Possible bad injectors? Getting them really hot while the engine is hot and running can blow them in half.

I have seen the same on 60G's but there was a lot less plug to look at.

Duraterms have not given me trouble and I have really long, 20 second plus, glow times on 2 engines.

 

[Turbine Doc]

Are you sure they are 60Gs picture may be deceptive but those tips look really short to me, 60G stamped on the bodies ?

 

[DB2]

Yea they are 60G's. You're right the picture does make them shorter, and of course so did my abuse, the only good one of the batch is the left one that I had laying around and threw in to help fire it up. I guess I'll have to try the duraterms 20 secs of glow time would wake an engine from the dead. So I saw in the attached post that the mentality seems to be that there really isn't a limit on what you can run these, but my GP's are barely a year old if even so something must not be right. And they were consistent in being blown, which leads me away from the bad injector theory (plus my injectors aren't very old). Anyway just baffled by the whole bit, but I was holding them a good 30 seconds on desperate cold mornings before work sometimes while cranking, that's my honest guess.

 

[WarWagon]

The engine I had burn a hole in a scuffed and cracked piston had 60G's in it. I used a lot of ether to start the engine as it wasn't starting with glow plugs alone - I assume they were already burned up. Ether may have damaged any surviving plugs. The engine had a warped exaust manifold causing excess smoke with a GM3 and a cooling system failure of a bad fan clutch while working hard. So ECT got high and EGT was crazy no doubt.

I am not impressed with the 60G's as factory glow times do not get them really hot. Duraterms have the same issue of not getting as hot as the original glow plugs. Tunes address increased glow time needed. Old 1993 and older stand alone glow controllers do not!

I have run 1550 EGT without damage to the Duraterm glow plugs with an ATT turbo.

Factory turbo I have had a rust like surface 'melting?' on the next set of 60 G's. No extra glow times used. The rebuilt injectors were Chinese knock offs and after 20K miles had hard starting and were replaced at 30K miles after eating starters. There is a video around of the hard starting hit and stall while on the starter... The smoke rings out the exaust were interesting.

So with the above going on I can't say if it was high EGT with the POS factory turbo keeping heat in the engine, bad injectors, or sub par 60G's vs. Duraterms. However, even after being checked one set of injectors is the same from the blown engine, 30K miles and two sets of ruined/unusual glow plug failures.

I suspect the injectors were the cause of the glow plug failures, but, with the other factors I can't be 100% sure. The carbon build up that was 1/4" thick around one nozzle didn't make me feel better about the injector set. That nozzle was replaced and the rest checked when we pulled them from the blown engine having 15K on them. The engine was pulled again 7K later after totaling the truck on an elk with the new glow plugs looking like rusty metal texture yet shiny - melting or burning off the casing metal? Or was it when I pulled the engine again due to the bad injectors and FOD in the engine from an IP swap - I forget. This would have been 30K on the rebuilt injectors and 2 or 3 sets of glowplugs on 2 different engines. Follows the sticking open injectors IMO, but, as hard as I ran it with the factory turbo I will not say 100% for sure.

The one thing I did not do was extend the glow plug times on the 60G's - hadn't figured that out yet. Quite frankly you could leave them on till the battery died and not hurt Duraterms. (Only really extended times on Duraterms others have extended times on 60G's.) From the older glow plugs blowing in half I was scared to do this at first. So I do not think extended glow plug times are the cause of your problem. Look up the fellow who had one self limiting plug in a vise glowing for 24 hours. Sure when fuel hits it at 21:1 compression it is different...

 

[Turbine Doc]

Since you are replacing anyway out of curiosity & adding to the knowlegde pool, would you consider extend glowing the "used but good glows" you have; and see how long before it burns out in extended glow mode.

I'd do it myself, but I don't have any 60G on hand at moment.

Could be cumulative also vs 1 long glow event zapping them, .........a thought ocurred to me in past have you replaced the entire set or just the ones known bad as they failed ???

While trons really are not my prime forte... (for one of our resident tron savy folks) is it possible early death of the good glows with extra tron juice available feeding x number of remaining glows vs trons shared amongst 8 functional glows (you know that ohms law thing coming into play here) ? Reason I ask is there really no current regulation IIRC from the glow control AFIK it is pretty much an on/off unit via the contacts direct to battery then out to glow harnesses fromm the heavy contact side of the relay.

Additionally the glow relay is sort of unintelligent guided to be on or off by the PCM which is supposed to take ECT as a reference for glow on/off cycles, is it possible ECT always reading cold on you making many glow events more than required ?

While 60Gs aren't really for extended/many extended cycle/glow use like duratherms; they usually give fairly reasonable service life.

 

[NVW]

IIRC when all 8 glows are working the voltage is around 10.5-11 volts, taking a few out would up the volts but not to a great extent. I think it would be due to using the glows after the engine is running and the alt is kicking out 13.5 or more volts.

 

[DB2]

Well I'll admit I just did the driver side bank to hurry up and get me back to work. Been meaning to do the pass side but I only had four spare gp's sitting around and we all know the driver's side is the easiest to work on. (something about a big snail-shaped thing on the other side haha) Anyhow I like the sound of these duraterms and so maybe I'll start looking into that. I have a water meth setup I need to install soon, which if anything will clean things up in there for a new set of plugs to enjoy a bit more. So here's a quick question maybe revealing my ignorance on glowplugs--It is okay to fire them while cranking right?

 

[WarWagon]

The glow plugs come on in 'afterglow' when the engine is running. Cranking would be an extra 60A or so on the batteries. Other than that cranking when they are on doesn't appear to harm them.

 

[Turbine Doc]

Easiest way to get at the pass side glows is to jack up the vehicle, remove wheel, remove inner fender and then you have full access to everything on that side, looks daunting but it is not, takes about 5 minutes to do after you have done it the 1st time, only way I do maint that side is with inner sheet metal tub removed. Allows access to injector returns, downpipe, turbo bolts, starter/ starter brace, and gnds