Glow Relay decision - looking for advice (1 Viewer)

[Henry James the 47th]

Okay, here's the deal:

My 2H engine (out of a 24v. CDN-spec HJ60) originally had the dreaded Superglow system. I yanked all that stuff off, plugged the holes on my intake manifold and cylinder head and am planning to put together the simplest 12v. system I can, ala -'Wilson' switch. To that end, I obtained an early BJ60 ignition barrel, which allows me to use the 'G' position as a momentary switch for the glow plugs at any time. That replaces the need for a momentary switch on the dash.

I pulled off the fast glow plugs and replaced them with the 10.5 slow glow type.

I then found a OEM 'Glow Controller', which is a wire coil behind a mesh screen, fitted to the dash that glows in tandem with the glow plugs. Since there is a mounting hole in my dash for this unit, I would like to make use of it.

Now we come to the problem: the glow plug relay. The early ones (1980~82) simply are not available any longer, at least not from Toyota N. America or Toyota Japan. So, I need to move to a slightly more modern glow plug relay, as they are still obtainable. Toyota did continue with a non-superglow set-up for 'general designation' zones, but the glow relay for that set up is not available from Toyota any longer.

When Toyota went to Superglow sometime in 1982, they went to a system with two glow relays, a main and a sub. In the picture below, the sub is on the left and the main is on the right.

The sub relay looks just like the previous main relay in the earlier glow system with the single glow relay. The newer type of main glow relay looks like a giant solenoid. It looks heavy duty anyway.

The question is: which relay would you get, wiring from scratch as I am, the main or the sub?

Can either be used in concert with the 'glow controller'? I am not wiring a timer into the system - like I said, I want a really simple set up.

Can either be used in an intermittent manner, like a Wilson switch?

As it understand it, in a Superglow set up, the main glow relay supplies the initial big zap to glow the plugs, while the sub sends the subsequent lower rounds of voltage to the plugs. Can the sub relay handle regular use if used as a main? Will the main relay, used in a momentary fashion send too much power to the plugs and burn them out prematurely?

The local Toyota garage dudes thought that either would work fine, and I wanted to get some more opinions on this before buying the relay.

Need some 'outside the box' thinkers here who know something about these relays.

 

[cody c]

too many options, through in a wilson switch. you'll get the feel for how long you need to push the button. simplicity.

 

[Henry James the 47th]

too many options, through in a wilson switch. you'll get the feel for how long you need to push the button. simplicity.

You perhaps misunderstand - I already have the functional equivalent of the Wilson switch, as I explained in my post, with the ignition switch that I have. The Wilson switch is a momentary push-button that can activate glow anytime after starting, and that is exactly the same thing I have in the form of my early BJ60 ignition switch. I can glow the system, then go to start, and if the smoke out of the exhaust pipe isn't clearing up as fast as I would like, then I can place the key back to the 'G' position while the engine is still running and apply more current to the glow plugs. After 1982, 60 series trucks had a different ignition switch that doesn't allow function in this manner.

Too many options? Really? I'm trying to choose between a sub relay or a main relay - that's two options. Any fewer and the word "option" wouldn't apply, no?

 

[Big Blue 84BJ60]

i hooked up a wison switch to my truck 85 3b engine superglow type it went bad on me i burned out a set of plugs and got fed up with a broken timer after spending $160 from toyota on plugs. one set 10.5 plugs from ngk are alot cheaper. I used the main relay the round one and all has worked well 2 years later no problems i would go with the main one because i was affraid the secondary woud burn out. the first looked to be more heavy duty (bigger cable connected to it) and so thats the way i went the wilson switch is great no more spuddering on cold mornings just fire the plugs for longer (even with the truck not plugged in) ide use the main one my 2 cents

 

[Henry James the 47th]

"...I used the main relay the round one and all has worked well 2 years later no problems i would go with the main one because i was affraid the secondary woud burn out. the first looked to be more heavy duty (bigger cable connected to it) and so thats the way i went..."

That was some helpful info, thanks Big Blue 84BJ60. I was thinking the same thing. It's good to know that you've had no problem with the cylindrical relay after 2 years.

 

[tehcruiser]

If you want a heavy duty relay that is going to be around for a while, I would suggest a starter relay.
A relay does not limit the current flowing through it, it's just an electrically activated switch. If you are worried about the amount of current flowing to the glow plugs you could put an in-line resistor, and size it accordingly.

 

[brownbear]

Napa GPR 109,

12 volt heavy duty glow plug relay. Probably much cheaper than oem. Little wires are the switch wires, big ones.....well you know.

 

[cody c]

ok, i use a wilson switch as well. i suppose it would be comparable to a main and not a sub. when i start the cruiser i hold it on long enough for it to start. i have a feel for how long it takes through trial and error since ive had it. i also know that it tends to smoke after the initial start up, so i push the button for a few seconds atfer it has turned over and wait like 6 or so seconds more and press it for a few seconds again. I can see and hear a difference during this point. usually only do this process once or twice during startup. i have done this with the same set of glow plugs for about 4 years. so far so good. NGK y147t

long story short: main with wilson switch

if this is the wrong answer for you, i can suggest wiring a timed relay with a set of resistors in series with the glow plugs to help prevent over heating.

if this isnt a good suggestion either please post what you find.

 

[DanS HJ-45]

The relay on the left looks identical to the GP relay in my Hilux.

I'd probably take a test lead or two and try clicking each relay, to see if there's any real difference in function between the two.

Dan

 

[panoramic]

Hi Chris,

I have a more modern 12H-T with a glow screen installed in the intake manifold.
It is 24V, but it is really two 12V, independently wired screens. I measured the continuous amperage draw of one screen @ 12V and found it to be around 25 amps.

The glow-screen element is very thick metal and it is extremely far from the combustion chamber. I inquired with some salvage yards in Oz and they all said these things *never* fail. Is it possible to switch over to the modern glow screen on your manifold'? I can't see why not, since it merely heats the air in the intake.
In fact, I don't understand why all diesel don't use the preheated air principle instead of glowplugs.

I also went for overkill and purchased a marine-grade, continuous-duty, 65-amp starter/ignition/universal relay. The relay cost about $75. I doubt it will ever fail. It is about as compact as the relay that 'tehcruiser' mentioned, but it is water-tight, corrosion-resistant and continuous-duty @ 65 amps/12V.

Hope that adds some help.

- Eric

BTW: My rig is now operational effective last week.

 

[Henry James the 47th]

Awesome guys, thanks for all the replies!

Brownbear and tehcruiser, thanks for the suggestions about the heavy duty Napa glow relay and starter relays. John at E4 made the same suggestion and I am considering it.

The main relay I would not buy in Canada from Toyota, because at $262.50 the price is simply ridiculous. However, I can get the same thing out of Japan for around $100 - see picture below. So, the oem part is affordable and I will generally go with the Toyota product for my rebuild if at all possible, unless i can find a superior product.

I guess I should make clear that the driving force behind my questions , much as anything, is to understand the WHY of Toyota's decision to go to two relays. If I could understand their reasoning, if i could come to learn what the real difference between the two relays is, then I could make a more informed decision. The solution is less a concern than the understanding of why one system and not another.

After all, if either the main relay or the sub relay can be used in a Wilson switch type of arrangement, then why did Toyota design the two relay system for Superglow? Why use two relays when one, apparently, will do the job? If a relay is 'just a relay', then why use the two differnt relays - there must be something different between them in function, yes?

And why Superglow for some markets and not 'General Designation' (I presume it has to do with attempts to meet local emission requirements, but I'm guessing). I'm trying to get into the mind of the Toyota engineers and why they chose to do what they did, futile a task as this may well be.

Panoramic, the intake manifold for the 2H and 12H-t are very different, so I can't use the glow screen on my 2H without changing the intake manifold over. I'd be interested to learn more though about why you feel a intake heater is superior to a glow plug system. Do you have any pictures of what this glow screen looks like? Have you got a link to the "marine-grade, continuous-duty, 65-amp starter/ignition/universal relay" that you mentioned? Where did you find it?

 

[randynshoremn]

Help Please. I have a 89 HJ61 with the 12h-t diesel and appears to have the same setup as yours with the screens. The screen heating system has stopped working. I found the "starter relay" box on the passenger (right hand drive) engine bay. I didn't find anything marked "glow plug relay". I can't read the part number on my "starter relay". Help. Where do I start? randynshoremn@me.com Duluth, MN

 

[bj40green]

Hi Randy,

You're reviving an old thread on a H engine with glow plugs, but you have a 12H-T with glow screens. That's different.
My advice; start a new thread in this section and go from there.

Rudi

 

[Dieseler]

Darn I did not look at the dates on this post before I responded oh well my 2 cents worth on an old post

The 13Bt uses a glow screen and yes it is a far better system it heats the intake air for a rapid start compared to a GP which is slower at warming the combustion chamber..
The two relays give two different currents the main gives 24v and the sub steps down the current for an after glow without burning up the plugs.
I would go with the main relay and keep the time of use down to 20-30 seconds with the stock GP or go with the sub relay and go to a longer glowcycle on the plugs since you are going down to a 10.5 GP

panoramic I still don't see how the 12HT system breaks up into two 12volt draws I have looked at the wiring diagram and don't see how it turns 24V into 2 draws of 12V on the screen I am going to have to do some wire tracing and voltage checks along the system to figure that one out..

 

[bj40green]

Darn I did not look at the dates on this post before I responded oh well my 2 cents worth on an old post

The 13Bt uses a glow screen and yes it is a far better system it heats the intake air for a rapid start compared to a GP which is slower at warming the combustion chamber..
The two relays give two different currents the main gives 24v and the sub steps down the current for an after glow without burning up the plugs.
I would go with the main relay and keep the time of use down to 20-30 seconds with the stock GP or go with the sub relay and go to a longer glowcycle on the plugs since you are going down to a 10.5 GP

panoramic I still don't see how the 12HT system breaks up into two 12volt draws I have looked at the wiring diagram and don't see how it turns 24V into 2 draws of 12V on the screen I am going to have to do some wire tracing and voltage checks along the system to figure that one out..

Hi Dieseler,

Don't know, maybe You're in the wrong thread?
I think you'll find this thread interesting about the glow screens.
https://forum.ih8mud.com/diesel-tec...take-heater-glow-screen-help.html#post8841900

Rudi