Thread: Starter Solenoid or Glow Plug Relay are they different?

Originally Posted by 67hardtop

Just a quick thought Lionel, is there supposed to be a resistor in series on the glow plug circuit similar to the original 2.25 diesel glow plug circuit on a s2a or s3 diesel. Maybe u have burned out ur new glow plugs by putting too much voltage through them? I dont know about the toyota or indeed the land rover glow plug circuit but it makes sense to me, being a mechanic, that too much voltage, ie 12+V going into an 8.5V glow plug, means somethings gotta give...

Cjeers Rod

Hello Rod,

I reckon you are right 8.5 volt with 12 volts coming is 3.5 volts over the 8.5. Looks like there are at least three different options. The cheapest being making a circuit with a L7809 Linear Voltage Regulators and some capacitors... as per this bloke's circuit Accessed July 7 2018 from YouTube.

Here is a similar video about Linear Voltage Regulators - YouTube

Or I could buy something like this DC/DC converters 12 to 8.5 volts for using a Playstation 2 in a car or boat from PowerStream, Buck-Boost . which guarantees a steady 8.5 volts with more efficiency than a Linear voltage regulator - for many dollars more for the convenience!

There are also "buck" or step-down converters which a quick look on eBay finds a 12 volt to 9 volt one being available for $6.52 Waterproof DC to DC buck Converter 12V to 3/3.3/3.7/5/6/9V Power Module Supply T | eBay

There is a link on youTube that compares the operation of the Linear Voltage Regulators against the Buck converters. The Linear Voltage Regulators pump out lots of heat and require large heat sinks. From this commentary it looks like the Buck converter could be the way to go. YouTube

Anyone else have a different circuit or technique to avoid doing nasty things to about $90 worth of glow plugs?


Kind regards
Lionel

Lionel,

My Isuzu powered Series III uses the standard Land Rover Diesel resistor.

Ballast Resistor - Diesel - Paddock Spares
Land Rover Series 2a 3 Diesel Preheat Heater Glow Plug Ballast Resistor PRC1716 | eBay


Not sure what it drops the voltage to but works OK.


Colin

Hello All,

Ever the optimist - scoff - cough ... more possibly "ever the experimenter" - I walked up to the Series 2A for a first start for the day. I went through the same starting procedure that I used yesterday after I installed the new glow plugs and the new Ford four post relay. Turn ignition on - hold down glow plug button - watch the volt meter drop down and remain at a rock steady reading. Count to 15. Release the glow plug button and turn the key to start. Well knock me down with a feather - the engine started and purred like a kitten again - on the first attempt. Woo hoo!

Last night - hours after the first start I could not get the engine to start until cranking the engine over on the starter motor had caused it to reach the point to where there was sufficient warmth in the motor for it to kick over.

At this point I thought the new glow plugs were roasty-toasty. Today's experiment proved that they are still functional.

However despite this success, I am getting either a buck step down; and Colin's recommendation of a Preheat Heater Glow Plug Ballast Resistor PRC1716 voltage. I lashed out on the big investment of $8 for the buck circuit last night - so it is already on its way. I will be getting the PRC1716 as I found reference to it on LandyZone somewhere where someone wrote that it drops the voltage down to 7-8 volts.

Kind regards
Lionel

Hello All,

After following up on Colin's photograph and advice about the Preheat Heater Glow Plug Ballast Resistor PRC1716 voltage, I went for a walk into my spare parts vehicle paddock and lifted the bonnet on my two Series 3 diesel parts vehicles. There lurking low down on the firewall bulkhead, tucked near the accelerator rod mechanics, was this familiar looking bracket with a coiled wire inside the bracket space. It is a much bigger unit than I expected. Of the two ballast resistors one example is still fully wired to form a complete circuit. Something I can use as a guide I can follow when I remove the part from the other vehicle. The Series 3 with the full circuit is Number 3 vehicle on my restoration list .... my current restoration list - that is. Umm it might be a bit "subject to change" in its order of appearance.

Funny how things are much clearer once you know what the hell you are looking at!

Thank you again Colin.

It is now over to the penetrating fluid and some spanners! Looks like I will have a Buck converter as a spare part.

Kind regards
Lionel

Hello All,

While this information is tractor based it does detail how old pig-tail Massey Ferguson FE35 glow plugs and resistor system was replaced with "modern" genuine Land Rover "pencil" type glow plugs. Even a Land Rover heater Glow Plug Ballast Resistor PRC1716 was used as a replace part.

Accessed July 8 2018 from, Glow plug information

The new circuit using Land Rover parts also incorporated what is now a very familiar to me part - a four post Ford-Type starter solenoid.

Since the original Massey Ferguson FE35 and the PRC1716 both use resistance wire I was very interested to see what happens when that wire breaks. The author's friend bought some "14 gauge Nichrome" resistance wire and repaired the old Massey Ferguson unit.

This wire is described as Nichrome 60 resistance wire, 14 AWG (gauge), 30 feet. Where AWG is American Wire Gauge according to a chart this is 1.63 mm diameters YouTube I just have to measure the thickness of the Land Rover PRC1716 to determine what gauge Nichrome resistance wire was used on them - plus do a resistance measurement.

I used to love electronics when I was in high school. After I left school I worked for about six months in an electronic repairs store however an apprenticeship in electronics proved to be elusive. This was back in the early 80s, so it has been decades since I bent my head around electronics. The past couple of days has been challenging and it has rekindled an old interest. What is the old saying?
"A little knowledge in the hands of fools is a dangerous thing"

I have been trying to remember the name of a big box in the workshop where different sources: AC/DC, and different voltages could be set as a power source so circuits could be traced and things like resistance could be measured without plugging something into mains power. The only name I can recall is "power-pack" or "variable power supply". Can anyone provide this device with a proper name so I can track one down? Thank you.

Kind regards
Lionel

Originally Posted by sierrafery

Strangely there is a resistor on the glow plug circuit (PRC1716) ... i can't understand what's it's purpose

Hello Sierrafery,

I was just looking back on the earlier posts of this thread and you were the first to mention PRC1716.

To answer your query the purpose of the glow plug resistor is to reduce 12 volts down to about 7 to 8 volts so 8.5 volt glow plugs do not get fried and made roasty-toasty - causing about $90 worth of parts to go up in smoke!

Kind regards
Lionel

Hello All,

The glow plug resistor on my spares Series 3 must have been in the wrong place at the wrong time. Looks like something grabbed onto the wire and it broke after being stretched. Most of the coils had been pulled out of shape. Not wanting to pull apart Number 3 restoration project I ordered a new resistor online. It is a genuine Land Rover part from a little Mediterranean Island. It was way less expensive than the same genuine Land Rover part from the UK. It was also the last one they had in stock.

Kind regards
Lionel