In search of a glow-plug for my S1100

[jmw]

I have managed to get hold of a couple of IDI S1100 engines that are able to take a glow-plug.
Unfortunately they come without a glow-plug, and in its place is a blanking bolt.
I am now looking for a source of glow-plugs that will replace the bolt, but I'm having no luck finding one.
I have contacted my original engine supplier, and many other suppliers that I have used in the past, but it seems nobody in China (or anywhere else for that matter) can provide the correct type of glow-plug.

I will be resorting to machining the current two heads and fitting an insert, but that isn't a cost effective solution if I want to sell lots of these, which I do.

I've attached a photo of the blanking plug. The thread is much more course than currently used on modern day glow-plugs. I'd guess it's a 1/2"BSP, but I need to check it properly.

I would be extremely grateful if anyone could help me source an appropriate glow-plug.

Thanks,

     Mark

[mobile_bob]

i too have looked for a glowplug for the 195, which is the same needed for the 1100

my solution to the problem is to use what you call the blanking bolt (which is made to hold a wick)
and chuck it up in a lathe, drill and tap it for a pencil style glowplug like the ones used in fords 6.9 and early 7.3 diesel
engines.

i assume the ford injector has a thread pitch i can find a tap to match?  but haven't checked on that yet.

bob g

[jmw]

Bob,

You're a wealth of knowledge.

I'd assumed that I wouldn't be able to get a modern day glow-plug thin enough to put down the middle of the blanking bolt, but perhaps I'm wrong.

A 'wick'!!!!! Of course!!
I've been trying for ages to work-out why the bolt has a hollow end. Of course, it's for a wick. Thank you Bob.
Any idea what the wick is made of and what they look like?

Mark

[Crofter]

Try to find a glow plug of small enough size to be accommodated within the dimensions of the bolt. Also try to find one that will work on full 12 v without the need of a special voltage reducing drive circuit. What I used is a 2001 VW tdi engine plug. I believe it is 10 X 1.25 standard metric. sealing is done against a tapered shoulder below the thread so it is a bit of a challenge to turn out an adapter, but as Bob says, doable. A glow plug makes night and day difference in starting a diesel engine especially one that has only about 16 to one compression ratio.

I have used the screw in starting aids that looked like having a roll of cotton rag projecting that was dipped in something like the old strike anywhere matches. Likely supposed to compression ignite at a lower temp than diesel fuel and continue glowing for a few revolutions. In my case that old compactor refused to give anything more than puffs of smoke!

[jmw]

Frank,

You raise a good point about voltage.
Most glow-plugs available today are used in sets of 4 (or more) where the 12v dc supply drops due to the load of the glow-plugs.
This is confirmed by most glow-plugs which actually state 11v.
When a single glow-plug is used with a 12v battery, the voltages doesn't drop as much as it does when 4 plugs are used, which means the one glow-plug gets more volts than it is designed to take - I've burned quite a few glow-plug doing this.

Unfortunately, I haven't managed to find any glow-plugs that are designed to work in isolation, but I do believe that some manufacturers design their plugs to cope with over-voltage. Can't remember which manufacturer though.

Mark

[mobile_bob]

have the glow plug energize with the starter, that way as the engine cranks the glowplug gets hot
and the voltage is dropped because of starter draw.

bob g

[mobile_bob]

another alternative use pwm off the engine management controller to regulate the effective voltage
seen by the glowplug

bob g

[Ronmar]

Have you guys checked the chinese tractor dealers?  My tractor uses a 395 engine. I would not be surprised to find it has parts in common with your 195 engines...  I am at work now, but i will try and post a dealer link later to a guy that has online photos of most all the parts.  I could also pretty easilly pull one of my glow plugs to measure it if you like.

[jmw]

Ron,

I believe the 295, 395 and 495 engines have fuel-burning pre-heaters in the air intake.
This is another alternative, but these devices require a lift pump which the single cylinder engines don't have.

Mark

[Crofter]

I am not having a problem feeding a singe glow plug from a fully charged 12 V battery but if you had an alternator upping the ante and you didnt have provision to disconnect immediately, the charging voltage near 15 volts could do them in.

All plugs are not the same and for sure there are some that turn into photo flash bulbs (anyone here old enough to remember them) if they get direct voltage. I am just suggesting that if you are going to make an adaptor, have it suit an easily acquired, convenient voltage plug. Only modify the engine iteself as a last resort. I have an old David Brown tractor engine I would dearly love to have glowplugged in the cylinders instead of a token manifold heater, but I dont want to mess with it. Its Limey origins sure make it despondent in our northern Canada winter weather, lol!

[Ronmar]

Ron,

I believe the 295, 395 and 495 engines have fuel-burning pre-heaters in the air intake.
This is another alternative, but these devices require a lift pump which the single cylinder engines don't have.

Mark

No fuel burning preheater on mine.  The 395 on my tractor has an electric glowlug screwed down into each IDI chamber.  They pull about 10A each and are tied together in parallel with a bussbar for a 30A initial draw.  This 30A tapers off to about 22-25A after 20 seconds of preheat.  The key is setup as follows. Off,on,  preheat then start,  preheat and start are springloaded back to on.  The key is wired such that the glowplugs remain energized when the key is turned to start.  I will pull one this afternoon and get the dimemsions and thread pitch.

[oliver90owner]

Any idea what the wick is made of and what they look like?

I think Hatz may have them listed in various sizes.  Light and smoulder, like the Field Marshall tractors.  One problem sometimes occurs when the wick is not completely burned and lodges under a valve and just sits there reducing compresion to zero.

Made of paper or fibre soaked in a suitable accelerant like sodium nitrate, I would think.

Regards, RAB

[Ronmar]

OK, Pulled a glowplug out of my tractor head.  On mine, it is screwed in alongside/parallel to the injector.  Here is a link to a photo.  The background graph paper has 1/4" squares.  The thread outside diameter is .394" measured with a dial calliper.  The threads are approximately .040".  I would call that about a 10MM X 1.0 MM thread pitch.  These are about $25 from a chinese tractor dealer, Unfortunatly it dosn't look like the same configuration as the plug you pictured...

 

[XYZER]

my solution to the problem is to use what you call the blanking bolt (which is made to hold a wick)
and chuck it up in a lathe, drill and tap it for a pencil style glowplug like the ones used in fords 6.9 and early 7.3 diesel
engines.

Not to run this thread astray but is the hole in the plug that replaces the changeover on a 6/1 for a wick? I always wondered what that was for.

[jmw]

I've now measured the size and thread pitch of the blanking bolt.
It is a M12 x 1.75 (or possibly a 7/16 - 20 UNF).
I've spent quite a few hours searching glow-plug suppliers' websites for a glow-plug which matches this thread.
My conclusion so far is:- no such glow-plug exists.
Also, the smallest (diameter) glow-plug I have found so far is an M10. So it won't be possible to drill out the blanking bolt to use a narrow glow-plug in it. 

Mark