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10-1-2022
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| How
do they work... |
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Glow plugs
work because of a catalytic reaction between the methanol
based fuel and the platinum element. Without this fuel or
the platinum wire the glow plug would not continue to glow
when the 1 1/2 volt booster battery is removed. See also Fuels
and Compression Ratio
The
torque to tighten Glow Plugs should be 20 to 24 inch pounds.
Just snug, the copper gasket does not require much pressure
to seal, and a turbo type plug seals with little force also.
Volts to light a glow plug is 1.2 ~ 1.5
When the battery is attached the element should glow a bright
orange. Bright enough to make spots in your eyes.
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Different
Heat Ranges
More
info below
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Glow plugs
come in different heat ranges with different mixes of platinum
alloys and different size wire. The alloy used is considered
a trade secret and it is doubtful any manufacturer will disclose
the actual alloys.
Some plugs have
nickel plated bodies, some have black oxide finish. Some even
gold plating. Believe it or not these finishes also affect
the running characteristics of the glow plug.
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| Different
Sizes and Types |
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The thread
size is a standard 1/4 x 32 UNEF since prior to its invention
in the 1940's. This is a carry over from the spark ignition
engines of that time. Some engines back then did have 3/8
x 24 thread plug and some glow plugs were made in this size
but I don't think any were made since the early 1950's..
There
were for many years the thread length, or reach of
the plug was just short and long. Now there are what we consider
a medium reach, like our new K&B Detonator Plug used
on most car engines. Check your engine specs to be
sure which one to use. Most common is the long reach.
There
is also what is called a turbo plug. This plug uses an 8mm
thread and seals with a tapered seat at the nose of the plug.
This is done because it creates a smoother combustion chamber
thus producing better performance.
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.156"
5/32" thread length for the Short reach -- Not
Common used mostly on engines under .21
.177" 4.5mm thread length for the Medium reach -- Not
Common used mostly on car engines under .21
.218" 7/32" thread length for the Long reach --
Most
Common used on 96% of engines
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| What
glow plug should I use for aircraft engines? |
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For regular
use in engines equipped with mufflers a standard K&B 1L
#7311 plug is good. In older engines a R/C K&B 4520
plug may produce a better idle. If you have trouble with short
plug life a K&B 7310 heavy duty plug may be the best. |
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| What
glow plug should I use for Glow Plug Adapters? |
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The small
1/2A engines like a HOT plug like a standard K&B 1L #7311
plug for a long reach adapter or
a K&B 1S #7321 for a short reach adapter.
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| What
glow plug should I use for marine engines? |
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If
you are using less than 25% Nitro content fuel a standard K&B
1L #7311 plug is good. For 25% and higher content
Nitro fuel a K&B 7300 high performance plug is recommended.
Note: Early K&B 3.5 outboard and marine engines used short
reach plugs and later changed to long reach. Plug thread should
not extend past the threads inside the head combustion chamber. |
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| What
glow plug should I use for auto engines? |
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Check to
see if your engine uses a long or short plug. We recommend a
K&B 1L #7311 long or a K&B 1S #7321 short |
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| What
glow plug should I use in 4 stroke engines |
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The K&B
4444 plugs work perfect in all poppet valve four stroke engines.
THESE ARE NOT FOR HP VT ENGINES |
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| What
glow plug should I use in HP VT 4 stroke engines |
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The
K&B 7311 works perfect in HP VT four stroke engines. Don't
use an R/C, 4 cycle, miracle or any other plugs that have
anything extending from the end. These plugs can hit and destroy
the rotary valve. Note: Early VT 21's use a standard short plug
like the K&B 1S 7321. Look
into any port on the head and you
can identify the early version by the rotating valve, early
used a bronze valve in a chromed sleeve, all later engines used
a chrome valve in a bronze sleeve. |
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