CSOB Spark Plugs:
BG-341 Spark Plugs - Limited Quantities Available
Are you still spending over $20 each for spark plugs for your
Continental 470/520 Engine? Does your engine call for an RHB32E plug? Did you know that a Military Surplus spark plug is STC'd
(SE69WE) for many Continental Engines at something less than half the cost of
Champion or Unison options? It is the
Note that the 520B and 550B/BB Engines are not
listed in the STC documentation, but they do call for the RHB32E plug......You
and your mechanic decide!
Check the Champion Application Listing Catalog
See the BG-341 STC Numbers below and
Download the STC provided by request of a the
FAA by a CSOBeech visitor HERE
See the full set of STC Documents for this
Apparently, there are
thousands of these Brand New Sealed in plastic spark plugs still in circulation.
Buy a dozen now with the Buy It Now button below, limited quantities available.
Lower Bonanza Plug Removal Tips Article by
Fernando E., BE33 owner: HERE
Spark plug testing info from Tempest
PS: It does not look like it is STC'd for the
520B and 550B/BB.
But, remember, these engines call for a Champion RHB-32E plug and for all those
other engines that ALSO call for an RHB-32E plug, the BG341 is an STC'd
replacement. You and your mechanic decide what is airworthy for your aircraft.
Things that make you go Hmmmmmm!
Here is a pirep watch out from Stan S.
regarding the use of BG341's in the IO470C, -J and -K Engines. Note that these
engines are not listed on the STC paperwork either!
Note those BG 341 spark plugs that are the equivalent of the Champion RHB32E
are not appropriate for the 225 horsepower versions of the IO-470 (the IO-470-J
and IO-470-K) because they are a colder plug designed for a higher compression
engine. Those 225 horsepower engines require a plug with the number 40 in heat
range, a warmer plug. The 32 heat range is too cold for a low compression engine
and will foul regularly if used in a low compression engine.
Worst Case is that you pay about $9 for this plug at
Spruce their PN: 08-03699. I've
these plugs in my IO470Ls for over 1000 hours with no issues and keep a
stash in my hangar. Clean 'em or throw them out at annual if you don't
looks of them.
Here is a spark plug rotation method from "Old
Bob", he calls it "Spark Plug Swapping for Dummies"!
"Easier yet is the "Swapping for Dummies" method that I use.
I have a twelve hole Champion Spark Plug Caddy. It is marked
one through six for the cylinders. With the numbers right side up, I place the
plugs in the caddy as they are removed. Top plugs above the numbers and bottom
plugs below the numbers. After they are all cleaned and being careful to make
sure each goes back in it's proper spot, I rotate the caddy one hundred and
I then rename the holes as one through six with what was
number one now becoming number six. What were the top plugs will now all be on
If they are placed back in the engine with the top left being
top number one and so on you will find that all of them will have been switched
in just the manner Champion recommends."
a bulletin from TCM on spark plug rotation and spark plug application guide for
I have been flying behind NOS BG-341 spark plugs
for nearly 10 years in both of my IO-470L engines and have no complaints about
their performance and plenty of accolades for their price (when you can find
If you'd like to buy some BG-341 Plugs. I'll make
you a great CSOB deal on some of my stock and you'll be happy to know that your
purchase helps support the efforts here at CSOBeech.com
including USPS Priority Mail Shipping w/Delivery Confirmation to US addresses.
Still better than the price of Champion or Tempest plugs!
Support CSOBeech.com with your purchase. Use the
"Buy it Now" Button Below to Order.
Limited Quantities Available
Here are representative pics of the BG-341 NOS
Some of the plugs you may receive had the plastic sleeves burst open after 50 years
in storage, however, you can see that the cosmoline preservative has done it's
job and the electrodes are in fine shape.
Still thinking about fine wire
plugs? I'm told they last a much longer time than the massives, but in my CSOB
opinion may not be worth the acquisition costs unless you fly +FL200.
Fine Wire info Here
Fine Wire Woes?
Recently, a CSOBeech.com visitor contacted me
with the info relating to problems he was having with some RHB32S fine wire
plugs after only a couple hundred hours TIS (time in service). His fine wires
were measuring OPEN resistance. Image of his resistance vales are below. The
user reports poor starting hot and cold and poor combustion performance measured
by his digital engine monitor.
His reference to "change out" refers to the
use of resistors salvaged from NOS (new old stock)BG341 plugs.
Here is a close up shot showing the tracking
lines and arcing of the original RHB32S resistors
High resistance values in spark plugs (OPEN is
as high as it gets) causes the ignition system to work very hard. Parts within
magnetos will see excessive stress and can wear out prematurely.
After replacing the resistors in his plugs and
measuring the values noted in the above image, the submitter noted the poor
performance was gone.
If you have plugs with high resistance - this
could be a possible reason for some of the poor performance you are experiencing
in your engine.
Here is a tool find by Beech Lister and
Bonanza Owner, Greg G. that helps to deal with that pesky ignition wire to spark
plug nut. Even better it is sourced at CSOB Tool Heaven, Harbor Freight, for a
It's an offset oxygen sensor wrench with the
perfect 7/8" socket opening and a 3/8 drive. The cutout for the sensor wire
leaves ample space to slip the TCM ignition wire through it.
Big thanks to Greg for his contribution to the
We've just extended Greg's CSOB Membership
Card for another 6 months FREE
Here's another cool Harbor Freight 7/8" socket
that could do a nice job on our aviation spark plugs.
A whopping CSOB $7!
Socket Tool Mod
While we're on the subject of cool tool mods
for aircraft stuff, here's a mod by Beech Lister and Bonanza owner, Ben W. that
he used for installing the CHT probes for his GEM engine monitor install
Ben's mod consists of a 3/8" drive 1/2" deep
well socket with a 1/2" hole drilled in the side for the probe lead to come
through. You'll note this was in a Harbor Freight socket from Taiwan so drilling
into it proved easy for Ben.
Big thanks to Ben for his contribution to the CSOB Club.
We've just extended Ben's CSOB Membership Card
for another 6 months FREE