TEST AND ANALYSIS OF GERMAN MADE SPARK PLUG

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP81-01044R000100010006-5
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 7
• Document Creation Date: December 14, 2016
• Document Release Date: May 17, 2001
• Sequence Number: 6
• Publication Date: September 25, 1950
• Content Type: REPORT

VW P113--chased i.. Fin L d during early 1950. The ply wr ;i i bears the
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.:i 8-14/175 e by Porzalla wezk ev q e s~ 1 ~.~ ~ itz9
i Twos e ~ ~ eA ao'ozIe? o
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Yi REPORT
INFORMATION REPORT
COUNTRY Gear (Sow w)
SUBJECT Test and Analysis of Gea^ ?~a Made Spark Plug
1 atio ? Of the spark plug has io- 'ea l d the following:
(a)
In appasowce and genera , co) ist ?u cticon the subject e,;pa k p L` bees
a decided -re e la cce to the generall line of c a~, a :ro s2c?k plugs
as zta,ct ?ed by Bosch.
(b) The shell seal utilized a ce e at r ion. ae&ex crimped under
the sb. fl lip & per Bosch practiua plug is by pea m of cc t and
ca ed alusInum 4e. t at the tea 1, _scre
(e) Atte .t-ism. is c .ed to the fact-that the c eater elects .'s c e ists of a
sha t length, of t sten brased to e 1 h of doper v:LTe; tyre copper
wire- bei feted a sarle of step opp a,ite side the upper
end of the whole electrode fitting loosely Into a , drilled in the
terminal ecre . This c t pthon o` I.ou ly is armed .at Conse t be,
to . ^ :ed In ' ie - electrode tip and in ..keepi thAt -tami e o . the tip
_ ed: ,tqc __cco gpru t , ~proii5h~cts ends -=Ier severe g( L ati ~. .q co t oms o ld
be subje~1., to rap 2
d g ~.d14./ .7.o..5~16 and ( CG blt N, \_iI4:Y,M 4..ly G_
~ 'ilectrode construction
is, retaIned "the Insulator bore by m-s.; a _jf c 2_,1- a .e and if the e
entice z: eratio . were poorly perfoa ed, there wo d. be a distinct oasi
STATE NAVY NSRB D(STRBU ON
ARMY AIR FBI
CLASSIFICATION
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DATE DISTR,
i J -Sep 1950
NO. OF PAGES 3
NO. OF ENCLS.
(LISTED BELOW)
SUPPLEMENT TO
REPORT. NO.
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bility that this part would move and short out against the side electrode.,
or what would be much more serious, fall into the engine cylinder. This
construction,is a radical departure from that employed by Bosch, -
The shell was judged to be well.chined and of good finish except for
the threads which appear to be die-cut and ragged in finish.
The designation "14/175" is believed to indicate a 14 min plug with an
rating of approxi at ely 175
I a dicated Mean Effective Pressure
and would indicate that E'TL Ltth-A Test Laboratory Engine m- a variable
compr?easion9 single-cylinder engine now adopted by-all U.S. spark plug
manufacturers for wing standard tests] engines are availab] e in
Germamy that the SAE LSociety Automotive E inec;.,rs j rating method
has been adopted. Inspection of the end of the shell shows a small
cc n terbore which would b4"mAsry operation on an auto .tic- screw
machine and which appears to serve the purpose of ccorrecti for sill
owes in rating which may result from the use of dif'eren insulator
materials.
The external seat gasket supplied with the subject plug is made _of steel
and though poorly formed., would appear to be adequate for the purpose.
Available on loin from the CIA Graphics Register are the following four
photor'aphs of this spark plug.,
(1) General appearance of plug
(2) Insulator assembly and shell seal parts
(3) Insulator and center electrode assembly
() External seat gasket
2. The results of tests and analyses performed on the Neuhaus plug are as follows:
Prior to a pre-ignition test in the 1706 cubic inch ETh engine the subject
spark plug was checked for leakage at 225 psi, The shell leakage was
found to be 2,0 cc/zdm. and the center electrode leakage was 0,0 cc/mina
The plug was dielectrically sound as checked onr flaah-over type di-
electric tester (Tesla coil circuit).
(b) The pre-ignition rating of the Neuhaus 8?l4/175 spark plug was found
to be 189 using the SAE test mrcethod. For a direct comparison two
Auto-Lice AE?61" rea; ap 14 mm spark plugs were rated before the Neuhaus
plug; the average rating bei 187,8 I MEP. After the pre-ignition test
the Neuhaus spark plug was a t checked for gas leakage and to determine
whether it was dielectrically sccund4 The gas 1e a at 225 psi was
found to be 20 cc/min. at the shell seal and 0,0 cc mi,n. at the center
electrode. The plug was found to to di.electrically, ssound using the flash-
over tester,
(c)
The shell material was found on analysis to be a chrome-manganese steel
similar to SAE 5115, The reason for using a steel of this type which
does not have good machining characteristics is unknown. The actual
analysis of the steel is as follows
Carbon
415 Per cent
Manganese
1,.1
Phosphorus
.023
Sulphur
;0kk2
Nickel
.27
Chrome
.84
Molybdenum
.00
(d) The Rockwell. hardness test of the shell ranged over the following hard--
ness numbers:
84 - 92R':8
CONFIDENTIAL
C0 rDOTI
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The insulator is well designed.
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(e) The side electrode stock was found to be nickel-manganese
taining 1.93 per cent manganese.
(f)
oy con- 25X1 A
The composition of the insulator was found to be approximately 90 per-
cent alumina; the in size is larger than in Americaan practice being
found to average 18 micronso The bond between the alumina grains was
found to be siliceous glass. The characteristic pink color is due to
a solid solution of chromic acid with the alumina. Judging from the
grain size, this material is believed to be an electric f ?nace pro-
duct and is generally of high quality though probably with lower
physical properties than alumina bodies generally used in the USA,
3. The evaluation of the Neuhaus plug is as foilo
On the basis of the single plug available and the one pre-ignition
rating test conducted it would appear that the shell seal in the subject
plug, in spite oil-its similarity to the Bosch design, was unsatisfactory
for the purpose. With few exc*-pti , any one-piece shel.,l seal spark
plug made in the iJS today can be run trough a pre-ignition test on the
ETL engine without developing any measurable shell leakage whatsoever,
(b) The construction of the center electrode has two serious drawbacks in
that copper is exposed to combustion products and woad be subject to
rapid erosion under severe operating conditions, and the whole center
electrode construction is retained by cent alone; and there-is a
distinct possibility that the part could move and short-circuit, or-,
fall into the engine cylinder where it might cause considerable dp6age.
(c) The shell was machined from un ;itabie steel.
(d.) The side electrode was inserted into a hole in one side of the shell
and peened in place. This method of retaining the side electrode has
becc obsolete in the TUSA because it affords poor heat transfer;
welding at this point is employed almost universally in the USA..
(e) The plug marking reveals the probability that E' engines are available
in the Sovzone and that the SAE rating method has been adopted.
{f) The materials used in the, plug are generally of high quality mad the
workmanship is good.
(g) There are several features of the design of the plug which appear to
be hazardous and inadequate for the purpose.
(h) In the writer?s opinion, the plug would give satisfactory service in
passenger cars, but would be inadequate for severe truck or commercial
use.
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