Page 1 - Combined_1_OCR

INTER COMPANY CORRESPONDENCE

FILE DATE
CODE August 4, 1970
TO - NAME DIVISION PLANT/OFFICE
DEPT' Special
H. P. Bruns Vehicle Development Engineering Office Highland Park
FROM - NAME DIVISION PLANT/OFFICE
DEPT’ Huntsville
W. P. Wright Race Operations Engineering Office Huntsville
SUBJECT:
Thermal Insulation For Grand National Race Car

Plymouth Race Car Number 097 has been insulated in the floor pan and
fire wall area with Rigid Fluorocarbon Expanded Urethane Foam. The Dodge
Test Car Number 088 was also insulated with this material in February 1970
prior to extensive track testing.

The urethane foam offers the following properties:

Density lb/ft2 1.8 -2.2
Thermal Conductivity (k factor
BTU/hr. /ft. 2/°F/in.) @ 75°F 0.11 - 0.13
Tensile Strength psi at break 40 - 60 ’
Compressive Strength psi at yield 35 - 50

The following procedure is used in application of Urethane foam:

Surface Preparation

Only a clean, dry, oil free painted or unpainted surface is required
since material adheres similar to an epoxy.

The engine, transmission cross member propellor shaft and exhaust
pipes are removed from under car. The seat, floor mats and ignition system are
removed internally.

The car is cleaned with a gunk gun and/or a good high pressure car
wash gun and air dried. The cars painted finish surfaces, instruments and glass
area are covered with plastic or paper to protect from spray mist since no solvent
removes the urethane over spray.

Areas under insulation requiring inspection or access are masked off
with tape or aluminum foil. Foil is preferred in areas where insulation is to
remain but inspection of surface required since a sharp knife can be used to cut
around and through foil protected area and the insulation lifted out. After work
on area is performed the insulation block may be set back in place and cracks
taped up. .

84- 110-7879 REV. 1-63