Doug Thorley Headers THY-464-1 User manual

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PARTS INCLUDED
HARDWARE INCLUDED
WARRANTY NOTES
TOOLS REQUIRED
1) The utmost care is taken at Thorley Headers to maintain the highest standards of quality.
However, Thorley Headers cannot control the installation of the product. For this reason, the
Thorley Headers warranty covers only the replacement of the components - not the labor for
the installation.
2) The use of any type of “header wrapping” voids the warranty. Using any sort of wrapping
material on the headers destroys the tubing’s ability to dissipate heat, causing very rapid
deterioration of the metal and the subsequent failure of the headers.
3) The chrome plating applied to all Thorley headers is a high-nickel chrome finish applied to
retard corrosion. This is a “heat” chrome to preserve the metal. This finish is not “show
chrome” intended for the sake of appearance. This high-nickel chrome turns colors and
approaches black as it cooks into the metal. The brilliance of the chrome finish is not cov-
ered under the warranty. Contamination of the surface by foreign substances may produce
other color patterns. This can be prevented by routine cleaning.
1 - Right side header
1 - Left side header
1 - Y-pipe assembly
1 - Hot air pickup
2 - Header gaskets
2 - Collector gaskets
1 - Catalytic converter gasket
Heating torch
Mig welder
Cut-off saw
Sawzall
3/8", 7/16", 9/16", 1/2", 3/4", 7/8" Wrenches
10mm, 13mm Wrenches
9/16" Line (flare nut) wrench
5/16", 7/16", 1/2", 9/16" Sockets
3/8", 7/16" Deep sockets
15mm Deep socket
5/8" Spark plug socket
Ratchet and extensions
Pliers
Crescent wrench
Torque wrench
Rust penetrant
High-temp sensor-safe silicon sealer (rated at 600 degrees+)
6 - 3/8”-16 x 1-1/4” Hex head bolts
6 - 3/8”-16 Hex nuts
6 - 3/8” Star lock washers
6 - 3/8” Flat washers
BY SUMMIT INDUSTRIES
THY-464-1
NISSAN V6
86-89 HARD BODY,
PATHFINDER PICKUPS

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4) Retain all paperwork pertaining to the purchase of your Thorley product. Save your receipt!
Your limited warranty is not valid without a receipt of purchase.
The installation of headers onto any vehicle must be performed in accordance with all govern-
mental regulations that might pertain to the particular vehicle receiving the headers. Please call
your Thorley Headers distributor if there are any questions regarding the legality of
the installation. The Executive Order (“E.O.”) number for this part number is D-540.
WARRANTY NOTES
1) It is important that you read the entire instruction sheet before initiating any installation.
2) Thorley headers are designed to fit only factory installed engine and transmission combi-
nations. We cannot guarantee that Thorley headers will fit in the case of “engine swaps” or
“transmission swaps”.
3) Due to restricted room in the engine compartment, your headers may come close to cer-
tain body and chassis components. This is normal for an installation of this type. However,
a careful inspection must be completed to insure that the distances and placement are
reasonable and logical, especially with regard to electrical, fuel, and brake components.
4) Because of the requirement to raise the engine to facillitate header installation, the engine
mounts should be carefully inspected at that point of the installation. It is highly recom-
mended that questionable or deteriorated engine mounts be replaced during the
installation of the headers. In some cases, the engine mounts need to be loosened and
repositioned to provide optimum header clearance from some components.
5) Because of car-to-car variations, Thorley Headers strongly recommends that these head-
ers be installed by a competent exhaust shop that has welding and fabrication capabilities.
INSTALLATION NOTES
LEGALITY NOTE
THY-464-1
NISSAN V6
86-89 HARD BODY,
PATHFINDER PICKUPS

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WARNING! - Do not rely on bumper jacks or chassis jacks for support during header installa-
tion. The subject vehicle should be raised and supported with jacking equipment and
jackstands or ramps intended for undercarriage auto maintenance. It is extremely dangerous to
work under an improperly raised and/or supported vehicle.
WARNING! - Make certain there is ample clearance around components such as brake lines,
brake proportioning valves, fuel lines, hoses and pumps, and electrical components and wires.
In some cases it may be necessary to relocate items that may be adversely affected by exhaust
system heat.
NOTE: These procedures are documented on factory standard-equipped vehicles with original
configuration compliance. Any modification of the subject vehicle may dictate modification to
these procedures.
INSTALLATION PROCEDURES
1) Disconnect the battery.
2) Raise the front of the vehicle approximately 24 inches and support it with jack stands or
other suitable supports. (WARNING! - Do not rely on bumper jacks or chassis jacks for
support during header installation. The subject vehicle should be raised and supported with
jacking equipment and jackstands or ramps intended for undercarriage auto maintenance.
It is extremely dangerous to work under an improperly raised and/or supported vehicle.)
3) Remove the front wheels.
4) Remove the rubber mud shields from the wheel wells.
5) Remove the brake line heat shield from the passenger side.
6) Disconnect the emission control lines from the stock exhaust manifold (pulse air, EGR,
oxygen sensor, etc.).
7) Remove the hot air pickup and the air cleaner.
8) Remove the two head pipes leading from the exhaust manifolds to the catalytic converter.
9) Remove the stock exhaust manifolds.
THY-464-1
NISSAN V6
86-89 HARD BODY,
PATHFINDER PICKUPS

4
10) Clean all traces of carbon deposits from the cylinder head exhaust port surfaces.
11) Remove the engine oil dipstick.
12) (Note: The use of high-temp sensor-safe silicon sealer between the header flange and
header gasket is highly recommended.) Install the passenger side header and supplied
header gasket from below the vehicle. Place the header on the stock studs and tighten
securely using the stock nuts.
13) (Note: The use of high-temp sensor-safe silicon sealer between the header flange and
header gasket is highly recommended.) Install the driver side header and supplied
header gasket from below the vehicle. Place the header on the stock studs, connect all
emission control lines, and tighten securely using the stock nuts.
14) Reinstall the engine oil dipstick.
15) Install the supplied hot air pickup and reinstall the air cleaner.
16) Attach the supplied Y-pipe assembly to the header collectors using the supplied
collector gaskets, 3/8”-16 x 1-1/4” hex head bolts, nuts, and washers. If applicable,
reconnect the oxygen sensor.
17) Attach the rear of the supplied Y-pipe assembly to the catalytic converter using the
supplied catalytic converter gasket and the stock hardware. (See Illustrations, Figure 1
for a view of the assembled system.)
18) Reinstall the passenger side brake line heat shield.
19) Reinstall the mud shields.
20) Reinstall the front wheels.
21) Reconnect the battery. Start the engine and check for leaks.
THY-464-1
NISSAN V6
86-89 HARD BODY,
PATHFINDER PICKUPS

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THY-464-1
NISSAN V6
86-89 HARD BODY,
PATHFINDER PICKUPS
ILLUSTRATIONS
THY-464-1 ASSEMBLED
FIGURE 1