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baptistbusman
Advanced Member
USA
301 Posts |
 Posted - 06/29/2007 : 9:46:07 PM
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Does anyone have the torque specifications for the bolts on a 93 GMC 366 exhaust manifold.
Im starting to believe that although these engines are known for eating the manifolds, a lot of problems are being caused by incorrect torque.
Also, GM recommends no gasket? I have seen some of the engines with 2 gaskets per manifold. Anyone have better luck with no gasket? 2 gaskets?? |
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Wolf0r
Top Member
USA
2181 Posts |
Posted - 06/30/2007 : 09:04:58 AM
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One gasket, drill out the smaller holes in the mounting flange to match the bigger holes. Use anti-seize on all hardware. Studs/nuts=22ft lbs the bolt = 40ft lbs.
Call your GM dealer and ask for bulletin "GMC TRUCK 67-61-21b" this has all part#s and instructions on the upgrade. Hope this helps.
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“The good thing about science is that it's true whether or not you believe in it.”
Neil deGrasse Tyson |
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Wolf0r
Top Member
USA
2181 Posts |
Posted - 06/30/2007 : 09:08:52 AM
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ENGINE NOISE (INSTALL NEW DESIGN CAST IRON EXHAUST #67-61-21B - (Mar 1, 1998)
REVISION: 02/03/98
THIS BULLETIN IS BEING REVISED TO CHANGE PART DESCRIPTION INFORMATION FOR CLARIFICATION. PLEASE DISCARD CORPORATE BULLETIN NUMBER 67-61-21 (SECTION 6-ENGINE). ______________________________________________________________________
REVISION: 02/17/98
THIS BULLETIN IS BEING REVISED TO ADD THE GMC LOGO WHICH WAS INADVERTENTLY OMITTED. PLEASE DISCARD CORPORATE BULLETIN NUMBER 67-61-21A (SECTION 6 - ENGINE). ______________________________________________________________________
SUBJECT: ENGINE NOISE (INSTALL NEW DESIGN CAST IRON EXHAUST MANIFOLD, STAINLESS STEEL GASKET AND ATTACHING HARDWARE)
MODELS: 1991-95 CHEVROLET AND GMC C6, C7, B7, P CHASSIS MODELS WITH 6.0L AND 7.0L ENGINES (VINS P, M - RPOS LS0, LR0)
CONDITION:
SOME OWNERS OF THE ABOVE MENTIONED VEHICLES MAY COMMENT ON ENGINE EXHAUST NOISE WHICH IS NORMALLY LOUDEST DURING COLD ENGINE OPERATION.
CAUSE:
AN EXHAUST LEAK MAY HAVE DEVELOPED BETWEEN THE CAST IRON EXHAUST HEAD AND THE ENGINE'S CYLINDER HEAD MATING SURFACE CAUSING THE CAST IRON EXHAUST MANIFOLD TO WARP AND/OR CRACK AT THE OUTBOARD FLANGES.
CORRECTION:
A NEW EXHAUST MANIFOLD, STAINLESS STEEL GASKET AND ATTACHING HARDWARE HAS BEEN DEVELOPED TO CORRECT THIS CONDITION. REPLACE THE EXISTING CAST IRON EXHAUST MANIFOLD AND GASKET WITH THE NEW DESIGN EXHAUST MANIFOLD, NEW STAINLESS STEEL GASKET AND NEW ATTACHING HARDWARE. DISCARD THE EXISTING ATTACHING HARDWARE SINCE IT WILL NOT BE REUSED.
INSTALLATION PROCEDURE 1. INSTALL NEW STUDS (1). TORQUE STUDS TO 30 N.M (22 LB FT) (FIGURE 1). 2. INSTALL NEW STAINLESS STEEL GASKET (2). 3. INSTALL NEW EXHAUST MANIFOLD (3). 4. INSTALL NEW NUTS (4) AND BOLT (5). THE BOLT IS TO BE INSTALLED IN THE NO. 4 POSITION RIGHT SIDE OF ENGINE. TORQUE NUTS TO 30 N.M (22 LB FT) TORQUE BOLT TO 54 N.M (40 LB FT) 5. INSTALL OIL LEVEL INDICATOR TUBE AND SPARK PLUG SHIELD (1) (FIGURE 2). 6. INSTALL NEW SPARK PLUG SHIELD ATTACHING NUTS (2). TORQUE NUTS TO 20 N.M (15 LB FT).
SERVICE PARTS INFORMATION REFER TO THE FOLLOWING PART NUMBERS WHENEVER REPLACEMENT OF THE EXHAUST MANIFOLD IS NECESSARY.
PART NUMBER DESCRIPTION QTY. REQUIRED
12551387 EXHAUST MANIFOLD-RIGHT 1 12551385 EXHAUST MANIFOLD-LEFT 1 9442946 NUT (EXHAUST MANIFOLD) 15 3909821 BOLT 1 12551449 GASKET 2 12554867 STUD 15 9442958 NUT (SPARK PLUG SHIELD) 8
PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.
WARRANTY INFORMATION FOR VEHICLES REPAIRED UNDER WARRANTY, USE:
LABOR OPERATION DESCRIPTION
J0100 MANIFOLD, EXHAUST RH-REPLACE J0101 MANIFOLD, EXHAUST LH-REPLACE
USE PUBLISHED LABOR OPERATION TIME.
FIGURES: 2 ATTACHMENTS: 0
FIGURE 1 1. INSTALL NEW STUDS 2. INSTALL NEW STAINLESS STEEL GASKET 3. INSTALL NEW EXHAUST MANIFOLD 4. INSTALL NEW NUTS 5. INSTALL NEW BOLT
FIGURE 2 1. INSTALL OIL LEVEL INDICATOR TUBE AND SPARK PLUG SHIELD 2. INSTALL NEW SPARK PLUG SHIELD ATTACHING NUTS
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“The good thing about science is that it's true whether or not you believe in it.”
Neil deGrasse Tyson |
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ModMech
Top Member
USA
948 Posts |
Posted - 07/01/2007 : 10:28:31 AM
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| Also NEVER install an exhaust manifold that is not FLAT on the inlet side (use a straight-edge to verify). It WILL leak and or crack in sort order... been down that road a few hundred times. |
If you want customer service, you NEED an International! |
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Topic |
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Exhaust Manifold torque
