: Head Bolt Torque



jeffrsmith
05-20-08, 09:55 PM
I have been reading up in my FSM in preparation for doing the HGs on my 99 SLS and as has been reported here in the past there is a discrepancy in the torque values in the different sections of the manual. Can someone clear up what is the "better" values to use? I have been reading in other posts to try to figure this out but I still have the question.

The manual states in the spec section (6-9) and then again in the Cylinder Head Installation (6-222) to torque to 30 lb ft, then 70, 70, 60 for a total of 200 degrees.

Then the manual states in the Cylinder Head Replacement procedure (6-111) to torque to 22 lb ft, then 60, 60, 60 for a total of 180 degrees.

Then I read in the 97 ETC Head Gasket Replacement thread that some people torque to 30 lb ft, then 60, 60, 60 for a total of 180.

Which specification should I/we really be using? I want to make sure I get it right.

Jeff

RickyHenry
05-21-08, 11:55 PM
I have been reading up in my FSM in preparation for doing the HGs on my 99 SLS and as has been reported here in the past there is a discrepancy in the torque values in the different sections of the manual. Can someone clear up what is the "better" values to use? I have been reading in other posts to try to figure this out but I still have the question.

The manual states in the spec section (6-9) and then again in the Cylinder Head Installation (6-222) to torque to 30 lb ft, then 70, 70, 60 for a total of 200 degrees.

Then the manual states in the Cylinder Head Replacement procedure (6-111) to torque to 22 lb ft, then 60, 60, 60 for a total of 180 degrees.

Then I read in the 97 ETC Head Gasket Replacement thread that some people torque to 30 lb ft, then 60, 60, 60 for a total of 180.

Which specification should I/we really be using? I want to make sure I get it right.

Jeff

Engine - Cylinder Head Tightening Specs Clarification

File In Section: 06 - Engine/Propulsion System

Bulletin No.: 99-06-01-016

Date: October, 1999

SERVICE MANUAL UPDATE
Subject:
Cylinder Head Tightening Specification Clarification

Models:
1993 Cadillac Allante, Sixty Special (FWD)
1993-96 Cadillac Fleetwood
1993-99 Cadillac DeVille, Eldorado, Seville
1994-99 Cadillac Concours
1995-99 Oldsmobile Aurora
with 4.0 L or 4.6 L Engine (VINs C, Y, 9 - RPOs L47, LD8, L37)





This bulletin is being issued to clarify the cylinder head tightening specification listed in the following procedures in the Engine Mechanical 4.0 L and 4.6 L sections of the appropriate Service Manuals:
^ Specifications - Fastener Tightening Specifications

^ Cylinder Head Replacement - Installation Procedure

^ Cylinder Head Installation

The torque specification and sequence for the cylinder head bolts (1--10) using J 36660-A is:
1. First Pass - 40 N.m (30 lb ft)

2. Second Pass - 70 Degrees

3. Third Pass - 60 Degrees

4. Fourth Pass - 60 Degrees (190 Degrees total) The torque specification for the three front M6 cylinder head bolts is:

12 N.m (106 lb in)

jeffrsmith
05-22-08, 06:19 PM
Thank you RickHenry

tateos
05-22-08, 09:35 PM
I did my left head 22 60-60-60, then I thought I read 30 60-60-60, so I did the right 30 60-60-60, and left the left head as is. No problems so far.

RickyHenry
05-22-08, 11:16 PM
I did my left head 22 60-60-60, then I thought I read 30 60-60-60, so I did the right 30 60-60-60, and left the left head as is. No problems so far.

well, if one goes first, maybe we can finally settle this debate. You have setup a nice controlled testing environment.

btw, i did both of mine 30 60-60-60, then later found in another section of the service manual completely different specs. Confused the hell outa me. I'm not about to pull the engine again to adjust to proper specs, i'll just play the waiting game.

tateos
05-23-08, 03:13 PM
Right - that is what I did - left it alone and hoped for the best



well, if one goes first, maybe we can finally settle this debate. You have setup a nice controlled testing environment.

btw, i did both of mine 30 60-60-60, then later found in another section of the service manual completely different specs. Confused the hell outa me. I'm not about to pull the engine again to adjust to proper specs, i'll just play the waiting game.