Cadillac Owners Forum banner

1 - 20 of 25 Posts

·
Registered
Cadillac
Joined
·
52 Posts
Discussion Starter #1
Can anyone tell me what to torque the headbolts down to on a 1999 4.6 Northstar engine? I just timeserted the block, what should I put on the threads to prevent them from coming out?
thanks, Dan
 

·
Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
·
86,987 Posts
You don't put anything on the threads. They are already coated with a thread locker. You are using new bolts aren't you? I don't recall the torque exactly. I seem to recall 37 ft. lbs. and 60 degrees plus 60 degrees, but don't quote me ont that til someone verifies it.
 

·
Registered
The Northstar Tuner
Joined
·
2,759 Posts
Document ID# 641058
1999 Cadillac DeVille


--------------------------------------------------------------------------------


Subject: SMU - Cylinder Head Tightening Specification Clarification #99-06-01-016 - (10/04/1999)



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

1999 Marine

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:

First Pass -- 40 N·m (30 lb ft)
Second Pass -- 70 Degrees
Third Pass -- 60 Degrees
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)
 

·
Registered
Cadillac
Joined
·
52 Posts
Discussion Starter #5
Okay Great so with new headbolts there is no reason to put anything on them? What about if I reuse the old ones?
 

·
Registered
The Northstar Tuner
Joined
·
2,759 Posts
Okay Great so with new headbolts there is no reason to put anything on them? What about if I reuse the old ones?
I have always replaced them, But If you want to chacne it you can reuse them. You will need to put Thread Sealer on the threads and the base of the washer. Thread Sealer like Pipe Thead Sealer Not lock tight.
 

·
Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
·
86,987 Posts
Okay Great so with new headbolts there is no reason to put anything on them? What about if I reuse the old ones?
I have always heard that they are not reusable. That is why a gasket kit includes new bolts. I would not reuse them.
 

·
Registered
2001 eldorado,2008 DTS,2005 XLR, '96 eldo,'95 eldo,' 89 eldo,'78 eldo,'11CTS-V
Joined
·
1,785 Posts
Here's why you shouldn't reuse head bolts. They may look just fine, but they're 'stretched'. The tightening sequence requires a certain torque (40 ft-#?), and three incrimental degree tightening. This tightening puts tension (stretchs) the bolt. Doing it again, weakens the bolt.
 

·
Registered
The Northstar Tuner
Joined
·
2,759 Posts
I have always heard that they are not reusable. That is why a gasket kit includes new bolts. I would not reuse them.
The bolts ARE NOT TORQUE TO YEILD!
They are Torque angle and can be reused.
The Rod bolts are Torque to yield.
Trust me on this I have been over the description for every bolt type on Northstars.
The reason GM recomends replacement is so the correct amount of sealer is on the bolt.
 

·
Registered
The Northstar Tuner
Joined
·
2,759 Posts
Here's why you shouldn't reuse head bolts. They may look just fine, but they're 'stretched'. The tightening sequence requires a certain torque (40 ft-#?), and three incrimental degree tightening. This tightening puts tension (stretchs) the bolt. Doing it again, weakens the bolt.
I see you must have been trained by our goverment. The Army?
Do you have any idea how much money a Cadillac heavy duty tech makes?
We get paid well to know how to fix them.
The main bolts are torque - angle and they don't get replaced.
The oil pump bolts are torque - angled and we reuse them also.
Do you know what a torque - angle is?
 

·
Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
·
86,987 Posts
I could swear I remember the Guru saying they should never be reused. That is what I based my answer on. Guess I stand corrected.
 

·
Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
·
86,987 Posts
Good to know it is not just me. I also thought he said that they where torque to yield, but I could be mistaken there.
 

·
Registered
2001 eldorado,2008 DTS,2005 XLR, '96 eldo,'95 eldo,' 89 eldo,'78 eldo,'11CTS-V
Joined
·
1,785 Posts
What do I know. I've been a GM wrench for 40 years. I've been told they were torque to yield, and should never be reused. I do as I'm told.
 

·
Registered
The Northstar Tuner
Joined
·
2,759 Posts
Did you go to the Northstar Mechanical Systems trianing course?
Are you world class?
Guess what I am.
I have the Northstar book in front of me currently and it says they are Torque-angle
 

·
Registered
2001 eldorado,2008 DTS,2005 XLR, '96 eldo,'95 eldo,' 89 eldo,'78 eldo,'11CTS-V
Joined
·
1,785 Posts
Chill, my friend; don't get your balls in a knot. I've been taught to replace headbolts. When doing a Northstar, you don't want to make mistakes.
Since you're well trained, perhaps you could tell me who has the best prices on Timeserts?
 

·
Registered
The Northstar Tuner
Joined
·
2,759 Posts
Chill, my friend; don't get your balls in a knot. I've been taught to replace headbolts. When doing a Northstar, you don't want to make mistakes.
Since you're well trained, perhaps you could tell me who has the best prices on Timeserts?
What Year and is it for the heads?
 

·
Registered
2001 eldorado,2008 DTS,2005 XLR, '96 eldo,'95 eldo,' 89 eldo,'78 eldo,'11CTS-V
Joined
·
1,785 Posts
The next one is a '93 seville. head bolts. 11155. Best price so far is from threadkits.com for $2.32
 

·
Registered
94 ETC,97 STS
Joined
·
3,531 Posts
From my research and having been corrected previously:

They are Torque to angle but not torque to yield.

They are replaced because of the special coatings on them, not because of metal failure. The guru said they reused them (and HG's) at times during testing on dynos but that was different than reusing them in your car.
 
1 - 20 of 25 Posts
Top