See full version: What Is the Tightening Sequence on a Engine
The intake manifold has 12 bolts that must be torqued in two steps with different sequences. Both steps require a torque setting of 35 foot-pounds. The bolt numbering for the initial torque is 8, 1, 9, 10, 11 and 12 on the passenger side and 2, 3, 4, 5, 6 and 7 on the driver side. The final torque should go around the manifold counterclockwise starting at the driver's side front of the manifold. here
The 4.3L GM motor has 13 head bolts. The upper seven bolts are numbered from front to rear---under the valve covers---as 12, 8, 4, 5, 1, 9 and 13, while the lower bolts are numbered 11, 7, 3, 2, 6 and 10. The bolt numbering is the sequence in which they should be tightened. The first time around, torque these bolts to 25 foot-pounds, then move up to 45 foot-pounds and finally 65 foot-pounds. more
When rebuilding your GM vehicle's 4.3-liter engine, certain engine parts must be tightened in a specific pattern and to specific torque values. Three of the most significant parts that require specific patterns and values are the intake and exhaust manifolds and the cylinder head.
Accepted practice in the automotive industry when installing exhaust manifolds is to start in the middle and the work to both ends. This prevents manifold warp. These bolts must be torqued to 33 foot-pounds.
Mike Aguilar is a freelance writer with over 30 years of professional experience as a mechanic and over 10 years experience in the construction and home-improvement fields. He also attended an electrical apprenticeship for two years in Santa Clara, Calif., becoming a licensed low-voltage technician.
The new radiator shop I go to says the extended coolant's 'acid'
component attacks some gasket materals and if there are crevices
between the gasket & metal surfaces, it will eat them both. [links]
I believe there was a second revision not too long after the first one. both sets of GM gaskets I have used had steel inserts. those pics of yours are either the original ones or the first "update" and I agree I wouldn't use those ones. here's a pic of the newest updated ones with steel inserts and different shaped water passages, and a couple other things. here
The problem is that this 'rust' is reactive with O2 and air in the coolant system
becomes an accelerating catalyst turning the rust into gelatinousness acidic
globs which precipitates out of suspension during a cool down phase.Such
as in the radiator, which then sticks to the tubes to block & eat it away.
That would be new to me. Is there a 2nd revision? here
Since the GM gaskets DO NOT crush fully, there are gaps (backwater)
spots that hold Deathcool to rot out the gasket and metal. Part of this
is due to the too low torque to manage the stupid angular fastening
sandwich of parts (sliding action to roll the O-Ring portion).
Post by Aloicious » Fri Jun 05, 2009 11:37 am more
I've found "Right Stuff" to be far superior to even the "Ultra Black" RTV. The above combo is the ONLY way to fly on Vortec manifolds. [links]
I highly recommend those metal Fel-Pro gaskets as well, and for the front and rear "China Wall" on the block, use Permatex RIGHT STUFF black RTV. here
Also, clean ALL the old threadlock off of the lower intake manifold bolts and use Permatex Medium Strength (#242) Blue threadlock when re-assembling. With those metal Fel-Pro gaskets, you can go up on the torque spec just a bit over the stated spec. I recommend going a bit tighter, nothing crazy though.
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