1996 4L head and intake torque sequence
#1
1996 4L head and intake torque sequence
So the 1996 Ford manual supplement (and ONLY the 1996, not the 1995 or 1997) says the torques should be 22 ft-# (heads), 3 (lower intake manifold), 52 (heads), 6 (manif), 90 degrees more (heads), and 11 (manif).
The FelPro instructions (revised 11/05) say 44 (heads), 3-6 (manif), 59 (heads), 6-11 (manif), 80-85 degrees more (heads), and 15-18 (manif).
The 1997 Ford manual says tighten the head to 22-26, then 52-56, then 90 degrees more. THEN the manifold at 6, 11, and 16 ft-#. What is so special about the 1996 that it requires the heads and manifold to be tightened at the same time? Or should all of 'em be tightened the way the 1996 is, and the manual just never got changed? It wouldn't be the first time I've found errors in the "official" manuals (there are quite a few in my experience).
I'm inclined to follow the FelPro instructions, but the 18 ft-# for the M8-1.25 manifold bolts has me a bit worried. If they're grade 8.8 or higher, it's probably OK. I'll check 'em next time I'm fooling with it.
A look at others' comments on this issue seem to indicate that higher torque is better for the manifold, that otherwise it can come loose and leak. Any other thoughts?
The FelPro instructions (revised 11/05) say 44 (heads), 3-6 (manif), 59 (heads), 6-11 (manif), 80-85 degrees more (heads), and 15-18 (manif).
The 1997 Ford manual says tighten the head to 22-26, then 52-56, then 90 degrees more. THEN the manifold at 6, 11, and 16 ft-#. What is so special about the 1996 that it requires the heads and manifold to be tightened at the same time? Or should all of 'em be tightened the way the 1996 is, and the manual just never got changed? It wouldn't be the first time I've found errors in the "official" manuals (there are quite a few in my experience).
I'm inclined to follow the FelPro instructions, but the 18 ft-# for the M8-1.25 manifold bolts has me a bit worried. If they're grade 8.8 or higher, it's probably OK. I'll check 'em next time I'm fooling with it.
A look at others' comments on this issue seem to indicate that higher torque is better for the manifold, that otherwise it can come loose and leak. Any other thoughts?
#2
So I got the head bolts and lower manifold installed today, following the FelPro guidelines noted above.
1. BUT there was insufficient clearance between the left bank forward bolt and the gasket hole for same, so the gasket rode up about 0.080" on the head. Whether this is problematic from the standpoint of sealing the intake ports, i don't know. I'm inclined to wait for the silicone on the end rails to dry, then remove it and start over after enlarging the dang hole in the gasket so it will clear reasonably. Should've cut this hole out a bit bigger to begin with. The FelPro side gaskets have bent tabs on top to hold against the head, thereby locating them vertically, so there's no excuse for them to make the bolt holes too small.
2. I applied silicone slightly up the side of the heads at front and rear to seal those "corners". But after putting the intake/port gaskets on, I neglected to put a dab of silicone sealant on top of the gaskets at those same corners. Faked it afterwards wtih some surface application, but dunno if it will seal adequately. But if I pull 'em off and re-do the job, then I'll take care to do it right.
3. Whyinell is there a requirement to tighten the head bolts and lower intake bolts in the same alternating sequence? If an intake is replaced without doing the head gaskets, wouldn't one just tighten the intake bolts in sequence and ignore the head bolts? Don't tell me that you have to remove the head bolts, buy new ones, and put them in place (and maybe even the head gaskets?!) in order to replace the intake manifold. There's an awful lot of strange "requirements" going on here. Naturally this concerns me because if I now replace the intake gasket (or even re-use the current one, since it hasn't been used in service, but only clamped cold), I am not looking forward to replacing the head bolts (and gaskets) just to properly re-fit the intake gaskets. Pffft.
Jeez-moneez, this is a bitch of a job in so many ways.
1. BUT there was insufficient clearance between the left bank forward bolt and the gasket hole for same, so the gasket rode up about 0.080" on the head. Whether this is problematic from the standpoint of sealing the intake ports, i don't know. I'm inclined to wait for the silicone on the end rails to dry, then remove it and start over after enlarging the dang hole in the gasket so it will clear reasonably. Should've cut this hole out a bit bigger to begin with. The FelPro side gaskets have bent tabs on top to hold against the head, thereby locating them vertically, so there's no excuse for them to make the bolt holes too small.
2. I applied silicone slightly up the side of the heads at front and rear to seal those "corners". But after putting the intake/port gaskets on, I neglected to put a dab of silicone sealant on top of the gaskets at those same corners. Faked it afterwards wtih some surface application, but dunno if it will seal adequately. But if I pull 'em off and re-do the job, then I'll take care to do it right.
3. Whyinell is there a requirement to tighten the head bolts and lower intake bolts in the same alternating sequence? If an intake is replaced without doing the head gaskets, wouldn't one just tighten the intake bolts in sequence and ignore the head bolts? Don't tell me that you have to remove the head bolts, buy new ones, and put them in place (and maybe even the head gaskets?!) in order to replace the intake manifold. There's an awful lot of strange "requirements" going on here. Naturally this concerns me because if I now replace the intake gasket (or even re-use the current one, since it hasn't been used in service, but only clamped cold), I am not looking forward to replacing the head bolts (and gaskets) just to properly re-fit the intake gaskets. Pffft.
Jeez-moneez, this is a bitch of a job in so many ways.
#3
#4
I think you're right, 99f350sd. The head bolt "final solution" was to say "screw Ford's stupid requirement to tighten the head and manifold together." I'm suspecting that whoever made that requirement (apparently ONLY for the 1996 4.0) was an inexperienced engineer looking to solve a bad design with what is a pretty silly, and IMO, ineffective fix. After all, the clamping force on the heads is huge compared to the intake manifold, so the heads, also doweled, will go down where they're supposed to no matter what you do with the intake manifold. And I noticed that if this was so important to do the heads and manifold together (as the manual says it is) then any time the intake manifold gaskets were replaced you'd have to do the heads also--pfft. Anyway, it's always a challenge to balance the manual's edicts with one's own experience and knowledge. That's what makes this forum so useful!
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