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vortec intake manifold torquing
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Post vortec intake manifold torquing 
Hey guys, so I know the stock intake manifold is torqued to 11ft/lbs....HOWEVER, I'm running Max's TBIā„¢ for vortec heads manifold modifed for the whole vortec setup and true MPFI, and I'm putting on some RHS heads. I found this from the RHS site:
http://www.racingheadservice.com/Information/Technical/Heads/TechSheets/12407_IS.pdf

it states the intake manifold torque is 35ft/lbs. I'm going to be using the updated GM vortec manifold gaskets, so I'm wondering if I should torque to 11 like the stock vortec setup is, or to 35 like the RHS spec sheet says.

I'm trying to contact RHS as well but haven't heard back and I'm hoping to have it all together next week sometime. (hopefully with the whipple too Very Happy )



Last edited by Aloicious on Sat Jun 06, 2009 3:43 am; edited 1 time in total
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The 13lbs is to prevent the Vortec manifold from cracking and to keep it from squeezing out the gasket. This is an intake issue, not a head issue. I would use the torque specs for the new intake.

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I used the updated BS too. Now I can't sleep good. Next time I'll use FelPro.

Picture speaks for itself:



...in case it does not: no plastic carrier material.

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Thanks guys, I've actually used the updated gaskets before with good success. everywhere I read seems like the torque specs are for the gasket itself rather than the intake or heads, so I believe the 35ftlbs the RHS page states is for when using their own gaskets. so I would think with the GM gaskets, you would use the stock 11ft/lbs specs. but any additional info woule be very helpful.

for those who aren't aware about the manifold its like this:
this is my manifold
http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=219078

and it has been modified into this:


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1999 Tahoe 4x4 wrote:
I used the updated BS too. Now I can't sleep good. Next time I'll use FelPro.

Picture speaks for itself:



...in case it does not: no plastic carrier material.


I thought the newest GM gasket supplier uses steel inserts to limit gasket deformation too?

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Took these during a private tour of Stillen's R&D design center (thanks to Marty)

While looking at their install bays, noticed more Fords. They said that was
the sign of the times (circa 2004) and a customer, a customer... Sad

On one mechanics bench was the makings of a Whipple going into an Escalade
or other GM SUV. Notice the gasket and the new boss poking into a complimentary
counter bore in the head. This is to manage the sliding between the manifold and
head, which rolls the O-Ring in the gasket, which will create leaks later. Not a traditional
O-Ring, but a GM variant.







My guess is that GM went to this stupid bolting scheme to reduce their manufacturing
cost. Instead of having to do each bolt, a gang torquing fixture comes down directly and
does them all in one stroke.

Ditto that stupid quick connect water heater to manifold fitting....for 'their' convenience, not
a mechanics.

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PSWired wrote:

I thought the newest GM gasket supplier uses steel inserts to limit gasket deformation too?


they do.

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Aloicious wrote:
PSWired wrote:

I thought the newest GM gasket supplier uses steel inserts to limit gasket deformation too?


they do.

That would be new to me. Is there a 2nd revision?

I used the revised gasket GM Part#89017465 with "washer" torque stops imbedded and the color of the o-ring was light blue instead of white like on the old ones.

I think on the old ones there is more going on than just torque issues.
Picture shows old gasket, ckeck out the coolant-side vs. air-side.



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1999 Tahoe 4x4 wrote:
Aloicious wrote:
PSWired wrote:

I thought the newest GM gasket supplier uses steel inserts to limit gasket deformation too?


they do.

That would be new to me. Is there a 2nd revision?

I used the revised gasket GM Part#89017465 with "washer" torque stops imbedded and the color of the o-ring was light blue instead of white like on the old ones.

I think on the old ones there is more going on than just torque issues.
Picture shows old gasket, ckeck out the coolant-side vs. air-side.



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.



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Aloicious, the picture you posted is the revised version and that is indeed the one I installed.

HOWEVER:

We are talking about different things. I'm talking about the carrier material of the o-ring. On FelPro the whole thing is METAL.
This is important because it seems like the plastic seems to be softened by the coolant. Look at my pictures, you'll find evidence for that. That is what I meant with other issues than torque and that is what causes me loss of sleep.

The FelPro seems like a forever solution while the revised GM plastic seems like it might have issues some time in the future.

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I don't know about acidity, Senior, but I've read that the problem existed before Dexcool. I can't comment on that.

What I can say is that the gasket on the right dosen't appear to be Fel-Pro.
And the coolant port has shrunk (Besides being deformed).

The clamping bolts bordering that coolant port causes too much localized pressure (imo).

I think shearing forces from initial installation or heat cycles are causing this. There is also deformation/damage at other areas away from coolant but not as dramatic.

Why not RTV the whole thing and forget about crappy gaskets. Evil or Very Mad

You know, looking back, I think I was leaking coolant. The front bolts where hard to remove and full of coolant gunk. And you can see the crap in the hole.



Last edited by CrazyHoe on Fri Jun 05, 2009 8:53 pm; edited 1 time in total
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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.

Traditional American Green does NOT have an acid in it's makeup
they say. Extended coolants are OATs and HOATs (Organic Acid Technology
and Hybrid Organic Acid Technology) has an acid component that etches
rust away and suspends it in the liquid.

The silica coats and protects in a few hours, while OATs and HOATs takes
a couple thousand to etch and then coat, while floating that etched metal
to form it's nastiness waiting for O2 to get in there.

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.

This is one of the better articles on Deathcool (OATs and HOATs).
http://www.motor.com/article.asp?article_ID=816 Too bad
they removed the pictures, as that made the original article even
better.

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).

The newer gaskets first had a different O-Ring material, then the boss
and metal insert to allow higher torque and now see a full metal gasket
with higher torque recommendations.

My 1996 7.4L is now starting to lose coolant (American Green). Plus
just replaced the radiator due to a crack in the plastic hot tank (rebuilt
it around 1999, retanked and new gaskets).


Find that American Green is tough to find, then found it at Kargens under
the "O Riley's" brand name. OATs/HOATs are $15/gallon and O Riley's is
$10/gallon.

It's been 10 years since switching to American Green and several flushes
and still found some pink globs of Deathcool. Think hiding in the block's
backwater passages. Guess have to take the block drain plugs out and
coat hanger it out.

Think I'll have to replace my intake gaskets soon and will do the
quick connect at that time.

youngster Ben, notice that the bolt holes in the gasket are not round...
Oblong for that wacky angular, therefore sliding action. Get the new
gasket made from all metal and use the higher torque they recommend.
Please report back, as this is the first I've heard of an all metal gasket
and interested on how it goes...

Swear GM was reading our Suburban forum back then, as every one
of our suggestions turned into actual product. Tab and reciprocal
counter bore, the metal insert to allow higher torque and not crush
the O-ring and a full metal gasket...

Old Ben

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Thanks Old ben, good info, I am running green for probably a decade in the truck, non deathcool, and have flushed several times as well, any additional dex will be very minimal. so, you;d suggest the felpro metal based gaskets that '99 tahoe posted earlier and to set them at 35 ft lbs?

'99 tahoe, I get what you're saying now about the metal base not just the inserts. I may just get them and go with it. but then the question arises about the torque again since the felpros are a different material. I'll have to research it some tonight.

I'll post anything interesting I find.

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Bent1 wrote:
...extended coolant's 'acid' component attacks some gasket materals and if there are crevices between the gasket & metal surfaces, it will eat them both...

Like on this picture below?

I got really mad when I saw it. Origninally I wanted to machine the surface but then compromised to smoothening it out with sandpaper (yes, making the surface uneven, i know Mad), so hopefully the o-ring can never the less sit better / do it's job better.



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Bent1 wrote:
Traditional American Green does NOT have an acid in it's makeup they say. Extended coolants are OATs and HOATs (Organic Acid Technology and Hybrid Organic Acid Technology) has an acid component that etches rust away and suspends it in the liquid.

As recommended on a webpage (http://www.gwrauto.com/RadStrip1.htm), I use PH-Strips to test my coolant for acid.
I use Dexcool and preemtively change it every two years.

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Quote:

At what torque must the Intake Manifold Bolts be tightened to on a 98 Chevy 350 Vortex Two years post replacement the manifold seems to be leaking again?
In: Chevy Silverado, Air Filters and Intake Manifolds [Edit categories]
[Edit]

Intake Torque specs on 98 350 Vortec

The 98 Vortec 350 CID engine has an aluminum intake and a plastic plenum mounted to it. I just had to tear mine down due to a blown intake manifold gasket on the water port located above #1 Piston. This caused MAJOR leak of Anti-Freeze into the "Valley of lifters" and consequently into my oil.
The Aluminum intake manifold on a 98 Vortec 350 engine should have 8 bolts total, located in the 4 corners of the manifold.
The Torque order is the center bolts in an "X" pattern followed by the outers in a line pattern. Following the cylinder numbers of 1 - 8 (1, 3, 5, 7 on drivers side, and 2, 4, 6, 8 on passenger) you would tighten them down 3, 6, 4, 5 for the "X" pattern, then 7, 8, 2, and finish on 1.
You tighten them down in steps
1st round goes to 26 in lbs.
2nd round to 106 or 116 in lbs.
Then last round is 11 ft lbs

The Haynes manual is correct on that but they do not mention the ft lbs behind 11 on that last step

Hope that helps
Wink


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When I did mine I did not have a low-torque wrench at hand. But I think using it might have been a bit confusing anyways. Because, despite torquing evenly, it seemed like at applied torque of even much more than 11 ft lb, the manifold still was going down and still seating. Indeed the only way I could tell that the manifold was seated, was by feeling on the ratchet. With the longer handle of a torque wrench I might have not felt that. Once I realized that the manifold was "all the way down" seated, I retorqued with feeling. Crushing is limited by the inserts, so you only torque so the bolts/threads don't come loose. I used some locktite (GM#12345382) on the bolts too. I think threadlock came with the GM gasket.

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looks like the ms98000t is the way to go from what I can read. I think I'll return the GM gaskets and get a set of the felpro's

also reading, it looks like they are still to be torqued to 11ft/lbs, so I'll stick with that, I'm sure a few lbs over wouldn't be bad because the steel inserts would help prevent crushing, but the 35ftlbs that the RHS site states is a bit excessive for these gaskets, I'm sure those specs are for the RHS brand intake gaskets which according to their site are "thick paper with silicone"... Rolling Eyes no thanks.

edit. I also forgot to mention I got some ARP vortec intake bolts and I'll be using blue threadlocker as well. anyone see a problem with the ARP vs using the freakin' expensive GM brand intake bolts?

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Learn something new every day, I'd always thought the 11 ft lbs was due to the manifold being made of plastic.

Nothing wrong with silconed paper gaskets, GM used them for decades with no problems. I've even used poker cards and silicone for thermostat housing gaskets with success, back in my younger days when I could afford a thermostat or a gasket, but not both... Laughing

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Aloicious wrote:
specs are for the RHS brand intake gaskets which according to their site are "thick paper with silicone"...

If you are talking about the specs CrazyHoe had posted, those are GM specs for first original OEM gasket design.
So I think a little more than 11 ft lb is better. You really want to make sure the manifold is seated. Otherwise even the FelPro might leak just from not being torqued properly. I truly belive that with the inserts the torque limit is largely irrelevant from the gasket perspective. Torque limitation with inserts rather serves to not to stip the threads. It is like torqing your e.g. waterpump bolts.

Speeder wrote:
...back in my younger days when I could afford a thermostat or a gasket, but not both... Laughing

Laughing Laughing Laughing

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