Lower manifold gasket observations

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Thanks a bunch Mr. Cuda. You have eased my mind immeasurably. It's reassuring and educational to discuss this job with someone who has been there and done that a number of times.

wrote:

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wrote:

More Usenet groups should contain discussions like this one. Very educational and noone calling somebody an a*hole or worse. Quite refreshing these days....
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Nice reply! I second Bishoop on his reply.
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Silver Surfer wrote:

In theory, you should be replacing the bolts as this is what is called for in the bulletin released by GM. I believe the reason why they call for the new bolts is that the new bolts already have the loctite applied to the threads, and GM figures that there are enough lazy techs out there that will not clean the old bolts up and re-apply new loctite. So in your case, using the old bolts would be fine.

The new style replacement bolts don't have this washer...so I don't think it will really matter. I've never used RTV in the area you mention, nor have I ever seen any leaks develop from those locations.

I use a flex socket that works for all four of the diagonal bolts.

Do the new gaskets have the two metal pellets imbedded in the gasket at either ends? If so, here is the torque spec.
Tighten
1.. Tighten the vertical lower intake manifold bolts (1) to 7Nm (62 lb in). 2.. Tighten the diagonal lower intake manifold bolts (2) to 7Nm(62 lb in). 3.. Tighten the vertical lower intake manifold bolts (1) to 13Nm(115 lb in). 4.. Tighten the diagonal lower intake manifold bolts (2) to 25Nm(18 lb ft).
Ian
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My torquing sequence was very close to what you described.
Torqued ALL bolts to 62 lb-in in sequence Torqued ALL bolts to 115 lb-in in sequence Torqued diagonal bolts to 18 lb-ft in diagonal sequence
Made several intermediate checks of the center bolts to ensure they were maintaining their torque as the gasket compressed per Mr. Cuda's advice.
Did not look for any metal pellets that you reference. I assume that such a feature is present for GM replacement gaskets; however, my new gaskets are made by FelPro as recommended by a couple of esteemed gentlemen in this group.
Also made a mistake right from the get go. After setting the manifold in place the first bolt I put in was one of the diagonals on the pump/alternator end. That was a blunder. Had much trouble getting the bolt on the opposite end and side started after that. Later after the dust had settled it occurred to me that the center bolts should have gone in first and been given a 62 lb-in torquing. That should have squeezed the gasket enough to let those diagonal bolts line up correctly on both sides of the manifold. Lesson learned.
Still don't have a real good feeling about the end sealing. Not sure I used enough Right Stuff, but it did squeeze out of the joint. Due to disruptions there has been no job progress past reinstalling the lower manifold. I'm about half tempted to take the lower manifold off again and start over from scratch now that I know what I know. Would those FelPro gaskets seal properly again after they've been torqued once?
You have piqued my curiosity about the tool you use on those diagonal bolts. I can hardly get my 3/8" drive socket and swivel head on two of the bolts unless they are almost all the way in. It was my impression that a specific torque applied at an angle doesn't produce the desired torque at the bolt. That's why I used the crow's foot per the service manual's instructions. Made a correction of about 6% to account for the length of the crow's foot.

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Silver Surfer wrote:

Yes, good advice.

I haven't seen the FelPro gaskets. We couldn't use them anyway... warranty issues. Doesn't mean they aren't as good or better...just that we have to use what GM provides.

Yes.....I usually start the diagonal bolts that do line up...usually the two that go into the rear head....by hand and then use the middle bolts to suck down the manifold until the other diagonal bolts can be started by hand. Which you learned by experience.

Probably. Why don't you feel good about the end sealant? The most important thing is that the intake and block surfaces should be spotless and dry. I usually soak part of a rag in Brake Kleen and then rub both surfaces until I don't get any debris appearing on the rag. I've seen way too many "comebacks" from techs that neglect this step and their RTV ends up leaking within 6 months. GM will not do a parts warranty repair on leaking RTV....so the shop eats it.

I use a Snap on 10mm swivel in conjunction with another Snap on swivel (no socket end on this swivel...which allows you to double up the swivels...amazing where you can get to with this setup). As far as the "desired" torque....you might be right....but I really don't care. GM doesn't pay me enough to be worried about 6% torque one way or another. Sorry, an old flat rater talking here!
Ian
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