I've been having a problem with a high idle and from what anyone can tell me, it has to do with a vacuum leak somewhere under the upper intake. So... I went and got some new FEL-PRO gaskets for myself and I'm going to try this again. I'm not too upset about it though, it'll give me a chance to remove the throttle tubes for cooler air into the engine and clean up the clutter a bit, and maybe to take that rear valve cover off to be cleaned up and repainted. (might as well hit the front one again only this time adding some clear coat for a richer look and improved durability)

So the question is: What should I use for the gaskets? I have the FEL-PRO black RTV Silicone that came with the set- which seems to me to be the way to go since the mfr sent it... or, some of this Permatex Super High Tack Gasket Sealant that I have?

We use the Permatex and never had a problem. And when they say high tack, they mean it. I had to use an engine lift once to seperate the upper plenum, that stuff is strong.....

if you read the instructions ,the rtv is to seal the ends of the lower intake where there are no gaskets .i also use permatex but only on the lowest manifold .the top two will seal up without sealant and then you can reuse them .follow the proper torque values and sequence from the manual .unless the manifolds are warped or deeply scratched ,you wont have a problem .

quote Originally posted by wftb: i forgot to add that i found that i had to torque the bottom manifold down over the course of a couple of days .there was a lot of crush area built into the gaskets so that you get false torque readings .retorquing took about four times until the gaskets crushed down and the wrench finally clicked without turning the bolts more .i only torqued them twice the first time and i had a leak .

That would be a little less of a pain if the fuel rail wasn't in the way. I'll keep that in mind when I start tightening things down. Guess I'll have to invest in a torch wrench. I may have found the problem- I don't have a manual open right now so I don't know exactly what this is called but there's a hose connected from under the lower intake to a metal tube that slides into the underside of the throttle body. It was on, but seemed too loose. I think what I'll do is put a hose clamp at the bottom of it and tighten it up good.

One of the other things I'd like to do is find a way to put a breather on the hard-to-reach valve cover, and eliminate the hose and metal tube setup there. The proper way for this to be set up is that it connects to the air filter. I currently have it with a small breather on the end- I think I did this because I needed to replace the piece that connects the plenum and the air filter (where the hose would normally connect) due to the Isuzu shift cables that made the fit too difficult.

Anyone have any feedback on something that they have done with the hard to reach valve cover air supply?

Thanks for starting this thread Andrew, btw the way I love your new avatar!
I'm also removing my intakes next week to replace my fuel injectors and valve cover gaskets. I purchased this gasket set from TFS http://www.fierostore.com/Product/Search.aspx Should we use RTV on the outside edges as well?

quote Originally posted by wftb: if you read the instructions ,the rtv is to seal the ends of the lower intake where there are no gaskets .

Can someone post a pic where there is no gasket and only RTV is required please

[This message has been edited by Gokart (edited 07-04-2007).]

The RTV goes on the left and right "S" shaped flat surfaces in this photo:

quote Originally posted by Gokart: Thanks for starting this thread Andrew, btw the way I love your new avatar!

I had to, if only for a little while...

quote Originally posted by Toddster: F-I-E-R-O, is your avatar doing anything Saturday night?

The photo above doesn't look like anything I'm working on...

that is the underside of the bottom intake manifold .the 2.8 v6 has a three piece intake manifold .if this lower intake is not leaking(and unless your motor has been torn down , it probably isnt ) leave it alone .this is the only manifold that you need to torque down over the course of a few days . the other ones dont have crush space ,and dont need any sealant .

well, a slight correction to that. the true intake, the part that mates to the head only uses sealant on the outter edges, as was mentioned. the manual instructions cover that very well.
if you torque it properly, following the sequence in the manual, even with the std felpro aftermarket gasket set, you only need to do it once. if you need to do it again, you didn;t do it right in the first place.
the middle and upper plenums should use no sealant, and be torqued according to spec. be absolutely sure that all mating surfaces are clean!!!!!!!!!!!!!!!!!!!!!!!!!!!! that is the biggest problem I;ve seen on assembly of any intake, lack of proper cleaning.
the other side of that is someone hitting it with a sanding wheel, which is also wrong. use a good scraper. examine ti carefully while cleaning it. only remove old gasket, not the metal mating surfaces.
not to start any wars on this, but the lack of proper cleaning and torquing is the biggest issue in intake problems. and the torgue number is not nearly as important as that all are set to the same value, you don;t want to warp anything.

quote Originally posted by tjm4fun: well, a slight correction to that. the true intake, the part that mates to the head only uses sealant on the outter edges, as was mentioned. the manual instructions cover that very well. if you torque it properly, following the sequence in the manual, even with the std felpro aftermarket gasket set, you only need to do it once. if you need to do it again, you didn;t do it right in the first place. the middle and upper plenums should use no sealant, and be torqued according to spec. be absolutely sure that all mating surfaces are clean!!!!!!!!!!!!!!!!!!!!!!!!!!!! that is the biggest problem I;ve seen on assembly of any intake, lack of proper cleaning. the other side of that is someone hitting it with a sanding wheel, which is also wrong. use a good scraper. examine ti carefully while cleaning it. only remove old gasket, not the metal mating surfaces. not to start any wars on this, but the lack of proper cleaning and torquing is the biggest issue in intake problems. and the torgue number is not nearly as important as that all are set to the same value, you don;t want to warp anything.

exactly.
there is no sealant used anywhere on the upper & lower plenum. there is RTV used as the front & rear seal on the intake manifold. and, there is 2 small daps of RTV used on the valve cover seal at the point where the head & intake manifold meet on each side.