Installing lower intake on 2.9L

[j-driver]

Pulled the intake off my 87 XLT and am reinstalling it. I've not done a V-type engine intake manifold before, and I've read that lower manifold installation on this engine is an easy thing to screw up, so I want to give myself as much chance to get it right as I can. I have the paperback Chilton manual for that year and I've read KTRANGER's tech article on 2.9L head replacement that includes the 5-step torque-down sequence for the lower manifold.

I'm using an ROL 1-part folded cardboard gasket, which has cork sealing strips at the front and back of the lifter valley but no sealing rings around any of the intake or coolant ports. So I'm assuming I'll have to apply a thin coat of rtv around each of them, on both sides of the gasket, and get things in place and the initial torque-down done before it skins over. I have the original gasket, which had cork strips and blue sealant rings/strips at the critical mating surfaces, so I imagine I can use that as a guide as to where I need to apply silicone.

Here's what Chilton gives as the torque sequence:

To me this seems goofy, I've always thought that with manifolds and heads you start from the center and work out toward the edges. I'm wondering if I I'd be better following this sequence for the first one or two torque-down steps and then going 5-6-7-8-4-3-2-1 for the higher torques. Chilton has it this way for the 2.9 and 4.0 engines but basically opposite for the 3.0. Since my gasket has no preinstalled sealant I'm also thinking about first installing it dry at low torque and leaving it overnight so it gets used to the shape and location where it needs to be and I don't smear sealant everywhere when I'm doing the final install.

What have I missed, and am I out to lunch somewhere? Many expert members here, and I'd very greatly appreciate any tips, guidance, or feedback people can offer before I get started.

 

[Shran]

I would follow the instructions and not deviate much from them.

Weird that it doesn't come with the sealant rings on the gasket? I might suggest using a better gasket. I think if you try using RTV there it's going to smear around no matter what.

As to your final torque, I have best luck following the procedure in the manual where it mentions letting the engine go through a couple heat cycles and then retorquing the bolts. I think that is really important on Cologne engines.

 

[j-driver]

Many thanks, I'll take your advice and follow the torque instructions. If I deviate from it at all it won't be until the final torque after a few warm-ups.

The ROL gasket was a big disappointment. I bought it from an ebay seller who listed it as an equivalent of the Fel-Pro set, but the ROL set didn't even include plenum gaskets. That said, I'll probably try to work with it so as not to have to wait on more parts before I start putting the truck back together. If it fails, I'll know to buy the Mahle/Clevite set next time. That one seems to be the only design that includes cork strips on the ends and sealant rings on the mating surfaces.

 

[Shran]

No prob. I'm not sure that the cork strip style is better, it's just different. I would probably still use some RTV on the ends of the strips and maybe some gasket shellac on the sealing surface of the strip. I think I used some old stock Carquest gaskets on the last 2.9 that I worked on, and it had cork strips, and worked fine.

Some of the 4.0 lower intake gaskets are two pieces and they expect you to use a ludicrously large bead of RTV in the valley in place of a gasket... I think that style is stupid but it does seem to work (unless you don't use enough RTV.............)

Probably goes without saying but while you're in there, replace the distributor o-ring if you haven't already, there is no time like right now and it is a common leak spot on 2.9's.

 

[SenorNoob]

Yeah my 4.0 has to have like a 3/8ths bead of RTV at the front and back. It is pretty stupid. First time i did one, it leaked badly and had to be redone the next weekend.

 

[Terrys87]

I have seen where you start in the center and work out and the way you just pointed out in Chilton. I would go with the manual on this one but don't think center to outside would hurt you either. I would recommend getting the blue Fel Pro valve cover gaskets when you get to the point. A little more pricey but so worth the money in the long run. Been a long time since I did the lower intake so not much help there.