The Stovebolt Site Forums The Shop Area Engine Shop Huge Intake Manifold Leak !!!

I discovered that my 235 c.i. has a huge intake manifold leak at the head by spraying starter fluid around it. Will just putting a new intake/exhaust manifold gasket fix it? Is there a easy way to determine if the intake manifold is warped? Should I use some high temp RTV to seal it? I appreciate any help.

The funny-looking keepers are "bridge clamps".
Someone may have left out the "alignment sleeves" that keep the intake aligned wth the head (no, the bolts won't do it). If left out, the manifold may warp over time (this happened to me, a PO had left out the sleeves). It won't damage the intake, it's the exhaust that will be warped; such that when the bolts are installed at the ends, the intake is out of alignment.
The sleeves are like $5 from any "re-pop" outfit.
Gaskets are cheap too; put the shiny side out.

Take the exhaust and intake manifold as an assembly to a machine shop. Have them surfaced together. The last one I done was $35.00. Warping is a common problem on long inline manifolds. Follow torque recommendations in your service manual when reinstalling the manifold assembly. You will be good to go. Also, the alignment sleeves as mentioned by GMC248, help both with reassembly and longevity of the repair.

The alignnment rings aren't just a good idea, they're absolutely essential for a good, leak-free assembly. Ditto on the milling of the manifolds, especially the exhaust. I don't believe both manifolds can be milled as an assembly, however. One word of advice, tighten the intake/exhaust flange, where the heat riser fits, after all the manifold-to-head bolts & nuts are torqued. This allows both manifolds to get the best possible fit to the head, before they're pulled together.
Jerry

Hot Rod, it is time to find another machine shop if they cannot mill them as an assembly. It is standard procedure for my machinist. It guarantees both manifolds are in one plane.

I do that operation routinely, but I separate the manifolds first. Since it's difficult to get a solid mount on the assembled pair, and keep it from shifting around, I always mill them separately. Then, I snug both manifolds up to the head before tightening the bolts between them at the heat riser. I try to mill approximately the same amount of metal from each one, though. Doing both together is just a time-saver, it's not a better procedure.
Jerry

What are you using to surface manifolds?

I have a Blockmaster block and head mill, with about an 18" wheel-type cutter head, with 40 or so carbide cutters. It handles everything up to Cummins 855 diesel engines, and all automotive blocks, heads, and manifolds. Most shops use a big belt sander, or something similar, for manifolds.
Jerry