Intake manifold removal

[mh434]

Had a real fight to get the intake manifold off at the weekend. Someone had run gasket sealant around every available surface. The photo shows how much it restricts the water passages. Im sure I read somewhere that you should only apply RTV to the front and back of the block sealing edge.

Jon

[pbf777]

you should only apply RTV to the front and back of the block sealing edge.Jon

A thin coat of sealant about the water ports, if evidence of corrosion pitting, and as a substitute for the cork seals upon the "china-walls" to intake surfaces front & back, is as I would advise.

Also, note as to whether your engine has the alignment pin pressed into the block (front china-wall), to register the position of the intake upon mounting; if not, you will want to insert the distributor (dizzy) for referencing the proper front to back position prior to tightening the retaining bolts.

Scott.

[simplyconnected]

Jon, your picture shows the effects of too much sealer. Too much can be worse than not enough.

FE engine intake manifolds are tricky to seat because of a couple design flaws:

• We tighten horizontal bolts through the manifold, into the heads, and expect them to pull the intake manifold down.
  
• We install cork gaskets on the block, which does a good job of holding the intake manifold up. This prevents the intake from descending all the way.

Don't use just any RTV because 'bathtub calk' will break down in oil. I use Permatex Black, Permatex Red or Permatex Grey as they are 'oil resistant' and made for engine assembly.

Make sure your metal surfaces are clean. After scraping down to bare metal, apply lacquer thinner or acetone on the metal until a white rag 'shows clean'. Then, spread your RTV as you work it in with your finger. The RTV bond should not peel off easily but it can be cut off with a razor blade.

I apply a thin coat just around the water port holes. A thin coat will cure quickly but that is ok. For the block and mating intake surfaces, I leave the cork gaskets out. That's right, I don't use them at all. I work-in a heavier bead of RTV into both mating metal surfaces and let it cure.

Then, assemble the intake manifold. Make sure you use flat washers (preferably 'hardened') under the bolt heads. Tighten them evenly and in 'steps' to allow the intake manifold to 'slide down' the bolts. I tap the bolt heads sideways with a small hammer to help this process.

RTV sticks to itself nicely. When you are satisfied everything is seated, fill-in the front and rear block/intake surfaces with RTV. I don't squeeze it in from a tube, I simply use a putty knife for this because too much RTV will go into your engine. Let it cure then paint your engine.

Follow these steps and you will enjoy a good assembly that won't leak. - Dave Dare

[newyear]

Well that got me searching for "china walls".....

[mh434]

Dave
Great write up, lots of good info there thanks a lot.

Jon