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View Full Version : Trick for installing intake manifold?



chris anderson
08-28-2010, 02:03 PM
My SS is running a little poorly and a friend said I had an intake manifold leak. I hear its common. So, I picked up new manifold nuts, brass inserts and the CORRECT tool. lubed it up lightly with anti-seize as well. Problem is, it doesn't want to thread back on or take purchase on the threads. Seems like a tight tolerance. Is there a trick to getting the treads to started or do I have to muscle it?

MJW
08-28-2010, 10:39 PM
will the nuts thread on without the manifold and inserts holding it back? perhaps some Peek seals would crush down further?...Mike

20scout
08-29-2010, 12:28 PM
Mine can be a real bearcat to thread on too. Most of the time I find it easier to losen up the base nuts on one of the cylinders for a little give.

T. Cotten
08-29-2010, 02:16 PM
Chris!

Let us first inspect your seal ferrules to be certain that the angle on the seals that is compressed by the nuts is approximately 75 degrees.
This will greatly affect the geometry and amount of threads that are exposed within the nuts, and freedom to thread upon the nipples.

Then arrange the seals so that they are about a sixteenth of an inch past the ends of the manifold spigots.

With the nuts pulled back to expose the seals, place the assembly up against the nipple to inspect their angularity and contact with the nipples. Hopefully they will mate squarely.

Next, slip the nuts over the seals and hope that they will start to screw onto them by finger pressure alone.

Brass is extremely unforgiving, but it is all there was at the time.
Today we have a noble material called PEEK that has both the tensile strength to support the gap between spigot and nipple, as well as the compliance to tweak and seal easily.

If your spigots are pristine and un-blemished, then molded PEEK seals are hopefully available from http://www.enfieldracing.com/8.html.
If not, or if your spigots are blemished, then many folks are now custom-cutting both spigots and seals to match.

No matter what you end up with, it is critical that you pressuretest your assembly as discussed at http:virtualindian.org/11techleaktest.html to avoid further grief.

With Sport Scouts especially, it is critically important to test the nipples and headbolt bores above them, as all too often, too long of a bolt had be installed at some time, and crushed the nipple away from the casting bore.

Good luck!

....Cotten

chris anderson
09-08-2010, 01:14 PM
I found out the problem was me. I recleaned everything and then flipped around the brass seals - Had them on backwards! Still need to test for leaks. Thanks for all the advice. Chris