Intake Manifold Removal Question

[Paul Workman]

Just to add:

To keep the IH bolts in place, some BLUE Locktite on the threads will keep them from backing out again.

While you have the plenum off, now would be a good time to check the vacuum harness for the secondary port throttles and replace any dry rubber or cracked plastic tubing.

As for the oil in the bottom of the V, a new breather box gasket from Jerry's Gaskets might be a consideration too. And, as were the IH bolts loose, so too might the bolts on that breather box be loose (mine were). The blue Loctite will keep them in place.

As for the connections to the Digital Ignition Controller*, you want to take care to align that long connector (with its many small pins) carefully. You should be able to easily push it in place by hand to be sure the pins go "home". It isn't often that a pin gets bent, but it happens - especially if the connector is started in at an angle and snugged into position with the force of the clamping (center) bolt!

* The "DIC" was mounted where it is - underside of the plenum - for cooling of the internal circuitry, which generates a lot of heat and requires some serious heat sinking. If for any reason the DIC is removed, such as for porting or perhaps powder coating the plenum, there must be a thin coat of that white (zinc oxide) heat sink grease between the DIC and the plenum. AND... be especially certain there isn't so much as a grain of sand or other debris/grit sticking to the "grease" when placing the DIC against it's heat sink surface. Such debris - even a grain of sand - will prevent heat transferring properly to the plenum and the DIC will be in danger of overheating and failing. (And, they don't make those anymore; a critical piece of equipment, that fortunately doesn't often fail...if properly installed.) If the "grease" gets contaminated, it is best to remove it completely and replace it with some fresh heat sink goop (Radio Shack and other electronic supply stores have it). KEEP THE NEW COAT THIN!

Another tip I learned watching Marc Haibeck remove a plenum is the throttle cables don't necessarily have to be removed if only dealing with something else under there. The plenum can be rolled over on its back to rest gently on the driver side of the engine/wheel well out of the way, and rolled back into place afterward; throttle cables intact.

When installing a new plenum gasket, I first spray the top side of the gasket with silicon spray as a release agent to ease removal in the future (taking precautions to keep the spray the hell away from the open IH ports and the car in general). The bottom side remains dry, and the mating surface of the IH is first cleaned with a razor blade, followed by a scrubbing with (CRC Brakleen; non-petroleum) brake cleaner - getting the metal sterile and dry.

The next time the plenum is removed, the gasket will usually stick to the IH well enough so that removing the plenum only requires me to slip a thin putty knife between the plenum and the gasket and sliding the knife down the length of the gasket, the plenum comes free and the gasket usually remains intact for at least 2 and sometimes more uses (or at least Jerry's gaskets do!), depending on the number of heat cycles or how long the interval between plenum pulls has been.

I like to remove the rubber collar gasket from the "Weatherpak" connectors and with a dot of dielectric grease between my thumb and finger, massage the gasket to coat it with a thin layer of fresh grease before reinstalling the connectors. It will prevent moisture, of course, but also facilitates removing them next time and lessens the chance of one tearing.

Hope something here is useful.

P.