wondering about gasket makers?

[Turbo Joe]

I found this in a thread and believe this should be a sticky to help out some of the members from being confused. This was posted by member " NAJ" so props to him.

There are numerous places where form-in-place gaskets are used on the engine. Care must be taken when applying form-in-place gaskets. Do not use form-in-place gasket material unless specified. Bead size, continuity, and location are of great importance. Too thin a bead can result in leakage while too much can result in spill-over, a continuous bead of the proper width is essential to obtain a leak-free joint.

Two types of form-in-place gasket materials are used in the engine. Mopar® Silicone Rubber Adhesive Sealant and Mopar®Gasket Maker, (anaerobic) each have different properties and cannot be used interchangeably.

CAUTION: Silicone sealer and anaerobic sealers each will inhibit the cure of the other and care should be taken to keep usages separated as much as possible.

MOPAR® SILICONE RUBBER ADHESIVE SEALANT
Mopar® Silicone Rubber Adhesive Sealant or equivalent, normally black in color, is available in three ounce tubes. Moisture in the air causes the Mopar® Silicone Rubber Adhesive Sealant material to cure. This material is normally used on flexible metal flanges. It has a shelf life of one year and will not properly cure if over age. Always inspect the package for the expiration date before use.

MOPAR® GASKET MAKER
Mopar® Gasket Maker is an anaerobic type gasket material normally red in color. The material cures in the absence of air when squeezed between two metallic surfaces. It will not cure if left in the uncovered tube. It is normally red in color. The anaerobic material is for use between two machined surfaces. Do not use on flexible metal flanges.

MOPAR® TORQUE CURE GASKET MAKER
Mopar® Torque Cure Gasket Maker is a unique anaerobic type gasket material to be used ONLY between the bedplate and engine block. The material cures in the absence of air when torqued between two metallic surfaces. It will not cure if left in the uncovered tube. This anaerobic material is specially made to seal the area between the bedplate and cylinder block without disturbing the bearing clearance or alignment of these components.

GASKET DISASSEMBLY
Parts assembled with form-in-place gaskets may be disassembled without unusual effort. In some instances, it may be necessary to lightly tap the part with a mallet or other suitable tool to break the seal between the mating surfaces. A flat gasket scraper may also be lightly tapped into the joint but care must be taken not to damage the mating surfaces.

SURFACE PREPARATION
Scrape clean or wire brush all gasket surfaces to remove all loose material. Inspect stamped parts to ensure gasket rails are flat. Gasket surfaces must be free of oil and dirt. Make sure old gasket material is removed from blind attaching holes.

FORM-IN-PLACE GASKET APPLICATION
Assembling parts using a form-in-place gasket requires care but it's easier then using precut gaskets.

Mopar® Gasket Maker material should be applied sparingly 1 mm (0.040 in.) diameter or less of sealant to one gasket surface. Be certain the material surrounds each mounting hole. Excess material can easily be wiped off. Components should be torqued in place within 15 minutes. The use of a locating dowel is recommended during assembly to prevent smearing the material off location.

The Mopar® Silicone Rubber Adhesive Sealant gasket material or equivalent should be applied in a continuous bead approximately 3 mm (0.120 in.) in diameter. All mounting holes must be circled. For corner sealing, a 3.17 or 6.35 mm (1/8 or 1/4 in.) drop is placed in the center of the gasket contact area. Uncured sealant may be removed with a shop towels. Components should be torqued in place while the sealant is still wet to the touch (within 10 minutes) The usage of a locating dowel is recommended during assembly to prevent smearing of material off location.

[Kevin Johnson]

Here are some tips on using RTV successfully.

1) Make sure the surfaces are clean -- especially oil free. If there is a film of oil you are building in a leak.

2) These materials are typically driven by a chemical reaction with moisture in the air. So, the more humid it is the faster the reaction will proceed and vice versa. Also, the chemical reaction speed is temperature dependent. If it is hotter, it will cure faster and vice versa. Pay attention to the curing time mentioned on the package -- usually 24 hours.

3) Use sufficient material but not too much -- this is touched upon in the first post in the thread. If you look in factory manuals there are often specific patterns and bead sizes recommended for particular parts.

4) Once initial set is achieved do not try to shift the parts. Initial set is when the material turns rubbery. If you shift the parts you will create internal tears in the material and greatly increase the likelihood of leaks. Better to strip it all off and start again.

5) If there are blobs of material extruding from the joint DO NOT pull them off. This will delaminate the material from the surfaces inside the joint greatly increasing the chance of a leak there. In fact, 3M has a line of removable adhesives that depend upon this effect. Instead use a razor sharp blade to trim the material away without pulling on it.

Related to this discussion are attempts to use a standard gasket on a part that originally used only RTV. On completely flat surfaces you can often get away with this but beware when curves or "humps" are involved.

Oil pans with curved end areas for the crank are a prime example. The additional thickness of the gasket material will cause the ends of the arc to hit before the part is fully and evenly seated. Subsequent torquing down of the bolts will distort and ruin the parts, not to mention create vast areas for leaks.

[88chrydayt]

You can also buy some neoprene at various thicknesses, and cut your own gaskets. I do this on a cork lined work bench and a fresh exacto knife. You need a pattern of course, so this can only be used on parts like a valve cover or oil pan where you can use the part as a pattern. A cross section of sharpened pipe (die grinder) can be used to cut out the bolt holes.

[moparfwdsleeper]

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