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EQUIPMENT basics |
Making gaskets
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| Photo 1: Clamp the gasket material between thin pieces of wood and drill the large hole with a hole saw. Photo by Scott Nesbitt. |
For lack of a gasket, your machinery may sit idle in the shop instead of working out on the golf course. Here’s how to make a good, solid gasket that can get you going. Made properly with the right material, it can perform as well as the original and last just as long.
A gasket forms a seal at the point where two metal pieces are bolted together as part of a system that carries a substance of some kind — cooling water, lubricating oil, intake air or exhaust gas. The gasket makes up for imperfections in the mating metal surfaces.
In the photographs that illustrate this article, the gasket seals the joint between an engine manifold and the muffler/exhaust pipe on a small diesel tractor. The dealers for this brand of tractor were all closed on a Saturday afternoon, and the machine was needed ASAP to finish some grading and seeding in advance of yet another hurricane-driven rainstorm. Here’s what to do.
First, study the original gasket material. If it looks like a layer of rubber, the gasket was formed in place using RTV (room temperature vulcanizing) silicone gel. Clean the gasketed surfaces, removing all pieces of the old gasket. Clean with solvent to remove oil. Spread on a bead of the gel. Wait about 10 minutes until a skin forms on the RTV, then assemble the parts and tighten the bolts. You’re ready to go.
What’s the material?
RTV is most commonly found on water pumps and other cooling system assemblies, valve covers and oil pans, and sometimes where things like fuel pumps and oil distribution tubes are mounted to engine blocks. The material comes in different formulas, which are rated for temperature resistance. If you don’t know how hot the gasket will become, choose the high-temp formula rated for 650 degrees F or more.
If you find a “real” gasket made of some type of flat material, you need to choose the right material for your new gasket. There are three basic types. For parts bolted to the main engine block, where temperatures don’t exceed about 300 degrees F, the original gasket is made of a paper-like material or cork.
In some applications, like the oil pans on small air-cooled engines, the gasket must be a specific thickness to provide proper clearance for the crankshaft support bearings. You’ll need a factory-made gasket. But for external components like fuel pumps, water outlets and carburetors, you’ll be able to use “universal” gasket material.
The third type, designed for extra-hot parts like intake and exhaust manifolds, is a multi-layer material that is made of metal, fibers and heat-resistant synthetic material. It handles the sliding and movement that naturally takes place as parts heat up and cool down. Two of the commonly found product lines of this material are Fel-Ramic from Fel-Pro or Coramic from Victor/Reinz. Your supplier may have a comparable product from a different gasket maker.
To make your gasket, start by finding a hole saw that matches the size of the main component hole. Clamp the gasket material between two pieces of wood (thin plywood works well) and drill through the wood and gasket (Photo 1). The wood protects the gasket from being ripped.
Keeping the gasket clamped on wood, place the component on the gasket and align the large hole with the component’s hole. Clamp the component and gasket together and bore mounting bolt holes using a regular twist drill bit (Photo 2).
Trim the gasket to size with tin snips, and you’re ready to reassemble the component onto the engine. Note that if your gasket material has only one steel-faced side, place that side toward the manifold.
Toothpaste in a pinch
If you’re making a gasket for a complex omponent like a carburetor and you couldn’t save the old gasket as a pattern, you’ll need to transfer the component pattern onto the gasket. Try using toothpaste. Spread a thin layer on the component, press it firmly onto the wood, and you’ll see exactly where you need to bore holes. If you have a set of hole punches, you can usually work directly on the gasket surface. The toothpaste easily wipes away with a damp cloth.
Once you’ve installed your gasket and tightened the bolts, you should be ready to roll.
Check bolt tightness after the engine warms up. Be careful not to overtighten the bolts; you may crush the gasket and cause a leak.
If you’re uncertain how long your gasket will last, you may want to order the factory-built gasket and install it when you don’t have a rush that demands the machine be on the course, making golf a beautiful game.
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