Motorsport Plumbing Systems: Making Gaskets
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Making Gaskets
09.18
| 00:00 | Realistically we don't tend to pay too much attention to gaskets until they fail and result in a leak, or we're working on our plumbing and they get damaged. |
| 00:09 | But why do we need to make our own gaskets when the supplier, whether that's for the vehicle or part manufacturer, should be able to provide a replacement gasket anyway? In some cases the part might be out of stock, not available in time, or we might just need to make a custom setup that we can't use an off the shelf part for. |
| 00:28 | So, in order to make our own gasket, we first need to select the appropriate material and thickness to make the gasket from. |
| 00:37 | This isn't as straightforward as it seems as gaskets come in a variety of different materials like paper, rubber, silicon and cork as well as composites using a combination of these and other materials. |
| 00:50 | More demanding applications like head gaskets and those for exhaust manifolds might also use multi layer steel head gaskets, but of course it's unlikely we'll ever be making our own MLS gasket. |
| 01:03 | While the best method is usually trying to make the gasket utilising the material that's been used by the supplier, this often isn't possible and in motorsport use, the original gasket might not have been up to the task in the first place which is why we're replacing it. |
| 01:19 | We need to first understand the maximum and minimum temperatures the part will be seeing, as this will allow us to compare to the gasket sheet supplier's specifications to see if their product is up to the task. |
| 01:32 | However, for motorsport use, we almost always just want to maximise the temperature it can withstand. |
| 01:39 | Usually something with a maximum temperature rating between 200-230 degrees Celsius or 400-450 degree Fahrenheit will be a safe bet. |
| 01:50 | The material we use is mostly application based, and while we won't cover every different material and its applications, let's look at some examples to give you an idea. |
| 02:01 | For simple gaskets that are really just to keep dust out, a cheap and thin paper gasket is suitable and by thin, I'm talking anything that's less than about a millimetre or so. |
| 02:12 | Thin paper gaskets are also commonly used to seal water for components like water pumps, and need to be thin to not space the water pump out too far and run into clearance or performance issues. |
| 02:25 | These paper gaskets also use a wax on the surface that helps to repel water and prevent damage to the gasket itself. |
| 02:32 | PTFE or cork based gaskets are often used for sealing air on the intake manifold side. |
| 02:39 | These are often a bit thicker so the extra squish helps with sealing, but the main purpose is to insulate the parts of the manifold from the engine, preventing heat transfer and keeping temperatures down. |
| 02:51 | Oil sealing gaskets like those for an oil pan are commonly cork, rubber or silicon based. |
| 02:57 | These gaskets are usually a few millimetres thick, so the gasket compresses and creates a good seal which is most critical for this application. |
| 03:06 | Suppliers like Falpro for example offer a long list of different gasket sheet materials in a range of thicknesses. |
| 03:13 | While some sheets might be useful for multiple applications, the chances are we'll probably end up needing a selection, so it's lucky that they're relatively cheap. |
| 03:23 | The best method here is always going to be reviewing the supplier's specifications and then comparing them to your requirements. |
| 03:30 | Let's next take a look at how to actually make a gasket. |
| 03:33 | With our new sheet on hand, we need to cut out our desired gasket outline and ideally we'd copy the original gasket if it's not too damaged. |
| 03:42 | But if we don't know what the original part looks like, it's important to not accidentally block any holes for fluid exchange as this could cause performance issues or serious damage, so we may need to do some research before diving in. |
| 03:56 | With that said, the most practical thing to do for this instance is to trace our outline of the mating surfaces. |
| 04:03 | Before we do this, we need to make sure the surfaces are clean and smooth so they can sit flat on our gasket sheet without damaging it or getting it dirty. |
| 04:12 | Then we simply trace around the profile using a sharp pencil or fine pen. |
| 04:17 | Some gasket materials will be dark so it's just a matter of using something that you can see clearly. |
| 04:23 | After we have our outline, we need to cut it out with a blade on an appropriate surface that we're not too worried about damaging and won't damage the blade. |
| 04:32 | For example, a cutting board, hobby mat or a piece of wood would be perfect. |
| 04:37 | Scissors can also be a fast way of cutting out the shape if it's not too complicated. |
| 04:43 | Cutting and marking holes can be a little bit more tricky. |
| 04:46 | Using a hollow punch of the correct size is the best option here. |
| 04:49 | This is simply a matter of lining up the punch concentric with the whole outline and striking it with a hammer to cut through the material. |
| 04:57 | Again we want to do this on a surface and platform we won't damage, but is firm enough to support the material. |
| 05:03 | At this point we should have a complete gasket, but naturally gasket maker also needs to be discussed here. |
| 05:10 | This is also known as liquid gasket which as the name implies comes in a thick and viscid liquid form. |
| 05:17 | When applied to the sealing surfaces, the sealant will cure into a rubbery solid that fills any irregularities in the surfaces and keeps the gaps closed with any movement and vibration. |
| 05:29 | It can be used both with and without a physical gasket, but we'll discuss the limitations of just using liquid gasket in a moment. |
| 05:37 | There are really two categories here: anaerobic and RTV silicon based gasket makers. |
| 05:44 | Anaerobic gasket makers will remain liquid while exposed to oxygen and naturally cure when not. |
| 05:50 | This is best for sealing tight gaps with close fitting rigid surfaces that aren't going to move, like water pump housings or transmission cases. |
| 05:59 | RTV, or room temperature vulcanised silicon, on the other hand cures at room temperature by reacting to the moisture in the environment. |
| 06:08 | These are better for thin walled metal flanges where we expect to see some amount of movement like oil pans or simply where there's a larger gap we need to fill. |
| 06:18 | In saying that we might want to avoid this if possible for applications like water pumps and oil pans because excess gasket maker can break free inside the fluid and be drawn through our engine and other components causing damage. |
| 06:33 | Sometimes though if we really want to ensure a seal, gasket maker is necessary, usually applied to each mating surface and used along with a gasket. |
| 06:42 | The supplier service manual may even recommend it, in which case we should follow their instructions. |
| 06:48 | As we touched on earlier, if we simply can't get a gasket or gasket material in time, it can be used by itself temporarily, although this is clearly less than ideal as the seal will degrade faster than a gasket. |
| 07:01 | We also need to be very careful if going down this route because we could end up with a messy and unprofessional looking job at best, or rogue sealant loose in our engine at worst. |
| 07:12 | Usually the best method here is running a small bead along a thoroughly clean surface and then carefully smoothing this flat into a tidy thin layer with our finger. |
| 07:22 | We just need to make sure we're wearing gloves made from something like nitrile rubber. |
| 07:27 | With the gasket in place and the components secured, it's important to leave the part for at least the supplier's recommended cure time before use if we want to ensure a good seal. |
| 07:38 | In any case, for all gasket makers, the suppliers will have a range of offerings specifically designed for certain applications and temperature ranges. |
| 07:47 | So, again we just need to review this and compare it to our requirements. |
| 07:51 | On that note, for gaskets that will be in contact with gasoline, we need to use a solvent based gasket maker, as most RTVs and anaerobic gasket makers will not hold up to repeated contact with gasoline. |
| 08:04 | Regardless of the purpose, we always recommend using OEM spec sealants like ThreeBond 1215 for example. |
| 08:12 | While the cheaper auto parts store offerings might be tempting, a quality product like 3Bond will give the best chance of a successful seal, likely saving time and money in the long run. |
| 08:23 | Let's summarise our key points before moving on to discuss the alternative sealing option of o-rings. |
| 08:30 | Gasket material is available in sheets with a range of different properties, specifications and performance capabilities. |
| 08:37 | It's important we choose a suitable material for our application where the specifications meet our requirements. |
| 08:43 | With our gasket sheet in hand, we can trace our outline using the original gasket or mating surface. |
| 08:49 | Then it's just a matter of cutting it out with a knife, scissors and/or a hollow punch set. |
| 08:55 | Gasket makers also have their place with anaerobic offerings for tight fit ups with minimal movement, and RTV silicone for bigger gaps and possible movement. |
| 09:05 | Just be careful to work with clean surfaces, avoid overusing them where excess could end up in components or the engine and allow the sealant to cure before use. |
