Need a Gasket for an Intake Manifold? Here’s What You Need to Know.

Intake manifolds…the gateway to the engine…the place where it all begins. For those of you that are new to this, the intake manifold’s purpose is to provide an entry path for the fuel mixture of both air and fuel to enter the engine. These are typically cast aluminum pieces with curved runners to each cylinder. Newer versions are now molded polymer construction, allowing more complex designs for improved airflow and also less weight.

If your intake manifold gasket isn’t doing its job, you are going to see a poor performing engine all around. A flange that isn’t properly sealed will likely allow additional air into the cylinder, causing poor performance. Worse failures can include fluid leakage, where coolant can leak through the gasket either internally into the crankcase, or externally to the ground. As with any seal point, you need to fully understand the environment in order to make a proper gasket material selection. Below are the considerations you need to be aware of when selecting such materials.

What To Pay Attention To

1. Fluid Compatibility

Is your gasket compatible with the designated fluids? Initially, make sure that the material will not be degraded by contact with the fluids. This will make sure the integrity of the material will not be compromised.

2. Temperature Capability

Confirm that the gasket material is designed to survive the temperatures the intake manifold will see (some have coolant ports and some have EGR exhaust ports, requiring better materials). Also, with high temperatures can come expansion and contraction. (see #4 below) Is your gasket material robust enough to handle the scrubbing?

3. Conformance

Find a material that best meets the compressibility / recovery / creep-relaxation requirements that you need. Some joints require thicker gaskets to overcome variations in the gap. This can be achieved with composite laminates. All gasket materials perform differently, and you can see drastically different results from materials that you might perceive to be similar based on these properties.

4. Release or Slip Tolerance

Consider whether you need an anti-stick coating for easier removal. Facing materials tend to stick, particularly with heat and fluid exposure. Also, if there is a lot of expansion/contraction due thermal conditions, an anti-stick coating will protect the material allowing it to slip without destruction.

Making Your Decision

In general, gasket materials that are designed to seal fluids tend to perform well in the intake manifold. Many cast metal intakes have flat flanges, providing the opportunity for a typical die-cut gasket to do the job. Be sure to select the right material for the conditions to get the best long term performance. If you have any questions about which materials best meet the above conditions, please don’t hesitate to contact your trusted gasket material supplier.

What issues do you have with your intake manifold gaskets?

Corseal product comparison

Metal Tech offers our CS794 specifically for intake applications. It features a performance facing with good fluid and temperature resistance applied to the Corseal core for a mechanical bond. MTI also offers various solid core grades, such as SB643, in different thicknesses for various intake manifold applications. These grades are typically coated with the TechCoat anti-stick coating to allow for slippage due to thermal motion, and also a cleaner release. The CS830 and CS920 products can also be considered for intakes.

What To Do If Your Gaskets Continue To Blow Out

Is it Groundhog Day? You may feel like it if your life is a never-ending saga of blown gaskets. At some point, it’s time to say enough is enough and figure out what you need to change in order to prevent this problem from occurring again.

Your first instinct when a gasket is blown should not be to immediately try a different gasket. There are many things that could be the root cause of your issue, and unless you understand why the gaskets are failing, you are probably going to wake up tomorrow and have the same problem.

So What Next?

Ok, so you’re now staring at an application that isn’t running, and you are holding a blown gasket in your hand. How should you be troubleshooting this? There could be any number of issues. Here are some of the more common problems and why they can cause a blowout. Hopefully at least one of these will get you pointed in the right direction.

1. Temperature

How hot is your application running? One of the most common culprits of gasket issues is heat and the reality that your application is running hotter than you think. Do some additional testing, consider the peak exposure, and select a material that is designed to survive those conditions.

2. Pressure

Are you expecting your gasket to seal a high pressure joint? If so, is your gasket reinforced? Metal reinforced gaskets can provide enough radial strength to hold up to the high pressure.

3. Assembly

Ensure that your joint is properly assembled. There are recommended torque values as well as a sequence that should be followed. If you are using a compressible gasket, a final torque once operating temperature has been achieved is helpful to maintain load over long term service.

4. Flange Loading

This is one of the most critical pieces of the bolted joint. Without the proper loading, no gasket will seal. Be sure that the flanges are in good shape and have adequate flatness and surface finish. Loading needs to be sufficient to establish an initial seal but also maintain load to seal the joint over the long term, after the initial heat cycles.

5. Thickness

How thick is your gasket? In most cases, the thinnest gasket you can use is the best choice. There are a few instances where you would want to increase the thickness (ex. compensating for flange conditions). Thinner gaskets have less chance for blowout since the load is concentrated over less volume, which provides higher shear strength.

6. Material Type

If you’re sealing fluids, be sure that the gasket material is compatible with the fluid and will not degrade over exposure time. Think of using a plastic bag to hold water vs a paper bag.  Both will hold water, but the paper bag has a clock ticking.

Moving On

Sometimes, none of the above gives you any insight into your problem. These are the difficult ones to fix. Unfortunately at this point, it tends to boil down to a less than ideal joint design and the difficulties associated with finding a gasket material to compensate for these issues. Obviously, if you have gotten this far in the process, changing the design probably isn’t going to be an option (unless it is really bad). It is up to you and your trusted gasket material supplier to find a material that is going to work. In most cases, you’ll find something that’ll seal. However, you may be in a situation where you find that you need to design a material to meet your specific needs. If your gasket material supplier isn’t willing to help walk you through your options, be sure to find someone that is.

What causes most of your blown gaskets?

Case Studies

4 Questions to Ask When You Need to Seal Fluids

Whether you are new to the fluid sealing market or you’ve been immersed in it for years, there are some considerations that must be made when you need to seal fluids. Some may be made subconsciously, but others sometimes require much debate and testing. This week, we thought we’d lay out the important questions that need to be asked (and why) when you are faced with a joint that requires fluid to be sealed.

The List

1. What fluid are you sealing?

Is it Coolant? Oil? Fuel? Water? Other? This can affect your material choice.

2. At what temperature will it be operating?

It is best to identify operating usage extremes, to understand how the gasket and the fluid will age or withstand exposure to elevated temperatures for extended periods of time.

3. How aggressive is the fluid? Is it compatible with my gasket?

Some gaskets are designed to “swell” when in contact with fuels and oils. This “controlled swell” actually creates a better seal on the inside contact edge of the gasket. Of course compatibility must also be considered so the gasket does not disintegrate. A good example of what not to do is using a low cost exhaust material in an oil-sealing application. The material will be weakened by the absorbed fluid.

4. What sealability level do I need?

Sometimes in engine applications, additional features are added for various purposes. A silicone coating for “cold sealing” an engine is one example. This provides additional sealability while the engine is still warming to its operating conditions.

Seal It

Sealing fluids can be a tricky project. When the goal is to find a material that will meet or exceed the design service life, you need a material that is right for your application. Your gasket material supplier is your best resource to talk through your material requirements. Whether you are in the planning stage, troubleshooting your current material, or on the hunt for a replacement material, a good supplier of gasket material is going to be with you every step of the way. Nobody knows our material better than we do!

What issues have you had with sealing fluids in your applications?

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