A engine mount article I just finished tonight.
03-12-2004, 11:34 PM
#1
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Thread Starter
A engine mount article I just finished tonight.
Just to help people pick out what mounts to get, and buy what is the best for them. Not just get the latest bandwagon bling part.
Engine Mount Article
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Honda isn’t known for having big horsepower engines in all their cars. If you want more power, you can either modify the current engine, or swap another higher horsepower engine in.
In this case you have the option of either custom fabricating mounts to bolt the new engine in, or to purchase some prefabricated mounts that are designed to be a no headache installation.
First lets keep in mind the cost of the situation. In a perfect world everything would be either free or cheap. But we live in a world where if you want high quality parts, you HAVE to pay for it. There is an absolute law that is consistent in every part of every industry; to build nicer quality parts, the cost of production will be higher.
With this in mind think of how you are going to budget your whole swap. You have figured out how much it’s going to cost for the engine swap, for the new hoses/belts/fluids, and for labor if you are going to pay someone for it. Within your budget you have to factor in getting the proper engine mounts for you car that meet your needs.
First to be discussed is the isolation material and firmness of the material.
Most of the materials used in common mounts are good quality and should last a decent amount of time. Ask either the sales person or manufacturer how long the warranty for the material is and how long they should expect them to hold up before it needs to be replaced. When a company offers a lifetime warranty on their product, to me that has a lot of value. They are not only saying that their products are engineered, designed, and manufactured right. They are also saying they are standing behind their product and plan on being in business for a long time. Make sure that this is in writing either on their website or on a sheet of paper that is sent out with the products. If its just said over the phone and no where to be found in print, then that’s a bad sign of a poorly run company.
There are 2 extremes with mount firmness and in-between there is an ideal setup for your car. OEM mounts aren’t stiff enough if you have a lot of torque. If you get brand-new OEM mounts they will last a while but aren’t a good choice for long term because of their design. It’s usually easy to see if the mounts aren’t firm enough when the car is on a dynamometer. When the car is accelerating and a load is put on the engine you can see the motor move around in the engine bay. When the motor is moving around, that is lost power that isn’t going to the wheels, instead its inefficient power transfer. Some wheel hop can result from too soft material used in the mount as well.
The other downside of OEM mounts is that they are stamped steel. This is the best for production costs because they can produce large amounts but at a low cost. This isn’t good for car with a lot of power. The mount just won’t last.
Some mounts on the market are too stiff. They are more designed for racecars where it doesn’t matter if the car shakes from the engine. In a racecar little or no movement is wanted. Some of the cars in the NHRA or NDRA drag series; you might find that the motor is actually directly bolted into the engine bay/chassis with zero absorption purposely designed (more power transfer)
There is a happy medium between the 2 of them. That is why based upon your own application its important to get the right mount with the proper stiffness of material. For instance Hasport allows you to pick 3 different stiffness settings in their mounts. While most other companies only have one material to offer. You can get lucky with the material stiffness; it could be exactly what you are looking for. Or it could be way too stiff and the car has a rough vibration all the time due to the engine having a more direct connection to the car. It could also be too soft and you just paid a couple hounded dollars for mounts that are to weak for you application.
It is a matter of compromise, if the mount is soft there won’t be any or very little chassis vibration but the engine will be able to move around. If its too stiff then the engine wont move around at all, but it will feel like you have a race car (not a good thing if you don’t want it) and the chassis will shake around a lot.
Once again, the choice of stiffness all depends upon your setup and what is best.
Besides stiffness of the material, each mount manufacturer uses its own choice of rubber type material. Some use urethane and OEM Honda uses rubber. The problem with the OEM design is that there are actual holes or gaps in how Honda designed the mold for the rubber.
The problem with this design is that when the mount is under compression, due to the voids in the mount, the rubber has some place to go when compressing (under an engine load). The other problem is that the durability of the rubber mount isn’t going to last as long as a urethane. That is why OEM mounts don’t last the lifetime of the car versus some aftermarket mounts have a lifetime warranty.
Prothane inserts try to put a band aide over the design of the OEM mount. Their inserts actually put an “insert” into the rubber voids. The problem with this, then the rubber OEM mounts will feel even stiffer than other mounts then give up ride quality but will only last as long as the rubber OEM mounts.
How the mount places the engine in the engine bay is another important aspect.
Honda spent a considerable amount of time, money, & research/development to get the engine fitted ideally in the engine bay. Ask yourself: did the company that designed your hybrid mounts spend the right amount of time and money to research where the H22 Prelude engine goes into your 1995 civic hatchback? Also factor engines like the H22 was never designed to go into any car but the Prelude. Its not a simple task to get another engine from a completely different chassis to fit properly.
First you need to find out how low the engine will sit and how much ground clearance for the oil pan exists. A good sign of an all around poorly designed engine mount is when the engine sits to low. That is the easiest and one of the worst ways to design a mount kit. The motor really should be as close to the hood as possible and as far back to the firewall as possible. If the valve cover is close to the hood then that means that they maximized the oil pan clearance. This also means you have plenty clearance for your header. Its very pricey to get your header fixed if it kissed the pavement. If it costs 300 dollars to fix a header or buy a replacment, might as well just pay the money up front for properly designed and engineered mounts that will minimize the risk of engine bottoming out onto the pavement.
If the intake manifold is about 3-5 inches from the firewall then that is ideal. Find out if the intake manifold interferes with any of the things mounted to the firewall or the firewall itself. If you going to run a supercharger or aftermarket intake manifold will there be a problem?
Other placement considerations are for proper oil pick up. If the motor sits at an angle then the oil pump wont be able to get the proper amount of oil and then the engine will blow up. This will be dependent upon the angle at which the engine sits.
Other things to ask the mounts manufacturer is if important things like power steering & air conditioning will work within the fitment that they have set up. Its fine if weren’t planning on running either or, but if you its 2am in the morning and you want to have your car running in the morning to get to work. If the power steering pump doesn’t fit in the engine bay, you are pretty much out of luck. Find out if it’s guaranteed to fit, or if it needs some “customization” to fit.
Another very important factor due to engine placement is the axle setup. Ideally the axle should have a direct straight line out of the transmission to the wheel. If there is too big an angle then it can lead to the axle binding or breaking. Some people have put a lot of miles on the street in a car with a swapped motor and mounts from brand XYZ, and never break an axle or have other issues. When they get to the drag strip for the first time and launch with sticky tires, a lot of stress is placed on the axles. In that initial launch (first 0-100 feet or so) will be the time if anything is going to break. If the axle angle is poor, due to bad mount design then the axles have a high chance of breaking. Only solution is a tow home or a trip to your local auto part store.
Now that the mount company figured out where to place the engine, the metal mounts need to be constructed. There are two common varieties out there. One is using a CNC machine to carve away a block of solid aluminum into the desirable shape that the designer/engineer choices. The benefit of CNC mounts is they are produced with very high accuracy rate tolerances. Meaning if the mount is supposed to be 5 inches wide. A good CNC machine can get it to within 5.001 (+/- .005). Usually this is a great thing because it allows extremely consistent results and very high accuracy. Downside is that if the engineer didn’t design the mount correct, the mount could be wrong, but the CNC machine still did it exactly & perfectly wrong. Solid aluminum that was CNC-d is also extremely strong and it won’t ever rust.
The downside is that it costs more to produce. The CNC machine costs a lot along with the Aluminum. It does mean higher costs to the consumer, but it also means that the consumer is getting top-notch quality mounts.
The other option that is a little bit more common is a process where pieces of metal are welded together. The metal is placed into a jig and then welded to become a mount. Positive side is that it doesn’t cost as much as the CNC process. If done properly it can be a good way to build a mount. The dependent factor of its quality is the quality of the metal, welder and his tools, and the jig that the pieces are put into. Some jigs have too much “wiggle” room meaning that there is a lot of variance in how each mount is produced. Some may be accurate, some might not be. It all has to do with the welder and the jig.
Downside is that it ultimately isn’t as strong as a chunk of aluminum and doesn’t have the extremely consistent day in and day out of the CNC machining process.
However there are different grades of aluminum that may be used for the CNC process. Find out what grade is used and where on the aluminum quality level chart it stands. If the bulk aluminum is low budget grade then it wont last as long as the higher quality aluminum and could be more prone to defects and later breakage of the mounts.
If you do your research and make a good buying decision then it will be one less thing you have to worry about breaking.
</TD></TR></TABLE>
http://honda-central.com/forum...t=266
Engine Mount Article
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">
Honda isn’t known for having big horsepower engines in all their cars. If you want more power, you can either modify the current engine, or swap another higher horsepower engine in.
In this case you have the option of either custom fabricating mounts to bolt the new engine in, or to purchase some prefabricated mounts that are designed to be a no headache installation.
First lets keep in mind the cost of the situation. In a perfect world everything would be either free or cheap. But we live in a world where if you want high quality parts, you HAVE to pay for it. There is an absolute law that is consistent in every part of every industry; to build nicer quality parts, the cost of production will be higher.
With this in mind think of how you are going to budget your whole swap. You have figured out how much it’s going to cost for the engine swap, for the new hoses/belts/fluids, and for labor if you are going to pay someone for it. Within your budget you have to factor in getting the proper engine mounts for you car that meet your needs.
First to be discussed is the isolation material and firmness of the material.
Most of the materials used in common mounts are good quality and should last a decent amount of time. Ask either the sales person or manufacturer how long the warranty for the material is and how long they should expect them to hold up before it needs to be replaced. When a company offers a lifetime warranty on their product, to me that has a lot of value. They are not only saying that their products are engineered, designed, and manufactured right. They are also saying they are standing behind their product and plan on being in business for a long time. Make sure that this is in writing either on their website or on a sheet of paper that is sent out with the products. If its just said over the phone and no where to be found in print, then that’s a bad sign of a poorly run company.
There are 2 extremes with mount firmness and in-between there is an ideal setup for your car. OEM mounts aren’t stiff enough if you have a lot of torque. If you get brand-new OEM mounts they will last a while but aren’t a good choice for long term because of their design. It’s usually easy to see if the mounts aren’t firm enough when the car is on a dynamometer. When the car is accelerating and a load is put on the engine you can see the motor move around in the engine bay. When the motor is moving around, that is lost power that isn’t going to the wheels, instead its inefficient power transfer. Some wheel hop can result from too soft material used in the mount as well.
The other downside of OEM mounts is that they are stamped steel. This is the best for production costs because they can produce large amounts but at a low cost. This isn’t good for car with a lot of power. The mount just won’t last.
Some mounts on the market are too stiff. They are more designed for racecars where it doesn’t matter if the car shakes from the engine. In a racecar little or no movement is wanted. Some of the cars in the NHRA or NDRA drag series; you might find that the motor is actually directly bolted into the engine bay/chassis with zero absorption purposely designed (more power transfer)
There is a happy medium between the 2 of them. That is why based upon your own application its important to get the right mount with the proper stiffness of material. For instance Hasport allows you to pick 3 different stiffness settings in their mounts. While most other companies only have one material to offer. You can get lucky with the material stiffness; it could be exactly what you are looking for. Or it could be way too stiff and the car has a rough vibration all the time due to the engine having a more direct connection to the car. It could also be too soft and you just paid a couple hounded dollars for mounts that are to weak for you application.
It is a matter of compromise, if the mount is soft there won’t be any or very little chassis vibration but the engine will be able to move around. If its too stiff then the engine wont move around at all, but it will feel like you have a race car (not a good thing if you don’t want it) and the chassis will shake around a lot.
Once again, the choice of stiffness all depends upon your setup and what is best.
Besides stiffness of the material, each mount manufacturer uses its own choice of rubber type material. Some use urethane and OEM Honda uses rubber. The problem with the OEM design is that there are actual holes or gaps in how Honda designed the mold for the rubber.
The problem with this design is that when the mount is under compression, due to the voids in the mount, the rubber has some place to go when compressing (under an engine load). The other problem is that the durability of the rubber mount isn’t going to last as long as a urethane. That is why OEM mounts don’t last the lifetime of the car versus some aftermarket mounts have a lifetime warranty.
Prothane inserts try to put a band aide over the design of the OEM mount. Their inserts actually put an “insert” into the rubber voids. The problem with this, then the rubber OEM mounts will feel even stiffer than other mounts then give up ride quality but will only last as long as the rubber OEM mounts.
How the mount places the engine in the engine bay is another important aspect.
Honda spent a considerable amount of time, money, & research/development to get the engine fitted ideally in the engine bay. Ask yourself: did the company that designed your hybrid mounts spend the right amount of time and money to research where the H22 Prelude engine goes into your 1995 civic hatchback? Also factor engines like the H22 was never designed to go into any car but the Prelude. Its not a simple task to get another engine from a completely different chassis to fit properly.
First you need to find out how low the engine will sit and how much ground clearance for the oil pan exists. A good sign of an all around poorly designed engine mount is when the engine sits to low. That is the easiest and one of the worst ways to design a mount kit. The motor really should be as close to the hood as possible and as far back to the firewall as possible. If the valve cover is close to the hood then that means that they maximized the oil pan clearance. This also means you have plenty clearance for your header. Its very pricey to get your header fixed if it kissed the pavement. If it costs 300 dollars to fix a header or buy a replacment, might as well just pay the money up front for properly designed and engineered mounts that will minimize the risk of engine bottoming out onto the pavement.
If the intake manifold is about 3-5 inches from the firewall then that is ideal. Find out if the intake manifold interferes with any of the things mounted to the firewall or the firewall itself. If you going to run a supercharger or aftermarket intake manifold will there be a problem?
Other placement considerations are for proper oil pick up. If the motor sits at an angle then the oil pump wont be able to get the proper amount of oil and then the engine will blow up. This will be dependent upon the angle at which the engine sits.
Other things to ask the mounts manufacturer is if important things like power steering & air conditioning will work within the fitment that they have set up. Its fine if weren’t planning on running either or, but if you its 2am in the morning and you want to have your car running in the morning to get to work. If the power steering pump doesn’t fit in the engine bay, you are pretty much out of luck. Find out if it’s guaranteed to fit, or if it needs some “customization” to fit.
Another very important factor due to engine placement is the axle setup. Ideally the axle should have a direct straight line out of the transmission to the wheel. If there is too big an angle then it can lead to the axle binding or breaking. Some people have put a lot of miles on the street in a car with a swapped motor and mounts from brand XYZ, and never break an axle or have other issues. When they get to the drag strip for the first time and launch with sticky tires, a lot of stress is placed on the axles. In that initial launch (first 0-100 feet or so) will be the time if anything is going to break. If the axle angle is poor, due to bad mount design then the axles have a high chance of breaking. Only solution is a tow home or a trip to your local auto part store.
Now that the mount company figured out where to place the engine, the metal mounts need to be constructed. There are two common varieties out there. One is using a CNC machine to carve away a block of solid aluminum into the desirable shape that the designer/engineer choices. The benefit of CNC mounts is they are produced with very high accuracy rate tolerances. Meaning if the mount is supposed to be 5 inches wide. A good CNC machine can get it to within 5.001 (+/- .005). Usually this is a great thing because it allows extremely consistent results and very high accuracy. Downside is that if the engineer didn’t design the mount correct, the mount could be wrong, but the CNC machine still did it exactly & perfectly wrong. Solid aluminum that was CNC-d is also extremely strong and it won’t ever rust.
The downside is that it costs more to produce. The CNC machine costs a lot along with the Aluminum. It does mean higher costs to the consumer, but it also means that the consumer is getting top-notch quality mounts.
The other option that is a little bit more common is a process where pieces of metal are welded together. The metal is placed into a jig and then welded to become a mount. Positive side is that it doesn’t cost as much as the CNC process. If done properly it can be a good way to build a mount. The dependent factor of its quality is the quality of the metal, welder and his tools, and the jig that the pieces are put into. Some jigs have too much “wiggle” room meaning that there is a lot of variance in how each mount is produced. Some may be accurate, some might not be. It all has to do with the welder and the jig.
Downside is that it ultimately isn’t as strong as a chunk of aluminum and doesn’t have the extremely consistent day in and day out of the CNC machining process.
However there are different grades of aluminum that may be used for the CNC process. Find out what grade is used and where on the aluminum quality level chart it stands. If the bulk aluminum is low budget grade then it wont last as long as the higher quality aluminum and could be more prone to defects and later breakage of the mounts.
If you do your research and make a good buying decision then it will be one less thing you have to worry about breaking.
</TD></TR></TABLE>
http://honda-central.com/forum...t=266
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