A complete guide to modifying stock motor mounts to make your own motor mount inserts
If you’ve already done your research, you know for sure you want the DIY motor mount, skip down to the actual creation of the motor mount insert. But if you need a little convincing, keep reading.
A breakdown of the article:
- Pros and Cons
- Hardness Options
- Materials Required
- Prepping the Mounts
- Setting up the Mounts
- Mixing the Urethane
- Pouring the Urethane
- Finished Product
Before you dive into creating your own motor mount insert, its a good idea to understand the few basic principles of motor mount inserts and why you would even want to use them. There’s pros and cons, like everything, in making your motor mounts more solid. So before you do, here’s a few pros/cons:
- Increase Horsepower Potential
- Reduce Wheel Hop
- More Responsive Motor
- Increase Cabin Vibration
- Increase Cabin Noise
So taking those pros and cons a bit deeper, the first and foremost reason to firm up your motor mounts is to hold the engine firmly in place. Often the more pliable stock motor mounts allow the engine to move excessively – resulting in wheel hop and loss of power. The more extreme version of this is when an owner has to increase the vehicle’s horsepower more than the stock motor mounts were designed to handle. This can cause tearing of the stock motor mounts as well as damage to the engine and engine bay should the engine be allowed too much movement.
Easily the most frustrating result of solid motor mounts is increased vibration felt by passengers in the vehicle. Stock motor mounts are designed with a fair amount of flex, designed to absorb natural motor vibration and reduce vibration noise. In most cases, this increase in noise and vibration is not terribly significant, however, it is increased by the firmness of the urethane used to fill the mount and the number of mounts that are filled.
Cabin Noise, Really?
The trade off for increased performance is cabin noise and vibration. The harder, more firm your motor mounts are the more efficiently they will transfer horsepower to the wheels. Likewise, the softer the motor mounts are the less vibration and noise will be transferred to the rest of the vehicle. There are a number of ways to make the trade off between vibration/noise increase and performance.
Firming up the Correct Motor Mounts
Most Front Wheel Drive vehicles have several motor mounts, typically 4 or 5. Some of the motor mounts are designed significantly different from the others. TORQUE mounts are the motor mounts designed to reduce the amount of engine movement when power is applied. Main Mounts are the mounts designed to support and hold the weight of the engine.
Torque mounts are the most effective mounts at providing a great rigidity to the engine assembly without transmitting as much natural vibration to the driver. Torque mounts are typically located at the front end or rear of the engine. Main mounts are typically located higher on the engine assembly as the engine weight usually hangs from these.
While it is typically possible to firm up all the mounts on a vehicle – the torque mounts will provide the best trade off between performance and vibration.
Using a Softer or Harder Universal Motor Mount Insert Formula
There are several firmness or “durometer” levels offered:
- 60A – For the Daily Driver – This is the softest formula offered that will still make a noticeable difference in vehicle performance. This softer formula is best for tuners that still want to increase performance without trading off as much personal comfort.
- 80A – Even trade off between performance and vibration – When it comes to motor mount inserts, this formula is the most popular for its ability to significantly increase vehicle performance while still allowing some small amount of flex in the mounts to keep vibration and noise to reasonable levels.
- 80A HIGH PERFORMANCE – The next best step – A newer version of the most popular choice balances high performance with ride quality, while boasting a higher tear rate and standing up to heat even better.
- 94A – Race Quality – Not for the daily driver. This formula is the hardest of the 4 available. Providing the best reduction in motor movement – this version will also allow a rather significant amount of engine vibration to be transmitted into the vehicle. Best you can get without going with an aluminum mount.
With four choices in hardness, there is a formula for any level of performance
Materials Required for this Project:
All items listed are absolutely required in order to complete this project safely and easily. In total they shouldn’t cost you more than $10 from your local Home-Depot or Wal-Mart (aside from the actual urethane). Save yourself future frustration and buy these before starting the project!
- Liquid Urethane – available in the 60A, 80A, 80A High Performance, and 94A
- Contact Cement – Helps the duct tape seal against greasy surfaces
- Duct Tape – Seals one side of the mount
- De-greaser – Cleans the mount of grease and oil
- SAND – in a box – vital to the project – DO NOT skip this step
- Level – makes sure the mount if level for a level pour
DIY Motor Mount Inserts
Prepping The Mounts
Step One – CLEAN!
For the urethane to bond correctly and to ease the overall process – the mounts must be thoroughly cleaned of grease and dirt. A little cheap degreaser can go a long way over simple soap. Take the time to use real degreaser – it’s usually just a spray on – spray off process anyway.
Cleaning the mounts with a degreaser will allow the urethane to properly bond to the rubber
Step Two – Sealing One Side
The motor mount inserts are made by pouring a liquid urethane into the voids of the mounts and allowing it to dry. In order to do this you’ll need to completely seal off one side of the mounts. When you first pour the urethane into the mounts it will have a very liquid consistency. Even the smallest hole in your sealing jobs will allow the urethane to seep out.
Contact cement will give you an improved seal job to ensure your urethane stays in the mount
The best way to do this is with some contact cement and duct tape. While duct tape alone will usually work – the contact cement will ensure a good seal – especially if there’s any greasy residue on the mounts (the tape will not adhere properly). Start by painting the outside edge and inside circumference of the side of the mount you’re going to seal off – with contact cement. Anywhere you need to be sure there’s a good seal – use this liberally – you’ll be able to pull/scrape it off later.
Once you’ve set a good layer of contact cement, seal off the mount with the duct tape. Use several strips of tape at different angles from the center of the mount. Continue adding tape around the center of the mount until you’ve sealed it off completely. Some users wont have the center piece sticking out of one side and won’t have to work around it – either way just keep adding tape until it’s properly sealed off.
Duct tape is cheap – so use as much as necessary until you feel good about the job – then add a little more.
The better the tape job, the better the mount will turn out
Setting Up the Mounts
It’s important that the mounts are completely level before you pour the urethane into them. If they’re laying at an angle the mount will not turn out right.
Prepare a small box of sand for the mounts. Setting the mounts into the sand will serve two purpose:
- Allow a perfectly level placement – even if there are protrusions from the mounts that would otherwise make it sit screwy
- Help seal off any small holes in your sealing job. If the hole is small, a little urethane will leak out into the sand and the sand will help it congeal faster – effectively sealing the hole in the mount
DO NOT attempt to do this without the sand box. While it is possible to do so – using the sand box will help ensure you do the job right the first time. Once you mix the urethane, you’ll only have 15-20 minutes of working time before the urethane is to firm to pour. You won’t have enough time to decide you SHOULD have used the sand box.
Don’t skip the sand and the level, once you mix the urethane you won’t have time to realize you shouldn’t have skipped this step
Mixing the Urethane
DO NOT DO THIS UNTIL YOU’RE 100% Ready to Pour!
The correct mixing ratio is absolutely VITAL to the urethane setting correctly. That’s why each set comes in a pre-measured container. Do not attempt to use only PART of a kit – doing so may cause the urethane to not set correctly
Each kit should include:
- Urethane – in the hardness level you ordered. Comes in small paint can style container
- Activator – a very liquid substance in a small bottle
- Stirring Stick
Before doing ANYTHING with these substances read through all the warnings and adhere to them! Most importantly – mix and use these outside in a well ventilated area.
Thoroughly mix the activator and urethane with the provided mixing stick.
Once you’ve mixed the urethane and activator you’re ready to pour it into the mount! Once the urethane is mixed you only have about 15-20 minutes where it’s pour-able!
Pouring the Urethane
Slowly pour the mixed urethane into the open side of the mounts. Allow for the urethane to fill all the voids in the mount. It may take a minute for it to settle completely flat – so take your time. If it seems to be leaking out a LITTLE – don’t panic – the sand will help clot up the hole and slow the leak.
Fill the mounts to the top – it’s even OK if some spills over the outside edge.
Once the mounts are full wait about 10 minutes. In 10 minutes the urethane should still be very liquid and you can top off the mounts with the remaining urethane in the can. This is particularly important if you have a small leak in the sealed side of the mount. Don’t wait longer than 20 minutes to check up on the mounts as by that time the urethane will start to become less workable.
A Job Not So Well Done
It is very important that you use sand. If you do a poor job of setting up the mount in your sand, your results can be disastrous. If there is any type of hole in your seal job, the urethane can seep out. The sand can stop that, so be sure to pack the sand under the mount in order to clog any leak. If not, you get this:
If the urethane seeps out like this, you’re final product will be less than desired. Check out the mount we did with a poor sand job:
Make sure you pack in the sand and keep the mount level, otherwise you’ll get this..
The Finished Product
By the next day you should be able to take the mounts out of the sand box and remove the tape from the opposite side. Sometimes if you had a small leak you’ll find small clumps of sand attached to the other side – these pry/peel off easily and will not affect your new mounts.
The tape should pull off easily and if you want to clean them up further you can scrape off the left over contact cement – however if you really don’t care too much you could even leave the tape on – it won’t hurt anything.
Finished “Do It Yourself” Motor Mounts
Additional Notes For Users
Some users have asked if this will work for their mounts if the center portion has completely torn away from the rest of the mount. The answer: YES! The only additional consideration is the correct centering/alignment of the mounting point that goes through the mount. While the sandbox will make it significantly easier to do this – special care will be needed to ensure centering and alignment.
In using these instructions and urethane kits you accept complete responsibility for the outcome of your project. Only you can ensure this is done correctly and we will not be held responsible if your mounts do not turn out like you wanted.
A significant amount of information has been provided here – however some projects may be unique and will need special attention or a different mode of creation. While we’re happy to help with any questions – we cannot guarantee the outcome of your particular project.
You may not copy, post or reproduce this “How To” information or pictures without written consent from Diverse Suspension Technologies.