Urethane Filled Motor Mounts. Easy upgrade for everyone!

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BosnianLanos
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Urethane Filled Motor Mounts. Easy upgrade for everyone!

Post by BosnianLanos »

Hey guys! I'm back! I've managed to finally get around to doing some routine maintenance on my car after letting it get quite out of shape. I'm quite impressed with the results.

All work done on 2001 Daewoo Lanos Sport M/T

A few weeks ago, I noticed that my motor mounts were shot. I could feel it in the clutch pedal as well as the shifter, and you could see the engine shift under load. I jacked the car up and did a visual inspection and saw that the driver's side mount had a sizeable tear and I decided to go ahead and replace all 3 mounts.

I ordered the three mounts from RockAuto.com and the price was quite reasonable, only about $35 for all three. They are made by Anchor but I'm nearly certain they're direct castings from the OEM mounts because the OEM part numbers are still clearly visible in the actual rubber of the mount.

However, I went one better than just installing the replacement mounts on the car, and I decided to fill the mounts with urethane in order to achieve stiffer mounts that would allow less engine flex and vibration and last MUCH longer (think: Prothane or Energy Suspension mounts). I ordered 94a shore liquid urethane casting fluid from McMaster-Carr for about $35 and went to town on the mounts. I sealed off one side of both side mounts with aluminum flashing tape and filled them with the urethane liquid. I also filled the rear (transmission) mount, but I didn't end up using it. (More on that later). The 2-part urethane liquid hardens within a few hours, but only to partial strength. You need to let the mounts dry for at least a week to get them to their full cured strength. Installing them early could ruin the job as the urethane would still be somewhat pliable and therefore negate the "stiff" aspects o fit.

This past Saturday I installed all three mounts. I must say that as far as engine mounts go, Daewoo (or GM for that matter) did an excellent job in the location of all of the mounts. They are easy to get to and quite easy to remove. The rear and driver's side mount could each be done in 30 minutes, but the front passenger's side mount takes a little more effort (I ended up taking out the radiator and thermostat for better clearance, but even that is super-simple on the Daewoo). Everything was done in a couple of hours and it was time for a test drive.

HOLY CRAP. It's like having a totally different car. Granted, my old mounts were completely blown (front passenger's mount above the A/C comp was completely ruined, to the point that the center metal portion was no longer connected to the rubber in the mount), but I think that the benefits from urethane mounts would be evident to anyone. There is no engine rocking at all under load, you get MUCH better power delivery to the tires (since the old rubber mounts allowed flex which would rob torque), shifting response is much crisper, particularly when downshifting, there is no shifter slop, and wheel hop is COMPLETELY eliminated (I had some serious wheel hop issues under Nitrous). It just feels as if there is so much more torque throughout the powerband (I know there isn't, but since the engine doesn't flex at all, power gets to the wheels much quicker). I'm very impressed with this modification and I recommend it to anyone seeking a little more performance out of their car. It just makes driving so much more pleasurable. No shit, but I'm also getting slightly better gas mileage (I can't figure it out either.)

Yes, there is a very very slight vibration accompanied with installing these mounts (because the rubber no longer isolates the vibrations). But it's very very very slight! It just manifests itself as some light dash and trim rattle every once in a while. It's only evident in the lower RPM range and totally goes away once you get past 10 mph. It's basically a non-issue for all but the most discerning ears (and we're Daewoo drivers, lets be honest, we're used to some road and engine noise). I can't even notice it anymore.

I'm kicking myself for not doing a write-up/how to for you guys. It's just that once I start working on something I get a one-track mind and taking photos takes a back seat to the actual work. No worries though, a simple Google search turns up dozens of such how-to's from Nissan, Toyota, and Honda guys. Ours is very similar.

Some pointers:

*DO NOT. I REPEAT. DO NOT. Fill your rear (transmission) mount. Most of the engine flex is isolated in that mount and without an OEM style (Or perhaps very soft urethane) mount there, the vibration is transmitted directly into the body of the car. The noise and vibration were so unbearable (aggressive vibration, dash and trim rattle, and deafening roar at road speed) in the cabin that I had to buy a new OEM mount to install. I don't think that any normal human could put up with that much harshness in a daily driver. It was absolutely brutal, please trust me on this. Once I replaced the urethane mount with an OEM-style one, I got perhaps 95% of the benefits of having all three mounts filled with only 5% of the NVH (Noise/Vibration/Harshness). I feel it is the perfect compromise.

*Use the McMaster-Carr Urethane Liquid. I know some online write ups recommend the use of 3M Window-Weld as the medium to fill the mounts with, but having used the stuff as an adhesive earlier, I must admit that it is far too soft and pliable to be used in engine mounts, and it does not hold up well to the heat and pressure of the engine bay. It's primary use is as an adhesive (not to support weight) and it fails prematurely. the McMaster-Carr stuff is only like $20 more. The liquid is available in several different shore (hardness) ratings. I used 94a (which is the hardest stuff they sell), and I quite like it, but I feel that if you used 65a or 80a you could perhaps get away with filling that rear mount, and the softer urethane might even do away with any vibrations you may encounter. (Note: Energy Suspension and Prothane use 80a urethane for their engine mounts)

*Use brand new mounts. The old mounts tend to compress somewhat (from heat and relatively soft rubber) and therefore change the geometry of the engine position. This compression is just fine if the mounts are only OEM, as the engine can still flex, but if you seal them into that position with the urethane, you may skew the shifter linkage out of alignment and cause grinding of gears and other annoyances. Not to mention that if you use your original mounts, your car will have to be off the road for at least a week. Be careful when ordering mounts though, as the M/T and A/T mounts are very different. Be sure to clean up the mounts really well with soap, water, and MEK before casting as the urethane stuff doesn't like sticking to dirt and crud.

*These mounts would only benefit those of us with manual transmission cars :? . The 4T40E Automatic transmission of the Lanos shifts quite smoothly to begin with and I feel that urethane mounts on an automatic vehicle would be a waste of effort. If you aren't shifting by hand, I don't think you can actually make the engine move enough where the stiffer mounts would matter.

*Careful when using the urethane. It smells (freakishly) like chocolate. Don't get any ides. Surprisingly though, there are no harsh fumes or vapors, just a subtle chocolatey odor. Don't let the stuff drip anywhere important though, or it'll stay there a while.

I seriously feel that anyone with even the most basic technical skill can do this job, from the casting to the installation, but if you guys want I can start a small side business selling these Urethane mounts. I could do them for basically any car (Lanos, Nubira, Leganza, Aveo, Optra, Lacetti, Reno, Forenza, Lemans, etc. etc.) with very reasonable costs and turnaround time. Also, with the varying levels of hardness available with the Urethane liquid, you can customize how aggressive you want the mounts to be (from just slightly stiffer than stock to all-out race mounts, you can even mix and match) Just let me know if anyone is interested and we could work out some pricing deals. Also feel free to contact me for any further clarification on any step of the process or further information as to where to get the Urethane or mounts.

Glad to be back and I hope you guys find this useful!
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Re: Urethane Filled Motor Mounts. Easy upgrade for everyone!

Post by MMamdouh »

no pics?? :(

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Trey05Woo
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Re: Urethane Filled Motor Mounts. Easy upgrade for everyone!

Post by Trey05Woo »

Wouldn't this degrade the life of the mounts as opposed to say buying true ure mounts? I doubt they are even made for these cars, so i can understand your predicament. but I would think OEM mounts filled, would eventually degrade the rubber because what you have is a rubber shell with a urethane core. Not to mention urethane does not absorb vibration rather displaces it. this is why higher peformance mounts are made of a different quality metal than factory.

Just an observation dont think I'm crapping on your project. But interesting to see out how it works out.
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Re: Urethane Filled Motor Mounts. Easy upgrade for everyone!

Post by exist3nce »

Good write up, but I was hoping to see some pics too?
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