DIY repair/strengthening stock motor mounts
#1
01-28-2007, 07:02 PM
DIY repair/strengthening stock motor mounts
Since Claymore's thread mysteriously disappeared (
) with my post with someone explaining how to do it, i guess i'll make a new thread.
This was written by "Chunky", a very knowledgeable guy. If you're wondering about his credentials and background, this guy builds motors, engine swaps, etc etc. He fabricated his own set of performance camshafts for his EP3 K20a3, and made significant power off of them and dyno tuning them himself. They were the first performance cams ever made for the k20a3. Later, Skunk2 bought the design/blueprint on the cams from him, and are now selling them as their own.
This DIY is made for those who have busted stock mounts or want stiffer mounts since no aftermarket mount is available as of yet. Keep in mind that the engine torque damper (aka "stiffy") that most companies are releasing perform pretty good, but over an extended amount of time, they wear out the weak stock mounts. I've used the Ingalls TD on my car for about a year and a half, worked fine, but my stock mounts finally gave away. So i decided to go with full replacement race mounts instead.
The benefits of stiffer/stronger mounts:
Controls torque, diminishes wheel hop and improves manual transmission shifting drastically. Every shift is a nice firm feeling and car response is instant.
The negatives:
Interior cabin vibration and resonance. Like most power mods, theres a give and take with modding. Sacrifice creature comfort for engine power/response. Most ppl get used to the vibrations.
Window weld has a rated 55A hardness. Commercial mounts have a hardness rating of 60A for street vehicles. So the vibes shouldnt be too bad. The 75A are recommend for street and track vehicles that make more than average horsepower. This rating of bushing is also for those that would like a stiffer feel and less engine flex. The 85A Grey bushings designed specifically for race cars or drivers that seek a solid engine mount kit.
The thread originated here on ClubRSX.
For anyone that's killed their stock motor mounts - Club RSX Message Board
This method is used by MANY enthusiasts and pros alike.
Show time:
) with my post with someone explaining how to do it, i guess i'll make a new thread.This was written by "Chunky", a very knowledgeable guy. If you're wondering about his credentials and background, this guy builds motors, engine swaps, etc etc. He fabricated his own set of performance camshafts for his EP3 K20a3, and made significant power off of them and dyno tuning them himself. They were the first performance cams ever made for the k20a3. Later, Skunk2 bought the design/blueprint on the cams from him, and are now selling them as their own.
This DIY is made for those who have busted stock mounts or want stiffer mounts since no aftermarket mount is available as of yet. Keep in mind that the engine torque damper (aka "stiffy") that most companies are releasing perform pretty good, but over an extended amount of time, they wear out the weak stock mounts. I've used the Ingalls TD on my car for about a year and a half, worked fine, but my stock mounts finally gave away. So i decided to go with full replacement race mounts instead.
The benefits of stiffer/stronger mounts:
Controls torque, diminishes wheel hop and improves manual transmission shifting drastically. Every shift is a nice firm feeling and car response is instant.
The negatives:
Interior cabin vibration and resonance. Like most power mods, theres a give and take with modding. Sacrifice creature comfort for engine power/response. Most ppl get used to the vibrations.
Window weld has a rated 55A hardness. Commercial mounts have a hardness rating of 60A for street vehicles. So the vibes shouldnt be too bad. The 75A are recommend for street and track vehicles that make more than average horsepower. This rating of bushing is also for those that would like a stiffer feel and less engine flex. The 85A Grey bushings designed specifically for race cars or drivers that seek a solid engine mount kit.
The thread originated here on ClubRSX.
For anyone that's killed their stock motor mounts - Club RSX Message Board
This method is used by MANY enthusiasts and pros alike.
Show time:
I recently had an issue with my motor mounts that caused some serious problems for me. Previously I had the ES MM inserts. Well, they eventually wore out and my stock front motor mount was torn. This allowed a lot of extra play which led to vibration that knocked my front motor mount bolt loose. So then one fine day after a hard 2-3 shift, the engine rocks back so hard that it pulls off the lower radiator hose! 
As you might imagine, it wasn't a pleasant feeling to hear a THUNK as the valve cover hit the underside of my seibon hood, and then, seeing a cloud of white vapor ensuring a safe getaway from any potential pursuers.
Anyhow, I hate paying excess prices for things I can do myself so I started looking into polyurethane mixes with which I could "rebuild" my stock motor mounts. Because hey, the brackets were just fine, AND they're cast aluminum so they're strong and light.
Lo and behold, I came across some polyurethane products that looked like they'd work. So yesterday I rebuilt my stock mounts to what is essentially race mount hardness using the stock mounts. I doubt most people would want their mounts as firm as I have, but there are softer polyurethane products that will work and have more give.
I thought about using the tried and true "window weld" fix, but the cure time on it was kind of ridiculous. I settled on some 3m 2 part poly urethane mixes. It's part of their "Scotch-weld" lineup of products. These products certainly weren't cheap (they required the purchase of a rather expensive applicator gun AND you have to use a new disposable nozzle for each bottle of stuff you use), but they had really short cure times AND were much firmer than window weld. For reference, window weld has a hardness of 55A and the products I used had a hardness of 70D and 85A respectively.
The front mount I wanted to be basically solid with very little give at all. I used the 3M DP601-NS product. This stuff is HARD. It's a polyurethane, so it won't crack, and it has an adhesive strength of 2000+psi. Anyhow, the NS means "no sag" which means that it comes out thick and won't run. They also sell a self leveling version of the product which comes out looking a little nicer, but it's harder to work with. Anyhow, here's how the front mount looked after I was done.
I just filled the holes in the stock rubber mount (as well as putting some inbetween the two parts that tore). This mount cured fully in about an hour. You have to be very careful when putting the mount back on the car b/c the mount is solid, everything has to line up really well b/c you can't flex the mount into place like with the stock stuff.
For the rear mount, I did something a little unique. I wanted the mount to be as firm as possible, but I also wanted some give so that the idle was reasonable. The solution was to use the ultra-firm stuff on the top, and the softer stuff on the bottom. The softer mix is the DP604-NS. This stuff is rated to 900psi and cures in 6 hours. The great thing about these mixes is that they don't require heat or application in thin layers to cure all the way. It's a 2 part chemical reaction that occurs so you fill the whole mount in a single step.
I coated the whole outside with the black stuff just so it looked a little better. In the future I'll be able to make these a LOT prettier. I was pressed for time so I didn't get to make it look pretty by leveling with a spatula or something.
So the final result - these mounts are FIRM. There is still some give b/c the stock rubber is still inside. As a result, Idle didn't change much from when I had just the ES MM inserts. There is more vibration at low rpm between 2000-2500rpm. Highway cruising is about the same as before.
When I step on the gas with these mounts, there is zero hesitation. The car just gets up and GOES. The power goes into turning the wheels, not into compressing the mounts.
Oh, here's what my ES MM insert looked like after about 90k miles
It was destroyed. For anyone that drives agressively, this is definitely the low cost alternative for buying full new mounts. I wouldn't really reccomend that anyone use the gray stuff unless they're hardcore like me, but the black stuff is a good product and it will turn your mounts into the equivalent of a solid polyurethane mount.
The most expensive part of this was buying the mixer gun. How could something so tiny cost so much.
Here's the used containers. If it wasn't for that gun and the rush shipping I paid, I could have easily done both mounts for under $70. Not bad considering how much new polyurethane mounts go for. My front is actually stiffer than just about anything that is commercially availible.
On the bright side, if I ever have to do it again, I can do it for cheap. Oh, and there is no wheel hop. whatsoever. at all. :mgrin:
As you might imagine, it wasn't a pleasant feeling to hear a THUNK as the valve cover hit the underside of my seibon hood, and then, seeing a cloud of white vapor ensuring a safe getaway from any potential pursuers.Anyhow, I hate paying excess prices for things I can do myself so I started looking into polyurethane mixes with which I could "rebuild" my stock motor mounts. Because hey, the brackets were just fine, AND they're cast aluminum so they're strong and light.
Lo and behold, I came across some polyurethane products that looked like they'd work. So yesterday I rebuilt my stock mounts to what is essentially race mount hardness using the stock mounts. I doubt most people would want their mounts as firm as I have, but there are softer polyurethane products that will work and have more give.
I thought about using the tried and true "window weld" fix, but the cure time on it was kind of ridiculous. I settled on some 3m 2 part poly urethane mixes. It's part of their "Scotch-weld" lineup of products. These products certainly weren't cheap (they required the purchase of a rather expensive applicator gun AND you have to use a new disposable nozzle for each bottle of stuff you use), but they had really short cure times AND were much firmer than window weld. For reference, window weld has a hardness of 55A and the products I used had a hardness of 70D and 85A respectively.
The front mount I wanted to be basically solid with very little give at all. I used the 3M DP601-NS product. This stuff is HARD. It's a polyurethane, so it won't crack, and it has an adhesive strength of 2000+psi. Anyhow, the NS means "no sag" which means that it comes out thick and won't run. They also sell a self leveling version of the product which comes out looking a little nicer, but it's harder to work with. Anyhow, here's how the front mount looked after I was done.
I just filled the holes in the stock rubber mount (as well as putting some inbetween the two parts that tore). This mount cured fully in about an hour. You have to be very careful when putting the mount back on the car b/c the mount is solid, everything has to line up really well b/c you can't flex the mount into place like with the stock stuff.
For the rear mount, I did something a little unique. I wanted the mount to be as firm as possible, but I also wanted some give so that the idle was reasonable. The solution was to use the ultra-firm stuff on the top, and the softer stuff on the bottom. The softer mix is the DP604-NS. This stuff is rated to 900psi and cures in 6 hours. The great thing about these mixes is that they don't require heat or application in thin layers to cure all the way. It's a 2 part chemical reaction that occurs so you fill the whole mount in a single step.
I coated the whole outside with the black stuff just so it looked a little better. In the future I'll be able to make these a LOT prettier. I was pressed for time so I didn't get to make it look pretty by leveling with a spatula or something.
So the final result - these mounts are FIRM. There is still some give b/c the stock rubber is still inside. As a result, Idle didn't change much from when I had just the ES MM inserts. There is more vibration at low rpm between 2000-2500rpm. Highway cruising is about the same as before.
When I step on the gas with these mounts, there is zero hesitation. The car just gets up and GOES. The power goes into turning the wheels, not into compressing the mounts.
Oh, here's what my ES MM insert looked like after about 90k miles
It was destroyed. For anyone that drives agressively, this is definitely the low cost alternative for buying full new mounts. I wouldn't really reccomend that anyone use the gray stuff unless they're hardcore like me, but the black stuff is a good product and it will turn your mounts into the equivalent of a solid polyurethane mount.
The most expensive part of this was buying the mixer gun. How could something so tiny cost so much.
Here's the used containers. If it wasn't for that gun and the rush shipping I paid, I could have easily done both mounts for under $70. Not bad considering how much new polyurethane mounts go for. My front is actually stiffer than just about anything that is commercially availible.
On the bright side, if I ever have to do it again, I can do it for cheap. Oh, and there is no wheel hop. whatsoever. at all. :mgrin:
#4
01-28-2007, 08:46 PM
old trick you can do to just about any honda. never done it myself but know a few buddies that have, there's vibrations at idle and low RPMs but it's totally worth it. i'd do this before i'd do claymore's style
#5
01-28-2007, 10:17 PM
WOW! I would want to do this but would like to ride in some one else's Fit who has already done this to see how much vibration there is at idol and low RPMs. thanks for psosting this. good stuff!
#9
02-02-2007, 09:22 PM
wow, i just saw it yesterday at autozone.
i found this searching the googlez
3M(TM) Scotch-Weld(TM) Urethane Adhesive DP601NS Gray, 50 mL Syringe, 12 per case, distributed by R.S. Hughes - Industrial Distributor - Tapes, Adhesives, Abrasives, Safety, and Electronic Products
i found this searching the googlez
3M(TM) Scotch-Weld(TM) Urethane Adhesive DP601NS Gray, 50 mL Syringe, 12 per case, distributed by R.S. Hughes - Industrial Distributor - Tapes, Adhesives, Abrasives, Safety, and Electronic Products
#10
04-01-2007, 07:55 PM
finally got around to doing this on the Fit, i only did it to the mount in the driver lower front side, and on the one below the battery tray and WOW, no wheel hop.... i launch at 5000 smooth and no wheelhop. great mod thats for sure.
#13
04-30-2008, 11:30 PM
anybody have pics of the Fit MT motor mounts that they did this to?
just to clarify, you just take the stock mounts, and fill the voids with this stuff? is there any way to completely replace the rubber?
just to clarify, you just take the stock mounts, and fill the voids with this stuff? is there any way to completely replace the rubber?
Last edited by sl0wp0k3; 04-30-2008 at 11:55 PM.
#14
05-01-2008, 12:06 AM
u just fill the voids.
if u were to replace the rubber, u;re better off buying a new mount all together b/c it rubber would need to be pressed out. Also, i dont think Honda sells the rubber alone.
if u were to replace the rubber, u;re better off buying a new mount all together b/c it rubber would need to be pressed out. Also, i dont think Honda sells the rubber alone.
#18
05-20-2008, 12:44 AM
More because the forces from the movement of the engine are now passed into the frame where most of the components you mentioned are mounted to. But it will be a slight increase nothing to worry about.
#20
07-10-2014, 03:22 AM
Bringing this back to life lol. Would jb weld technically work for this also? It looks and sounds like the same stuff?