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Discussion Starter #1 (Edited)
Filling the B20a5 motor mounts.

Many Third Generation Prelude owners have used Urethane to fill their motor mounts. Several people have complained that the filled mounts are too solid. Engine vibration is transferred to the body of the car, making it very uncomfortable to ride in.

From what I understand, everyone fills their motor mounts to the maximum with Urethane. It's simply overkill unless you are building a car strictly for the track. Here's my take on it, and a solution to this problem. Don't fill the whole mount.

Materials:

- 3M Window Weld Urethane (Autozone)
- Caulking gun
- Carb and Throttle Body Cleaner
- disposable gloves
- old, crappy shirt
- motor mounts
- bathroom with ceiling vent, bathtub
- small 115v room heater
- a work area you can get dirty
- isopropyl alcohol for cleanup
- rag
- 17mm socket and ratchet or equivalent

Step 1

Remove the mounts from the car, safely. Maybe buy 4 junkyard mounts. Be prepared to wait at least 3 days for drying, so don't leave the engine hanging from a hoist.
Disassemble the mounts and clean them with spray. I used carb and throttle body cleaner. Just soak them and then blast the crap from the rubber part. A dark liquid should result.



Step 2

Tape the mounts on one side. Cover the entire thing in tape, where you like it or not. I had one mount that was in peices so I did not tape it yet. You will understand why in a moment.





The busted mount.



I coated the edges of the rubber piece where it was broken. This, alone, is not a fix. Now that is done I can tape the back. No need to dry it until it's all done.

Step 3

Analyze the mounts for a moment. You are not filling the whole mount. Decide what needs to be filled. Think about how the engine will rotate during a hard takeoff. Also, consider what section of the mount will cause the most vibration if filled.

Simply put, do not fill the bottom section.

Here is what the mounts look like:







Once you know how you want to do this, proceed to the next step.

Step 4

The messy part. Put on your gloves and shirt, lay out the woad or cardboard, and load the Urethane. Stick the syringe in the mount against the tape and fill. As you fill, slowly move the syringe up to the top, away from the tape. This ensures an even fill without air pockets.

Mounts should look something like this:



Notice I did not fill the area directly under where the through-bolt goes.

You can use a paper towel or something to smooth out the Urethane on top. Leave the tape on for a bit.

Step 5

The Urethane must dry. Heat them for about 6-8 hours immediately after filling. Temps can be from 100*F to 180*F, more heat for less heating time. I stuck them in a bathtub with a heater blowing on them.



Also, remember the Urethane will release a toxic, air-bourne chemical as it dries. You will need a ceiling vent in your bathroom. And close the door.



After heating for 6-8 hours, you must let the Urethane cure. It will be soft on the surface, but still fluid underneath. Don't push on the dried surface, or it will squish and burst, introducing air pockets and other problems.

Remove the tape.

Give the mounts minimum 3 days to dry at room temperature.

Hope this post helps. Questions, concerns, discussion welcomed. I will update this a little later. If I missed something, let me know.
 

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Very nice write-up. I feel a sticky coming along.
 

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good write-up man, and as always, way to DIY

most people say though, that the front and rear mount or your power mounts and don't vibrate, but the side ones do, so maybe, solide front and rear, and partial sides?

and i think this gets the award for most innovative use of an 8-track of 2008 :)
 

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Tried to stick it but I am having trouble with the site for some reason, I will get it in there soon.
 

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Tried to stick it but I am having trouble with the site for some reason, I will get it in there soon.
You have failed us all Sean. (hangs head in shame)







JK.
 

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This is old news what the hell ?

No shit this is old news, this in fact has been done before. The fact is this is a great how to writeup for those that have not been willing to accomplish this on their own. :newbie:
 

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A few notes to add:

I'd probably give it at least 2 weeks to cure. When I filled mine, the urethane I used said it cures at a rate of approximately 1/8" per day. That's from the areas where the urethane is touching air, not rubber, and you'll wind up filling a pretty thick area. I remember checking mine after 5 days and thinking they were still a little soft feeling.

Also, I found that using an ice cube worked very well to smooth it out at the surface.
 

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I keep meaning to do mine (front one at least) but never have the time to be without the car for that long.
Anybody got any urethane that cures in 30 minutes? ;-)


nice write-up. :emthup:
 

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Discussion Starter #12 (Edited)
A few notes to add:

I'd probably give it at least 2 weeks to cure. When I filled mine, the urethane I used said it cures at a rate of approximately 1/8" per day. That's from the areas where the urethane is touching air, not rubber, and you'll wind up filling a pretty thick area. I remember checking mine after 5 days and thinking they were still a little soft feeling.

Also, I found that using an ice cube worked very well to smooth it out at the surface.
That's a good idea, with the ice cube.

Two weeks is a very safe curing period. Did you heat them during that time?

Mind if I stick this quote in the thread?
 

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Excellent write-up. But i lovvve the vibration feeling... makes you feel like your in a race car, shit vibrating around i lovve it.
 

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is there something else you can use that cures a bit faster?
 

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The stuff I used is called Tiger Seal over here.
I left it overnight to cure, time depends on how thick you apply it .
 

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i just dont have a heater to dry it with. think it'll be ok if i just let them sit to dry?
 

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well i got the stuff from autozone today, now i just have to take the motor mounts out. i think im only gonna do the front two, cause the back one was just replaced and its one of the front ones that are broken.

so can i just leave them out in my garage and let them dry? cause i dont have a heater, i live in florida, so you can imagine my garage gets pretty damn hot during the day
 

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Discussion Starter #20
well i got the stuff from autozone today, now i just have to take the motor mounts out. i think im only gonna do the front two, cause the back one was just replaced and its one of the front ones that are broken.

so can i just leave them out in my garage and let them dry? cause i dont have a heater, i live in florida, so you can imagine my garage gets pretty damn hot during the day
You can and that's fine. Without heating, they take a lot longer to dry and cure.

If you have an oven, you can stick them in there at 180*F. It's probably best to do this at night when you can open the windows and air the place out.
 
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