Very useful modification to stock motor and tranny mounts!!
Thread Starter
Joined: Jun 2003
Posts: 1,324
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From: Western Colorado
Very useful modification to stock motor and tranny mounts!!
First off, this mod does away with having to buy aftermarket motor mounts and/or using the Racing Beat engine stabilizer brace.
Just thought I'd share a rather useful and cheap modification I've been doing for the past few years on motor and transmission mounts.
Most of the time I find old motor and trans mounts to be separated/ broken. Instead of buying another mount which tends to flex due to the fact that there is only rubber sandwiched between both metal pieces of the mount, I simply modify the existing separated/ broken mounts.
It's quite simple and can be done to un-separated mounts as well:
-On each side of the mount, there is a stud. Grind these off flush.
-Use a center punch to mark the center of where the stud was.
-Using a drill bit that is slightly wider than the old stud, simply drill where you have made the mark with the center punch. (most of the time, the welding that held the old stud in place tends to break away leaving a nice circular hole.)
-Do this for both sides of the mount.
**option 2: for the plate without the rubber, grind off the back side where the welding is and pop out the stud.**
-More than likely, the rubber is still stuck to one side of the mount. You'll need to drill straight through the rubber moving the bit back and forth constantly to eat away at the rubber to make the new bolt slide through more easily.
**IMPORTANT!!: this next step requires the plate without the rubber attached to it to be held onto the rubber side exactly how it was (aka: spin it until it fits where it separated)**
-Once that is done, put the motor mount "assembly" in a vice, line up the holes (eyeball it), and drill straight through the whole assembly to ensure that the new bolt will slide through easily.
-Now go to the parts store and find a pair of bolts that fit the hole on the metal plate ONLY. If I remember correctly, I used either 3" or 4" long bolts. Make sure to buy nuts and lock washers as well for the bolts!! Or you can buy self locking nuts. (the nuts with lock washers will do just fine and have never loosened on me.
-**VERY IMPORTANT STEP** Grease up the bolts and possibly inside of the rubber mount (If the fit is rather tight, re-drill through the rubber to eat away more of the rubber. (USE only 1 size drill bit for the whole mount, don't go larger than the holes on the metal that you have drilled!! It makes for a pain in the *** installation when the mount is "falling apart on you"!!!)
-Now tighten up the mounts to your liking. If the mounts are too tight, you will notice engine vibration inside the car.
-Voila!! You are done!! NO more engine movement!! (well, VERY slightly)
This mod applies to 1st, 2nd, and 3rd gen RX7's
Brian
Just thought I'd share a rather useful and cheap modification I've been doing for the past few years on motor and transmission mounts.
Most of the time I find old motor and trans mounts to be separated/ broken. Instead of buying another mount which tends to flex due to the fact that there is only rubber sandwiched between both metal pieces of the mount, I simply modify the existing separated/ broken mounts.
It's quite simple and can be done to un-separated mounts as well:
-On each side of the mount, there is a stud. Grind these off flush.
-Use a center punch to mark the center of where the stud was.
-Using a drill bit that is slightly wider than the old stud, simply drill where you have made the mark with the center punch. (most of the time, the welding that held the old stud in place tends to break away leaving a nice circular hole.)
-Do this for both sides of the mount.
**option 2: for the plate without the rubber, grind off the back side where the welding is and pop out the stud.**
-More than likely, the rubber is still stuck to one side of the mount. You'll need to drill straight through the rubber moving the bit back and forth constantly to eat away at the rubber to make the new bolt slide through more easily.
**IMPORTANT!!: this next step requires the plate without the rubber attached to it to be held onto the rubber side exactly how it was (aka: spin it until it fits where it separated)**
-Once that is done, put the motor mount "assembly" in a vice, line up the holes (eyeball it), and drill straight through the whole assembly to ensure that the new bolt will slide through easily.
-Now go to the parts store and find a pair of bolts that fit the hole on the metal plate ONLY. If I remember correctly, I used either 3" or 4" long bolts. Make sure to buy nuts and lock washers as well for the bolts!! Or you can buy self locking nuts. (the nuts with lock washers will do just fine and have never loosened on me.
-**VERY IMPORTANT STEP** Grease up the bolts and possibly inside of the rubber mount (If the fit is rather tight, re-drill through the rubber to eat away more of the rubber. (USE only 1 size drill bit for the whole mount, don't go larger than the holes on the metal that you have drilled!! It makes for a pain in the *** installation when the mount is "falling apart on you"!!!)
-Now tighten up the mounts to your liking. If the mounts are too tight, you will notice engine vibration inside the car.
-Voila!! You are done!! NO more engine movement!! (well, VERY slightly)
This mod applies to 1st, 2nd, and 3rd gen RX7's
Brian
sounds like a good cheap mod tho, thanks!
Interesting idea, and I just ordered solid mounts. I think one of the best ways to do this would be to find polyurethane replacements for the rubber, then use your method for the install.
Joined: Jul 2002
Posts: 7,301
Likes: 3
From: District of Columbia
with those solid mounts cant cracking occur on the front cover ?
Last edited by Hyper4mance2k; Sep 10, 2005 at 12:31 AM.
I tried solid motor mounts once. You know the bolts that hold the front mount to the front cover? When I removed them to go back to stock, there was a bunch of aluminum gunk that built up around the threads due to vibration. I'm glad I went back to stock before it could get worse.
The reason I tried solid mounts was because I was curious and had one bad motor mount that allowed too much engine slop from left to right. I went back to stock after I got a good used motor mount which cured the slop. The interior was also quieter.
The reason I tried solid mounts was because I was curious and had one bad motor mount that allowed too much engine slop from left to right. I went back to stock after I got a good used motor mount which cured the slop. The interior was also quieter.