crazy parts bin engine mount upgrade! (OEM engine damper)

This has been reposted from the original ClubProtege thread (on Aug 10, 2005). Negativity on the "cost" or "expense" of these parts will not be tollerated. Yes I ******* know all this s*** is expensive as hell, so you don't have to rub it in!

I am so stubborn that I didn't want to get urethane engine mounts because my car is a daily driver and I don't want all the crazy harshness associated with it. So I decided to take a gamble and experiment with a crazy brew of OEM parts AGAIN. I knew from long ago that the automatic 2.0s came with a funky part attached to the front engine mount bracket called a "roll damper" (as mazda calls it). As the name implies, it is designed to keep the engine from rocking too much. It's also now widely known that the manual 3rd gens have floppy motor mounts that makes driving it smoothly a b****.

About a year ago I checked if installing the roll damper on a manual 2.0 would be possible by looking through all the OEM 3rd gen parts available due to the fact that automatic's engine mount bracket is very different from the manual one. The roll damper is actually attached to the engine mount bracket and not the engine mount itself. It is also bolted onto a stud from the crossmember. It turns out that the 4WD sport20s (both manual and auto) are equiped with the roll damper also and are the only other 3rd gens that have it. Further investigation by looking through countless pictures of the 4WD sport20 engine mount bracket showed that its engine mount bracket being installed on a manual 2.0 a real possibility. Both versions of the 4WD sport20 use a G tranny so that was further evidence that some of the parts from it are interchangable with the FWD G tranny. Yes, the engine mounts attach to the tranny (except for the one by the belts of course). Also thanks to Autoexe for releasing the member brace set over a year ago, I was able to see how the bottom of the 4WD sport20 look for the first time. Thanks to those pictures I was also able to determine that the crossmember (the one running from the radiator support) is shaped very differently from the FWD versions.

Knowing this, I know I have see if the FWD automatic 2.0 crossmember and the 4WD sport20 engine mount bracket will work. I also checked if there was any 3rd gen that uses a different front engine mount in attempt to find something stronger and I found that ONLY the turbo diesel version uses a different front engine mount. All of the other 3rd gens uses the same weak sauce front engine mount regardless of engine used. Mazda probably decided to use a different engine mount on the turbo diesel model because it is also the engine that makes the most torque (~170lbs/ft) out of all the 3rd gens. I decided to give this engine mount a try also. I had no fear of it not fitting because it turns out that the stock crossmember used on the manual 2.0s are the same as the one used on the turbo diesel model, hence the reason for some unused bolt holes.

So I got these parts about a week ago and installed them yesterday....
B28V-39-800B engine mount member (from automatic FWD FS-DE cars)
B28V-39-990 roll damper (from AT FWD FS and AT & MT 4WD FS-ZE cars)
GJ21-34-031 nut (from AT FWD FS and AT & MT 4WD FS-ZE cars)
BJ3A-39-050C #2 engine mount (from European RF turbo diesel cars)
B29A-39-020A #2 engine mount bracket (from AT & MT 4WD FS-ZE cars)

When checking for the stiffness difference between the stock and turbo diesel motor mount, it was hard to conclude which was better... the stock one didn't seem like it moved around as much as the turbo diesel one, but the turbo diesel one didn't move much and seemed like it would dampen very good when even force was applied to both sides of the bolt hole.... it feels floppy only when you move it from one side... the turbo diesel mount is filled with rubber all around but not all the way to the outside... so in otherwords only a narrow portion of rubber are in the middle... this is a very different design compared to the "I" shaped design used on the stock mount... it appears that when force is applied to the turbo diesel mount, the rubber from the narrow middle portion will expand slighly and then touch the outer donut rubber portion, basically making it like a solid piece at that instant. I can only guess that Mazda chose this design because they needed something that can dampen the crazy diesel engine vibrations yet at the same time providing sufficient stiffness to keep the engine from torquing around. Like I said, it was hard to tell which was better until I drove the car with the turbo diesel mount...

Amazingly, all the crazy parts from various different models fit perfectly and I drove it around for a few miles. First impression was, the engine did not nose dive as soon as I let off the gas... when I got back on it by jamming on the pedal instead of easing on it like I would normally do, the engine did not buck around either.... I also tried bad shifting techniques (up shift but just letting off the clutch without slipping as well as just downshifting) and the engine just compliantly bucked about 2 times and stopped instead of having the whole car hopping around like before... I then did hard redline shifts and it felt solid the whole time... there was no knock or shudder feeling during those shifts but the engine did not flop around and not put power to the ground either..... mind you this s*** is still rubber and not some crazy solid s***, so don't expect it to let you spin tires during shifts... but it was solid the whole way, basically the same kind of smooth but solid feeling when driving a 1st gen with mazdaspeed mounts.... gear change operations are now a lot easier and less clutch slipping is needed to drive smoothly... this means everything can be done effortlessly quicker than before.... the car NEVER drove this good before, EVEN after the mazdaspeed #3 engine mount upgrade!

mad quix0rs shifting yo!

Here's a description of the roll damper from the 2001 service highlights manual:http://www.clubprotege.com/forum/attachment.php?attachmentid=11349&stc=1
 

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the roll damper... it's actually made by oiles, a japanese bearing company.... inside the white plastic part is actually a spring of some sort.... it looks flimsy if you judge by how small it is and how tiny the connecting arm is... but it works! I guess there's some black magic involved
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the 4WD #2 engine mount bracket... and a comparision between the stock s*** and the 4WD bracket
 

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thanks to people who have done tranny conversions, they have reported that using the stock automatic crossmember works with the manual tranny just fine.... and now there's real proof, they're shaped the same except for some minor parts mounting differences
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the RF turbo diesel engine mount, and a comparison of it and the stock s***
 

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and a perfect installation! people who have a 1.8 and want this s*** can do so also... the FAQ already has been updated with the info... sucks to be 1.6 owners again
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UPDATE:
No real deterioration of the engine mount or "roll damper" effectiveness since installation. Everything is still pretty solid (for rubber s***... obviously, you can't compare this to having urethane mounts where nothing really moves)... back in december, I dumped the clutch at 3000rpm and the car just took off like a bat out of hell! There was no wheel hop (upgraded suspension helps), and all I heard was the engine/front end clunk a bit for half a second!

here's what the FWD automatic bracket looks like compared to the 4WD (manual & auto) bracket (it's gimpo2's as part of his auto to manual swap)... you can also see that the mounting hole for the "roll damper" is better reinforced in the 4WD bracket:
 

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Bala

quitas Veritas
Contributor
:
2003.5 323F
Good find! ... again. Here's a shot of my auto P5's roll damper with the AWR "auto" front mm. It shook the car so bad in drive with the brake depressed (ie: stoplights) I had to go back to the stocker. A diesel mm may be in my future.

4m.jpg
 

khaosman

Member
Contributor
:
2006 Honda S2000
Bala de Plata said:
Good find! ... again. Here's a shot of my auto P5's roll damper with the AWR "auto" front mm. It shook the car so bad in drive with the brake depressed (ie: stoplights) I had to go back to the stocker. A diesel mm may be in my future.

Indeed, my AWR rear motor mount rattles everything terribly. Very good to see some "new" ;) alternatives on motor mounts! :D
 

Kansei

Banned
Wow how did I miss this thread. I need to check the general performance section more often!

I am very interested in doing this. Any info about stuff for the rear mount or should I just replace it with a new OEM one? I think mine might be torn because even with the AWR 95 durometer or 70 durometer my engine bucks. Really the only difference that I notice is that either AWR mount makes my car shake more haha.
 

julius77

Member
:
2001 Mazda MP3
I just purchased some AWR Motor Mounts... after reading these post I'm a littler nervous that I may be throwing money away. Its for my MP3, which has some wheel hop that drives me crazy.



KanseiZM said:
Wow how did I miss this thread. I need to check the general performance section more often!

I am very interested in doing this. Any info about stuff for the rear mount or should I just replace it with a new OEM one? I think mine might be torn because even with the AWR 95 durometer or 70 durometer my engine bucks. Really the only difference that I notice is that either AWR mount makes my car shake more haha.
 

chicaboo

Member
:
02 Mazda 323 Astina 1.8
Hi Edwin,

Have you tried the regular proteg engine mount in-place of the diesel mount yet as a comparison? I ask as I have a spare brand new mount, and I would like to know if it's worthwhile trading it for a diesel mount instead.

Interestingly, my old auto never had any wheelhop, it would just hook up and drive smoothly with a hint more vibration at idle than my manual did when it was stock.

Cheers,
Gav.
 

chiefmg

MOTM July 2015
:
'81 RX-7 GS, '00 Miata SE, '16 Camaro (wife's), '15 CX-5 GT AWD
Somewhere on the forum there is a thread with a guy who found a solid rubber replacement mount for the passenger side, I think it was from Autozone (on line). That might be another choice. I have to check into it myself as my gf's '99 has that mount broken.
 

chicaboo

Member
:
02 Mazda 323 Astina 1.8
I'm pretty happy with my AWR inserts for the side mounts. Just that I find the Corksport inserts still a bit rough at idle when the AC is on. I might do the GND/Pin10 short and reset my idle to 900rpm to help with that a bit.
 

chicaboo

Member
:
02 Mazda 323 Astina 1.8
Hi guys,

Does anyone know where I can get the "B29A-39-020A #2 engine mount bracket (from AT & MT 4WD FS-ZE cars)", as they're not available in Aus. I assume there is an english website for Japanese genuine Mazda parts that I don't know of? Everything else I can get locally as automatic parts.

Cheers,
Gav.
 

Kansei

Banned
So what was the total parts cost for the front mount stuff?

Also, what are you doing in the rear? With the AWR 70 duro and stock rear mount my car bucked like crazy.. though it seems to be the tranny-side mount where all the motion is coming from.. but anyway I installed the RR Racing rear motor mount inserts and now the vibration is just awful.. it's impossible to drive the car smoothly like this, it makes the dash shake violently. If there was a mount like the turbodiesel front but for the rear, I'd be interested in sourcing one of those.