I just recently purchased a 89 gtu, Now i need to change motor & tranny mounts on it because the engine & tranny shake. Im planning on buying poly tranny & motor mounts from ebay but my question is, Will they fit on the regular metal brackets that the mounts sit on? If not what do i need to do. Thanks!

 

Are you sure it's the engine/trans mounts?

yes

 

If the center support on the trans crossmember is pushed down from collapsed trans mounts, you'll need an entirely new crossmember along with the mounts.

 

I doubt they're collapsed, Well how would i kno? I mean the car still runs but whenever i rev it Or turn it on when its cold and the rpm goes below 1000 the engine shakes. which leads me to think its the mounts.

 

Guess again! Mounts aren't going to fix your problem.

 

+1^

 

Then what is? Crossmember? That's the bar that the tranny mounts sit on correct?

 

Engine.

 

Your engine isn't running properly which causes it to shake.

 

Im guessing due to a bad rebuild, the guy i bought it from said it was rebuilt by his friend. Anyway i can fix it? besides having to rebuild.


Brutal! Im sure its due to a bad rebuild, guy i bought it from got it rebuilt. Anyway i can fix this problem with out having to rebuild?

 

Story:

Found a 1987 Rx7 GXL in SC for sale a while back. Paint was REALLY nice, interior was immaculate. Guy said he just rebuilt the engine, and said he worked for a company that rebuilds rotaries (yes, as an engine builder). I asked him some questions about the rebuilding process, and he seemed to understand the basics. So I started probing into the advanced. "So, what size thrust spacer did you end up having to use?" I ask. At first, he thought for a little while, and ended up saying that he used a #4. Okaaay..... what weight were the rotors? "Oh! I used lightweight ones!" Hmm.... sure. And you're selling it for $2k?

Ok, let's go for a test drive! Damn engine nearly shook me apart. Guy said it needed an engine mount. I checked all the mounts with a prybar... everything seems good.

So I asked him if he wouldn't mind me doing a compression check. He said I didn't need to, he JUST rebuilt the engine less than 2k ago. So after checking compression.... 110 psi on front rotor faces. Nice. 65 psi on 2 faces in the rear.

Moral of this story? Never trust anyone.


And check your compression.

 

yep, compression test tells all.

it bugs the **** out of me that even new owners refuse to want to do a compression test on their car because "i bought it with a rebuilt motor".

talk about denial, but we see it everyday.

at least you'll know what the root cause is instead of spending money on mounts when it could be better spent on fixing the motor. these engines really do not idle roughly when running properly, so even if the mounts were nonexistant the motor should not be vibrating that roughly.

 

Wow amazing. Def. agree with not trusting anybody, but i dont know how to check the compression by other than cranking the motor & hearing how it starts up. But im sure its not a very accurate, right? I kno when it has low compression it cranks up with a really whinny sounds while when they have good compression it'll have a more muffed sound, which is how my engine sounds.



LIke i said to the other dude i dont know how to check the compression by other than hearing the way the engine cranks. Which i thought would be enough to determine whether compression is good, but its probably not very accurate. How can i precisely measure my compression bro? & I just know my basic's about rotary & still learning which is why i came on here lol

 

I've never heard of checking compression like that. There should be a write up on using a standard compression gauge on here somewhere.

Use the search feature.

 

****** a right. That was one of the selling points of my vert was a compression test was done with me there at the dealer.

 

My n/a motor has solid compression all around. The motor shakes like crazy since i have a **** poor idle. Im sure i need to check a few things again but im able to grab the motor and shake it back and forth by hand, it NEEDS mounts and other things sorted out....

 

Also another problem on mine is the idle. When she's cold if i dont gas her until she's warm it'll cut off. but once the engines warm it idles beautifully, Anyway to fix that my self?

 

Thats a broad range of potential problems. What if any emissions equipment does your car still have? If you dont have a clue lots of good pictures would help in deciding that.

 

http://www.rotaryresurrection.com/2n...ion_check.html

except i would replace a few steps, one being disregard the comment about holding the schraeder valve on the side down. replace the step with remove the schraeder valve from the bottom of the line to the spark plug hole and simply watch the gauge during cranking. doing it as kevin describes gives very poor accuracy(very low figures which will not tell you if compression is marginal or not). watch each peak bounce in successions of 3 pulses, you will get 3 pulses per rotor, one for each pair of apex seals.