My 91 has 93K on it. Do the motor mounts on these cars stiffen up from age?

 

What I've seen is that they become soft and sag.

 

I've got a built motor and it seems I can feel the idle in the car a little more than I remember. You know how that is it comes on over time and it's hard to tell if it was there before or not because of the gradual symptom. I can see if they get soft that would impart more engine movement into the chassis. Has anyone replaced theres after alot of miles and noticed a difference?

 

When I did mine I was concerned about oil pan clearance and could not tell they were sagging until I actually took them out of the car (car had approx. 50k on it ). I replaced them with F body poly inserts, it did improve the motor movement, and it also raised the motor approx. 1/2" from the older sagging mounts.

 

Are the poly inserts something you buy to rebuild the existing mounts, or a whole new mount? Were to you get them and do you remember the part number?

Thanks for the info.

 

Still running my original 84 mounts. The car has had 4 different motors, runs quick, has made thousands of passes and has had no motor mount issues. Spend your money elsewhere.

 

i replaced my mounts a few months ago, when i put the 421 in. the mounts needed to be changed but they didnt appear to be shot after 21 yrs.

 

I replaced my mounts too when I did my 383..yes the movement was more noticable, the main thing is under hard acceleration the worn mounts allow for the motor to "twist" in there too much.

 

They are energy suspension inserts for the clam shell style mount 93-97 camaro/firebird. You will be rebuilding the stock mounts. They are pretty easy to do and comes with what you need. What I have here is the Energy Suspension pn 3.1127G.
They are listed as a left and I believe I used 2 lefts. It's been awhile since I did this, so I'll have to double check. I should be able to go through everything by tomorrow and post back for you.
Summit etc. sells them, link to pic/details:
http://www.energysuspensionparts.com...FRDxDAodgTh0nQ

 

Thanks so much for the information

 

I would like more data, pictures are always welcome too.

 

you're welcome, and after going through my "stuff " I ordered/used 2 lefts to do both sides (L/R) mounts in the car.
Not sure what kind of data I could provide. My logic is that a fresh poly insert is better than the 15 year old visibly sagging (when removed) rubber ones on my car. I never bothered taking pictures of this mod. I can only say that it is fairly easy job.
When rebuilding the "clam shell" style motor mounts, you will first drill out the eyelet/rivet that holds both parts of the clam shell together.
Remove stock rubber inserts by separating clams using a large screw diver or small pry bar. If the rubber ones are "stuck" to one side of the steel clam, a propane torch serves to persuade the old inserts out.
Next, clean clam halves (now is the time to re-paint/coat) and replace w/the new inserts, making sure that the direction of the new insert matches the form of the steel clam (as the front and back have a different male/female pattern).
Re-assembly is done by using the new grade 8 studs/with locks/and washers to attach both halves of the clam shells together. I chose to use some 'lock-tite' (blue) on the threads for extra insurance. When finished tightening down the new fasteners, the mounts are ready to re-install on the block. Fitments on mine was excellent and I had zero issues.
This year however I will be pulling those in favor of the solid ones I have.

 

mseven:
you might want to reconsider going to solid mounts. I went to solid mounts on my 90 camaro (unibody construction) and the vibration transmitted into the cabin is quite a bit. i thought something was wrong with my AC compressor when it cycled on and replaced it, then discovered replacement had just as much vibration & noise, so it was normal. just that now I was hearing it. like having the feeds from the auto stethoscope fed into the interior.

on my C3 with motor mounts, since it's a perimeter frame car, with the body insulated from the frame, not a problem, the body mount bushings isolate the NVH.

however, after a while, i got used to the "surround sound audio" in my IROC. did consider switching to poly-U mounts, even went out and bought them, but then changed my mind and decided i'd rather live with the audio. my radio doesn't work anyways.

but it was a shock since i had done my C3 first and that was fine, but the 90 F-body was a totally different experience. the C4 is also unibody construction.

just my 2 cents.

 

my tuner is fabbing some solid mounts, I need to move the engine back a little in order to fit the dry sump.

 

ahhh, that makes sense. one of the reasons i went with solid mounts in my C3 was to lower the motor.

dry sump! wow. letsee, 10qts of Mobil1... oil change.

yup, I'm just jealous.