Are poly motor mounts a good idea?
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Staging Lane
Joined: Apr 2011
Posts: 55
Likes: 0
From: Metro Deroit
Are poly motor mounts a good idea? A while back i bought porthane poly trans and engine mounts for my 98 Z28 i installed the trans mount only at first and it sucked! rattles and vibrations galore. so i took it off and replaced with stock. now for the question part, i was wondering if i should go ahead with motor mounts or just sell them. do the motor mounts vibrate like the trans mount? what was everyone elses exp with them? Thanks for all the info. this really is the best place for f body info on the net!
A while back i bought porthane poly trans and engine mounts for my 98 Z28 i installed the trans mount only at first and it sucked! rattles and vibrations galore. so i took it off and replaced with stock. now for the question part, i was wondering if i should go ahead with motor mounts or just sell them. do the motor mounts vibrate like the trans mount? what was everyone elses exp with them? Thanks for all the info. this really is the best place for f body info on the net!
I have the poly Motor Mounts and a Rubber Trans Mount. I have read on here and other sites that the poly trans has too much vibration. I am happy with my selection. I have a 98 Z28 A4. I barely notice any vibration from my MM.
I put poly motor mounts in a few months ago and it was definitely worth it. Vibration is barely noticeable. General consensus seemed to be that putting a poly trans mount in made the vibration much worse than poly motor mounts so I used poly motor mounts and a stock replacement trans mount. I've been very happy with that combination.
Oh yeah and if you will be installing the motor mounts yourself start mentally preparing yourself for it to be a royal pain in the ***.
...much more dificult than trans mount.
Oh yeah and if you will be installing the motor mounts yourself start mentally preparing yourself for it to be a royal pain in the ***.
...much more dificult than trans mount. 
TECH Fanatic
Joined: Jul 2011
Posts: 1,074
Likes: 2
I have had the poly motor mounts for a year and a half now, I have no complaints with and no vibration problems, I also have a poly trans mount, it does have a little vibration but nothing near what people sometimes say it has.
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I've never heard of a complaint with the poly engine mounts, only praises. Poly trans mounts are a different story. Some have good luck, some don't. I put a poly trans mount in my M6 and it was terrible! It vibrated so bad that I couldn't stand to get the car over 55mph. You could watch pieces of paper walk across the floor mat! When I heard that 9 second cars are running with the stock trans mount I thought that there's no reason I need one of these things, so off it came and the stocker went right back on. Problem solved. BTW, I've got poly engine mounts too. If you plan on doing them then go ahead and do LT headers while you're at it. Neither will be in the way of each other for the install.
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I have poly motor mounts I would def say go for it feels alot tighter , I can comment on the trans mount right now though since mine is ripped in half ...>.< I think I'm just gonna shell out the 70 for the new rubber stock one
I just put poly motor mounts in mine and it vibrates the car in drive or reverse if you're at a stand still, but nothing that's bad. I actually thought replacing the motor mounts were fairly easy, just very time consuming. I even got both the bolts lined up the first or second try, no using the scissor jack
AmarilloWS6
How long did it take you to put the new mounts in? Im thinking about doing the swap this weekend, any suggestions? I also put the poly TM in already and haven't noticed any annoying vibrations or anything.
How long did it take you to put the new mounts in? Im thinking about doing the swap this weekend, any suggestions? I also put the poly TM in already and haven't noticed any annoying vibrations or anything.
I read on here and decided to rubber trans mount with poly motor mounts. It vibrated for about a week and theyve softened up quite a bit. As far as the install, I paid someone and he had one hell of a time haha. Either way good luck.
I'd put my money on the driveshaft doing the vibrating more than the engine. It's a speed sensitive vibration when you've got all three mounts, and if you think about it the trans mount is able to absorb a lot of the hinging vibrations between the rearend and the engine. If you've got a poly trans mount and rubber engine mounts then I'd bet that the engine is doing a lot more vibrating than it should, and it might not be as uncomfortable as having ALL poly mounts.
In any case I don't think anyone here needs a poly trans mount. MidWest Chassis has told me about customers who's cars run 9's in the 1/4 who have stock trans mounts. Poly engine mounts... or solid engine mounts are really only needed for average cars because their exhaust is banging the floor. The trans mount is usually added out of curiosity, or because their stocker is rotten. My car did feel more firm when I had a trans mount, but it was so firm that it was underivable above 65 mph.
In any case I don't think anyone here needs a poly trans mount. MidWest Chassis has told me about customers who's cars run 9's in the 1/4 who have stock trans mounts. Poly engine mounts... or solid engine mounts are really only needed for average cars because their exhaust is banging the floor. The trans mount is usually added out of curiosity, or because their stocker is rotten. My car did feel more firm when I had a trans mount, but it was so firm that it was underivable above 65 mph.
