Prothane motor mounts

[HoLLo]

Who uses Prothane motor mounts and how do you like them?

[$hawn]

I got them, I had to trim one of the corners a little bit on the passenger mount so the bolt would go in straight, other than that no problems.

[96LT1355Z28]

I've got them. They went in with no problems. I somewhat wish I'd gone with solid mounts now, but that's my fault no the mounts. I have no complaints.

[Adam]

I have them, nice pieces but drilling the stock mounts was a pita.

http://gottaphoto.com/album_mod/upload/691.jpg

http://gottaphoto.com/album_mod/upload/670.jpg

[HoLLo]

A lot of people say it adds a whole lot of shake to the motor/car. Is that true in yalls case? And is there a writeup anywhere to replace the mounts?

[BLK WS6]

I did have a noticeable increase in vibration...but that just comes with the territory. Nothing I couldn't live with.

[Alex94TAGT]

A lot of people say it adds a whole lot of shake to the motor/car. Is that true in yalls case? And is there a writeup anywhere to replace the mounts?

I can't remember if I installed the black ones or the red ones. The black are a little softer, iirc. I have polyurethane everywhere, so the car is a little rough, but we're not exactly working on a Cadillac to begin with. Poly engine mounts and transmission mount will make the car rumble a bit more.

Not much to the replacement. The factory rubber mounts are encased in a metal 'clamshell' -- you must separate the two halves of the clamshell by drilling out 5 rivets or so. Just be sure to get the proper orientation of the new mounts when reinstalling, zip-tie the clamshell together, and bolt everything back up. Unless you're removing the engine, it's obviously best if you do one side at a time -- helps with alignment.

Keep in mind that doing this will likely make your engine sit 1/2"-1" higher in the engine bay. Stock mounts tend to sag after a decade.

[BLK WS6]

I have never heard that one color is softer than another...why would this be?

[KissMyWhtSS]

Stupid question, but I'll ask it anyway. If they cause a noticeable increase in vibration... why do people run them? Are they just suppose to be stronger?

[Alex94TAGT]

I have never heard that one color is softer than another...why would this be?

I didn't notice that the thread title says Prothane. I used Energy Suspension. I was told black was softer, but I really don't know that for certain -- just what I was told at the store. I do know their black bushings are impregnated with graphite, which is used as a lubricant to keep it from squeaking. Perhaps that makes it inherently softer as well.


Stupid question, but I'll ask it anyway. If they cause a noticeable increase in vibration... why do people run them? Are they just suppose to be stronger?

If you're going after comfort, then you probably shouldn't be looking at any polyurethane bushings/mounts, period. I did it for longevity (after looking at the stock mounts you'll see what I mean), plus it keeps the engine from torquing around under the hood. It might look cool to see the engine rock back and forth in the engine bay, but it's definitely not a good thing. (Now when I "rev" the engine, the whole car moves.) Unless you have an adjustable torque arm, this would also affect pinion angle in racing applications.

If you don't care about vibrations, it's more of an issue of "why not?" They're like $16 bucks a pop...

[ClovisAutomotion]

I didn't notice much difference between the stock worn out mounts and the Poly's on my car, I like them. I drove a car that had solid mounts on it the other day and it was WAY noticable. I'll stick with Poly mounts unless I build a racecar that needs solid mounts.

[RumbleZ]

I skipped the poly mounts and went for the moroso solids in a DD Z. A/C, seats, carpet, etc. Not a race car. I think they are fine, the poly's would probably be similar.

The solids made the interior quieter and everything about the car seem smoother.. the stock rubber mounts were shot and the engine moved around a lot though. The interior was terrible about rattling and buzzing and a majority of that went away after the solid mounts. For the first couple weeks or so there was a little bit of interior buzzing at idle and at off-idle take off but it pretty much went away too. The buzzing was an improvement from the rattles it had before though. Really nice improvement in car feel all the way around without the engine's weight shifting around. before the solid mounts you could actually hear the engine clank around loudly over bumps and stuff, inside and outside the car.. I thought it was the stock shocks at the time but that noise was gone too after the solid mounts. This also contributed to a lot less rattle in the car over bumps and on bumpy roads, down to almost nothing actually. Really big difference there for mine.

I run a poly trans mount as well. Kind of the same deal with that, there was more vibration and buzzing the first couple weeks but it pretty much went away. Like the solid engine mounts though they do give you some feedback. I think feedback is a better description than vibration, but technically it is added vibration. most of it is not really audible, more like a low bass kind of vibration, for mine. there hasn't been any negative comments about how the car feels from passengers. If you like to feel the car under you.. in the wheel, pedals, shifter, seat.... then you would probably like them. Otherwise you may be driving the wrong car to begin with :jest: Nah, some people are more tolerant than others and different combinations and etc may give different results. For anyone that does install the engine mounts or trans mount either one, definitely give them a couple weeks driving around if initially you think they are too harsh etc. For me, the solid engine mounts was definitely a good upgrade, along with the poly trans mount.

[HoLLo]

I've got the Prothane transmission mount, but I am dreading installing motor mounts!

Thanks for all the feedback so far!

[NicksTAgt]

I've got the Prothane transmission mount, but I am dreading installing motor mounts!

Thanks for all the feedback so far!

I helped install a set of prothane poly mounts on my friends '01 SS camaro, They were a huge PITA for us. After we took both of the stock mounts out the motor was being supported by a jack with some wood blocks. Once we had the new mounts all assembled we bolted them to the block and tried to drop them back into their home... That thing would not go in straight, but we kept raising the motor and lowering it back down slightly until, 12 hours later, we were able to smack the long bolt through.

Good luck though :jest:

[James Montigny]

Made it a little tougher to line the mounting bolts up when we put the motor in (less flex) but no complaints otherwise.

[BIGT94z]

whats the difference in the poly's and solids? im sure the solids dont go bad like the stockers and like the poly's would eventually.

[KissMyWhtSS]

whats the difference in the poly's and solids? im sure the solids dont go bad like the stockers and like the poly's would eventually.
http://ltxtech.com/forums/showpost.php?p=5060&postcount=10

[BIGT94z]

that doesn't help my question :frustrated:

[Alex94TAGT]

whats the difference in the poly's and solids? im sure the solids dont go bad like the stockers and like the poly's would eventually.

Well, do you want your engine mounted on bushing to absorb some vibration, or do you want the engine bolted directly to the k-member? How opposed are you to having your teeth rattle as you sit at stoplights?

RumbleZ seems to have had really good experiences with solid mounts, so he would be better able to answer any specific questions you have. (Note that his username is RumbleZ though. Probably a reason for that, haha. Kudos to him.)

It seems I remember reading years ago about someone developing hairline cracks in the engine block's mounting holes while using solid mounts. I'll have to verify that though -- hopefully not a common occurrence. I would also be concerned with the knock sensor being subject to outside noise which could be picked up as false knock.

Unless they somehow manage to melt under the heat, I really don't see the car outlasting the polyurethane engine mounts. Polyurethane is essentially a high-quality plastic -- like a weatherproof rubber. The stock rubber mounts generally look terrible after 10 years -- mine did, with only 72000 miles.

Entirely your choice...

[JoeliusZ28]

Question about the poly mounts - would getting a set of additional stock motor mounts help in the sense that I could do the modifying beforehand, and then just direct swap one side and then the other?

I think my motor mounts might be apart of my car "acting its age" lately.

[RumbleZ]

(Note that his username is RumbleZ though. Probably a reason for that, haha. Kudos to him.)


:jest: the rumble refers to the exhaust but is more just a play on the word rumbles since with the Z it could be read as rumbles or Rumble "Zee".

Anyway the solid mounts really aren't bad at all. Seriously... they don't rattle you around at stop lights. It's hard to convey the difference between feedback and a rattle or shake. The car is very tame with them in my opinion, it just feels more solid and you can feel what's going on. The solid mounts were an improvement for me in every way.. but that's just my experience. I have not been in one with the poly engine mounts that I was aware of, but I have had a set in hand and I don't thnk they'd be all that much different in feel. I just didn't want to have any potential issue with the poly's heating up and getting soft ever, so I went with solids. Just one of those things that with the solids there's no question that I shouldn't have to replace them, ever.

I had a friend that was convinced the solid mounts were just a horrible idea and it was going to ruin the car and make it really harsh and racecar-like etc etc. So, I didn't tell him I installed them so I could get a real reaction from him... a few weeks after I put the mounts in we took my car out and without asking or saying anything about the car feeling different, within a few minutes he commented the car felt a lot smoother... more solid... and no more major rattles. He asked if I had swapped shocks or something... :jest: Nope, just put in those "terrible" solid engine mounts. He thought I was BSing him until I popped the hood and showed him the passenger side where you can see the mount in there.

I had concern about knock initially so I did a lot of datalogging after the solid mounts install looking for knock, or false knock, and found nothing out of the ordinary. There is a slight amount of knock count increase at WOT, but not enough to show any significant spark retard, just .1 - .3 for a split second here and there. I dug up older datalogs before the solid mounts, they showed the same slight knock count increases and same .1 - .3 for the spark retard. Over significant bumps before the solid mounts I would see brief small increases in knock count and a bit of spark retard, that also went away now that the engine doesn't clank around. In my comparisons, everything seems to be normal in regards to knock and I have not seen anything that concerns me at this point.

As far as cracking the block, I've never seen any comments on that about it actually happening to LT1's, but I've never searched around about it specifically either. Years and years ago I heard comments about ford 5.0's having that issue, but I don't know if there was any truth to that. LS guys run solid mounts on the aluminum blocks and although I've never went searching for somebody having an issue, I've never seen comment about this happeneing or even any warnings about it when talking about running the solids. That being said I won't be surprised if someone can manage to turn something up with google.... if you're around these cars or any cars long enough you will see some people manage to break some pretty strange things in some pretty strange ways. So I'm not saying it isn't possible, for sure. But it doesn't concern me at all personally.

Here's a shot of the solid moroso mounts. They replace the stock mounts/shells entirely.

http://static.summitracing.com/global/images/prod/large/mor-62635_cp.jpg

here is a shot of the poly's mounted in the factory shells


http://i190.photobucket.com/albums/z280/rumblez28/polymts1.jpg

Again this is just my experience with them so far, I've had the solid mounts in for about a year or so now I think. Your results may vary. Also, I didn't post this stuff up to sway anyone to pick up the solids over the poly, just wanted to share my experience in response to the question about why someone would run a stiffer mount if it added noticeable vibrations. My results have been positive all the way around.

[BIGT94z]

very great post rumblez thats exactly what i needed to know. ill be going with solids over poly's