Couldn't really find out what i wanted in the search, but here goes:

I think my motor mounts might be on their way out (also my fuel pump). My question is, what exactly do Poly motor mounts do for you? I thought poly deformed over time as its compressed... do these last longer than regular rubber motor mounts?

Also, if i take out the headers (SLP 1.3/4" 94/95 style midlengths) ... how much of a pain in the *** is swapping out motor mounts? I have to yank the headers anyway (going to get them coated and reinstall some new copper header gaskets) I heard that there are rivets that you need to take out .... is this true?

any input would be cool, you guys (as always) rock!

 

Poly mounts are more solid than factory.
Don't use a poly tranny mount,the car will viberate your teeth out.
Not a bad job to change.
No rivet's.

 

Where would one find these poly motor mounts??

 

Polyurethane *should* last you as long as you own your car. Yes, motor mounts have rivets but they are only used to hold the rubber bushing inside. The mount itself is attached to the k-member and your engine using normal bolts. Once you have the mounts off, then you can use a Dremel bit to grind away the rivet heads to open up the mount, toss away the rubber bushing, and replace with a nice poly one. The poly engine mount kit should come with new bolts to put instead of the old rivets. BTW this will be a PITA just be careful and have patience.

 

Jegs or Summit should carry them in stock.

 

Poly mounts are more rigid and thus do not break down as often as the production rubber mounts.

We have the mounts if you are in need give us a call.

 

Poly Trans mount doesnt vibrate any on my car. As long as the motor mounts are changed at the same time, you shouldnt experience any excessive vibration. I speak only for m6 trannies... dunno about the autos.

 

With the headers out of the way it should be easier. I changed mine out with LTs and the headers really didnt hurt the process any.. it was still a PITA.

Getting the mounts out isnt too bad if you have an eye for these things meaning you dont give up 5 seconds after the struggle. Like for instance.. take the mounts completely loose from the motor and the kmember so allow yourself extra mobility to get the camshell out. The mounts you buy are only the inside portion too. You must take the camshell as they call it appart and then just replace the guts of the mount. On the pass side be prepared to trim the mount on the corners with a good sharp blade b/c it will get in the way of 1 or 2 bolts and you cant bolt the mount bak down to teh kmember.

Drilling out the rivots isnt to hard.. just keep drilling till the rivot falls to peices basically. Youll need a large bit though!

The drivers side mount has some different rivots in place and the only way i got it appart was with 20 minutes on a grind wheel... its just a PITA so be prepared. But once everything is appart the assembly goes pretty fast.

The only bit of advice on the install I have is to not tighten up any of the bolts before you get that large bolt back thru the mount or youll have a hell of a time lining it all up. What really helps is having a nice small 2ton pneumatic(sp) jack that you can easily change the lift on the motor with! That tool was invaluable to me compared to a floor jack.

Hope that helps you out a little.

 

Mine shook like a dog s****** peach seed's. Changed back to stock and the vibe's went away.

 

Did you change your motor mounts to poly at the same time?

I changed my motor mounts at the same time, as did turbo_Z, and have no vibration what so ever.

 

I changed my trans mount only, and went with a poly one and it vibrated more than with the stock on. Still not too bad though. The trans mount got replaced because the stock one broke (as usual). There is no way in hell I'd change all the mounts at the same time just because the trans mount broke. That's about 10 times more work than is required. I've really never heard of anyone breaking a motor mount, so I'd just go with the stock ones if yours are getting a little soft.

 

If you are producing more hp than stock, poly is the only way to go. Once you start producing alot more hp, the stock ones are so soft it will allow the motor to pull alot to one side, causing things such as headers and exhaust piping to make contact with things it shouldn't be hitting.
The poly mounts will make it rock solid, yes there will be more vibration...thats why the stockers are so soft, but if you are making the power, you shouldn't care about the vibration, otherwise get a Cadillac.
Once I put polys on my GN, an engine torque strap was no longer needed, if the engine moves, the entire front of the car moves now!

 

Well now you've heard of someone who has broke a motor mount: me. I actually broke both, the rubber cracked and split causing my engine to go sideways a bit.

 

Congrats, you're number 1