Fierce-LS1

iTrader: (3)

Those of you with the poly motor mounts ... was it direct fit or did you have to modify your original ones to work with the kit ? I ordered one from Thunder Racing and I guess I have to modify my stock ones to work with the kit.

I thought a mount was a mount

Fulton 1

iTrader: (9)

If you got the Prothane mounts, they are a direct fit per se. The motor mount setup consists of a metal "clamshell" that's riveted together with a rubber bushing captured inside. The clamshell bolts to the engine block while the motor mount bolt goes through the rubber bushing. The poly mounts do not include the clamshell, so you have to drill out the rivets in the factory setup and remove the rubber bushing. Then the poly bushing replaces the rubber one you removed and the clamshell goes back together with bolts/nuts you get in the kit.

Pulling the clamshell apart might be a bit of a PITA since the rubber bushing is bonded in there. One of mine was a bitch and the other one pretty much fell apart, so maybe you'll get lucky. Its pretty self explanatory once you get the stock mount off - just be patient. A torch of some kind might help to loosen the rubber bushing if you have trouble.

Fierce-LS1

iTrader: (3)

Thanks for the response ... that is what I was afraid of

99ssleeper

iTrader: (98)

Mine Prothanes were a direct replacement...albeit a bitch to put in .

Fierce-LS1

iTrader: (3)

Where did you get them from ?

Fulton 1

iTrader: (9)

Don't be confused by the term "direct replacement" here. As I noted above, they are (in theory) a "direct replacement", but the bushing that they "directly replace" is in that clamshell I mentioned. The Energy Suspension mounts used to be for an LT1 and required some shimming - not so with the Prothanes. That's why people like to call them a "direct replacement".

If you want a complete motor mount to bolt in (by that I mean clamshell and all), then I would suggest picking one up from a junk yard or buying a new stock unit. Then modify that one instead of yours.

FEAR THE LS1

iTrader: (1)

One thing I encountered after I installed new poly motor mounts was the motor didn't sag in the back with the transmission off. What I mean is if you un bolt your transmission and the motor is only sitting on the motor mounts it will lean towards the back of the car or the firewall with the stock mounts. After I installed the new poly mounts and bolted the motor onto the K-member it sat perfectly level. This is great and all until you goto bolt your transmission back on. It was more difficult to reach the top bellhousing bolts with the motor sitting level and not leaning back like with stock mounts. I actually has to jack up the front of the oil pan under the crank pulley a little to tilt the motor some to reach the bolts.

I do have a Th400 transmission with an ultra bellhousing, but even with a stock tranny the bellhousing bolts would be difficult to reach. Just a heads up for you all.

The poly mounts are the way to go. I installed my mine when the motor was out of the car

Lee

demonspeed

iTrader: (7)

I've heard the extra vibration can cause false knock. Any truth to that?

2MCHPWR

iTrader: (10)

got any pics of this? can you tell me how you shimmed it?
thanx!!

Fierce-LS1

iTrader: (3)

I had it all taken care of yesterday. The car feels GREAT
No more exhaust banging and the car feels more solid

No extra vibration whatsoever. You will only get vibration with solid mounts not the poly mounts (or if you do ... it is so minimal that you don't notice). I installed the mount on both sides

Fulton 1

iTrader: (9)

Nope, no pics. I recall there were some pics floating around here at some point, but I used the Prothanes instead. Never had a problem with them. One of the better little mods I've done over the years.

jfm

iTrader: (4)

Great info Fear The LS1.I got rid of my Solid mounts because you had to pull the intake to remove the transmission[A4].It would not tilt at all,made it a PITA.I will go with a ProThane on the drivers side soon.

demonspeed

iTrader: (7)

Vibration isn't a bad thing... I figure you need to take the bad with the good. The only thing i'm worried about with going to a poly tranny mount is this whole false knock issue.

Fierce-LS1

iTrader: (3)

yup, the tranny mount will be a vibration in the ***

mitchntx

iTrader: (14)

I've had my ES poly trans mount in the car for 4 years ... no vibration

Fulton 1

iTrader: (9)

FWIW, I could feel no increase in vibration due to poly motor mounts. I also felt no difference between one poly mount (driver side) and both poly mounts.