** The best poly motor mount write up ever written **
Question for the others:
the long 6” bolt that goes thru a LS engine motor mount, in my manual it says to tighten the head of the bolt to 70ft lbs, it also says tighten the nut of the same bolt to 56ft lbs. Problem is, do to the poor design by gm, there is no way to get a torque wrench on the nut end so if I torque the head end down to 70ft lbs, will I be ok? In essence would the nut then be torqued down correctly if I only torque the head?
YES, on my back, tip: lay down plenty of cardboard, it makes it easier to slide around while on your back under the car and saves your knees too when kneeling down. BTW-in hindsight you could NOT give me $450 to do it, but in the end knowing YOU did it is some reward. By far, with out a doubt the most aggravting miserable job of all time on f-bodys is doing motor mounts with out a lift, IMHO.
Question for the others:
the long 6” bolt that goes thru a LS engine motor mount, in my manual it says to tighten the head of the bolt to 70ft lbs, it also says tighten the nut of the same bolt to 56ft lbs. Problem is, do to the poor design by gm, there is no way to get a torque wrench on the nut end so if I torque the head end down to 70ft lbs, will I be ok? In essence would the nut then be torqued down correctly if I only torque the head?
Question for the others:
the long 6” bolt that goes thru a LS engine motor mount, in my manual it says to tighten the head of the bolt to 70ft lbs, it also says tighten the nut of the same bolt to 56ft lbs. Problem is, do to the poor design by gm, there is no way to get a torque wrench on the nut end so if I torque the head end down to 70ft lbs, will I be ok? In essence would the nut then be torqued down correctly if I only torque the head?
Regarding the bolt torquing, you're fine as long as the bolt was not binding in the mount when you torqued to 70ft-lbs. If the bolt was binding, then your nut saw less than 70ft-lbs of torque. How much? Depends, but it was less.
Just did it on my back with tons of old shirts and bubble wrap under the car... made for great makeshift pillows and prevented scratching parts. I did it all on jackstands, the little ones. More room would have been nice, but it wasn't necessary.
Regarding the bolt torquing, you're fine as long as the bolt was not binding in the mount when you torqued to 70ft-lbs. If the bolt was binding, then your nut saw less than 70ft-lbs of torque. How much? Depends, but it was less.
Regarding the bolt torquing, you're fine as long as the bolt was not binding in the mount when you torqued to 70ft-lbs. If the bolt was binding, then your nut saw less than 70ft-lbs of torque. How much? Depends, but it was less.
So after years of owning my car, I decided to bite the bullet and buy some poly motor mounts. I read this thread and plan to use it, and another one I found with pics. I don't think I'll make any hurry to get them installed, only when I know I got plenty of time to spare and money to borrow a lift. Unfortunately, I'll be doing it with longtube headers already in the car.
Just to bump this beauty. I'm going to be doing this with my longtubes in. I installed a new rubber driver's side mount when I put the headers on...... for everyone wondering.... Don't just do that side. Still flexes like **** literally a couple inches probably.
Also, taking the bolts off the motor and taking the pedestal out is the way to go hands down. Driver's side is tricky bc of the heat shield, but when I put mine back on it had to go in after the long tubes and that's how I did it.
Also, taking the bolts off the motor and taking the pedestal out is the way to go hands down. Driver's side is tricky bc of the heat shield, but when I put mine back on it had to go in after the long tubes and that's how I did it.
Just finished this up tonight... Ive done just about everything you can do to an fbody, and this by far was the biggest pain in the ***, especially without a lift. In hindsight, I should have done it when the LQ4 went in, but I didnt feel like waiting for mounts.
I did it with BBK longtubes already installed, they really didnt get in the way at all. I loosened and moved the alternator and AC compressor, which gave enough room to work. 13mm universal sockets on a 3/8" impact got all of the 8 clamshell to block bolts out, and gear wrench got all of the pedestal bolts out. The pedestals MUST be unbolted, though you dont need to remove them from the car. Drilling out the old clamshells was cake, didnt even bother using the drill press. Reinstalling the clamshells, I opted to not reinstall the heat shield as with long tubes, it really serves no purpose. Doing this allowed me to grind off the threaded standoffs on the top of those bolts for the heat shield, so I could use the shallow 13mm swivel socket for reinstallation. Doing this saved a good amount of time as well.
Realigning the 18mm bolt was a BITCH, its best to leave both side pedestals a bit loose and to put the pass side bolt in first... as others have said, make sure you have a big pry bar and a buddy with a mallet to get that drivers side bolt in from the back.
But in the end, it was all worth it. The banging that was plaguing my car is gone, feels much more solid, and the horrible vibrations above 55mph are gone as well. It was, by far, the biggest pain in the *** job aside from removing the entire drivetrain, but it was well worth it.
I did it with BBK longtubes already installed, they really didnt get in the way at all. I loosened and moved the alternator and AC compressor, which gave enough room to work. 13mm universal sockets on a 3/8" impact got all of the 8 clamshell to block bolts out, and gear wrench got all of the pedestal bolts out. The pedestals MUST be unbolted, though you dont need to remove them from the car. Drilling out the old clamshells was cake, didnt even bother using the drill press. Reinstalling the clamshells, I opted to not reinstall the heat shield as with long tubes, it really serves no purpose. Doing this allowed me to grind off the threaded standoffs on the top of those bolts for the heat shield, so I could use the shallow 13mm swivel socket for reinstallation. Doing this saved a good amount of time as well.
Realigning the 18mm bolt was a BITCH, its best to leave both side pedestals a bit loose and to put the pass side bolt in first... as others have said, make sure you have a big pry bar and a buddy with a mallet to get that drivers side bolt in from the back.
But in the end, it was all worth it. The banging that was plaguing my car is gone, feels much more solid, and the horrible vibrations above 55mph are gone as well. It was, by far, the biggest pain in the *** job aside from removing the entire drivetrain, but it was well worth it.
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On The Tree
Joined: Jul 2010
Posts: 158
Likes: 1
I just put in ebay long tubes to replace my crushed and flattened SLP headers, and installed poly mounts at the same time. Also did an impromptu a/c delete, until I can get enough parts to make the a/c work again. I like the ebay headers. Tons of ground clearance. A little light (thin metal) but for a replacement set a good bottoming or a manhole cover might trash again, I'll take it.
Oh, btw, I have a lift, air tools, pole jack, the works and it still sucks major *** to put in. I could have had the engine out and back in with less time. Gah.
I'll have it finished up sometime tomorrow and give it a good romp and report back.
Oh, btw, I have a lift, air tools, pole jack, the works and it still sucks major *** to put in. I could have had the engine out and back in with less time. Gah.
I'll have it finished up sometime tomorrow and give it a good romp and report back.
A word of advise that could help line up the passenger side MM bolt it was being a real bitch to get it so I used my scissor jack from my car and placed it in between the mount and fender well or what ever you want to call it played with that jack and the one under the motor and I was able to push the bolt in with one finger.
I've taken motor mounts out and put em in a few times. Definitely sucks the first time. With an impact wrench, air ratchet, the right extensions, universals and ratcheting wrenches you can do this in about 4-5 hours with the headers in the car. It's not that bad. Oil pan is WAY worse. Another tip... Do one side at a time so everything lines up easier. Yes the access is worse but you will thank yourself later...
On The Tree
Joined: Jul 2010
Posts: 158
Likes: 1
In the middle of the swap I would have rather raped myself with a hot fireplace poker than do another one. However after putting some miles on the car and seeing /feeling the difference I'd do it again in a minute. It's that good.
On The Tree
Joined: Jan 2012
Posts: 182
Likes: 0
From: Boston
Finished this swap the other day. Got the Energy suspension poly mounts. Install went great, used the method laid out here on the first page. THANKS!
The best part was putting the inserts in the clam shells backwards / having the insert flipped 180....and having the PS reserviour empty on my head (because I forgot about that hose)
PS: I left the headers in the car and there was plenty of room.
The best part was putting the inserts in the clam shells backwards / having the insert flipped 180....and having the PS reserviour empty on my head (because I forgot about that hose)
PS: I left the headers in the car and there was plenty of room.
I am a stationary engineer by trade. A hands on mechanic at a power plant. So, yes, I spin wrenches for a living. I have also built a few big block chevys for a few badass Chevelles I have owned. But I do not know how much room I have between my wrapped headers and motor mounts on an LS motor. Cause I haven't done one yet. So I guess I assumed correctly while you did not. 
Finished this swap the other day. Got the Energy suspension poly mounts. Install went great, used the method laid out here on the first page. THANKS!
The best part was putting the inserts in the clam shells backwards / having the insert flipped 180....and having the PS reserviour empty on my head (because I forgot about that hose)
PS: I left the headers in the car and there was plenty of room.
The best part was putting the inserts in the clam shells backwards / having the insert flipped 180....and having the PS reserviour empty on my head (because I forgot about that hose)
PS: I left the headers in the car and there was plenty of room.
Going to be doing the prothane poly mounts with my TSP 1 7/8 headers this weekend. Have the ratcheting wrenches, air ratchet, extensions, u joints, etc. but no lift. Will be on my back with jack and stands. After reading this I will be trying to borrow an impact wrench too. Besides this write up any have any other guides to recommend?
TECH Apprentice
Joined: May 2004
Posts: 318
Likes: 14
From: Chicago, IL
Going to be doing the prothane poly mounts with my TSP 1 7/8 headers this weekend. Have the ratcheting wrenches, air ratchet, extensions, u joints, etc. but no lift. Will be on my back with jack and stands. After reading this I will be trying to borrow an impact wrench too. Besides this write up any have any other guides to recommend?
https://ls1tech.com/forums/generatio...otsa-pics.html