** The best poly motor mount write up ever written **
...if I were in Hell.
I am about 90% completed with this poly motor mount swap. We got all the way through it...driver's side is all bolted up and got the pass side bolted to the block. Now trying to get the 18mm bolt lined up...the hole is 3/8" off.
I read through this writeup and will now be loosening the drivers side 18mm bolt and backing it out half-way...maybe that will belp us get the other bolt started.
I worry about hammering on the bolt...won't that damage the threads? I'd be so f-ing pissed if it did and I had to go get another bolt and start over.
Some of my woes/thoughts:
I also had issues with the two halves of the clamshell not lining up perfectly...had to remove the passenger side mount again and line things up in order to get the bolts in the block.
The passenger side is 11ty billion times harder than the drivers sides....zero room even with the AC and starter out of the way. The drivers side took about 3 hours....spent another 5 on the passenger side and still haven't finished.
Taking the tranny mount loose does not help get things aligned AT ALL!
You will need a huge prybar...get one at least 18 feet long and find an 800-lb gorilla to operate it.
On a 99 Z-28, there are 4 bolts on the AC compressor...I also removed the compressor bracket, which is another 4 bolts.
On a 99 Z-28, there are 4 bolts on the alternator...not 3.
Be sure to take the electrical connections loose on the alternator and the AC compressor....the wires are tiny and they will snap.
Working on your back with the car on jackstands for 8 hours blows...Get someone to help...I had a friend helping me out (thanks Robert P.) and I can't imagine doing this job by yourself.
Good Luck!
Update: I finally finished...we loosened the drivers side and backed the thru bolt out halfway, then used two prybars to get the passenger side bolt through. Then we used a large prybar to get the drivers side the rest of way through. Took 15 minutes with the right parts!
I'm so glad this is over with.
JC
I am about 90% completed with this poly motor mount swap. We got all the way through it...driver's side is all bolted up and got the pass side bolted to the block. Now trying to get the 18mm bolt lined up...the hole is 3/8" off.
I read through this writeup and will now be loosening the drivers side 18mm bolt and backing it out half-way...maybe that will belp us get the other bolt started.
I worry about hammering on the bolt...won't that damage the threads? I'd be so f-ing pissed if it did and I had to go get another bolt and start over.
Some of my woes/thoughts:
I also had issues with the two halves of the clamshell not lining up perfectly...had to remove the passenger side mount again and line things up in order to get the bolts in the block.
The passenger side is 11ty billion times harder than the drivers sides....zero room even with the AC and starter out of the way. The drivers side took about 3 hours....spent another 5 on the passenger side and still haven't finished.
Taking the tranny mount loose does not help get things aligned AT ALL!
You will need a huge prybar...get one at least 18 feet long and find an 800-lb gorilla to operate it.
On a 99 Z-28, there are 4 bolts on the AC compressor...I also removed the compressor bracket, which is another 4 bolts.
On a 99 Z-28, there are 4 bolts on the alternator...not 3.
Be sure to take the electrical connections loose on the alternator and the AC compressor....the wires are tiny and they will snap.
Working on your back with the car on jackstands for 8 hours blows...Get someone to help...I had a friend helping me out (thanks Robert P.) and I can't imagine doing this job by yourself.
Good Luck!
Update: I finally finished...we loosened the drivers side and backed the thru bolt out halfway, then used two prybars to get the passenger side bolt through. Then we used a large prybar to get the drivers side the rest of way through. Took 15 minutes with the right parts!
I'm so glad this is over with.
JC
Baahahahaha!!!.........Aint that the truth. I getting me some help tommorrow, this damn bolt is kicking my ***. I used this as a guide when doing my motor mounts on the slow SS this weekend. I was doing headers and thought might as well also do the mounts. all I have to say is man what a bitch that job was. I've done heads, cams, converters etc... and nothing has gotten me worked up & frustrated like the motor mounts did. LOL 
yeah its pretty much a rite of passage though. Sort of like boot camp for LS1 people. If you do this, with the headers and starter on the car then you're ready for about what ever you want to do with it. The cam was eleventeen times easier. Lots of 
involved with motormounts. I think it took me 3 days... but I was taking long breaks ( ) and having to fix reamed out bolt holes in the block 
And that laddies and gentlemen is why I put my faith in a tap and die set 
involved with motormounts. I think it took me 3 days... but I was taking long breaks ( ) and having to fix reamed out bolt holes in the block And that laddies and gentlemen is why I put my faith in a tap and die set good mounts are a must for a tight fitting exhaust. not to mention the fact that the motor winding up is not putting power to the ground.
pipes banging the bottom of the car can cause the pcm to pull timing. (Knock retard) a stock KR routine can pull 15*
they are not fun but the pain is worth the gain
solids just suck if you do them buy 2 sets so you can change the left one over and over.
pipes banging the bottom of the car can cause the pcm to pull timing. (Knock retard) a stock KR routine can pull 15*
they are not fun but the pain is worth the gain
solids just suck if you do them buy 2 sets so you can change the left one over and over.
Finally finished mounts! My cliff notes:
-Writeup is great!
-I completely removed the alternator, alternator bracket, A/C compressor (set aside on the swaybar), both idlers and brackets by the A/C compressor, and all of the exhaust (doing headers at the same time).
-The bolts were torqued to hell from the clamshell to the block. It was a royal bitch breaking those loose because we couldnt really fit our air tools back there
-Clamshell rivets were pretty stout. We had to sharpen the drillbit a couple of times to get through.
-The poly mounts actually fill the whole clamshell unlike my old rubber ones that looked like hell
-Getting the clamshells bolted back to the block was pretty easy, we just jacked the motor pretty high.
-The biggest pain in the *** was realigning the motor to get the long 18mm bolts through each mount. Me and some buddys pryed with all our might, jockeying the jack up and down and trying to hammer the bolts in but nothing seemed to be working. We could get one but then the other was off by about 1/4 to 1/2 an inch. I finally decided to grind the driver side bolt to a point and with a little prying and hammering she finally went in nicely.
I'd have to say the biggest lifesaver in this install was 13mm ratcheting wrenches and socket U-Joints and extensions. Also grinding that bolt is a MUST!
Overall, it was a big pain but we'll see how she feels when I finally fire it up. I still have to install the headers but that seems like a breeze compared to the mounts. Hope this helps anyone about to take on this bear of a task!
-Writeup is great!
-I completely removed the alternator, alternator bracket, A/C compressor (set aside on the swaybar), both idlers and brackets by the A/C compressor, and all of the exhaust (doing headers at the same time).
-The bolts were torqued to hell from the clamshell to the block. It was a royal bitch breaking those loose because we couldnt really fit our air tools back there
-Clamshell rivets were pretty stout. We had to sharpen the drillbit a couple of times to get through.
-The poly mounts actually fill the whole clamshell unlike my old rubber ones that looked like hell
-Getting the clamshells bolted back to the block was pretty easy, we just jacked the motor pretty high.
-The biggest pain in the *** was realigning the motor to get the long 18mm bolts through each mount. Me and some buddys pryed with all our might, jockeying the jack up and down and trying to hammer the bolts in but nothing seemed to be working. We could get one but then the other was off by about 1/4 to 1/2 an inch. I finally decided to grind the driver side bolt to a point and with a little prying and hammering she finally went in nicely.
I'd have to say the biggest lifesaver in this install was 13mm ratcheting wrenches and socket U-Joints and extensions. Also grinding that bolt is a MUST!
Overall, it was a big pain but we'll see how she feels when I finally fire it up. I still have to install the headers but that seems like a breeze compared to the mounts. Hope this helps anyone about to take on this bear of a task!
TECH Addict
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Joined: Jan 2004
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From: Miami, Fl. - Hurricane Highway
^ Considering the mission you just went through you might as well go install a cam. I have yet to do motor mounts, and these instructions sound like a headache compared to a cam swap.
-Joel
-Joel
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I got my drivers side done the other day by myself i was very frustrated and had to just walk away for a while but when i got back it just slid right in. Now i have to do the passenger side and im not looking forward to it at all! Im also installing pacesetter LT and they fit very very nice im just happy with them!
I did the poly's when I installed my headers. If I had to guess, the single best move I made was doing it one side at a time. It took a little jack-work to get the driver side to line up. The passenger side bolt slid right in, first try. No pry bar required.
Im planning on doing this this weekend. i work at a dealership so i have access to lifts, air tools, specials tool, and most of all my roomate is a tech. makes it cheap and easier for me. we are going to take off the starter etc and see if we can get to it. i might just loosen up the headers and change out the plugs while im there. i will let you guys know.
after wrestling with it for a while I found it to be easier to put in the passenger side one first since it provided less room to work with, then move to the driver side where there was a lot more space. had i done it this was way to begin with instead of doing the driver one and fighting myself forever on the pass side im sure i could have saved myself at least an hour of frustration.
****...
I'm at a crossroads. I'm helping a friend put full exhaust under his 98 Z28 and we have the JET HOT LT's in and have reassembled the engine bay, including new plugs and wires. My problem is do we undo what we have completed to install poly motor mounts? Or do we take our chances and try to install them with the headers still on? We are waiting for his ORY to show up from FEDEX, so the car is open headers for the moment. (Which BTW sounds ******' AWESOME!) I thought I had done some pretty indepth research before beginning this project, I don't know how I missed needing to do this at the same time. Anyways, I've read through this entire thread and have seen that it can be done with the headers on the car, but this would be the easiest time to take it apart. So...here I am...****!? Thoughts? Advice? Opinions? Anybody just wanna laugh at me? Nows the time. LOL
Thanks guys...
I'm at a crossroads. I'm helping a friend put full exhaust under his 98 Z28 and we have the JET HOT LT's in and have reassembled the engine bay, including new plugs and wires. My problem is do we undo what we have completed to install poly motor mounts? Or do we take our chances and try to install them with the headers still on? We are waiting for his ORY to show up from FEDEX, so the car is open headers for the moment. (Which BTW sounds ******' AWESOME!) I thought I had done some pretty indepth research before beginning this project, I don't know how I missed needing to do this at the same time. Anyways, I've read through this entire thread and have seen that it can be done with the headers on the car, but this would be the easiest time to take it apart. So...here I am...****!? Thoughts? Advice? Opinions? Anybody just wanna laugh at me? Nows the time. LOL
Thanks guys...
Put the mounts on. Be prepared to struggle with the passenger side. Fought it for 4 hours and finally sharpened the tip of the bolt and drove it home with a hammer. You will need to use a good pry bar and have someone lift up on the mount from the top why you drive the bolt home. You will need to slide the compressor way over the anti-roll bar...it will go just take your time.
I have a theory that the torque arm causes the motor to yaw to the right making it damn tough to line up the bolt.
I have a theory that the torque arm causes the motor to yaw to the right making it damn tough to line up the bolt.
I spoke with my buddy and briefed him on the situation. He wants to give it a shot. I'm not sure of our plan of attack yet, but we'll try our best. I ordered 2 Prothane Poly Motor Mount Kits from SpeedInc.com for $59.99 ea. A set for Dave's car and one for mine for when we do my header install. Is it worth changing the Tranny Mount as well or should we save our money? I didn't order it yet. I figure its not a pressing issue, so I can wait to find a good deal if we do decide to tear into that as well. Wish us luck...
When I did mine, the passenger side was a bitch, I fought with it for probably 2-3 hours, still couldn't get it so I left the car overnight. Then when I went at it again the next day it took probably 10 minutes to get it lined up. Weird...
