Poly Motor mounts and BMR LS1 K-Member Issues
#1
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Car: 1990 RS
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Axle/Gears: 3.73 9 bolt
Poly Motor mounts and BMR LS1 K-Member Issues
Well I went to put my motor in yesterday and I had purchased a BMR k-member and a set of Prothane poly engine mounts for the LS1. When I went to install the 2 together there was no way to get the motor to fit in the k-member. The poly mounts made it so the mount itself was a good half of an inch from dropping in. I tried to pry it back and for it in and I could never even get it close. I could get one side in but there was no way to get the other one in. I even bent the tabs on the side i could get in and still nothing. I put the stock rubber mounts back in and it went right in. Anyone else have this problem? Should I try a different brand of poly mount? I really do not want to shave down the poly mounts if that is a solution.
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Car: 1990 RS
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Re: Poly Motor mounts and BMR LS1 K-Member Issues
I did not snap any pics of it and I just put the stock mounts back in and put the motor in. The tabs actually bent when I was prying it trying to get the one side to drop in. I tried to drop them both in at the same time, one at a time, even unbolted the mount from the block and into the k-member and it still would not line up. The mounts are both the same so the orientation can only go one way. To me it almost looked like the mount itself was made wrong so the steel part where the bolt goes through did not sit in the middle. Maybe they are supposed to be like that, but who knows. Thanks for your help.
#4
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Re: Poly Motor mounts and BMR LS1 K-Member Issues
Sounds similar to the question I have. Looking at these mounts in their clamshells, How do you know which one will go on the drivers side vs the passenger? The offset of the insert realy is confusing? I am still looking for the answer. Prothane could not help.
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Car: 1997 K1500 SS/SB
Engine: LT1 with TPI on top
Transmission: 4L60E/np241,
Axle/Gears: 3.73
Re: Poly Motor mounts and BMR LS1 K-Member Issues
I will have to look but I believe that the bushings are in backwards. As I recall when using the "3" hole mounting, the "2" adjacent holes are on the top, or outside. Which according to your pictures has the "bars" setting High when they should be setting low, the whole geometry is off. I'll get pictures later today.
#6
Senior Member
Re: Poly Motor mounts and BMR LS1 K-Member Issues
Thanks Tinbender, And not to hijack your thread RickyzZ28. As per the instructions they should be in the clamshells correctly. The question is what side does the insert stick out to the front, Driver or passenger?
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#8
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Car: 1990 RS
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Re: Poly Motor mounts and BMR LS1 K-Member Issues
No problem and its not a hijack. I never could get my poly mounts to fit in the K-member. I just put the stock mounts back in. I am going to order a different brand this winter and see if they fit any better. As for the orientation if I remember correctly once you install them on the motor they will only bolt on one way. Yours look correct in the picture jazzdadss. There is no way to flip them as they really only fit in the mount one way.
#9
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Re: Poly Motor mounts and BMR LS1 K-Member Issues
Just a couple more pics to show the delema which is illogical and cant physicaly be correct. With the drivers side the insert is to the rear, with the passenger side the insert is to the front.
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Car: 1997 K1500 SS/SB
Engine: LT1 with TPI on top
Transmission: 4L60E/np241,
Axle/Gears: 3.73
Re: Poly Motor mounts and BMR LS1 K-Member Issues
oh man, you got it all wrong those pieces go on the frame, they are called the saddles, I will get the pictures of both halves in the morning (if I have time) Cataract surgery at 12 noon, ye Haw!!!
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Car: 1997 K1500 SS/SB
Engine: LT1 with TPI on top
Transmission: 4L60E/np241,
Axle/Gears: 3.73
Re: Poly Motor mounts and BMR LS1 K-Member Issues
ok here is the motor mount uppers, "clam shells" "rider 1 & Rider2 and the lower Or saddle is here as well. you need 3 holes 2 high and 1 low to bolt the Saddles to the frame, further you will notice that the Clam shells have 3 holes that match perfectly to the motor mount bosses on the motor. I will see if I can get better pictures if needed. I have a couple of motors out that I can use. the saddle is actually a V6 unit but the V8 sets the same way 2 bolts high single low, and if you have only 1 bar on the rubber I goes low, so as not to be in the way when the clam shells on the motor are lowered into place.
Last edited by Tinbender59; 08-29-2012 at 01:34 AM.
#12
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Re: Poly Motor mounts and BMR LS1 K-Member Issues
Thats the old style, for my LS swap I am using the new style. This is a borrowed pic from dpresd68. I.m hoping he can chime in.
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Car: 1990 RS
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Re: Poly Motor mounts and BMR LS1 K-Member Issues
jazzdadss I think that the pictures you posted are the only way the mounts will fit. Mine are exactly like that and even the stock one looks like 1 side sticks out further than the other. On the part of the mount that bolts to the engine block there was a tab so you could only install them on the motor one way and the poly mounts only fit in it one way as well. I think you have them right.
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Car: 1983 Firebird SE
Engine: C5 LS1
Transmission: 6 speed
Axle/Gears: 3.42
Re: Poly Motor mounts and BMR LS1 K-Member Issues
I have the BMR K. Trying to remember, think I used stock mounts because the polys would not fit. Can not check, for sure, as I am away from the car right now, but I am pretty sure that is the case. Here's the thread, but it's window dressing. No pics of the motor mounts.
https://www.thirdgen.org/forums/ltx-...u-gets-c5.html
The K should add a bunch of stiffness. Not having poly motor mounts should not be a big deal. Good luck.
https://www.thirdgen.org/forums/ltx-...u-gets-c5.html
The K should add a bunch of stiffness. Not having poly motor mounts should not be a big deal. Good luck.
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