Here is a nice alternative for the radiator supports, position 1

http://www.montecarloss.com/community/ubbthreads.php?ubb=showflat&Number=751220&#Post751220

Hi Folks,

I thought I'd explain the reason for the cups: they're a geometric device to create non-linear stiffness in the bushing, tending toward the condition of a nearly solid bushing with very high compression, and a soft bushing under tension.

I think the engineers thought this non-linearity was desirable to give good NVH with small road irregularities, but with increasing structural support derived from fender's vertical stiffness when encountering very large bumps.

The relative motion between the frame and the fender is surprisingly large at the #1 location.

Best,
MAP

Mark

Why do you think they went away from the cups in '07 and '08?

Larry

would it be possible to run aluminum bushings on the #1 and # 7 locations? Instead of Delrin?

MAP would be the one to answer this one.

Hey MAP, GuysMonteSS has a good question for you.

There's some great info in this thread & I've been keeping track of it, but I am curious about one aspect of making these delrin bushings. From checking the #1 location on my own car & seeing that they could use replacement, I noticed that the lower bushings is a "stepped" peice. There is a smaller upper half, (all one bushing just changes size if that makes it any clearer) of the lower bushings the fits inside the mounting point on the body of the vehicle.
While reviewing the measurements provided by MAP to make these bushings in the link posted & throughout this thread, I see no mention of this change in size on the lower bushing. Am I now to assume that just due to the weight upon them & the "sandwich" effect, there is no longer any need to step the size down to fit inside the body location? If so, it seems to me like there would be the chance of excess body over bushing movement side to side. Anyone care to comment

Could you clear this up for me ???
Guy

Hi Guy,

It's been so many years since I removed those old OEM bushings that I admit I have no recollection of whether my bushings had the frame-hole-registering step or not.

The step certainly would help to keep parts from sliding with respect to each other, but from simple friction with proper tensioning of the mounting bolt (I'm guessing in the vicinity of 80 ft-lb with a grade 8 bolt,) I've noted no relative motion of parts over the years.

Best,
MAP

I think I asked that, not Guy? (pg 3)

Why, my apologies Monte_ExpreSS if I misidentified the poster! I saw two names in that post and drew the wrong conclusion.

Thanks,
MAP

No problem MAP, so long as we get a answer from you. My post was actually directed toward Larry.

Any confusion here is probably my fault from this post;
http://www.montecarloss.com/community/ubbthreads.php?ubb=showflat&Number=771211&page=3
I was asking Larry about some bushings that Monte_ExpreSS had refered to.
Guy

I probabaly contributed to the confusion as well

Larry

Just wanted to bring this "up to the top."


Anyone else want to pull P/N's, Brands and comparative stiffness info to the top as well?

Good link for the #1 position bushing alternative discussion

http://www.montecarloss.com/community/ub...;gonew=1#UNREAD

Found a site with listings for mounts but am unsure of the correct sizes etc. Here's the link and if anyone can sort out the numbers let me know as I have to replace all mounts on the wifes 83.

Drew

http://www.oldcarstuff.com/catalog/index...t=3a&page=1

That is tough since each GM body mount are not only different shapes/sizes, but different hardness for each body mount.

has anyone use alum body mount bushings? i was thinking of trying them on my monte.

i've have a set installed on my monte now, got them here http://www.tntraceshop.com/g-body_solid_mounts.html
they are going to ride extremely harsh for the street just f.y.i.
but they stiffen the chassis quite a bit. mike

can it cause any cranks in the body?

haven't had a chance to twist mine up.lol know a few guys running solid mounts with out issues so far, both g bodies and some camaros. hasn't ever been a topic. you could call TNT or email them and ask. i would think you may get cracks if you don't get and keep them torqued down. mike

Here are a couple of pictures from my 86 Monte Carlo GM Service Manual.
In the first picture can anyone tell me what the difference is between a model 37 & Model 80?

I also did not find any real information on the rad support bushings.





Now, here is a picture of the busshing currently installed in my Monte. I showed this to mark (Map) and he was astonished at the gap between the rad support and the frame rail (3.5") Can someone else take a picture of their and post it up for comparison.

i can try to get a pic of mine tomorrow.. im in the process of putting the doors and fenders back on the car..the parts car i bought and also my 86 SC has a descent size gap like that. it seems to me like adding/removing washers is how you adjust the fender so that it is straight and level with the rest of the body?

also while im thinking about it, i know that when you go to gap everything you start from the quarter panel/back of the door then work to the front of the door/rear of fender so my question is about how much of a gap should there be between the quarter panel/rear of door and the front of door/rear of fender? thanks

Spencer,
I am currently on the road in north Carolina but I can scan the page from my manual when I get home. There is a page that lists all the tolerances for the body panel gaps. I'll be home this coming weekend if you can wait that long.

Hi John S,

"37" Definitely applies to the MCSS, but "80," by inference (and by studying the picture,) I believe applies to the El Camino.

I commented in a PM that this gap is about 1" in my Malibu (just sold, incidentally,) and about 1.5" in the 1981 MC I have, and supported on jackstands at the corners of the frame inside the wheel locations - that is, with the front end of the frame drooping under sag.

With the bushing removed, the vertical stiffness in this gap is amazingly low, and illustrates just how floppy the frame and body are, although the body measures about 3x stiffer here in a vertical sense than the frame. Even so, the difference between a 1" gap and a 3.5" gap is beyond any reasonable range I can explain.

Best,
MAP

I have had quiet some G bodies in my time. And the worst core support gap I can recall is 2.250. But that car was a front end wreck car and was my previous build (slow).