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#1055870 - 02/13/18 12:57 AM Re: Front suspension mount blueprinting [Re: Warriorridge]  
Joined: Feb 2013
Posts: 113
Warriorridge Offline
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Warriorridge  Offline
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Posts: 113
Petersburg PA
Originally Posted by Richie Cat
Educate me. I understand as I'm reading this, that the mount points upper and lower, not symmetrical. But if you get your C/L of the spindles 90* to the C/L of the chassis and across from another. aren't they both in the same location to each other by using shims? Or are you doing this to gain more angle adjustment ?

Right, the frame mounts on the frame are not symmetrical. I don't think that it's by design, just poor manufacturing tolerances. On an average daily driver or cruiser it's not that big of a deal, you just use shims to do your alignment and that mostly compensates for it. What I'm trying to though is build a car that will handle very well, I'll probably autocross is and maybe some road course as well. In a case like this, the differences from to side, especially on the lower arm mounting points where you can't adjust with shims, can affect the handling. Also, depending on what control arms you're running, you may not be able to get enough castor for a good high performance alignment, so by moving the mounts in the right direction, you can gain a bit of caster potential. What I did in the above posts was bolt up my front suspension and check to see what kind of castor I can get before I started moving mounts, so I could see if I need to make any changes to get more castor. Turns out that with the parts I am using I'll be able to get plenty, so I don't need to try to add any, but I'm still going to adjust the mounts to make them symmetrical.

Last edited by Warriorridge; 02/13/18 01:05 AM.
#1055873 - 02/13/18 02:21 AM Re: Front suspension mount blueprinting [Re: Warriorridge]  
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Warriorridge Offline
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Warriorridge  Offline
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Posts: 113
Petersburg PA
Got the upper mounts adjusted today. I started by getting things set up to measure the location of the mounting points. I needed measure the distance of each hole on the upper control arm mount from the frame centerline, its height, and its position fore and aft. To measure the height I measured from a piece of square tube laying across the frame table. For the distance from the frame centerline I set up a laser to shine right down the frame center line. It can be a bit of a pain to get it set up perfectly, but once it is set up taking measurements is easy, just look where the laser is shining on my ruler. For the distance fore and aft, I needed a line to measure from. It didn't really matter where I put this line, as long as it was perpendicular to the frame centerline. I chose to holes near the front of the frame, I set a piece of angle iron across them, checked to see if it was indeed perpendicular, then tacked it in place
[Linked Image]IMG_20180212_111049 by Justin Yoder, on Flickr
After getting the measurements, I cut off the mounting points
[Linked Image]IMG_20180212_144044 by Justin Yoder, on Flickr
All cleaned up
[Linked Image]IMG_20180212_155918 by Justin Yoder, on Flickr
The passenger side mount was further back than the drivers side mount, and the drivers side mount was angled in toward the back a little more than the passenger side mount. I decided to put the drivers side mount as far back as the passenger side was, and split the differance in the side to side measurements between the two. Here they are tacked back into place
[Linked Image]IMG_20180212_165746 by Justin Yoder, on Flickr
[Linked Image]IMG_20180212_165756 by Justin Yoder, on Flickr
I didn't weld them in yet because I might end up not using these actual mounts, I'd like to install some keyed ones something like what MC96 mentioned a few posts back, and I also need to build a coilover mounting bracket in that area, so the mounts are just tacked in until I get all that finalized.
Anyhow, here are the before and after measurements of the upper mounting brackets:
[Linked Image]IMG_20180212_192442 by Justin Yoder, on Flickr
[Linked Image]IMG_20180212_192413 by Justin Yoder, on Flickr

#1055875 - 02/13/18 05:15 AM Re: Front suspension mount blueprinting [Re: Warriorridge]  
Joined: Jan 2000
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mmc427ss Offline
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mmc427ss  Offline
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Posts: 3,846
Pottstown, Pa
The lack of suspension symmetry from left to right sides of the frame would be fairly common on the old frames. On Justin's frame his UCA mounts are off, for me it's the right LCA rear pocket. Justin and I both are looking to fix what misalignment we can and be able to get lots of caster, 9+ instead of the usual 4 -5 max. Because he is using coilovers both the UCA and LCA needed have the ball joint moved to increase static castor to 10+, so his concern is correcting control arm pivot points. For me the project is reusing the stock LCA but moving the ball joint forward via moving the pivot locations and at the same time blueprint the LCA locations. There's a little more than that to my my project, more on that later.

The rear pockets and UCA mounts are welded to the frame later in it's production. So they can easily deviate from "spec" when you have 30 seconds to weld them in. When you do a generic alignment on the front end there is usually enough range in the UCA shimming to adjust out the misalignment of any of the 8 pivot points of the control arms. You can notice this when you look at 30 Montes parked together, Carlisle, where ever, odd shim stacks from side to side. Hmmm, why is that, symmetry.


For pretty much all the cars we drive worrying about the pickup points is something not to lose sleep over. Lance beats on his car, I applaud him for it, Justin is building a car to beat on, me I'm just beating an old horse trying to make it better so i know it's the driver that's killing all those cones, not the car.
Bob

#1055880 - 02/13/18 12:24 PM Re: Front suspension mount blueprinting [Re: Warriorridge]  
Joined: Mar 2012
Posts: 587
MC96 Offline
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MC96  Offline
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Posts: 587
St. Johns MI
For coil over mounts I have some bay bars with a jack bolt running through them. I dont have to worry about packaging other than making sure my coil over can pass through the upper arm.

Like this port city chassis (with a set up rod in place of the coil over)
[Linked Image]

I built all my suspension myself but it is very similar to this, just packaged to fit a stock clip.


86 SS
400SBC, 4l80e, MSD Atomic injection/trans controller, Tilt glass clip, all tubular arms, corvette brakes, 9" rear
In progress
#1055881 - 02/13/18 12:36 PM Re: Front suspension mount blueprinting [Re: Warriorridge]  
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Posts: 587
MC96 Offline
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MC96  Offline
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St. Johns MI
I should add that I cut out the outer half of the stock spring bucket and plated the hole shut.


86 SS
400SBC, 4l80e, MSD Atomic injection/trans controller, Tilt glass clip, all tubular arms, corvette brakes, 9" rear
In progress
#1055882 - 02/13/18 02:50 PM Re: Front suspension mount blueprinting [Re: Warriorridge]  
Joined: Dec 2007
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SSLance Offline
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SSLance  Offline
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Peoria, AZ
Nice work Justin... Just a tip...you might want to trim those ears off inside the coil pocket while the upper mounts are easy to get off. They'll have to be trimmed back or eliminated to make room for the coilovers when the time comes.


Lance
1985 Monte Carlo SS Street Car
#1055897 - 02/14/18 04:38 PM Re: Front suspension mount blueprinting [Re: Warriorridge]  
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mmc427ss Offline
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mmc427ss  Offline
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Pottstown, Pa
After plotting all the points, 6, for the LCAs then transferring them to a scale drawing yesterday I can now see that how I planned to move the lower ball joint forward has changed. Because the two front pockets center axis is but 1 1/4" ahead of the two ball joints axis moving the front pocket bolt hole inboard will basically just change camber, with little effect on adding caster. Moving only the rear pocket holes outboard will have a much greater effect on gaining caster, move the ball joint forward. This explains why the right ball joint is forward of the left, the right rear pocket holes are already 1/4" outboard of the left side.

So now the plan is to not touch the hole in the front of both front pockets. Their height and distance from centerline are almost perfect. I will use them as the starting point to mod the rear pockets. There is plenty of area to relocated the holes in the rear pockets. The left side points of the LCA are actually very good, it just that right rear pocket that is way off. Both front pockets have equal down front angle, .65 degrees, the back holes of the front pockets will be adjusted to add some more down angle and also used to move the pivot axis outboard. Once that is done the 12 mm rod can be used to locate the rear bucket holes. The thinking is the right rear bucket holes are already 1/4" outboard, will need to go another 1/4" to hopefully pickup another 2 degrees caster. Then the left side will be moved to image the right side. Trial and error trimming of the pocket holes then install parts and plot the new ball joint location. The goal is to gain 3 to 4 degrees added caster through relocation, add a little more down angle and have both sides symmetric.

This is one of the slowest moving projects I've done on the car. Measure and think about it 10 times, cut once.
Bob

#1055935 - 02/16/18 03:50 PM Re: Front suspension mount blueprinting [Re: Warriorridge]  
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Warriorridge Offline
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Warriorridge  Offline
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Posts: 113
Petersburg PA
Well I got the lower arm mounts done since the last time I posted. Before I started I filled in the notch I cut in the frame for ac compressor clearance. I wanted to get this finished up before I blueprinted the lower mounts, just in case the welding would shift things a little. (I doubt it did, but I needed to do it sometime anyhow, so may as well be safe.
Here's before
[Linked Image]IMG_20180213_114814 by Justin Yoder, on Flickr
And after
[Linked Image]IMG_20180213_122147 by Justin Yoder, on Flickr
With that being done, I measured the lower mounting points. Here are the measurements before
[Linked Image]IMG_20180214_194515 by Justin Yoder, on Flickr
Then use a rod and washers to line up the holes. I figured out which way I needed to move each hole, then reamed out the holes in the direction they needed to go. Once the holes were ground out enough to put the rod trough all of them and get it where I wanted it. Then put the washers on the rod, line it up exactly where you want it, and tack the washers in place. Then pull the rod out and weld in the washers all the way.
[Linked Image]IMG_20180214_155526 by Justin Yoder, on Flickr
[Linked Image]IMG_20180214_155512 by Justin Yoder, on Flickr
[Linked Image]IMG_20180214_162239 by Justin Yoder, on Flickr
[Linked Image]IMG_20180214_162157 by Justin Yoder, on Flickr
Then repeat on the other side. These are the final measurements
[Linked Image]IMG_20180216_094859 by Justin Yoder, on Flickr
Once the mounts were all finished I put the suspension back on to see where my castor settings where. With the upper arms set near the middle of there adjustment range (both adjustors about 1/2 inch out) I had around 13* of castor. In fact I pretty much had to max out the adjustment on the upper arms to be able to get the castor down to 9.5*. Any less and I would have to use shims. When I finish my upper control arm mounts I think that I am going to move them forward about 3/8", that will give me about 9.5* of castor with the arms set in the middle of there adjustment range, If I do that I should be able to get any alighment in the range I want to be in without having to use any shims.

#1055949 - Yesterday at 04:29 AM Re: Front suspension mount blueprinting [Re: Warriorridge]  
Joined: Dec 2007
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SSLance Offline
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SSLance  Offline
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Posts: 5,536
Peoria, AZ
I gotta say, I'm pretty stoked that a couple more of you guys are going down this road. Nice work!! It'll be worth the effort, I promise.

I also have to say you lay down some pretty sweet welds with that little Hobart.


Lance
1985 Monte Carlo SS Street Car
#1055958 - 18 hours ago Re: Front suspension mount blueprinting [Re: SSLance]  
Joined: Sep 2007
Posts: 3,053
1 Slow SS Offline
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1 Slow SS  Offline
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Joined: Sep 2007
Posts: 3,053
Small town USA
I'm glad I had my Trans am in front of my Monte frame upgrade, this is exactly what I needed to see. I will do mine the same way other than adding the front coil over brackets. Great thread on taking the frame to the next level.


Be a car builder, not a googler!
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