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Need advice on camaro subframe

3K views 12 replies 4 participants last post by  garretthes 
#1 ·
History
59 Suburban with grafted 74 Camaro Subframe

Goal
Safe, daily driver

Problems
Negative castor. Steering is touchy especially at interstate speeds.
Springs not adequate. Had to use 2 spacers to get correct height.
Squeaks when turning and going over bumps

This is a budget build. My brother and I have done all the work and really enjoyed the process. Other than the touchy steering the Suburban drives great and handles surprisingly well.
I need advice on how to fix the touchy steering. Basically, it's too easy to steer. The power steering is TOO efficient so you can turn the wheel too easily. Also, the steering is too sensitive, easy to over compensate. I noticed some guys are selling different ratio gear steering boxes. Wondering if this would help.

Thanks for the help.
 
#2 ·
that is one sweet suburban. i have a 58 pu with mustII front end, so i can't help you there,
but there is a 55-59 chevy truck thread that you should also ask this question in here
how many miles on the camaro subframe?
common problem with subframes is that they are worn out when installed.
i looked at a camaro and volare subframe and even went as far as to buy a volare wagon.
when i figured the cost of rebuilding, that's when i started looking at options.
 
#3 ·
70s Caddy springs will bolt into a Camaro sub, no changes.

If there is not enough adjustment to set the caster, the sub is installed at the wrong angle, IE tipped forward, or the frame has sagged in at the top. You might be able to get enough caster by using camber compensator shaft in the upper A frames, they are offset 1/8" for more adjustment.
 
#4 ·
We installed it to the exact instructions of a video published by No Limit Engineering. I was not a happy camper when the GM tech told me I had 2 degrees neg castor. I did received an email today from a guy at Custom Works Products who says he has an upper control arm that can add up to 5 degrees pos castor. I might go that rout.
 
#5 ·
To answer your questions Ogre, I have no idea on the mileage. I would say a lot and it must have sat for a long time.
I spent around $1500 on the entire transformation including the 2004 5.3 with 4L60e tranny. I had no choice! My brother was a HUGE help.
Again, it drives and handles great except for the touchy steering. THe engine sits very low in the frame so the center of gravity is very low.
 
#7 ·
This is something that seems to be a "secret" in the hobby, setting the upper control arm angles properly. When I did one of these clips years ago I was looking at an article in a truckin magazine on the swap. There were a lot of photos and a lot of text, I thought it was tell us all we needed to know.

Then as I was studying the photos I noticed something that was not mentioned in the article, there was an "angle finder" on the upper control arm shaft! Why would they not mention this?

I did a little more study and found just how important that angle was to maintain, you needed to put it exactly the same as it was on the Camaro, or you are screwed. Most everyone who does one of these swaps is more worried about getting it to mate to the truck frame nice, to make a nice cut to make sure the frame "looks good" and few think about geometry, is the car going to align properly? Is the wheel base correct? These are two of the most common mistakes.

There is "Off set" control arm shafts that will allow you to get more caster, a no brainer, you MUST install these to get your truck to drive correct.

Brian
 
#8 ·
By the way, a zero or negative caster is actually used on cars when racing around a tight course. As you turn into it, the wheel "bites" the ground pulling you thru the corner.

I now have a much better understanding of alignment specs as I have been doing the alignments at a bodyshop for a number of years. The large "touring" cars like a BMW 745 will have six or seven degrees caster being they are designed to roll down the autobaun at high rates of speed. While the little hot rod like a Mini Cooper will have only one or two degrees being they are made to cut around small towns like a go cart.

Brian
 
#12 ·
garretthes said:
I believe the tech said the 74 camaro castor spec was +2. Where do I find the offset control arm shaft? Also, all I have read about offset control arms is that they give you more or less camber, not castor. Am I missing something?
Caster and camber use the same adjustment points. Simplified, you shim both front and rear evenly for camber, then add at the rear, remove at the front to gain caster. Offset control arm shafts allow you to add more at the back, and remove more at the front, to gain caster without changing camber. It's not quite that simple, but you get the idea.
 
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