Centre of Gravity

[dodj]

Any body have an educated guess as to where the centre of gravity of a big block e-body is?
Being a new owner of a two post lift, I thought I should know, but I can't think of a way to weigh the front end and the back end to calculate it.


It's a 9000 lb lft so I'm well within it's capabilities but I'd like to be sure I'm positioning it properly.

[Cuda Cody]

What type of two post lift do you have?  I have a asymmetrical two post lift and I pretty much put the mirrors about lined up with the posts.

[1 Wild R/T]

I've set the pads on the rear frame member that the front of the leaf springs bolt to & the front frame just as it flattens out behind the rear wheels for many years, very stable never an issue....

FWIW I saw a factory drawing that pinpointed  CG it is about 12- 14" behind the front fender to door seam & about the same distance up from the rocker pinch weld..

[dodj]

I have a symmetrical lift Cody. I centered the car relative to the posts and put the pads where Wild said. But then I was thinking..
Hmmmm...that 440 up front probably weighs more than the gas tank out back. So being a new lift owner I was wondering if I was
doing it right. Like maybe I should have a little more car behind the posts?

[RUNCHARGER]

It's been a while since I weighed one but as I remember there was 500lbs more on the front wheels than the rear on my 70 Challenger with a 426 Hemi and a Dana 60.

[Dakota]

The article linked below describes how to figure out the center of gravity mathematically.  From what I can tell for the front/back CG from this method, you'd need to know the total weight of the car, the weight on at least one axle and the wheelbase length see equation 5).   

http://www.thecartech.com/subjects/auto_eng/Center_of_Gravity.htm

If you don't have the weight info, then, in the words of Roseanne Rosannadanna, "Never Mind".

Good luck!

[HP2]

COG is roughly on the top of the transmission, just behind the bell housing.

[Chryco Psycho]

  with HP2

[GoodysGotaCuda]

Post of the lift should be roughly at the front door window cranks.

That said, the lift is pretty forgiving on a "small" car like this. I've lifted hundreds of cars on a 2post lift, just eyeballing the balance point.

[Flatdad]

When retrieving my challenger project from a storage unit, I had to change some flat tires. There was only enough room to get the jack centered on the intersection of the front frame rail and torsion bar mount. But, instead of lifting the front wheel, it lifted the rear one. It had a 400, 727, & 8 3/4  at the time. These cars must be crazy front heavy.

I agree with '1 Wild R/T' & 'HP2'

[HP_Cuda]

This is kinda interesting to me because I used to care a lot about CG when building scale planes.

The CG would be affected by the motor choice for the car, heavier motor up front the farther the CG moves back. I don't know by how much but it definitely will move. Definitely could be calculated.

[1 Wild R/T]

heavier motor up front the farther the CG moves back.

I think you got that backwards....   The CG moves forward.... It follows the greatest mass...

[HP_Cuda]

 

Your right I got that backwards. Dang work has me spun around an axle!!!