Center of gravity

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Mysons68dart

Mysons68dart

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I'm doing a 4 link , 360 , auto , in my 68 dart. I still have the /6 and trans and front end in the car. I would like to get a guesstimate of where my instant center is going to be before i finish the rear end . My question to you 68 dart 360 sb owners is what frt tire size you have and a measurement from the ground to cg which is about engine cam height at the front spindle. I know there is a lot of variables, like i said just a guesstimate for now which will really help me. Thanks in advance.
Gary.
 
In reality you need to finish the car first then weigh it. I forget the exact formula but it like weigh the front with the back 2 ft off the ground then weigh the rear with the front 2 ft off the ground then you can find you instant center or center of gravity were you could put a piece of pipe through the car and pick it up and it would be perfectly balanced.
 
For simplicity's sake and close enough for hand grenades, you can figure your CG as center of balance and cam high. That's what I use and it's pretty close.

If you are trying to make several chassis exactly the same, you have to do as Brian said above and you have to do some calculus.
 
QUOTE="yellow rose, post: 1972597954, member: 41803"]For simplicity's sake and close enough for hand grenades, you can figure your CG as center of balance and cam high. That's what I use and it's pretty close.

If you are trying to make several chassis exactly the same, you have to do as Brian said above and you have to do some calculus.[/QUOTE]
 
Mysons68dart said:
QUOTE="yellow rose, post: 1972597954, member: 41803"]For simplicity's sake and close enough for hand grenades, you can figure your CG as center of balance and cam high. That's what I use and it's pretty close.

If you are trying to make several chassis exactly the same, you have to do as Brian said above and you have to do some calculus.
Click to expand...
[/QUOTE]

I know that YR i dont have the SB in the car thats why i need that measurement.
 

I know that YR i dont have the SB in the car thats why i need that measurement.[/QUOTE]


Got cha. You need a measurement for cam height on an A body? I can do that after a bit. I'll measure the tire height so you know.

Then I'll post it up for you.
 
Hillbilly method: put a 2x4 under the car from side to side. Put a floor jack under each side under the 2x4 where the 2x4 contacts the jack point on the car you want to use. You may need to use some other lumber to distribute the load on the car so as not to damage anything. Jack it up on both sides even. You can use a tape measure for height and position to get it level and even. Repeat the process till the car balances.

That gets you front to back, I would assume side to side is in the center.
 
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Ok, my eyes finally are good enough to read the tape measure.

With a 25 inch tall front tire, and at my ride height which is 3/4 inches lower than OE, the cam centerline is 19 15/16 inches.

YMMV by tire diameter and actual ride height. Also where the engine mounts in the chassis can make a difference.

That should get you close.
 
yellow rose said:
Ok, my eyes finally are good enough to read the tape measure.

With a 25 inch tall front tire, and at my ride height which is 3/4 inches lower than OE, the cam centerline is 19 15/16 inches.

YMMV by tire diameter and actual ride height. Also where the engine mounts in the chassis can make a difference.

That should get you close.
Click to expand...
Thank you sooooo much i really appreciate it.
 
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