Low and dirty 33 chevy master sedan 4 door

[serrata]

I'm not happy at all with the travel of the front suspension.
I'm trying like crazy to be able to have a 4 link and keep 4 wheel drive, as well as be able to drop this thing to the ground.

I set the pinion angle at the lowest point, but figured I had enough adjustment in the links to adapt to driving height.

Uh... Not so much. When I raised the suspension, the angle changed like 30 degrees. Holy cow.

Sooo... I shortened the longer arms and moved the frame mounting point forward 10.5 inches.

Here's what it looks like now...

I have another major problem.

The front end is so heavy with the engine up there, the air bags won't lift the front more than like 4 inches. I had placed the bag near the center of the beam, which pretty much doubles the weight they carry, but would notionally double the lift height. It didn't work out that way.

When I shortened the lower arms, it made the weight problem worse. Now it only comes about 2 inches off the ground and movement is very soft and mushy.

Also, pinion angle change on lift is still pretty severe. I'm realizing that having the height of the frame-mounting points for the 4 links all at about the height is exacerbating the problem. The rear isn't suffering from this problem mainly because the diff in height at the frame side mounting points is about the same as the height diff at the axle side.

So....
I'm thinking I need to move the bag closer to the axle to resolve the weight problem.

And I need to somehow raise the frame-side mounting points for the inner triangulated upper arms without getting in the way of the future front driveshaft. And possibly make the 4 bars closer to the same travel length.

Ugh.

 

[Old Iron]

Or use bigger bags

 

[sneakysnake]

The further from the hinge point the more you can lift but takes more travel, the bigger the bag the easier to lift but takes more air.Set pinion angle at drive height, you may get a harsh angle on drive line on drop but it wont be driven in that position.Be sure to not let the bag touch any surface or it will cause the bag to fail prematurely.

 

[serrata]

Thanks guys.

I notionally understood the mechanics. I think I completely overestimated the front air bags themselves.

Some of the ebay sellers list the DII-2600 as 2600 lbs, and the DII-2500 as 2500 lbs. I just found a good spec on them that completely differs from that. The 2600 maxes out at 3049 lbs, the 2500 at 2096 lbs. I didn't do enough homework on this.

I currently have (2) 2600's in the rear and the (2) 2500's in the front.

Now for some junk math...
The engine with trans is probably close to 1000 lbs. Add another ~500 for frame. With the bags set at 33% of the distance from the frame along the bar, they can only hold (2096/3) = ~700 lbs each. 2 bags = 1400 lbs. That's why they can barely lift it at all.

If I put the 2600(instead of the 2500) bags in the front, and moved them out to halfway along the bar, I could get 1500 lbs each, which should be good enough to allow road bounce and vibration, right?

Man, sometimes I wish I had gone with a lighter and more nimble design.

 

[Old Iron]

By Jove I believe you've got it

 

[Skip]

By Jove I believe you've got it

Oh, good. Because I was already pretty much lost.

 

[serrata]

I'm back at it. I haven't posted in a while. Trying to get her road worthy this fall/winter so that I can title and register it.

Here are some updates. It runs and drives. I've pulled it around the driveway a few times and I'm now working on glass templates and door panels. I think I've figured out window motor and door latches/locks for one door, and now need to get the other four done. Seat mounts done for the front and bought to cheap leather seats.

 

[oneeye]

[cl

 

[earthman]

There you are! Did not see that you had posted recently. Thanks for the update.

.............[P

 

[offroadrolls]

This thing is cool as heck. Nice to see a change from the typical Cummins ratty.

 

[bob w]

Did all your suspension calculations work out? That's a one of a kind looking machine you have created. Very cool.

oneeye, nice to see you posting.