1946 chevy truck build.

[gokellurself]

dude Chizzler I gotta to see that truck in person one day..

I'm just seeing this post for the first time for some reason, sounds like the makings of a great build. Any other photos so far?

[dillonv2008]

Non so far I've been busy working and remodeling are new house maybe in another month I'll be able to work on it. But I have oreded and have rims and tires. Crags 69 with 2.38 white wall tires. Ifs m2 with air bags, 4 link for rear, air line and air bag parts. I have almost all the parts to do full suspension just don't have the time right now. Very soon though I'll be getting into it I hope..

[dillonv2008]

Update. I've removed old engine and have started the ifs install

[dillonv2008]

Need some help. I feel my 4 link is getting too much pinion angle change.
Ride height is 6.5 inches off the ground have it set at +3 for pinion angle. When aired down goes all the way too -6 degrees and i believe around +1 or 0 aird all the way. What did I do wronf?? My lowered are parallel with floor. My uppers are -3 , IC being at firewall. Lower bars are 21 inches bars alone. Uppers. 13 bars alone.
Need some help figuring out why this is getting so much pinion angle change

[joedoh]

your uppers are not 13 inches long measured along the frame, only measured along the bar itself. my guess is they are 9-10 inches long measured in the same plane as the lowers. your forward attachment point is less than halfway along the lower, you are going to have lots of pinion angle change. you will also probably notice the axle moves forward in the wheel arch quite a bit when aired out too.

this is why I recommend tacking the suspension together and running it up and down a few times, like you have. good work.

you should probably get longer uppers or reduce the angle on them to make them longer in relation to the lowers, because even if you resign yourself to driving only at drive height and accepting the pinion angle change as it gets lower, you need to be aware of something called "rear steer". measure from the axle centerline to a fixed point on the frame, then jack up just one side of the axle (like if the wheel was going over a bump) on the side you have jacked up you will notice the measurement gets shorter and the opposite side (which is pushed down) will get longer. this steers the truck from the rear suspension and is a way to have some crazy handling characteristics in corners. steering force applied at the end of the chassis is more unsettling than forces applied closer to the center of gravity (imagine a shipping container on grass. push in the middle and it probably wont move, push at the ends and you will be able to spin the container)

looks really nice so far!

[dillonv2008]

Yes it does roll forward when going up into frame. So I should set the uppers around 35*? They are at 45. The bars came all 4 same length 21" I believe. I cut uppers so they are 75% I believe they are 13 something I'll get better measurements once home. With link ends In idk what total length they are. @joedoh

[joedoh]

Originally Posted by dillonv2008

Yes it does roll forward when going up into frame. So I should set the uppers around 35*? They are at 45. The bars came all 4 same length 21" I believe. I cut uppers so they are 75% I believe they are 13 something I'll get better measurements once home. With link ends In idk what total length they are. @joedoh

I am not saying your bars dont measure 13", I am saying in the plane viewed from the side of the truck, the bars will be much shorter than 13", more like 9 or 10 effective length. make a mark on the frame at the axle, then measure forward to where the bar attaches, it will be 10 inches or less. this is all that matters in bar length, effective length. I could have a 70" long bar set at a 1/2 degree angle from the rear axle and the effective length would only be 2".

did you buy a parallel link and switch it to triangulated? all 4 21" sounds like a parallel 4 link setup. either way, to manage pinion angle change you need to get the bar lengths within about 80% of each other. so for a 21" bar that is 17" effective length. thats about how long it would be if you took a 21" bar and mounted it at an angle for a triangulated setup.

Most guys put the upper bars down because that is what the frame allows, but having them already at a down angle when the bottom bars are level means you will have lots of pinion angle change. Its true that "pinching" the front of the bars together (upper pointing down slightly to roughly level lower bars) changes IC. but with adjustable suspension I would recommend to try getting your pinion angle change and roll steer good and worry about IC as a secondary concern.

[dillonv2008]

Originally Posted by joedoh

your uppers are not 13 inches long measured along the frame, only measured along the bar itself. my guess is they are 9-10 inches long measured in the same plane as the lowers. your forward attachment point is less than halfway along the lower, you are going to have lots of pinion angle change. you will also probably notice the axle moves forward in the wheel arch quite a bit when aired out too.

this is why I recommend tacking the suspension together and running it up and down a few times, like you have. good work.

you should probably get longer uppers or reduce the angle on them to make them longer in relation to the lowers, because even if you resign yourself to driving only at drive height and accepting the pinion angle change as it gets lower, you need to be aware of something called "rear steer". measure from the axle centerline to a fixed point on the frame, then jack up just one side of the axle (like if the wheel was going over a bump) on the side you have jacked up you will notice the measurement gets shorter and the opposite side (which is pushed down) will get longer. this steers the truck from the rear suspension and is a way to have some crazy handling characteristics in corners. steering force applied at the end of the chassis is more unsettling than forces applied closer to the center of gravity (imagine a shipping container on grass. push in the middle and it probably wont move, push at the ends and you will be able to spin the container)

looks really nice so far!

Also I have my IC set around firewall and upper bars about 3* down is that about right or should they be level