http://www.jimobalek.com/?p=503 Just another WordPress weblog Tue, 01 Jun 2010 20:06:31 -0700 http://wordpress.org/?v=2.8.4 hourly 1 http://www.jimobalek.com/?p=503&cpage=1#comment-121 Jim Tue, 01 Jun 2010 20:06:31 +0000 http://www.jimobalek.com/?p=503#comment-121 Tim, adjusting a ladder bar without adjusters is just a bit more work as you need to remove the ladder bar from the brackets to make the adjustment. In your case, remove the right hand upper rod end bolt from the brackets on the axle housing, set the axle square and centered in the chassis on the rear lower rod ends, and your wishbone or panhard bar. Next set your pinion angle with the top left rod end, this is a little more difficult as you have to remove the bar for each adjustment change, but take your time and make it right. I usually remove the bars totally first, and make sure all the rod ends turn freely in the threads, lubricate them, and make sure all the bolts go in and out of all the holes nicely so there is no fighting with anything under the car. now that you are all set there, pinion angle, centered, and square, adjust the right hand upper rod end so the bolt just slides in through the brackets on the rear axle housing. This is zero preload. Now, based the corner weights you supplied here, I would be aiming to reverse the rear wheel weights, about 50 to a hundred pounds more on the right rear than on the left rear, this will push the left front down on launch, (or depending on how you look at it lift the right front more than it is being lifted now). You can add this extra weight by removing the bolt in the right upper rod end on the axle housing, now jack that side of the chassis up, I usually put the jack near the front ladder bar mount on that side, adjust the right upper rod end in, (making the upper bar on the ladder bar shorter), start with one turn and see what your weights are. If you release the jack fully you will not be able to get the bolt back in the holes, you will need to jack the chassis up on that side to get the bolt back in. If you are using a ruler to check your preload, and this is very rough as every car is different, you will find the right side of the body about half and inch or so higher than the left, with a bit of preload. I usually give my customers a measurement so they can at least get it close if they have felt the need to make changes without scales. If you have access to scales, and the time, make a chart of how much weight each half turn on your right upper rod end adds or removes. Then you can make adjustments at the track without scales knowing which way you are going and how much you are changing. Last, if you are using an anti-roll bar, after you have set the preload on your ladder bars, set the anti-roll bar to zero preload. As for your springs, 130# seems pretty light for a 3200# car, but using as light a spring as possible, and having the spring pads screwed way up to compress the springs gives you lots of kinetic, (stored) energy in the spring to aid in chassis separation, as long as the springs are not coil binding on bumps, and you are not experiencing any porpoising between the front and rear spring rates I would guess there is not a lot to be gained by changing springs at this point. Jim Tim,
adjusting a ladder bar without adjusters is just a bit more work as you need to remove the ladder bar from the brackets to make the adjustment. In your case, remove the right hand upper rod end bolt from the brackets on the axle housing, set the axle square and centered in the chassis on the rear lower rod ends, and your wishbone or panhard bar. Next set your pinion angle with the top left rod end, this is a little more difficult as you have to remove the bar for each adjustment change, but take your time and make it right. I usually remove the bars totally first, and make sure all the rod ends turn freely in the threads, lubricate them, and make sure all the bolts go in and out of all the holes nicely so there is no fighting with anything under the car. now that you are all set there, pinion angle, centered, and square, adjust the right hand upper rod end so the bolt just slides in through the brackets on the rear axle housing. This is zero preload.
Now, based the corner weights you supplied here, I would be aiming to reverse the rear wheel weights, about 50 to a hundred pounds more on the right rear than on the left rear, this will push the left front down on launch, (or depending on how you look at it lift the right front more than it is being lifted now). You can add this extra weight by removing the bolt in the right upper rod end on the axle housing, now jack that side of the chassis up, I usually put the jack near the front ladder bar mount on that side, adjust the right upper rod end in, (making the upper bar on the ladder bar shorter), start with one turn and see what your weights are. If you release the jack fully you will not be able to get the bolt back in the holes, you will need to jack the chassis up on that side to get the bolt back in. If you are using a ruler to check your preload, and this is very rough as every car is different, you will find the right side of the body about half and inch or so higher than the left, with a bit of preload. I usually give my customers a measurement so they can at least get it close if they have felt the need to make changes without scales. If you have access to scales, and the time, make a chart of how much weight each half turn on your right upper rod end adds or removes. Then you can make adjustments at the track without scales knowing which way you are going and how much you are changing.
Last, if you are using an anti-roll bar, after you have set the preload on your ladder bars, set the anti-roll bar to zero preload.
As for your springs, 130# seems pretty light for a 3200# car, but using as light a spring as possible, and having the spring pads screwed way up to compress the springs gives you lots of kinetic, (stored) energy in the spring to aid in chassis separation, as long as the springs are not coil binding on bumps, and you are not experiencing any porpoising between the front and rear spring rates I would guess there is not a lot to be gained by changing springs at this point.
Jim

]]> http://www.jimobalek.com/?p=503&cpage=1#comment-120 tim heiges Tue, 01 Jun 2010 16:12:13 +0000 http://www.jimobalek.com/?p=503#comment-120 i have a question about adjusting preload on ladder bar setup with no adjusters. the car is lifting the left front about a foot higher than the right. not sure if i have the right # springs on the rear. i have 130#. you said something about setting preload with a ruler? here are the weights with driver. LF 907# RF842# LR770# RR 710#. thank you i have a question about adjusting preload on ladder bar setup with no adjusters. the car is lifting the left front about a foot higher than the right. not sure if i have the right # springs on the rear. i have 130#. you said something about setting preload with a ruler? here are the weights with driver. LF 907# RF842# LR770# RR 710#. thank you

]]> http://www.jimobalek.com/?p=503&cpage=1#comment-119 Jim Mon, 31 May 2010 03:46:29 +0000 http://www.jimobalek.com/?p=503#comment-119 Hi Boyd, Without seeing your car, I would start by checking to make sure you have some sort of track locater, a wishbone or panhard bar. Next thing to check is the shocks and make sure they are working correctly. Beyond that I will need much more info about your car and maybe some photos or video of the car shaking. Hi Boyd,
Without seeing your car, I would start by checking to make sure you have some sort of track locater, a wishbone or panhard bar. Next thing to check is the shocks and make sure they are working correctly. Beyond that I will need much more info about your car and maybe some photos or video of the car shaking.

]]> http://www.jimobalek.com/?p=503&cpage=1#comment-118 boyd onnen Sun, 30 May 2010 22:18:34 +0000 http://www.jimobalek.com/?p=503#comment-118 i have a question about a2500 lb 72 vega 4 link car. i purchased a rolling chassis put in my motor and trans. it shakes side to side in the back on decelaration almost to the point of being scary. any suggestions i have a question about a2500 lb 72 vega 4 link car. i purchased a rolling chassis put in my motor and trans. it shakes side to side in the back on decelaration almost to the point of being scary. any suggestions

]]>