Body roll....help!!

treessavoy · 04-05-2010, 11:15 PM

That sounds like a pinion angle problem. I had that problem until I increased the pinion angle to 4 degrees but that's on a Mopar.

Some of the Chevy guys can help you with the proper angle.

JimR

Tom Goldman · 04-06-2010, 07:21 AM

By moving the springs inboard , you have effectively reduced the spring rate . How, did ths happen? ...By increasing the lever ratio the spring sees working against it. ......you have more axle housing outside the spring now ,so when the chassis rolls on launch, there is more leverage against it ...............As was suggested ,you could add a leaf to stiffen the right side. ....You could also counter the roll by staggering the shock valving from side to side., if you have a good set of double adj. shocks. ........I would probably go with the anti roll bar,as it is the easiest for a racer to tune at the track. ...............Your pinion angle may be off ,but excessive roll could have allowed the pinion to twist up to the point of binding ........If it's a Cal track or slapper type bar , go with no more than the suggested 4 deg. .........I've done this to quite a few cars over the years and have seen the problem a few times, usually on higher hp,longer wheelbase cars. .............Tom

ericsz · 04-06-2010, 07:47 AM

Just to let you know the car is definately not a HP machine, it is a mild 406 runs 7.20's in the 1/8th with CE Slide a Links. Has the Ranchos out back that Calvert recommends for the Caltracs.

Robert Simpson · 04-06-2010, 11:46 AM

Eric, what Tom said is exactly how I see it. I would not think that your drive shaft or pinion hit the floor due to body roll. If it did you have MAJOR roll. My first thought, without seeing or knowing your car, would be to put a additional leaf on the pass side, tighten up the shock on the pass side. But make sure that you leave your bars loose when making these adjustments then re set you bars. Yes, a sway bar would help. I am just thinking of inexspensive things to try. I hope you get it working out for you. Maybe it was just one of those things as far as your drive shafts breaking? Build it better and go back at it. But check the gear in your rear end. When things like that break, in our cars, we have to check other things because it sets a harmonic through the drivetrain that could crack a gear, and cut the life down on parts. Hope this helps.

04-05-2010, 11:15 PM	#1
treessavoy VIP Member Join Date: Feb 2009 Location: Dunnellon,FL Posts: 1,103 Likes: 0 Liked 4 Times in 4 Posts	Re: Body roll....help!! That sounds like a pinion angle problem. I had that problem until I increased the pinion angle to 4 degrees but that's on a Mopar. Some of the Chevy guys can help you with the proper angle. JimR __________________ Jim Rountree

04-06-2010, 07:21 AM	#2
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,477 Likes: 892 Liked 883 Times in 237 Posts	Re: Body roll....help!! By moving the springs inboard , you have effectively reduced the spring rate . How, did ths happen? ...By increasing the lever ratio the spring sees working against it. ......you have more axle housing outside the spring now ,so when the chassis rolls on launch, there is more leverage against it ...............As was suggested ,you could add a leaf to stiffen the right side. ....You could also counter the roll by staggering the shock valving from side to side., if you have a good set of double adj. shocks. ........I would probably go with the anti roll bar,as it is the easiest for a racer to tune at the track. ...............Your pinion angle may be off ,but excessive roll could have allowed the pinion to twist up to the point of binding ........If it's a Cal track or slapper type bar , go with no more than the suggested 4 deg. .........I've done this to quite a few cars over the years and have seen the problem a few times, usually on higher hp,longer wheelbase cars. .............Tom __________________ Tom Goldman 1500 SG , 1506 STK

04-06-2010, 07:47 AM	#3
ericsz Member Join Date: Jul 2007 Posts: 140 Likes: 0 Liked 0 Times in 0 Posts	Re: Body roll....help!! Just to let you know the car is definately not a HP machine, it is a mild 406 runs 7.20's in the 1/8th with CE Slide a Links. Has the Ranchos out back that Calvert recommends for the Caltracs. __________________ Eric Bowling

04-06-2010, 11:46 AM	#4
Robert Simpson Senior Member Join Date: Aug 2004 Location: Jacksonville, Florida Posts: 808 Likes: 7 Liked 20 Times in 12 Posts	Re: Body roll....help!! Eric, what Tom said is exactly how I see it. I would not think that your drive shaft or pinion hit the floor due to body roll. If it did you have MAJOR roll. My first thought, without seeing or knowing your car, would be to put a additional leaf on the pass side, tighten up the shock on the pass side. But make sure that you leave your bars loose when making these adjustments then re set you bars. Yes, a sway bar would help. I am just thinking of inexspensive things to try. I hope you get it working out for you. Maybe it was just one of those things as far as your drive shafts breaking? Build it better and go back at it. But check the gear in your rear end. When things like that break, in our cars, we have to check other things because it sets a harmonic through the drivetrain that could crack a gear, and cut the life down on parts. Hope this helps.