bizarre suspension problem

[neandethal]

Hi, we have had our dampers rebuilt by AVO and then refitted ( they needed to do them twice, as the first time they were soft when tested on a bench) however now the car sits about 40mm higher and there is no damping action when they are fitted to the car it bounces dreadfully but plenty when tested in a vice on the bench, and they vary with the adjusters as expected.

any good ideas, we haven`t touched the spring tubes or any other part of the suspension. any suggestions gratefully received.

[Richard hollis]

The shocks shouldn't make the car sit higher. I'm not sure why you have found this. We run our AVO's about 6 clicks back from maximum and they work ok but they are the budget end of the shock market. Having said that my car ran top ten with AVO's last season. Give me a ring if you want to chat about it (07891 017873)

Richard

[Richard hollis]

Just a thought - have you fitted the fronts on the back and vice-versa. The fronts are much shorter than the backs.

Rich

[neandethal]

update.

cut the spring tubes apart and found that there are 4 springs in each tube welded together as pairs, there is a thick coil of 80mm length and then a thin coil of same length welded to it, the thin coil is really easy to compress by hand, the thick one impossible. so the first movement will always be the thin one hence the bounce!

my question is what length should a race spring be? 80mm or 160mm, same front and back? or some other dimension. cheers for any help.

[Pete Sparrow]

there isn't a specific length for springs to be honest, lots of different types, sizes, rates and shapes have been tried over the years. On a standard car i think the rears are longer and a slightly higher rate. what matters is making sure you can get the car to sit at the correct height once you have the race springs in the cans. We normally use a spacer under the spring or a tube between the cup at the back of the spring and the tie rod to get the desired length, keep the tie rod un modified, they will generally break if they've been welded. Just make sure that what you do allows the rod to pivot slightly (as per the original cup arrangement) and that everything is nice and square to avoid any unnecessary loads.

[Ken Hanna]

Pete,
in case you'll be fettling any road cars, the rear springs are the shorter (and stiffer) ones.
http://www.flickr.com/photos/30132857@N06/6341616448/
Don't ask me about how these race cars are set up, though...   ;)

Ken

there isn't a specific length for springs to be honest, lots of different types, sizes, rates and shapes have been tried over the years. On a standard car i think the rears are longer and a slightly higher rate. what matters is making sure you can get the car to sit at the correct height once you have the race springs in the cans. We normally use a spacer under the spring or a tube between the cup at the back of the spring and the tie rod to get the desired length, keep the tie rod un modified, they will generally break if they've been welded. Just make sure that what you do allows the rod to pivot slightly (as per the original cup arrangement) and that everything is nice and square to avoid any unnecessary loads.

[Pete Sparrow]

I got it half right  ::)

[neandethal]

thanks for all the help, much appreciated see you all at Donnington