Mopar Muscle Association UK

Now the car is on all four paws and up to race weight we can set about installing the wheelie bars.

They are long 60" units, thanks to Turnip, Cheers!

Options for installation are very limited due to space on a narrowed axle.
I bought some pukka brackets but there is just no space to install them.....

The car is a ladder bar back-halved car.

The "best" (read "easiest and quickest") way of fitting them is to use the lower coil over mount to take the bottom of the Wheelie Bar set up on each side, and then weld brackets to the axle to take the top mounting points once we have the height adjustment in the ball park.

Does anyone have any major concerns about using the lower Coil over mounting points for this purpose?

Much appreciated.

Pete

Pete, without having seen the mounting arrangement, in my monds eye (which may not be correct you would be putting a bending moment on the lower shock fixing which doesnt sound adviseable. Eventually you would loose preload on the bolt and it will fail.

Have I visualised the arrangement correctly?

If it helps this is where they were mounted on mine.

Thanks Jon.

Clive - the lower point Jon highlighted in his diagram is where I am considering mounting them, but on a Ladder Bar set up it is not quite as robust, hence the question............

Pete, I would mount it as suggested BUT, you need to check the fixings you are using. Looking at Turnips picture, the lower shock mounts look to have nylocs on the bolts. Firstly, the bolts look too short. They need at least three threads protruding through the nut. second, nylocs are a poor choice for secondary locking (we NEVER use them in ANY application). Thirdly, bolts shouldnt be threaded up to the head - they should be shouldered for that sort of application and fourthly make sure the threads are rolled not cut.

Thing is, I believe the lower wheelie bar mount is going to put a rotation about the lower fixing (?) so if you clamp the joint up tight with a standard bolt and put the whole connection into compression, over time the rotation may stress the bolt and cause it to fatigue.


Trouble is, I dont know what forces are involved but I would expect they are high. I may be being over cautious. The bracketry looks fine but the bad choices look like they can all be made in the nut / bolt / washer / secondary locking areas.

Clivey- I understand everything else you say but why don't you use nylocs?

Clivey- I understand everything else you say but make sure the threads are rolled not cut ????

cut threads induce stress risers
bolt more likley to snap

rolled threads have a circumferance to both top and bottom of the peak and trough hence stronger...


Dave

db wrote:Clivey- I understand everything else you say but why don't you use nylocs?

The general consensus amongst engineers is that nylocs should only ever be used once, they can be affected by heat, moisture plus of course solvents and chemicals.

The alternatives are castellated nuts and split pins or locking wire, jet nuts, flange nuts or Flexloc nuts, all of which are 100% metal.

I always used titanium jet nuts and Thackaray washers on Weber carburettor set ups as nylocs where always coming loose.

Where I work, if we want to make absolutely sure that a bolt or screw does not work loose, apart from loctite, we use Nord-lock washers instead of any other type of mechanical method like nylocs, spring or shakeproof washers etc.

http://www.nord-lock.com/


And a few have found their way onto our propshaft / UJ screws, to stop them working loose, as they have a tendency to do otherwise

Thanks for the very detailed debate about fasteners - very useful in all applications.

However, at this stage i am more worried about "How" than "What with", so if anyone has practical experience of ladders bars I would really appreciatre their comments.

Thanks to one and all again.

Pete

Pete wrote:Thanks for the very detailed debate about fasteners - very useful in all applications.

However, at this stage i am more worried about "How" than "What with", so if anyone has practical experience of ladders bars I would really appreciatre their comments.

Thanks to one and all again.

Pete

i love your answers pete, is it just a nicer way of saying Bananarama! off with all that Bananarama! i just want to fit a set of weeli bars,

Thanks you kind sir, I always strive to be a gentleman.

What is your input to the debate then?

Getting back on track Pete, I've only had one car with wheelie bars (and it didn't need 'em!) but what would be helpful would be a bit more detail on the spec of the coil over mounts.

I don't see a problem with using them to mount the bars as the real stress must be taken to the top mounts.

Are they spring loaded bars or solid?

Hi Ivor.
They are sprung loaded ones, so that should take the hit out of the launch.

The top mounts will be solid mounted directly to the rear axle. I will make sure these are robust.

It was the potentially weaker lower mounts that I was more concerned about....cheers all!