Hi Guys,
Finally got some more parts built after several test parts and jig building. This is the New Front Upper Control Arm. It started out as simply a mono-ball bearing version of the stock arm to eliminate the binding in the stock CAV rubber bushings used in the pre 100 series cars.
After carefully examining the front end to be sure the new arms wouldn't adversely affect the stock uprights bolt on ball joint mounting blocks, I came to some startling realizations...
a) What we now know is that in bump you can bind the upper ball joint, thereby making the suspension go solid and putting a tremendous shock load on the ball joint mounting block bolts. The new upper arm uses a larger ball joint with 32 degrees of angularity vs 15 degress fror the stock CAV part.
There have been some failures of the upper ball joint mounting block to the billet upright. To address this Autofutura issued oval washers to increase bolt head support and changed the design for new production, CAV Canada offers Oval Nuts and an overhaul procedure which increases the surface area considerably more for older style uprights.
This problem appeared to be the bolt heads getting drawn into the aluminum upright and therefore loosing torque and allowing the mounting block to flex. The service parts for this will reduce this tendancy, so if you haven't fitted the oval nuts or washers give Roy at VIP or myeslf a call.
Note: The larger in diameter the front tires and lower the ride height the more likely the upper ball joint is going to bind. We've had no problems with 24" dia fronts and 4" ground clearance.
b) The 32 degree ball joints have a larger stud and won't fit the stock CAV uprights. This part is not backwards compatable and will require a new front upright. I really preffer to make backwards compatability but it just won't work in this case.
c) The new front upright. Ready soon, I can show you the components of the new front upright though. It is a weldment with no bolt on mounting blocks, uses the same CNC steel hub as our rear upright combined with CNC machined towers to pickup the ball joints and tie rod ends. Different ball joint tapers are accomodated by the bushing inserts so the New Upright Will Be Backwards Compatable with old arms.
We do not have a binding situation on this upright either as the upper ball joint tower is inclined to match the king pin angle instead to perpendicular to the axle as in the stock CAV part. The towers pictured have more machining to go through.
More about the new upright soon, rest assured we have worked out the bump steer, ackerman, roll center heights, camber climb etc. to extract the maximum from the chassis, provide positive feedback in the steering and give more predictable handling at the limit.
Cheers
PS Thats an original GT40 front upright on the right. Our new part will look like a machined version of the original part
Finally got some more parts built after several test parts and jig building. This is the New Front Upper Control Arm. It started out as simply a mono-ball bearing version of the stock arm to eliminate the binding in the stock CAV rubber bushings used in the pre 100 series cars.
After carefully examining the front end to be sure the new arms wouldn't adversely affect the stock uprights bolt on ball joint mounting blocks, I came to some startling realizations...
a) What we now know is that in bump you can bind the upper ball joint, thereby making the suspension go solid and putting a tremendous shock load on the ball joint mounting block bolts. The new upper arm uses a larger ball joint with 32 degrees of angularity vs 15 degress fror the stock CAV part.
There have been some failures of the upper ball joint mounting block to the billet upright. To address this Autofutura issued oval washers to increase bolt head support and changed the design for new production, CAV Canada offers Oval Nuts and an overhaul procedure which increases the surface area considerably more for older style uprights.
This problem appeared to be the bolt heads getting drawn into the aluminum upright and therefore loosing torque and allowing the mounting block to flex. The service parts for this will reduce this tendancy, so if you haven't fitted the oval nuts or washers give Roy at VIP or myeslf a call.
Note: The larger in diameter the front tires and lower the ride height the more likely the upper ball joint is going to bind. We've had no problems with 24" dia fronts and 4" ground clearance.
b) The 32 degree ball joints have a larger stud and won't fit the stock CAV uprights. This part is not backwards compatable and will require a new front upright. I really preffer to make backwards compatability but it just won't work in this case.
c) The new front upright. Ready soon, I can show you the components of the new front upright though. It is a weldment with no bolt on mounting blocks, uses the same CNC steel hub as our rear upright combined with CNC machined towers to pickup the ball joints and tie rod ends. Different ball joint tapers are accomodated by the bushing inserts so the New Upright Will Be Backwards Compatable with old arms.
We do not have a binding situation on this upright either as the upper ball joint tower is inclined to match the king pin angle instead to perpendicular to the axle as in the stock CAV part. The towers pictured have more machining to go through.
More about the new upright soon, rest assured we have worked out the bump steer, ackerman, roll center heights, camber climb etc. to extract the maximum from the chassis, provide positive feedback in the steering and give more predictable handling at the limit.
Cheers
PS Thats an original GT40 front upright on the right. Our new part will look like a machined version of the original part
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