At 06:14 PM 12/18/04 -0500, rsperbeck wrote:
"I see where people are putting MGB king pin set up on MGA because the MGA part is weak. Is this possible to put this on a Twin Cam?"

At 12:38 PM 12/19/04 -0500, Bill Spohn wrote:
"I've just been castigating people on the other group for doing this as it isn't legal for racing and in my view it is also unecessary - just use strong enough king pins.

If I WERE going to convert, I'd probably use Volvo 4 pot calipers, which are even better than MGB .... but as the thing outbrakes just about everything else in class already, I expect I'll just leave well enough alone."

At 04:57 PM 12/19/04 -0500, Roger Andreason wrote:
"I had a king pin failure many years ago when racing. As far as I could determine the cause of the failure was that the thread had been cut too far and the end of the thread had cut into the area where the section changes causing a stress raiser. I checked a few new kingpins and found two where the thread ended correctly and never had another problem.

I suggest looking closely at the original design parts and make sure that there is no undercut at the end of the threaded section. If necessary a small amount can be machined away - it will make the component stronger even though you have removed a small amount of metal. Obviously only do this on a new part, not an old one!"

At 03:37 PM 12/20/04 -0500, Dave B. wrote:
"Should have told BMC this so they wouldn't have made that expensive tooling change from the MGA to the MGB suspension!

But for those of you who do wish to make the change, to end up with decent steering geometry is not a slam dunk. Some folks shorten the tie rod arms (even seen this recommended by a West Coast specialist who should know better!) which really messes things up. You really need to shorten the rack - about 1 1/2"+ - and move the rack forward (the twincam chassis already has done this) and down a bit as well. I made this conversion on the Devin/MGA I sold a while back and the bump steer was at least as good as the original A suspension.

You also need to choose between the A or B shock. If you use the A shock, you can't simply throw some spacers between the arms and through bolt it. You need some rigidity in the assembly or it will get wobbly. I helicoiled one of the shock arms and put a jamb nut outside to hold the 1/2" bolt rigid and solidify the unit."