@Lane Anderson posted:@550aus, this one is going to be fun to follow along with. By the way, do you have a name we can address you by other than "550aus"?
Hi Lane, I also answer to Paul 👍🙂
Coincidentally, I've been wading through your excellent posts on the build of your coupe. What a lovely car, and some very nice engineering in there 👍
@DannyP posted:Dude, you are KILLING IT with your fabrication!
Might I echo a bit of what Ed suggested: mount the beam and line it up(make sure you have about 5 degrees of caster). Then weld it in on the bottom to the main longitudinal tubes. Put some smaller tubes diagonally down to the beam from your absolutely excellent dashboard roll hoop. You can place them just outboard of the fuel tank well.
Then cut out the entire beam-holding framework from Kitman.
Is the 5° you mention, the angle the top tube is leaning back relative to the bottom? Or is there a another measurement that needs to be taken when the front suspension is fully assembled. I've seen the caster shims that are sold to correct the factory settings, they go behind the lower beam tube to push it outwards I believe, and improve that angle.
I'm still inclined (excuse the pun) to work out a system where the front beam is bolted and braced in place, so I could remove it if I ever had to. Is the advantage of welding it in place purely the rigidity of the finished product?
Cheers
Yes, caster is having the top tube a little behind the bottom one.
Yes: welding the beam in is mo' bettah than bolting it. Weld it at the outboard frame tubes and gusset it, then put strut tubes in because you can. That will make it stiff. Once it's in, it's in. They last a lifetime. Porsche welded them in too, back in the day. If some day you decide you want to try to make an A-arm front suspension, cutting out the beam with an angle grinder will be the least difficult part of that effort.
And also, apropos of butt-welded frame tubes. Turns out that's the correct way to do that (assuming you can't bend them with a mandrel) so long as your welds are proper.
There's math and everything.
@edsnova posted:Yes, caster is having the top tube a little behind the bottom one.
Yes: welding the beam in is mo' bettah than bolting it. Weld it at the outboard frame tubes and gusset it, then put strut tubes in because you can. That will make it stiff. Once it's in, it's in. They last a lifetime. Porsche welded them in too, back in the day. If some day you decide you want to try to make an A-arm front suspension, cutting out the beam with an angle grinder will be the least difficult part of that effort.
And also, apropos of butt-welded frame tubes. Turns out that's the correct way to do that (assuming you can't bend them with a mandrel) so long as your welds are proper.
There's math and everything.
I will carefully consider my path forward regarding the front beam installation 😄
That's too much maths for my brain, but the end result was pretty clear. The sections I've added which have been butt welded have been sleeved as well, so they should hold. I think Carey may have broached the subject as main frame tubes which are bent to shape are a better option, rather than cut and welded.
Paul, yes, install the beam ensuring it is leaned backward about 5 degrees.
I've found that the space between the beam and the firewall is precious. It gets taken up by brake lines/front hoses and MC hoses/reservoirs. Plus horns(you are driving this on public roads, yes?) and the fuel line/lines. In my EFI setup I have both a pre and post fuel filter plus the pump itself. You'll want access from the bottom so you can adjust the beam. You also might want an anti-sway bar up front.
It all depends on how you do your fueling. I went with an external pump but you could easily do an in-tank pump. If you end up on carburetors external is easy and very functional, EFI can go either way.
