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Discussion Starter · #382 ·
Thanks, guys. I need to find the post, but it’s not my own idea. May even have been Nealric who made that wise suggestion when I started asking the question a couple months back. As always, I appreciate the input from the team here. Thank you.
 

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Discussion Starter · #384 ·
Thanks, guys. I need to find the post, but it’s not my own idea. May even have been Nealric who made that wise suggestion when I started asking the question a couple months back. As always, I appreciate the input from the team here. Thank you.
Found it. Credit for calling local shops goes to…75tickspark
 

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Discussion Starter · #390 ·
Little by little. Progressing on the new front crossmember tonight.
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DS tacked in with the removable plate bolted in place. PS next and then tacking in the crossmember tube before removing the crossmember and cutting out the temporary support tube that I tacked in while cutting out the old crossmember.
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I'd be doing the cross member build last.

Get the engine and gearbox in, fully bolted up. Engine sump, brake master cylinders, etc all in their place and you very happy, I.e. no more unsolved questions.

Then finish the conversion by making the cross member and engine mount solution
Pete
 

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Nice.
Are you using a plasma cutter? My friend with the plasma cutter moved away, so I use an angle grinder now. It's painful cutting 1/4" steel.
 

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Discussion Starter · #393 ·
I'd be doing the cross member build last.

Get the engine and gearbox in, fully bolted up. Engine sump, brake master cylinders, etc all in their place and you very happy, I.e. no more unsolved questions.

Then finish the conversion by making the cross member and engine mount solution
Pete
I don’t have any objections to that advice. I wasn’t sure if it would be problematic having no crossmember of any sort in place.
You’ve been around these cars a whole lot more than me though, so if there’s no structural issue with keeping the bay void of a crossmember during the fit up, I’m game.
Thanks (as always) for weighing in. I know you hate these conversions, but I really appreciate and listen to your input when you share. Thank you.
 

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About structure: When you cut major structure (like a roof, or crossmember) you must make provisions to get everything lined back up correctly when you restore the structure (like roof or crossmember). So hopefully, you braced the bodywork before the cut. However, I remember the Alfa Spider as having huge amounts of cowl shake (read this as, if you didn't probably wont matter that much).

Anyways, I have cut roofs and realigned, it's amazing how much flexing occurs without a roof. My Milano is noticeably less torsionally stiff than a modern BMW (this may be unfair comparison due to vintage, but E30's are also stiffer). If I jack up the right side, it takes a bit before the left side comes up, this happens quicker on BMW's. Anyways, for a convertible, torsionally weak from the beginning, I would still have tried to brace that interior space to minimize the body twisting.

That bar you have for the purpose of restoring geometry seems to still be in the way for fitting purposes, especially as the sump is where that bar is.
 

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Discussion Starter · #397 ·
About structure: When you cut major structure (like a roof, or crossmember) you must make provisions to get everything lined back up correctly when you restore the structure (like roof or crossmember). So hopefully, you braced the bodywork before the cut. However, I remember the Alfa Spider as having huge amounts of cowl shake (read this as, if you didn't probably wont matter that much).

Anyways, I have cut roofs and realigned, it's amazing how much flexing occurs without a roof. My Milano is noticeably less torsionally stiff than a modern BMW (this may be unfair comparison due to vintage, but E30's are also stiffer). If I jack up the right side, it takes a bit before the left side comes up, this happens quicker on BMW's. Anyways, for a convertible, torsionally weak from the beginning, I would still have tried to brace that interior space to minimize the body twisting.

That bar you have for the purpose of restoring geometry seems to still be in the way for fitting purposes, especially as the sump is where that bar is.
Your statements track with my gut feeling. My plan was to tack in my frame plates (orange in sketch below) on both the driver and passenger sides, then tack a tube steel crossmember (blue) to the plates that bolt to the frame plates. This will lock the present geometry into a reference crossmember before I cut out the tube I had tacked in (red squiggled out in picture below) prior to cutting out the original crossmember.
At that time I can unbolt them crossmember and get the engine in place, monkey it around to fit and plan the pan, mounts, etc. as needed, then confirm the car is still in shape by bolting the crossmember back in.
Hood Automotive tire Motor vehicle Automotive lighting Vehicle
 

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I think your idea is good. I was actually thinking of maintaining the vertical relationship of the lower A-arms, they should the same height off the ground when all finished. Your bar will maintain the width dimension with ease, but the vertical relation is difficult.

In practice the race car people will perform a corner weighting procedure so the 2 rear wheels have the same weight, and the 2 front wheels have the same weight. The left turn only crowd does something different. This is very easy to visualize as a four legged stool with one shorter leg.
 

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Looks good.
But because your dealing with a convertible (a very old one) I would make custom jack stands that support the rear trailing arm mounts so that they are level, and the same for the front A-arm mounts. I think the doors should be easy to open/close when fixtured. I also think that by design, they may have a larger than normal easy open/close range. (read that as sloppy door fit by design, or larger than normal adjustment range).

You may think this overkill, actually, because convertible. But, if you intend on a roll cage, it is good to minimize frame twist between front and rear suspension mounts, before roll cage is welded in place.
 
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