I have no bodywork skills yet, but part of the process of 'finishing' the car for me would include flattening out the hump protruding into the cabin. Granted I could just weld a flat sheet in there but I'd like to cut, bend, weld the stock panel so it's flat at the window frame. How would you slice and dice to avoid adding sheetmetal and still get a smooth flow to the bottom? Just to clarify, not touching the seat area, just the engine cooling air passage.

The 2 hammered looking parts are to clear the v6 heads, and it's getting covered in a nice rubber backed carpet.

I beleive that firewall is structural. I think you would need to triangulate a brace from the lower window corner to the opposite floor/long. This will stop the flex created by removing the hump.

the hump adds unit body strength

I say go for it.

My want to see what will collide though, and can you install or remove the engine if you do.

not the on the floor! the one on the back cabin wall!!

What's on the other side of the cabin wall? I'm guessing it's not stock from the hammmered mention so that makes it a little tough to tell what can be cut or not.

And if you cut the hump, can you remove the engine or the belt???

Ummm... what V6....???


I hope you realize that there have been many conversions done, and done very well, that did not require any modification to the rear firewall. Don't get me wrong, as you can see on my tag I am not a purist, but cuting the firewall is a deal killer on any conversion for me... or any car I would consider buying. But, as it has been said many times, it's your car and your money. I'm just saying that you may want to reconsider your current engineering path...


I guess I should have provided a cavat of the alien...

Does the hump allow a flat-six to be in the engine bay? It seems like the fan housing barely fits and the extra space makes it possible.

Yeah... No.

Click to view attachment
Click to view attachment

I have never felt so insulted.

But I'm going to let it slide as you joined after I did the conversion, and the scrolling sig hides the build link.

So anyways. Here's the oldest pic I can find with reason for the hammer marks.


Plenty of belt changing space as it's all below the area getting reshaped.


I updated the first pic with a better description of my goal. And this is what I'm thinking will work.
Red cut lines, yellow bend lines, so it's flush with the window frame plane.

I think the main reason for the center hump is to allow air to get to the inlet of the cooling fan of the two original motors (1.7/4 and 2.0/6).

Will there be room for a piece of square tubing going across the top of the firewall? If so, that is likely going to add more stiffness than could possibly be lost by removing the hump.

--DD

You would probably be amazed at how much stiffness the hump adds to the panel.

Something to think about- it is much easier to resonate (vibrate) a large mostly-flat panel vs one with a big hump.

If you really want to know, run a FEA analysis model. That will tell you.

Ah, vibration is a different matter. That would probably be worse, though having the panel broken up into several semi-independent sections (cutting and bending as the OP mentioned) would probably damp that out a fair bit.

FEA or actually building and testing would tell us with a higher degree of certainty. But I still think that a good brace of tubing across the top of the firewall would keep things at least as strong as the stock part.

If there's room for it, of course!

--DD

The box I built is 17 ga, with 1/2 angle iron around the opening. The removable panel is 18 ga. held with dzus fasteners. No issue with strength. The top section is like a package shelf and made of 18 ga. it's not going any place.