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Finished my Cobra Automotive-like 70 Engine Crossmember

buening

Active Member
I made a thread awhile back about two options for my design, the original Cobra Automotive style end brackets and what I felt was an improved version. I decided to run with my version, but in the end I doubt it will matter much. I would like to thank member hsr for getting the ball rolling on this and obtaining and drafting the dimensions up for the 65/66 crossmember, and would also like to thank jmn444 for measuring his CA crossmember and marking up the dimensions that are different on the 67-70 crossmember.

A little background on this. I installed a T56 trans in which I lowered the motor 1" and moved it to the rear 1.25". This meant the stock crossmember no longer fit. Rather than just making one similar to stock, I decided to tie in the LCA mounts to add more rigidity much like the Cobra Automotive crossmember does. I also wanted it to serve as a jacking point for now.

So since my situation was custom due to the oil pan location, I simply drew up the end brackets on a 2x8 piece of board, and cut out the center to follow the factory crossmember shape. I then put the board up in place like it was the crossmember, marked where cutting needed to occur, put the board back on the bench and cut as needed. I repeated this over and over until I had enough clearance. It resulted in the top of the crossmember center section being 1.25" lower than the stock piece.

The below drawings and dimensions are not intended for stock location engines. It will work for stock location engines, but it will just hang down lower. No guarantees of fitment for aftermarket oil pans. I'm working on drawings for this crossmember with a motor in its stock location, in case someone else wants to use this.

For the end brackets I used 2"x2.5"x3/16" angle. I believe the CA piece used 1.5"x2 5/16" bent plate. For the center sections, I used
16"%20wall
. Since the CA piece had 1.5" for the top leg of the end bracket with 3/16" thick, that meant if I used 1.5" square tubing with those CA dimensions the tube would stick out past the bent plate/angle 3/16", thus the reason to bump up to a 2" top leg. Now for some drawings and pics. I put some up close pics of the drawings as well as an overall view, as I'm not sure the dimensions will show too well in the overall view due to its length and picture size limitations.

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End Bracket:
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Bottom Tube section:
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Angled Tube dimensions:
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And top/plan view of end bracket:

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And here is the finished product (still in painting process though):

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Comparison to the stock piece:

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And pics of it sat in place (but not fully installed). Pictures didn't turn out too well since I was on my back and the chrome oil pan created some nasty reflections/backlighting

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As you can see, this car is no trailer queen by its dirt and grime. Its a driver It doesn't help the oil pan and PS pump is leaking, adding to the grime.

I have the Pro-Motorsports Eccentric Eliminators sitting on the workbench. My plan is to use a longer bolt with a nut in between this crossmember and the LCA, and another nut and washer on the face of this crossmember. For the pictures I just have the crossmember bolted in but not hooked to the LCA, as I have other suspension mods planned in the future and I don't want to mess with the alignment just yet (since its getting warmer out and I'll have the urge to drive the car).

I was a bit torn on how to handle the eccentrics. I had thought about removing the eccentric holder that is spot welded to the LCA mount and welding it to the face of this crossmember, which would make alignments MUCH easier. However, I was a bit concerned about the increase in bolt length and the distance between each eccentric plate. In the end I decided to leave it as is.

I also did not capture the top two dimensions of the overall view and the picture is tiny. The top dimension from frame bolt hole to frame bolt hole is 2'- 5 3/8". The dimension below it is from the centerline of LCA slotted hole to centerline of LCA slotted hole, and is 1'-7 1/8"
 
Last edited by a moderator:
Attached are PDFs of the stock mount as well as my modified crossmember with the motor 1" drop and 1.25" relocation to the rear. Again, due to the width to height ratio the dimensions appear small when printed on 8.5x11 paper. I recommend zooming in to see the dimensions. I can plot PDFs out in sections like my pictures above if there are requests for this.

I can help with modifying these drawings if someone has a custom application. I would basically need the dimension from the bottom of the frame rail to where you want the top of the crossmember center tube, as well as the top width of the center tube. If you notice the attached PDF drawings of the stock vs my modified one, as you move the center tube up with a set top width of tube, your angles and lengths of the side tubes all change. I can get that altered in CAD pretty quickly, so don't be shy to ask!

https://www.dropbox.com/s/wnx1z0z32097i ... dified.pdf

https://www.dropbox.com/s/0i3voqwr2raax ... 0Stock.pdf
 
Re: Finished my Cobra Automotive-like 70 Engine Crossmember

Looks nice Jeremy, I see that as a future project for mine along with your motor mounts. Guess that one guy on VMF fizzled out on getting a bunch of the motor mounts cut-up. I can probably get everything I need to do a set except for the DOM tubing.
 
Looking good. Its always fun to see the bottom side of cars, the business end. Sure the outsides are seen the most but to appreciate a car you have to see its inner workings..
 
Finished my Cobra Automotive-like 70 Engine Crossmember

Awesome work you constantly impress.
 
Thanks guys!

Grabber, you don't necessarily need DOM tubing for the bushing housing. You can use regular tube and just remove the weld seam on the inside. DOM just eliminates that extra step. You don't necessarily have to remove the weld seam, but it provides a line to wear the rubber bushing
 
"phlegm" said:
Looking good. Its always fun to see the bottom side of cars, the business end. Sure the outsides are seen the most but to appreciate a car you have to see its inner workings..

Yeah I have a TON of work to do on the underside in the engine area. I've just been slowly chipping away at items. I have plans for the suspension, so I haven't touched that worn out area as can be seen.

Having a 2.5yr old girl and a 4mo old boy has diminished my time, so I was lucky to even get this crossmember made!
 
Pics of the eccentrics that come with the Cobra Automotive crossmember. The thought process for tieing the crossmember to the LCA is the same, except instead of the oval/eccentric washers I will be using square plates with holes drilled (see below for Eccentric Eliminator pics)

231-060114123957-280940.jpeg


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mump_0901_11_z+mustang_performancre_steering_wheel+front_view.jpg
 
Excellent work. Join the multi-kid club. I had so much more time when my kid were young. This year is the first year that I can devote to my mustang in like 5 years I think. Now I'm jacked.
 
Re: Re: Finished my Cobra Automotive-like 70 Engine Crossmember

"buening" said:
Thanks guys!

Grabber, you don't necessarily need DOM tubing for the bushing housing. You can use regular tube and just remove the weld seam on the inside. DOM just eliminates that extra step. You don't necessarily have to remove the weld seam, but it provides a line to wear the rubber bushing

Thanks for the info I'll keep that in mind.


"buening" said:
Yeah I have a TON of work to do on the underside in the engine area. I've just been slowly chipping away at items. I have plans for the suspension, so I haven't touched that worn out area as can be seen.

Having a 2.5yr old girl and a 4mo old boy has diminished my time, so I was lucky to even get this crossmember made!

Congratulations on the new little one.
 
That piece looks fantastic. I don't know when I'll get to it, but I've already bought all the steel I need to make a copy.

Thanks for the inspiration!!


-Shannon
 
Its amazing how little this costs to make as long as you have a way to cut and weld. I think I have $10 in steel and a few hours fab time.
 
Back from the dead. Are the pics showing to anyone else? Or did they get lost in the switch over?

Bill
 
All pics in my threads were lost. I will try to upload them again sometime soon. They are on my work computer and I have the week off
 
"buening" said:
All pics in my threads were lost. I will try to upload them again sometime soon. They are on my work computer and I have the week off

Thank you. You've got some nice threads I've been wanting to view with pics. I like the right up you did on this one and I'm interested in seeing the pics of the Ron Morris style engine mounts.

Bill
 
Thanks for the compliments. I restored the pics of my T56 conversion thread on another forum (1969stang.com) and it took me two hours. The motor mount one will likely take longer since it had even more pictures. Guess I shouldn't post so many pictures :hs Even worse, none of the internet archives have the original thread with pictures so I know what order they were in....so I basically go off memory and/or guess
 
The ones on VMF are screwed cause they don't allow editing of posts after a certain thread age....so basically I can't change picture links on any of them on the VMF. :(
 
All pics are back up except for the installed pics. Still need to dig more to locate them. They weren't all that great since I don't have a lift.
 
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