subframe connectors redux

[moparmat2000]

hi Yall

i could never figure out how to add my pix to my original thread that i originally started but here goes with the new thread so i can show pix. the connector shown in the pics is a tacked together bunch of thinwall .083 thinwall scrap only for a mock up. this will not be used except as a template to make my heavy duty .125" 2x3 connectors. this makes it easier to make a template for what im going to do. i used a drill in the first pic and drilled holes on either side next to the frame rail so i could get a starting point on slotting the floor. i cut and fitted a little at a time patience works during this step, this way you dont have to weld back in anything you cut out later LOL

notice how i cut the framerail tips at the back and dovetailed the subframe tubing into them. this maximizes the solid 2" height and holds it tight to the frame with no lost ground clearance, which is why i ran them thru the floorboard too. trying to max the strength. i cant wait to buy the thicker tubing and weld em in for good. bigblock darts pix are lacking a bit in this area. maybe these pix i have posted will help somebody else out. i am also going to drill three maybe four 3/4" holes in the bottom of each subframe connector as drain holes for water.

check out pix
matt

 

[7dswinger]

Nice. What car is this going on?
To note though, be careful when you weld it all together not to warp anything with heat, go a little be at a time. Could happen or not but better to play safe.

 

[moparmat2000]

67 cuda coupe. the entire floor pan you are looking at in my cuda was donated out of a 74 dart 4 door along with its transmission crossmember. i do autobody as a side line, and have replaced everything from truck bedsides, to floor pans and rear quarter panels so i know about going slow with the welding, and only spotting it a little at a time especially the floor since its thin. the green primer is an aircraft epoxy etch primer. the actual color of the car will either be safety yellow or petty blue. you can view my progress photos just click the link (view photos by moparmat2000) in my post.

thanks for the kudos
matt

 

[longarm]

Nice job Matt !!:thumbup:

 

[Brad4406]

Looks good. Mine look like that, except I didn't bother with the front plate; I just welded them directly to the front crossmember.

 

[crackedback]

Before you weld them in, round the corners on your front plate.

 

[68dodge]

Very nice Job.

 

[moparmat2000]

I planned on rounding the corners on the fwd plates a bit. Since this is the template i didnt feel it necessary. I may modify this install a bit more as i put the thicker permanent ones in. The reason for the plates is since imgoing to use .125 or 1/8" tubing i dont want to weld it directly to the crossmember in the front. The 1/8" "fishplates"transition that load to the thinner crossmember, and will hopefully prevent cracking over time.

I work as an aviation structural mechanic as a living, and do auto body and sheetmetal as a side. When you use a thicker metal tied to a thinner metal you should transition the load, otherwise the thinner metal over time will fatigue and fail. The crossmember is .083" so using the "fishplates" to transition the load from the 125" or 1/8" 2x3 tubing to it i should never have a cracking issue. Maybe im over thinking it a bit, but ive been in the biz for almost 20 years i have seen lots of stuff fatigue crack , and fail. I look at this stuff a bit differently, i will prob cut the framerail back a little more and eliminate the dovetail in the connectors, as that is a weak point as well.

Thank you all for the nice comments. I wish the car was further along, but with 4 kids its a bit hard to get the scratch you need to do this kind of project.

Matt

 

[rgreule]

thats how i did mine but turned the it tall ways.. then pounded about 4 inches of the subframe connector into the rear frame rail.. worked out nice.. yours look very good

 

[moparmat2000]

I went sideways on the tubing for 2 reasons. 1 the issue with the parking brake cable hitting the subframe its a street car and not a dedicated track car. The cable clears the subframe easily this way, and 2 i didnt want the rails sticking up too high thru the rear footwell since it will still have a back seat. I thought about turning them upright but these were the problems i was facing. Since theres more than one way to do this, i liked all the different ways that everybody did theres. I actually took lots of different ideas from everybody to make mine LOL Now i will have the strength the car needs, rear foot well, and park brake cable clearance too. Problem solved via the internet, and many talented individuals on this site who were nice enough to share their ideas with me. Maybe my pix will help somebody else out who wants to do this.

Matt

 

[doug 371]

good job

 

[moparmat2000]

Well i got my thicker tubing, about 2 weeks ago and finally fabbed up my connectors that are actually going to go in the car. I cut the framerails back approx 1" more so i didnt have to dovetail the tubing, just cut the top off it.

I am using a 74 dart transmission crossmember under this car, and where the parking brake comes out on the 74 crossmember had to be modified. This way my mating plates for the front of the subframe connectors would sit flat. I believe this crossmember has this bumped out spot in the stamping from 73 to 76.

Anyway fixed that spot on the crossmember. Cut the bumped out section out, flush welded a flat plate where it was, drilled 2 new holes in crossmember to route the cable to come out above the subframe connector. This also allows it to clear the inboard upper side of the subframe connector so it wont rub.

So the connectors are done, got weld thru primer on everything that gets covered up when it goes together. Shop is a total mess, tools and air hoses everywhere. I got pix of em fitted, but not installed yet. Mebbe in another week or 2 i can get back under the cuda and weld em in for good.

I will post my new pix when i have time

Matt

 

[moparmat2000]

Well i got my thicker tubing, about 2 weeks ago and finally fabbed up my connectors that are actually going to go in the car. I cut the framerails back approx 1" more so i didnt have to dovetail the tubing, just cut the top off it.

I am using a 74 dart transmission crossmember under this car, and where the parking brake comes out on the 74 crossmember had to be modified. This way my mating plates for the front of the subframe connectors would sit flat. I believe this crossmember has this bumped out spot in the stamping from 73 to 76.

Anyway fixed that spot on the crossmember. Cut the bumped out section out, flush welded a flat plate where it was, drilled 2 new holes in crossmember to route the cable to come out above the subframe connector. This also allows it to clear the inboard upper side of the subframe connector so it wont rub.

I also drilled three 3/4" holes spaced the same in the bottom side if each connector as drain holes. Love that unibit lol.

So the connectors are done, got weld thru primer on everything that gets covered up when it goes together. Shop is a total mess, tools and air hoses everywhere. I got pix of em fitted, but not installed yet. Mebbe in another week or 2 i can get back under the cuda and weld em in for good.

I will post my new pix when i have time

Matt