magnumP5's RX-7 Build Thread

I was just thinking about this build today at work. Are you getting the hang of your MIG?
I'm getting better; just need more practice, but I've run out of material again. I think I'm to the point where I understand what the different sounds/behaviors mean so now I need to focus on keeping the nozzle close to the work space and moving at the correct speed. I think I'm ready to tackle the seat mounts, but I haven't come up with a design I like. Everything seems to require too many pieces or has welds everywhere.
 
I think it's pretty addictive! I spend a lot of time while working at work thinking about making pieces and parts. Most of it never comes to fruition, but it passes the time.
 
ya, i think about fabrication a lot lol. its super neato to tell people u made that lol.

btw, i have searched and searched, and cannot for the life of me find the welding thread...
 
^ haha thanks. i realized i could just go into my user cp and go to my subscribed threads...

damn coffee hasnt kicked in yet...
 
I got some work done over the weekend. The general frame for the seat mount is done.

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This is how it looked right before I cut it out so I could weld the backsides of the cross braces. The middle piece at ~90 degrees is temporary but I didn't think it was going to be at the time (hence the seam welds and not tacks). I know the welds on the cross braces are a little cold but it's all I could do welding them to 16 ga (the braces are 1/8"). They are also welded on the backside and from the "touching up" I've done it looks like there is enough penetration. The bracket is now cut out and has the holes drilled for the seat brackets. Since I don't have a drill press some of my holes are a little "off" so some reaming of the seat brackets is required. I decided instead of welding on M8 nuts I'm going to weld 1/4" plates on the undersides of the bracket and drill/tap them. After that the brackets get welded back in the car and some more 16 ga sheet is used to box everything back in.

I tested the height of the seat and my helmet now just barely touches the headliner. I can now freely move my head but it's still a little close for comfort so I'm going to ream the seat brackets a little to gain another 1/4" to 1/2".
 
Hmm, seems like your helmet will be awfully close to the ceiling. Does the headliner give a bit? Will the harness hold you in tight enough that on a big bump you won't hit your head on the ceiling? I can only imagine how that would feel at speed.
 
I was just looking at the rules for LeMons (not that you'll be doing that, but it seems like good general info) and they mandate 2" of clearance between the tallest occupant's helmet and the roll cage. Figure if you roll it (worst case) the roof comes down and you go up...
 
I agree with all points above but at this point, short of cutting out and welding in a new floor, there isn't much I can do. The seat is so low in its brackets that it's practically sitting on them and those brackets are only 1/4" off the floor of the car. Maybe I just have a big head/helmet. The rollbar goes all the way up to the headliner so right now my head is in-line with it. Eventually, when racecar, the headliner will be gone and I'll be able to add a roll cage that is 1.5-2" higher. The sunroof really cuts in on headroom.
 
Yeah, sunroofs are the devil when fighting for head room.

Once the headliner and mechanicals are out of the way, it frees up quite a bit.
 
Yeah, sunroofs are the devil when fighting for head room.

Tell me about it. I had to keep my head any from the sunroof in my 3 when I did that hyperdrive. If I wasn't carefull I kind of got stuck in there.
 
Wow an update!

I was able to get around to this Friday night and started with the seat anchor points. These are 2" sections of 1" x 1/4" flat stock welded to the back of the mount. I then drilled two holes in each and tapped them to M6 x 1.00. There are two holes because for whatever reason the holes in the bottoms of the seat brackets are at different widths depending on how you mount them.

2012-04-06_20-12-59_562.jpg


I have no idea why the HAZ shows so clearly on the rear bar and not the front even thought the settings were exactly the same and were welded at about the same speed. I still have a little ways to go on the welding anyway...

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Finally, test fited the seat.

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The new mount is now fully welded into the car and I've removed the temporary brace but it got dark and the pictures started to suck. Testing fitting the seat in the car shows a total height reduction of about 1". I know it seems like nothing but at least my head is no longer touching the headliner with a helmet on. I figure I'll ream out the holes in the brackets a little to gain another 3/8" and I should be good. All that's left is to measure/cut/weld some 16 ga. sheet to box everything in.
 
Nice! Looks like your getting the hang of that welder!
I'm getting better that's for sure. I just need more practice...

No pictures again (ARGH!), but I was finally able to remove what was left of the temporary support piece. Hopefully the difficulty I had removing them is a testament to the strength of my welds... Anyway, I got that done and I made the first plate of four that will box everything up. Those are going to take a while; both to make and to weld in.
 
Made the remaining plates on Saturday. It took me all afternoon to make the remaining three.

Over all idea:

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Forward side of the front (I know I need to remove some more paint):

2012-04-14_17-32-57_397.jpg


Back side of the front mount. The front plates don't go all the way to the floor because there is still some of the stock mount remaining to which I can weld.

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Front side of the back mount. Note the contour of the bottom. These were mich harder to make since there isn't any existing structure to use. Grind and fit and grind and fit and grind and fit some more...

2012-04-14_17-32-44_599.jpg


Lastly, the back side of the back mount, which was the biggest pain of them all.

2012-04-14_17-30-17_518.jpg


Tonight's plan is to prep all the surfaces for welding and tack everything in place. Welding is going to be a pain because I'm going to constantly have to switch settings to weld 1/8" to 16 ga and 16 ga to like 22 ga.
 
Remember to go slow and let things cool so that the seat will still mount up when you're all finished!
LOL, I remembered that... after I warped the front mount. The good news is the seat brackets bolt up to the outsides of the mount, which didn't move much, if any (they're much stiffer with the 1/4" plates). Over all everything will still work; it's certainly not pretty though, but not too bad for my first effort. No pictures yet but I've just about got the front done and the rear is tacked in place. I ran out of wire so I've got to pick some up on the way home tonight. I AM grinding down the beads on the top of the mounts because I want the seat brackets to sit flush. It actually looks pretty neat as it makes the mounts look like they were originally part of the car. So far several wacks with the BFH hasn't revealed any failures...
 
I don't know welding but I do like the progress, pics and hand built rails. (2thumbs)
 
Ugh, more set-backs. This time I ran out of gas (I will not use flux core!) and I'm slowly killing my angle grinder. Hopefully I'll be able to get out of work before 4:30 today to go and grab another bottle.

Everything is welded but I'm finding I need to go back over a lot of places because I wasn't getting penetration. Other than looking like utter crap, everything appears to be holding together. I've been having a really hard time welding with all the different thicknesses, and right as I was getting the hang out it I ran out of gas. Once I get a new tank I'll probably do another pass over everything to clean it up. There will be no pictures of the final product here...
 

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