so, i berkeleyed up. possibly irreparably.
when i did all the cutting and welding for oil pan clearance on the miata k frame, i didn't jig it, or support it or brace it, or stagger weld, or.....
really, cranked the welder to ALL OF IT and burned in my parts.
when i reinstalled it today, i was discouraged to say the least. the rearward "ears" that bolt to the frame toward the rear of the car are roughly an inch or inch and a half narrower than the holes in the body. to the point that the header doesn't fit on the drivers side, motor wont drop at the back end for trans, etc.
i THINK i can save it. somehow spread the rear legs of the k frame apart while keeping the studs that still fit finger tight.
my thought was to use a housejack between the two parts, as i don't own a portapower and really don't want tpo go buy one.
ideas? am i just berkeleyed?
Cut enough at weakest points to bend out and bolt it in. re weld in place slowly, moving around with small welds.
Would it be possible to sprrad it with a foundation jack? Or a bottle jack?
You can build a spreader outta spare steel tubing, 1/2-3/4" pipe oughta work. Weld foot pad on end to suit. 1/2" all thread or bolt w/ foot pad welded on, washer on pipe end w/ nut on thread to crank out to spread. I've spread truck frames w/ this.
Lighter and smaller than jacks or porta-power and does just as well but not as well cold bending.
Still prolly gotta cut, heat and bend your subframe.
Edit, found it:
Im going to try your spreader first!
Hoping to pull the repair off without cutting and welding. But i ain't holding my breath.
NOHOME
UltimaDork
7/8/18 7:17 a.m.
All manner of ways to force the thing into shape. First step is finding out where it needs to be re-shapped. Is it even flat or are you going to have to pull a twist out of it also?
I would start by finding a frame dimension document of some sort, nailing the k member on to a level piece of 3/4" plywood and seeing if it lies flat then measure what needs to bend to make it match. I am guessing it will all be in the front crossbar with maybe a bit of twist to get it flat. The only way this could be irretrievable is if the front is too wide or too narrow to fit in the space, and since you never cut it in half, I dont see that as the issue.
Pete
It is as flat as the car, so thats good.
The spot that is got me to notice is the rearmost two mounting bolts. The ones under the floor pans. They are both in the correct plane, but are roughly 3/4 of an inch inboard of the threaded hole they go to. So the rearmost parts narrowed as the welding warped things. However it is flat throughout, so i got lucky there.
I THINK the driver's side is the one that warped, as the header, which had almost no clearance, is now hitting.
Im thinking at this point:
Shift k frame so the passengers side bolts all line up if possible. Tighten passengers side bolts to ALL THE TORQUE.
Tgen, with drivers side loose, use the spreader bar ideato push the bolts into position if possible. Maybe slightly elongate holes if necessary.
Is that a reasonable course of action?
Where are you located? It's unlikely that you're in CT, but if so, I have NA front and rear subframes that I don't need any more.
Just checked your profile - NC, so I'm not much help.
Using the car as your jig might work, you'll probably want to take a few measurements once it's bolted back up to make sure you'll be able to align the suspension when it's all said and done.
In reply to Brotus7 :
Thank you for the offer! Good call on alignment specs afterwards. Hadn't thought about it.
My bet is that both sides pulled in. When I first started welding, I welded two pieces of square tube together at a 90. They were both 8 feet long or so. at the ends, they pulled in a foot as I remember. Just what happens with the heat.
I would have reservations about elongating the holes, because the suspension all bolts to the subframe. If it's bent inwards at the rear then the mounting points for the control arms are now also pointing inwards. That's probably going to lead to lots of caster and possibly to bumpsteer issues.
Good point.
Im still mentally preparing to tackle this. Definitely knocked me down a bit.
Good point.
Im still mentally preparing to tackle this. Definitely knocked me down a bit.
Can you apply heat to the frame, safely, as you are using the spreader? I think the frame would have "spring" in it spreading it cold. Make sure you use quality bolts/studs when bolting it up.
Measure before and after the spread attempt, to insure proper front end parts line up. You don't want the car to crab as you drive it.
To check your work, you can probably take a few measurements of the control arm mounting points relative to the subframe mounts. They ought to be pretty similar left to right.
THANK YOU GOD AND GRM!!!!!
Its spread and bolted. Scissors jack and a chunk of 6x6 did the job. Dad and i measured 7 ways from sunday, and found that only the last 8 inches or so were warped. 3 out of 4 holes on each side lined up already, with the 4th being an inch off on eityer side. Spread apart halfway down the rear leg, and it all went smooth.
If it wasn't for the screwjack idea, i wouldn't have even tried.
Great to hear, had similar issues in the past with welding. I try to remind myself to stagger weld and check the alignment, but it is easy to forget and just start attacking it. Glad to hear it ended up working out for you. When I did my R160 rear mounts on the Spitfire, one side bolted up fine and the other was at least 1/2 out of alignment. I had no choice except to cut my new brackets at the welds, bolt every thing together and then tack weld it together with it assembled and then remove everything and carefully reweld the brackets in the proper alignment. Was a pain, but it all reassembled easily. Good that you can continue your progress, can't wait to hear when you fire it up!
