cracked frame rail at crossmember

[ayge12]

The 6 Inserts that hold the crossmember are cracking
and pulling out of the frame rail. This failure could be
devastation if I was on the track and needed to stop fast.
31494862-5CC2-4413-A8E9-6D341F467CAD.jpeg2423035E-A199-43EB-A88F-DE6A301C2FCC.jpeg

So you can see where the motor/ trans would be above.
The trans cross member needs some support, so I’ll need to make some plates.
My first thought was to make some like these templates shown below
3DCF19F9-1402-4A81-94B0-A87C8362D95A.jpg

my second thought was to spread the load for more Support by
bending the steel reinforcement plate. The thought was to run several
inches up the side of trans tower and not just reinforce the bottom part.
but I’m not sure it will give much more support to the crossmember nutserts
which are the actual failure
7AB40631-B6C1-433C-A099-63B545EB4922.jpg

I’m not an engineer. Opinions on how to fix this are needed.
I’m also not scraping the car it’s not that bad, yet. Everything else has been reinforced RTAB, subframes, shock towers front and rear

[olemiss540]

I personally would weld in a reinforcement plate and then shim the tranny mounts with a washer if possible? Never have seen that failure mode before, cant be much load there if the rubber tranny mounts in a stock car dont tare in two pieces. Must have smacked the sht out of it? Arent only two of those holes used by the tranny cross-member?

[Def]

Honestly, if the material local to the nuts has failed to that degree, it might be easier to just cut them out and then have welded nuts on some 1/8" cold rolled steel you then weld to the original cross member.

You could hammer the threaded inserts back up into their original spot, stop drill the cracks, and tack weld over, then grind/flap disc them flat, THEN put on a 1/8" thick reinforcement plate... but that's probably 10x the labor of replacing the threaded sections at the same time you reinforce it.

You could use really long bolts to thread through the new part/nuts and into the original nuts (all facing the same orientation they'll be installed in) and then tacking the nuts to the reinforcement. That way you use the original chassis as an alignment jig. Hammer the inserts back to the proper installed location first obviously.

Some new nuts welded to some 1/8" cold rolled steel, welded to the frame rail along the bottom is more than strong enough.

If you want the same alignment, you could cut out the original framerail and recess the 1/8" reinforcement into it, but that's more work aligning things.

Lots of options, just depends on how you want the finish product to look/perform.

[ayge12]

I do think it took the weight of the motor and trans while I was as removing the motor. There was only 4 bolts in the cross member too. This is a 400whp LS swap using a ce009 as well so that complicates things.

[ayge12]

Thanks for the reply. I went ahead and made some reinforcements out of some hot rolled 10 gauge I got for free today at the local supplier as scraps. I def to hammer the nutserts back in place , I was debating if I needed to weld weld the cracks, so thanks for the advise there.

Your idea of welding nuts on the reinforcement plate is really solid I don’t think I’m up for cutting the old nuts out tho. Gonna ask a buddy to come look and tell me what he thinks.

- - - Updated - - -

Here they are, the need a little trimming. I’m not a fab guy. Just small stuff. I will drill some smaller holes for plug welds too…part of me wants to just epoxy everything with the 3m stuff the e46 guys use for subframe plates

[golgo13]

I swear these cars are just overpriced German Honda civics lol

[ayge12]

I swear these cars are just overpriced German Honda civics lol

Haha If only Honda Civic’s were wheel-drive I have owned a half a dozen of those too.
I wish I never bought this car to be honest, it has so many freaking problems starting with the spun rod bearing Now I’m going to have a beefy e36 it looks like shit on the outside lol trash car I should’ve just save some more money and bought the Porsche

[ayge12]

Here is an update, I am still. gonna drill some 5/16holes for plug welds and clean everything up.
next, i need to find a c25 gas welder to buy it.
the. I hope I don’t blow through !

Im debating if I should weld all the way around or stitch weld ? I might to a few tacks.
Then some stitches and then weld around those slowly.

Also not sure if I shoold quench woth air or not- I think it’s a yes TBH but I don’t wanna make it too brittle

02828A53-D966-4ED7-B4E9-BD19C445B536.jpeg

[Def]

Here is an update, I am still. gonna drill some 5/16holes for plug welds and clean everything up.
next, i need to find a c25 gas welder to buy it.
the. I hope I don’t blow through !

Im debating if I should weld all the way around or stitch weld ? I might to a few tacks.
Then some stitches and then weld around those slowly.

Also not sure if I shoold quench woth air or not- I think it’s a yes TBH but I don’t wanna make it too brittle

02828A53-D966-4ED7-B4E9-BD19C445B536.jpeg

Mild low carbon steel doesn't quench and temper like this. Just weld and let it be.

Not a bad idea to go around in 1" long stitches to slightly reduce distortion, but I'd probably weld all around just to seal things the best you can.

[ayge12]

I appreciate that advise! I think I gone a decent welder with some c25 gotta go test it and buy it

[Yahweh]

Weld in alternate spots about 1 inch stiches. IMO, 1 inch stitch with .25 spacing is better than 360 on sheet metal. 025/030 wire, 75/25 gas is what the welding shop will understand. Wouldn't worry about "hitting with air or keeping warm" A blow gun is nice to keep the smoke out of your face and work area. Wurth makes copper weld thru primer you can use between the metals to help keep future corrosion from happening.

BMW sells reinforcements for this location, its happened before.

[ayge12]

I was unable to find anyone who has had this area crack like this, nor was I able to find anyone who makes plates for this area.

I did get a welder last week and have gotten it setup correctly. I have practiced a little and been reading/watching lots of videos. Im gonna need some more practice before I shoot it for sure!

[Yahweh]

http://bmwfans.info/parts-catalog/E3...eton#2256494_2

#2

I have L & R in stock. Same concept as you did. You may even cover more surface area.

Welding upside-down is even more fun! Have a good welding jacket and neck protection.

[ayge12]

Well I’ll be! Thanks sharing those.
im surprised no one else in the other places have shown me those.
I’m gonna try and shoot em on this week
got the subframe supports all welded in.
they look like turds, but they will hold.
im gonna Plug weld and do some
stitches every inch and call it good

Neck protection, Great tip BTW

[ayge12]

@yahweh do you know of those plates you posted weld in ? Glue ? Or just sandwich?

[Yahweh]

Weld in.

Patience, Keeping heat on the plate. Some cavity wax or and old grease can be inside the sheet metal, so if you blow though it gets rough.