RB header hitting subframe
 

I need some ideas on what I can do to get the downpipe of my racing beat header from rattling against the subframe. I recently had the welds at the flange rewelded and I suppose since he didn't have a jig it pushed the end outwards away from the engine and into the subframe. Obviously having it rewelded again is an option but I want to see what else I could do before it comes to that.

So this is how close it currently sits. https://www.miataturbo.net/attachmen...ine=1396990698

I've thought of loosening the bolts and pushing it back, assuming the holes are bigger than the studs. I've also wondering how malleable the metal is and if I could take a pry bar to it without damaging it too bad.

Anyone else have any suggestions?

https://www.miataturbo.net/attachmen...ine=1396990027

And if that doesnt do the trick

https://www.miataturbo.net/attachmen...ine=1396990008

https://www.miataturbo.net/attachmen...ine=1396990698
Yeah, that's close.

My RB has no flex to it at all, its a pretty stout collection of tubes. Not sure how you would manage to bend it and maintain any sense of alignment while not collapsing the tube.

How are your motor mounts? If they are FUBARed, they will place the motor in a different position that may cause the header to hit the subframe. Another option would be to shim the mount at the cross-member to raise the engine for clearance.

They're MSM mount, but they're 4 years old or so. Motor mounts have been mentioned to me before.

The more I think about it, the more it makes sense to just have it welded into the correct position :facepalm:

Yea....that motor mount idea. I would start there. Whoever said that is a freaking smart guy.

I'm going to ask a dumb question: What year is the RB Header made for?

living up to you user name with the pointless question.

Have you recently loosened and tightened the 3 bolts connecting the transmission tail housing to the power frame for any reason? (like a recent clutch or transmission change?)

If your RB header hits the frame or floor you might loosen the 3 power frame to transmission bolts (2 long and 1 short) 1 or 2 turns. Then have someone push the transmission tail housing toward the passengers side while you tighten the 3 transmission - power frame bolts.

The bolt holes in the power frame are a little large allowing some movement in assembly.

It may save you having to cut and reweld your header.

Following the above if the motor mounts (the rubber part) seem a little twisted... you could support the engine (with a floor jack under the pan) then loosen then retighten the motor mount nuts at the front subframe. Again the looseness on the mounting holes will allow some movement reducing the sideways preload on the motor mount.

good luck...

He didn't mention that it was a 99-00 specific header. It could be a 94-97 one that he got for cheap.

Still would fit the NB chassis, just not the rest of the NB exhaust.

+1

It's a 99-00 RB header, bought in 09 or 2010 I believe.

Put it up on a lift last night and pried on it really really hard with some big pipes. Loosened the flange nuts and then jacked up the rear of the header and then tightened them. Both of those methods helped, but it still makes contact on decell, any right turn, and at partial throttle. But it doesn't do it at over 1/2 throttle and WOT anymore :D These pipes are pretty damn beefy, they didn't collapse even with some heavy pressure on them.

Going to try motor mounts next, because I think I need them anyways. I'll probably end up getting it rewelded this weekend though :-\

Have them fix it or if you don't want that person working on it again take it somewhere else.

i'm on the re-weld boat. I'd rather not dick with my motor mounts when I already know the best solution.

Unless its only hitting shit because the motormounts are toast and need to be replaced anyways.

MOTOR MOUNTS! It sounds as though your mounts are toast.

$15 for a small chuck of metal? Sounds like a rip-off to me. It isn't even machined very precise. I could make that with hand tools in less than half an hour.

Exactly, and at $60/hr on the very low end of the cost of fab work labor + like $2 worth of steel it doesnt seem to expensive now does it?