19 replies to this topic

[Sphinx]

I'm talking about the pair that run along the bottom of the car and are often bent by improperly placed jacks.

I've read about some folks "massaging" them back into their general shape, but they'll get bent again the next time the untrained puts a jack under there. Has anyone "reinforced" them or done something to prevent the unsightly sight of bent rails? I know flyin' miata sells some that I'm sure violate the rules.

[davew]

Any form of reinforcement would be non-compliant.

Technicly, bent ones would also be non-compliant.

With a roll cage the fram erails are non functional, just ignore the bends.

Dave

[SaulSpeedwell]

I'm talking about the pair that run along the bottom of the car and are often bent by improperly placed jacks.

I've read about some folks "massaging" them back into their general shape, but they'll get bent again the next time the untrained puts a jack under there. Has anyone "reinforced" them or done something to prevent the unsightly sight of bent rails? I know flyin' miata sells some that I'm sure violate the rules.

I hate squished framerails and pinch welds, too!

If you have the Harbor Freight "Prybar" kit (like huge screwdrivers with bent tips), the longer one can be worked into the nickel-sized drain holes and you can pull down on framerail's inner surface WHILE hammering on the bulged sides of the frame rail with a sledge hammer (a 2X4 helps in some places and in some places the bare sledge is better). Unless they are REALLY bad, the frame rail will magically "self-heal" back to its original shape while you hammer on it. Then do light taps around the drain holes to get those looking good again. Then spray or brush with black undercoating/bedliner.

[CruzanTom]

I'm talking about the pair that run along the bottom of the car and are often bent by improperly placed jacks.

They can also be bent by going off-track over hard curbs or ruts (like T11 before Bridge at Road Atlanta). Not sure how I know about this but I am glad the rails were there to protect the rest of the undercarriage.

[Bench Racer]

I'm talking about the pair that run along the bottom of the car and are often bent by improperly placed jacks.

I have jacked on the pinch weld continiously on two different Spec Miatas and on a F production Miata whith none of the pinch rails failing/bending in any manner. The rails you talk about are all screwed up, but that's from on track situations.

[Keith Novak]

I have jacked on the pinch weld continiously on two different Spec Miatas and on a F production Miata whith none of the pinch rails failing/bending in any manner. The rails you talk about are all screwed up, but that's from on track situations.

I've bent one of mine even jacking at the prescribed location. Probably due either to being sloppy about how I put the jack under there or accidentally releasing the jack too quick and trying to catch it by locking the jack mechanism as the car fell like a stone. I think he was talking about when people jack from the frame rails and not the pinch weld though.

[Bench Racer]

I understand he's talking about jacking on the frame rail. My point was, jacking midway between the wheels on the pinch rail works for me on three different chassis.

[Sphinx]

I understand he's talking about jacking on the frame rail. My point was, jacking midway between the wheels on the pinch rail works for me on three different chassis.

The pinch rail is better, but still bends too easily. The way I jack there is that i have a nice nylon jacking pad, with a little cutout groove for the rail, that I got from JC Whitney 10 years ago.

As for the inner rail, that's just a POS and I still don't understand why anyone would jack it from there. And I admit my desire to straighten it back is purely cosmetic.

As for reinforcement, the only reason is to have a better place to jack it up, nothing more fancy. But now I know how I'm going to win the run-offs, I'm going to protest every car with a bent frame rail!

[Johnny D]

Send a letter, see what you get back, couldn't hurt.
Maybe include how you would. Showing no benefit other than a good jacking point.
J~

[Zauskycop]

A nice alternate to the previously mentioned jacking pad, that some of us "northerners" use, is a hockey puck with a groove cut out for the frame rail...

[Bench Racer]

The way I jack there is that i have a nice nylon jacking pad, with a little cutout groove for the rail, that I got from JC Whitney 10 years ago.

If I ever notice bending I'll use a similar pad with a groove. Currently the jack has a round aluminum pad with a rubber insert, flex may help.

This is realy a fun subject. Last I looked at the production car rules it was illegal to have an extension from the roll cage extend through body panels for jacking purposes. X number of production cars have this.

[Qik Nip]

Any form of reinforcement would be non-compliant.

Technicly, bent ones would also be non-compliant.

With a roll cage the fram erails are non functional, just ignore the bends.

Dave

Dave.
I'm crushing mine right now! Do you think there's much of an aero benefit?
Rick

[Duane Polsley]

If you jack the car with the jack at a 90* angle that allows the jack wheels to roll in or out seems to help the pinch welds. If jack wheels cant roll then the pinch welds bend in a hurry.

[Ron Alan]

If you jack the car with the jack at a 90* angle that allows the jack wheels to roll in or out seems to help the pinch welds. If jack wheels cant roll then the pinch welds bend in a hurry.

I've seen the result of a crooked jack first hand!

[Glenn]

If you jack the car with the jack at a 90* angle that allows the jack wheels to roll in or out seems to help the pinch welds. If jack wheels cant roll then the pinch welds bend in a hurry.

Or jack a car in the "kitty litter" at VIR, LOL

[Sphinx]

Or jack a car in the "kitty litter" at VIR, LOL

Which reminds me of a war story. Jacking up my SRX7 from the cross member at Summit Point, 2004. 10 minutes before we're called to the grid for qualifying. Jack up the car, on gravel (stupid), no e brake, car slides backwards, radiator lands on the jack and a small coolant leak begins where the radiator attaches to the shroud right under the the fill cap.. Thank God for an ITS friend who had some permatex cold weld. 10 minutes, glued back together. I remember standing on the grid, with the hood open, just holding the joint together, hoping the hot sun will help it cure faster. 5 minute whistle, hood down, and off I went. TEmps held steady, ran the race that way too. Whew!

[PRFGDWRNCH]

Those rails are spot welded in place and at last check, were available from comp at under $100.00 per side. You could replace them if their condition bothers you. When we had the tub on the rotiserre last winter I thought about it but decided they would probably end up just as flat as they are now. They seem to function as floor stiffeners .
Dave
SM Rookie

[Sphinx]

The real problem is on the passenger side. The fuel lines are bolted to one side and depending on how that rail gets crushed, the fuel line could be damaged either by a jack or by the rail itself.

[LarryKing]

They seem to function as floor stiffeners .

Bing Bing Bing - Johnny, tell him what he's won. That's exactly what they are. "Frame rail" is a misnomer. The unibody support is in the door sills.

[Johnny D]

Bing Bing Bing - Johnny, tell him what he's won.

I don't know, what knowledge? Yay
J~