Made 11 passes and the pass side front is drooping

[1040Dart]

Had the car all set up and after a day of running at the track the passenger side front was drooping 1.25 inches. Reset the torsion bars, to the proper ride height and it started to droop again after 2 passes. Have inspected the t-bar mounts, cross member, shocks, all of the suspension for anything broken. This is a 67 Dart, 10pt cage, BB with a motor plate, Comp engineering 90/10 shocks on the front end, tubbed. I have the TTI headers where the t-bar passes through the header on the pass side. Could this actually be heating up enough to lose temper in the bar? These are new .890 383 bars. Help!

 

[dukeboy440]

Had the car all set up and after a day of running at the track the passenger side front was drooping 1.25 inches. Reset the torsion bars, to the proper ride height and it started to droop again after 2 passes. Have inspected the t-bar mounts, cross member, shocks, all of the suspension for anything broken. This is a 67 Dart, 10pt cage, BB with a motor plate, Comp engineering 90/10 shocks on the front end, tubbed. I have the TTI headers where the t-bar passes through the header on the pass side. Could this actually be heating up enough to lose temper in the bar? These are new .890 383 bars. Help!

What brand of bars

 

[Bad Sport]

I have the TTI headers where the t-bar passes through the header on the pass side. Could this actually be heating up enough to lose temper in the bar?

I wouldn't surprised if that's the case.

 

[NC Engine Builder]

Header heat causing it? not a chance. Probally just poor quality bars......

 

[ssba]

If your frame socket is solid and not twisting
it would be the bar.
I'd get it out of there before it snaps in two.

 

[1040Dart]

What brand of bars

Mopar Performance

 

[1040Dart]

Header heat causing it? not a chance. Probally just poor quality bars......

 

[1040Dart]

If your frame socket is solid and not twisting
it would be the bar.
I'd get it out of there before it snaps in two.

These are new bars from MP, havent heard anything negative about their product. Frame socket was my first thought but they are solid. I also thought it might be a stripped adjuster but they are fine

 

[dukeboy440]

These are new bars from MP, havent heard anything negative about their product. Frame socket was my first thought but they are solid. I also thought it might be a stripped adjuster but they are fine

Count the number of threads on the adjuster at ride height, then do you passes, count the number of threads again, do this a few time or until it droops, if the thread number changes when it droops, it's the adjuster

 

[1040Dart]

I wouldn't surprised if that's the case.

Have you heard of this happening? TTI says (of course) that it isnt a problem

 

[1040Dart]

Count the number of threads on the adjuster at ride height, then do you passes, count the number of threads again, do this a few time or until it droops, if the thread number changes when it droops, it's the adjuster

Thanks, will do that next time out.

 

[dukeboy440]

Have you heard of this happening? TTI says (of course) that it isnt a problem

I highly doubt the header heat would affect the bars. Unless your exhaust is glowing red at the end of the run. The T bars are heat tempered, your headers would dang near have to be 2000 degrees

 

[Bad Sport]

Have you heard of this happening? TTI says (of course) that it isnt a problem

No, but repeated heating and cooling can't be good for it.

How hot does that header get at WOT? With the bar going through the middle of it, I would assume it gets pretty warm.

I'm just spitballin', but if everything else checks out good, that only leaves the bar. Maybe a defective one? I don't know.

 

[dukeboy440]

No, but repeated heating and cooling can't be good for it.

How hot does that header get at WOT? With the bar going through the middle of it, I would assume it gets pretty warm.

I'm just spitballin', but if everything else checks out good, that only leaves the bar. Maybe a defective one? I don't know.

Naturally aspirated, maybe 1000 to 1200 degrees, at the extreme. I mean extreme. Boosted, you could see 1600.

 

[dukeboy440]

And if you're that hot on the TBars, they'll be glowing red and the melt the dust boots at the minimum.

 

[1040Dart]

I highly doubt the header heat would affect the bars. Unless your exhaust is glowing red at the end of the run. The T bars are heat tempered, your headers would dang near have to be 2000 degrees

I would think there would be some damage to the coating on the bar if it were getting that hot, but a possibility. The AF ratio is good so I know I am not running lean enough to cause the headers to get that hot.

 

[dukeboy440]

I would think there would be some damage to the coating on the bar if it were getting that hot, but a possibility. The AF ratio is good so I know I am not running lean enough to cause the headers to get that hot.

Yeah my money is on an adjuster backing out or a bad bar.

 

[Bad Sport]

Count the number of threads on the adjuster at ride height, then do you passes, count the number of threads again, do this a few time or until it droops, if the thread number changes when it droops, it's the adjuster

Good idea!

 

[1040Dart]

No, but repeated heating and cooling can't be good for it.

How hot does that header get at WOT? With the bar going through the middle of it, I would assume it gets pretty warm.

I'm just spitballin', but if everything else checks out good, that only leaves the bar. Maybe a defective one? I don't know.

Thanks for the thought, I suppose it could be defective. Looking to go coil over now, really dont want to go to fenderwell headers if thats the case.

 

[Bad Sport]

Whatever the case, keep us posted on what you find, my curiosity is up, lol.

 

[1040Dart]

Yeah my money is on an adjuster backing out or a bad bar.

Well cheapest thing to do would be to replace the adjusters. I took both out and visually inspected them for damage to the threads.

 

[dukeboy440]

Thanks for the thought, I suppose it could be defective. Looking to go coil over now, really dont want to go to fenderwell headers if thats the case.

Well if you decide that route, highly recommend Gerst Tubular Suspensions. There's a 68 cuda pulling 1000+ hp and HUGE wheel stands, things nearly indestructible. And it's not as expensive as others.


That said, I'd say try to check out the adjusters and bars. That's the cheapest option

 

[dukeboy440]

Well cheapest thing to do would be to replace the adjusters. I took both out and visually inspected them for damage to the threads.

Make sure you replace the flat thread piece too.

 

[Daves69]

Paint a straight line on the bar and see if it twists. You could mark the a-arm socket and adjust arm as well.
Just measure the adjuster bolt head to the plate for a reference dimension.
I'm thinking you can anneal heat treated steel around 1050°-1200°F. It would need to get a dull red. Are you seeing that on your header tube?
I'd guess a bad heat treat or even missed operation if the rest is sound.

 

[340duster]

New torsion bars will lose ride height until the bars take a set. Not sure why one side is dropping quicker than the other. If you are drag racing only maybe engine torque twisting is doing that. I had a set of MP torsion bars on my circle track car do the same thing (although they lost ride height evenly). It took a few races for them to settle out and take a set. Same thing will happen if you switch the bars side for side as the will take a set the opposite way.