Operation pesky headers;
Hey gang. Curious on what options people have used to cure this pesky situation. Friend brought over his 70 Challenger which has headers. Seems the idler arms wants to play tag with one of the header tubes. Any suggestions? Guess there is heating the tube and using a curved/cylinder to indent the tube for clearance, maybe swapping out the idler arm with a less bulky end, if there is such a thing. Orrrrrr, the harder option of a different set of headers..

Common issue. Easy fix. Wrap both ends of the idler in wet rags, cherry the center of the idler up with a torch and bend it down where you want it. Do it quick and then quench the idler. I suspect this fix will bring in some nay sayers, but I have done it numerous times and have not had a problem. I had to do that to the one on my Cuda and it has been on there for years.

There have been tests that show dinging header tubes has no effect on performance. (Roadkill Garage did a video on the subject that used to be on YouTube but Motortrend has since made it available only to paid subscribers.)

Rather than heating the idler arm and bending it, just take a BFH and a round piece of .120 wall tubing and create the clearance needed on the header tube. Piece of cake.

If it has a BB and he likes to spend money 2" TTI headers will clear even the longer fast ratio arms.
I have them on my 70 Challenger.

Fairly common for either the pitman or idler to hit a tube.
Had TTIs on a BB Duster and the arms swatted the tubes quite a bit, worse than anything else I recall.

I had the same problem with the moog arm I got a correct mopar repro and there if lots of clearance

...or modify the idler mount. Factory recommends ovaling the hole of the mounting bracket to alter the plane of operation, then welding a washer to the bracket to lock in desired location. Also be sure to shim steering box a similar amount.

you also could consider adding a shim between the motor mount and isolater to slightly lift the engine.

I'd be cautious that banging away on a header tube to clearance it doesn't break a weld at the flange on the head mounting surface, if you go that route.

which headers are those? which engine? which cylinder heads?

I could be as simple as finding a original or different brand/ style idler arm. They vary a lot in shape and style.

I would check the engine mount, if stock type rubber, it may be compressed some lowering the engine. Maybe switch to a more durable mount that won't compress like the after market poly types.
Also sometimes people have a washer to take up some space where the Idler arm bolts to the K, if so move the washer to the bottom to raise the idler up a little.

Where does one get the reproduction style Mopar arms.. I am interested to know...


The other suggestions all seem to have their merits..

try here
http://www.billrolikenterprises.com/proddetail.asp?prod=2535886

Can't tell from the pic, but are you using the fast ratio (c-body) idler with the fast ratio pitman? If so, swapping to the stock idler will clear.

Here's what you need. These insulators will raise the engine enough to clear. Used them on many A bodies.

are those truck mounts by chance ?

Never ever should you need to bend the idler arm. This will change the arc of the idler arm causing toe change as the idler arm pivots. It is possible that the idler arm pivot bolt location is off from the factory. If the centerline is not level to the chassis this may be the issue. Is the center link higher on the right side? If the centerline is level, leave the idler arm pivot alone. Either raise the motor by shimming or put a small dent in the header. It will not affect performance at all. If the center link is unlevel heat the K frame bracket and bend it until the center link is level. It bends very easily with a little heat.
Doug

Different brands of idler arms often position the drag link in different planes of operation in relation to the pitman arm. And the exact position of the idler arm mount on the 'K' can vary from car to car. All of that changes the arc. It is nearly impossible for most of us to know where the ideal position of all of it should be. And how can we be sure that the pitman arm is in it's correct plane. To say that bending an idler arm that may have the wrong angle to begin with is a bad fix, may not be true. I am not sure that bending the idler's mount on the 'K' to correct an improper angle on the idler arm itself is a better solution. And some folks may not be anxious to burn the paint off their 'K' member. But to each his own.

My background in suspension includes over 30 years of suspension/frame work for a living. You are correct the steering box could be in the wrong location. However I haven't ever seen one off a significant amount unless the car had been heavily wrecked. Idler arm brackets however are common. Whether welded crooked to start with or bent. Many years ago I came across this issue . The front end of the car would move in a circle over bumps. When it was in jounce it would go right. In rebound it would go left. Car had 22k and had not been wrecked. As a young mechanic I pursued a fix. Reading about suspension geometry I realised it had toe change (bump steer). Thinking nothing of it I heated and bent the idler arm. Car drove much better in a straight line as the right and left toe curves were similar. One day my wife pulled the car into our driveways. I saw something hanging from under the car. When she stopped the wheels were straight, everything looked fine. I watched as she turned the wheel. Imagine watching the idler arm swing down about 2" off the ground when turning left. And rising up nearly hitting the frame turning right. After talking to an old Chrysler dealer mechanic I installed a new idler arm and straightened the bracket. This fixed it (still own the car). If the idler arm is moving the position of the center link, it's the wrong or incorrectly built arm. The ideal position would have a parrallelagram formed by the inner tie rod pivot, outer tie rod pivot, lower ball joint pivot, and the center of the lower control arm pivot. Obviously the 2 inner tie rod positions are located by the height of the center link attachment points at the end of the idler arm and pitman arm. As a close starting point if the center link is parallel to the chassis thru its travel most cars will drive pretty well. It can definitely be tweeted to make it perfect. But for most applications this is unnecesary. Hope this explanation helps.
Doug

Numerous times I have had replacement idler arms hit the headers while the one it replaced did not. And to be honest, I never thought to blame that issue on the idler's mount. If the idler arm were built at the wrong angle (and that happens often enough) then bending it into correct alignment is no worse a fix than bending it's bracket. In fact, if the issue were to be the idler arm itself, then bending a correctly positioned mount in order to correct a problem with the arm, would not seem to be the best route to go. But to each his own.