65 mustang

Finally got the tube chassis car to the strip for some run time.It is the tube car I bought a while back,did some up dates on put in scottke's motor.Only made a couple of half way pass's .Motor ran good which was a relief,a rocker arm trunion broke and put needle bearings all over the place before I got it out of the shop.It ran 6.51 at 108 mph on a half way foot brake pass but went into violent front end shake when I lifted, when I say violent it was a under statement.Glad I shut it off a little early.I could find no visable problems.soI went back out to test transbrake and delay box it worked good picked up over a tenth in 60 foot maybe ran 80 feet as soon as I lifted right back in to front end shake.It has home made capri struts I'm thinking it's time to buy aftermarket struts and avisit to the chassis shop. Anybody have any other suggestions ?

Tire balance maybe? Just guessing though.

I don't believe it could entirely be the fault of the struts. Those style struts have been used on a bunch of fast race cars through the years with no problems, even when they were worn out. Could be an alignment/geometry/bumpsteer problem.

Barney it shouldn't be the tire's wheel's.They are the ones off my fox body.Before I changed to Bogart's on it.Maybe I should take and have the front end lined before I do any thing else.I'm not too faint of heart when it come's to driveing a car but tire wobble a 108 mph will get your attention.
I guess I have to agree with you the car ran fine last with trap speeds @ 100 mph.Last pass it went into shake at 50 mph ? or less.
One interesting note that has noting to do with this but I found out it is a early 64 1/2 not a 65,or so I am told.Something about door panels,dash and absence of side trim. ??? Never been into that suff but the guy that sprayed it is a old mustang buff.

Glad to hear motor did well.

The problem could be most anything that has already mentioned (tire balance, alignment, geometry, bumpsteer). And it could also possibly be badly warped brake rotors, or a badly worn out rack & pinion with a bunch of slop.

Years ago I worked on a very old full chassis car that had the ancient original design Strange struts (round aluminum strut body instead of the newer cast aluminum body). It's internal strut cartridges were completely dead & worn out. You could grab the tires & shake/wobble the whole assembly around because the internal bushings & piston were so far gone. But the car didn't only exhibit just a "shake" or "wobble", it also drifted around during the pass & braking because the toe-in kept changing from all the strut slop. Might not be the problem, but it is something else you might as well check out.

Got any pics of how the current setup sits in the car?

Not the brakes it starts before you touch the brakes .I'll get son photos of the chassis and post later. Thanks

I bought one of the alignment tools from summit. Then two 9 foot sections of conduit put equal length string through them to make parallel lines, and alignment was easy. I was surprised how simple it was. I have stock style suspension on my 66 coupe (TCP UCAs make it much easier), and I can align it in less than an hour. When I am tweaking it, it takes longer to set the strings up.

Sounds like toe-in/bumpsteer and/or something loose. I am worried about my truck's bumpsteer. I can't get it all out. I'm going to try again when I get back from vacation. I sure hope you find the problem and get it fixed.

Don't seem to be anything worn or sloppy.One of the local racers is a frontend guy and is going to look at it this wk.

dr's wife racing wrote:Don't seem to be anything worn or sloppy.One of the local racers is a frontend guy and is going to look at it this wk.

Caster

We found the rack was moving in the mount.It has a pinto rack.We welded tabs to stablize it.I'll have it lined and go from there I'll post any progress.Thanks for your help.

makes sense, when you loaded up the front end the loose parts moved.

David Willingham wrote:Sounds like toe-in/bumpsteer and/or something loose. I am worried about my truck's bumpsteer. I can't get it all out. I'm going to try again when I get back from vacation. I sure hope you find the problem and get it fixed.

David, what is the truck's current bump-steer profile looking like & how much total toe change is there (each side) throughout the total suspension travel?

For example, if each side (on it's own) showed a total travel (full compression to full extension) toe change of say something like .050" (or less) each side, while at the same time showed a bump-steer profile/curve that stayed mostly on the toe-in side of the scale, that really wouldn't be too bad. Especially since the Strange strut's don't have a bunch of total travel.

And even if the total toe change is more than .050" (each side) it might not be as much of a problem as long as the profile/curve stays mostly on the toe-in side of the scale. It will of course increase tire wear/scrub as the toe change increases, but if it's staying on the toe-in side of the scale it will at least still try to drive straighter.

However if any part of the profile/curve does move/sweep out to (or stay) mostly on the toe-out side of the scale throughout most of the total travel, then that can be a problem and can increase the chance the truck will "guardrail hunt".