Thread: And more questions: Front suspension & clearance

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Originally Posted by Itoldyouso

In case anyone wants to read about these:

www.ritzsite.net/Tiger/01_tiger.htm


Don


Right about now Faith is saying "where the h*** did my thread go?"

HIJACKERS! HIJACKERS!

Actually I don't mind the hijacking at all, it is the 'bickering' that is upsetting to me... For a moment there I thought I was going to have a bloody war on this thread Oh nooooo I really don't want this forum, which is SOOOO COOOOOOL to turn into another hotrodders.com cause I ran out of there as fast as I could, bullets were flying everywhere, heavy artillery blasting, everyone seemed to hate everyone and I think I had a target pratice sheet stappled to my forehead because many strangers were taking cheap shots at me, left and right... I sustained so many bullet holes, when I drink now, I turn into a sprinkler system

Clubhotrod.com has been so refreshing and such a wonderful departure from the horrible experience I had on the 'other forum' ... I simply LOVE IT here.

So far noone here has EVER said anything that has offended me in any way.
SO I BEG YOU, PLEASE DON'T FIGHT.... be nice to one another, yes we are all different, but somehow we are also all the same: hotrod lovers at the core...

Updates on engine height.

Hiboy was on the rack again yesterday. It gave me a chance to really look at my suspension, clearance etc... I aso looked under the belly of several other hiboys friday night at Bob's Big boy cruise night. People must have wondered why I was spending more time lying down on the ground with my head under the cars than standing upright hehe... Anywhoo, I found that my engine is sitting lower than anything else I saw that day. Consequently when you look inside my car I do not have a transmission buldge between driver and passenger size which results in lots of leg/feet space. In short my transmission is mostly under the car compartment. I noticed I have only currently about 1/4 inch space clearance between firewall and transmission. I also noticed the bushing on engine mounts are tired. Jeff (my significant other - who is a certified Chevy tech) mentioned we could get new bushings, which will bring engine up a hair, but the transmission doesn't have alot of room to go up. I know we are looking at a triangle, so if engine goes up 1/2 inch for ex transmission will go up less, maybe I can get away with a little raise of engine this way... New bushing cant hurt anyways, right? Worth a try since Jeff can do the work himself (saves me $$).

As far as leaf springs, I thank you all for yoru warning, I do cherish both my arms and I think I'll let the rod shop battle with the springs on their own.

As far as Panhard bars, all the roadsters here have them and I can tell you from experience that not having one is making my hiboy handle very poorly when we hit potholes, especially on the freeway... The car will suddenly jump sideways, by a good few feet!! Pretty scary. Me no likey.

It sounds like you're running the 48 Ford rubber biscuit style mount.

They do tend to give up the ghost - some of them are made of overly soft rubber.

Take a look at the white motor mount biscuits on my 31.
They're cut from UHMW (Ultra High Molecular Weight) plastic.
Similar appearing to Teflon, but 70% stronger from what I understand.

Hard as a cotton-pickin' rock too, but they do damp vibrations and after installing a pair of them in my 32 that uses the same style mount, the car seems smoother than it did with rubber biscuits.

UHMW is available at industrial rubber stores - places that cater to farms and oil field - in sheets of varying thicknesses.

Cut em out with a hole saw, clean up, drill for motor mount bolt size and you're in business.

If you buy some small UHMW sheet pieces from the remnants pile, it's usually pretty cheap.
UHWM costs about 1/3 of what Teflon costs fwiw.

Maybe $3.00 invested in both sets of motor mounts on my two cars - four biscuits.

Here's a slightly thicker pair on my 32.

I failed to mention that there is a small UHMW biscuit on the underside of the frame motor mount bracket.

The whole design is pretty much the same as the 48 - & earlier - flathead Ford motor mounts.

Thickness doesn't seem to matter much as far as vibrational harmonics go.

UHMW cuts easily with a regular saw if you need a square or rectangular shape.

You don't need the aluminum load spreader plates as seen on my cars.
I have a lathe and make lots of little goodies for the hot rods....

Faith, I guess I owe you an explanation about the Panhard bar. It is a suitable solution to the prevention of lateral movement of the axle relative to the frame. The problem I have with them in my opinion is:
1. Nobody makes them long enough. The longer the bar, the less pull and tug there will be on the axle/frame. If the bar is secured to a frame extension on the driver's side and secured to the axle via an extended mount on the passenger's side and is limited in its length only by the tires/wheels, then I say go for it.
2. Nobody mounts them properly. The bar should be level, the same distance from the ground left and right.

I would rather see you install a dead perch on the passenger's side than a Panhard bar, but that is your decision.

Mr. Techinspector, I thank you for your explanation of your opinion about the Panhard bar. Maybe I did come on too strong in my question. I didn't intend to be offensive, but only wanted to have some facts to back up your opinion. Peace?

You are right . . . a panhard should be as long as is practical in the car, and it needs to be level. Otherwise it will push the front end of the car a little sideways as the suspension moves up and down, and this will cause the car to wander around, rather than going straight down the highway (bumpsteer).

This is why I don't like a "dead perch". The dead perch connects one end of the spring directly to one of the perch bolts, without using a shackle, so half of the spring acts like a panhard. The advantage of this arrangement is that it's simple . . . no extra parts. The disadvantage is that this "panhard substitute" is very short, and it's not level. Two of the primary requirements for a good panhard.

The drag link should also be level with the ground for the same reason. As the suspension moves up and down, the arc that the right end (passenger side) of the drag link moves vertically, so it doesn't try to push or pull on the right steering arm. If both the drag link and the panhard aren't level, you'll get that dreaded bumpsteer problem.

Originally Posted by Hot Rod Roy

The drag link should also be level with the ground for the same reason. As the suspension moves up and down, the arc that the right end (passenger side) of the drag link moves vertically, so it doesn't try to push or pull on the right steering arm. If both the drag link and the panhard aren't level, you'll get that dreaded bumpsteer problem.

All above points have been well noted. However I am now confused I thought the panhard bar was supposed to REMOVE the bump steer I currently have? But you guys are saying if not set up right it will cause bumpsteer? More bumpsteer than I currently have WITHOUT the Panhard bar?? (if that's humanly possible ).

I don't think you can entirely eliminate bump steer with either a panhard bar or a deadperch because they both swing on a long arc which changes the effective length with the up and down motion. However, I would think either would GREATLY REDUCE bump steer compared to none at all. I think you can see in my picture a page or so back that the panhard bar on my '29 is parallel to both rods of the cross steer setup and the up and down motion is probably not more than an inch. Probably a dead perch has a slightly greater effective length but then don't forget that the spring changes length as it flexes as well, so all in all I think a panhard bar is much better than none at all!

Don Shillady
Retired Scientist/teen rodder

Thanks Don, after doing some reading I guess I'll have to agree.
O.K. Faith, put me down as being in favor of a long Panhard bar. (Boy, that was a long time coming, hey?)

Thanks Roy, peace.

Originally Posted by HiboyGal

All above points have been well noted. However I am now confused I thought the panhard bar was supposed to REMOVE the bump steer I currently have? But you guys are saying if not set up right it will cause bumpsteer? More bumpsteer than I currently have WITHOUT the Panhard bar?? (if that's humanly possible ).

Faith, that is why I have been so opposed to them in the past, because nobody takes the time to research the geometry and make them and install them correctly. This monkey-see, monkey-do business just irritates me to no end.

I agree with Techinspector on long and horizontal panhard bars.
A long front bar isn't too difficult to accomplish if you make it yourself and most manufacturers are making the proper length front bar.

The front panhard bars on my 32 and 31 are 27" long which is close to the same length of the draglink.
Matching panhard bar length to drag link length is a good idea because you want them to swing the same amount of arc.
Matching the horizontal angle of the panhard to the drag link - when the car has full weight on the wheels is a good idea as well, but if you're off a couple of degrees as a practical matter it doesn't make too much difference.
If necessary, a few degrees of mismatch in the vertical plane vis a vis matching the drag link angle tie rod angle - or lack thereof - won't hurt.

Making your own panhard bar is easy if you have access to a lathe.
3/4" OD DOM (Outside Diameter Drawn Over Mandrel) tubing is the way to go for street runners.

Making a rear panhard bar, 3/4" tubing will work fine, but most times manufacturers supply 7/8" OD tubing panhard bars.

I ended up making the rear panhard bars on my cars from 7/8" x .156 wall DOM tubing on my 31 and 1" x .120 wall DOM tubing on my 32.
In both cases, because that's the tubing I had on hand after making my own drag link, tie rod and rear four bars.

Rings for the ends of panhard bars can be made from 1 1/4" or 1 3/8" by .120 wall DOM tubing and welded on.
A grade eight bolt with the hex turned round gets welded on the threaded end.
Polyurethane bushings are available from Energy Suspension in the correct sizes.

As mentioned, a lathe makes life easy making panhard bars.
If you try to drill the the tubing the small amount required for proper tap hole size the drill will grab and the drill motor will come close to breaking your wrist.

A thinking person could figure out a way to set the tubing up in a drill press for drilling - and starting the tap - if necessary, but a lathe makes life a lot easier.

Far as length goes on the rear panhard bars, as long as you can make them is the rule.
The rear bar on my 32 is as long as possible and it steers quite accurately.
The 31's rear bar is shorter due to a packaging conflict with the transverse rear spring, sway bar and where the rear spring is.
Even so, it's longer than the very short bars sold by manufacturers for rear panhard bars.

It will be interesting to see how the 31 handles compared to the 32.
Front suspensions on both cars are similar, the 32 has rear coilovers and as mentioned the 31 has a transverse spring in the rear.

Not to get too far off the subject, but a rear sway bar really improves the handling on these little cars and it's probably the main reason the 32 handles so well.

Sometimes people worry about how much horizontal movement can be imparted to a suspension system component due to the arc of a 4 bar, panhard etc.

If you plot the swing of a particular length bar and measure how much there is at the extremes of travel you'll find it's not much to worry about if you have a reasonable length 4 bar, panhard etc.

Please excuse me for probably mentioning the obvious, but has anyone suggested to Faith that the steering box may need the adjustment before scaring her with panhard bars and bumpsteer stories?
I had a vega box on my 34 coupe without a panhard bar and it drove fine. It was one from a junkyard and it certainly needed adjustment before use.
I agree that panhard bars are a worthy addition to a car during a build up but kinda difficult (although not impossible) to add later on.