Full frame or front clip?????

[Leon]

When I put kits in, I use tape on the floor and a plumb bob to mark important items such as axle centerline, radiator support holes, and a few other points so I can make sure the frame hasn't moved as you work on it.  I take heights at those points also.  When you put the new one in, it gives you a few reference points for mounting things in addition to measuring to points on the frame.  If you end up not needing them, no harm.  But if you need some additional reference, you have the measurements.

[chevy 47 coupe]

ok here are other before i order the mustang11 kit .when i weld this kit on is it going to be lower in the front than it is now stock?  
also they said on there site when installing the front spring crossmember (is this the top pieces ,upper control arm area or  the lower control arm area or i assume they mean the whole kit top and bottom pieces of the crossmember?) take into account the final front axle caster settings.car at normal ride height will be 5-7degrees positive(tipped back at top) :? whats tipped back at top?? normal chassis rake approx.3-5 degrees.(how is this done? ) if you install the front crossmember square with the chassis you will lose some castor angle.they suggest you tip crossmember back 7-10 degrees.so that final front end alignment can be made without binding up the spring and shackles. do i need to worry about this? opinions and suggestions.they also have pivoting spring perches for adjustment if you welded crossmember flat. ( little confused i looked at them and cant figure out what they do and where they go)

[enjenjo]

This is a symplified answer, so take that into account.

Yes it will lower the front of the car, by several inches usually. If you get a universal kit, instead of one designed for your chevy, you can mount it so the car sets somewhat higher in front if that's what you want.

The right way to set up a new front suaspension, is to set the car on stands, so it is at the height you want front and rear. This will give you frame height and angle where the crossmember mounts. you can use this to figure the crossmember angle before installing it.

This  is not a hard thing to install, thousands have done it. But getting it right so the car handles well involves figuring in a lot of things like caster, camber, strut rod angle, steering clearance, antidive.ect. Assemble it first, tack welded in, set ride height with a strut instead of springs, and check all the alignment before welding it in place.

If you don't understand, ask more questions, we will be glad to help.

[Welder Series]

That's what we always tell our customers too... get the car at ride height (where you want it to sit going down the road) and put the wheels and tires you'll be using in the wheel wells.  Take a walk across the road, turn around and see how the car looks.  Try moving the wheels around in the wells until they're exactly where they look best.  

We've got an assembly video of the Mustang II crossmember on our website.

Look for "Mustang II".

If you stick with Heidts, Fatman, or the WS kit, you'll be happy.  There are lots of resources here to tap in to.

dw

[chevy 47 coupe]

sorry still a little bit confused :? (thats why we are here i hope) if i set the frame where i want it with the rake how does it affect where i weld the crossmember. i dont want to sound like an idoit ,but i want to do this the correct way.I dont have the rear yet and dont know what wheels and rubber i'll be useing.  should i wait till i get the rear then go from there? or should i  just weld the kit square to the frame? remember this is my first project with frame and suspention work and want to learn all that i can so this car will be driveable and enjoyable

[Leon]

You have to have the frame set at the attitude you want in the running condition so the crossmember can be set level and the spindles set at the proper caster.  If the whole thing is put in relative to the frame and the final ride angle is different, you may not be able to get the proper front end alignment, the lower control arms in the wrong angle, or the wrong anti-dive.    If you don't have the frame at the final ride angle, it can't be aligned when the pieces are tacked in.  You have to look at the alignment when it is assembled as well as when it is done.  If you don't understand caster, camber, etc. find a shop that is willing to show you and use that info to set your components up when tacking everything in.  Double check the settings before welding everything solid.

[tomslik]

just a thought about later model camaro subframes as donars.. 76 through 79 sevilles use an almost identical sub frame except for the frame horns wich were set up for big bumper shocks. and they are much more common in the junk yards out here in socal....

hey wayne, the one i had was a bit wider, don't remember how much but it was enough to cut up and send to the scrap.....

[Welder Series]

sorry still a little bit confused :? (thats why we are here i hope) if i set the frame where i want it with the rake how does it affect where i weld the crossmember. i dont want to sound like an idoit ,but i want to do this the correct way.I dont have the rear yet and dont know what wheels and rubber i'll be useing.  should i wait till i get the rear then go from there? or should i  just weld the kit square to the frame? remember this is my first project with frame and suspention work and want to learn all that i can so this car will be driveable and enjoyable

I'd recommend getting the rear end and wheels/tires before you start on the front end.  

If the frame was horizontal with the ground, welding the crossmember square to the frame would work great.  But, to get a desired "rake", the frame will end up lower to the ground at the front than the rear.  You have to take this angle into consideration when you're installing the crossmember.  The angle itself isn't important - it could be 5* or 15* - but you have to remember that the frame is on an angle.  Because our crossmember is "trim-to-fit", the actual angle of the frame is inconsequential.  Again, there are installation and assembly instructions on our website.  It's a weekend job for a novice if you read the instructions...

Please give myself, Heidt's, or Fatman a call if you have any questions.  We're all here to make sure your front end gets installed correctly, safely, and simply.

[1FATGMC]

We all tell someone doing this to get the frame at ride height, but fail to tell them that this can be difficult to do.

The front isn't so hard knowing that the bottom a-arms should end up parallel to the ground.  Put the tires/wheels on and use all thread in place of the shocks/springs and get the a-arm parallel to the ground and you will know where the frame will be there.

Now if the car/truck is all together from the cowl back you can put a rear under it and springs and see where the back sits with the normal weight on it.

The problem arises, at least it did for me, was putting the front end in when you are dealing with a bare frame without the body on it.  Now how far is the back going to go down??  I piled a bunch of weight on my frame as I had the cab on it ,but no interior, no motor/transmission weight (yes that will transfer to the back also), no bed, etc..  I then located the rear shackle bracket for the rear spring only to find out I needed to move it further rearward later when all the weight was there.  So I had the frame rake somewhat wrong, but it all seemed to turn out fine as the truck aligns fine and so forth.

 

In the picture you can see that the rear shackle is pointed the wrong way with no weight, yet it is 45 deg. the other way with weight.  This is where it had to be after I fixed it.  More pictures here:

http://purplesagetradingpost.com/sumner/underconstruction/underconstruction2.html

So how do you guys set the rear frame height if you are working with a bare frame??

I run air shocks in the back and that really helps to keep the rear the same height under different loads.  If I did it again I would run shocks and separate air bags along with the leaf springs.

c ya,

Sum

[Leon]

So how do you guys set the rear frame height if you are working with a bare frame??

On the Packard I'm running a 4 link with air springs so setting the final ride height is a matter of adjusting the air.  On the 54 I had all the dimensions before I tore the body off the frame (had a spare frame I was welding on) so I could compare "old" to "new".  On most that I've done I end up with a few degrees rear up at final ride height, but the wagon ended up almost level to the ground.  All depends on the look you want.  With the wagon, I got new springs for it and the guy that built them (from RB's) talked to me and I gave him dimensions of what I wanted.  After about 100 miles, the new springs settled in and were at the exact height that we planned.

[Welder Series]

Leaf springs are difficult to set up, since they don't have a designed ride height.  With coilovers or even air springs, you will know where the car will sit because they both have a designed ride height.  A typical rear coilover will have a 13" or 14" center-to-center dimension (measured at the mounting bolts).  All you have to do is drill 5/8" holes 13" or 14" (depending on your coilover) apart in a 1" square tube, and use that in place of your coilovers when you're setting up the ride height.  Leaf springs are definitely more difficult to know where they're going to end up.

It's totally correct that the lower arms should be horizontal at ride height, but that's hard to do if your crossmember isn't installed yet.  On the Welder Series kit, there is a notch in the crossmember where spindle centerline at ride height will be.  To be 100% sure of where the car sits, you really should have the fenders in place to accurately mark spindle centerline on the frame front-to-back.  An alternative is to measure someone else's car (whose wheels are nicely centered in the fenders) at a show.   It's so important to measure because although the center of the wheel (spindle centerline) will stay the same, it's where the centerline ends up on the frame that will change.



Please read the installation instructions on our website all the way through... they explain it well.

[enjenjo]

To figure ride height on leaf springs, here's a quick and dirty way to do it. If you are using new springs, you more than likely know the spring rate. That is the amount of weight needed to move the spring one inch. Take that figure, lets say 150 lb. Then take the weight of the rear of the car, for our purposes 1500 lbs. Take a straight edge, and measure the arch of the spring, from the spring eyes, with the spring out of the car, in this case we will use 7". Divide the weight of the car, by 1/2 to get the weight on one spring. Then divide that weight by the spring rate. So take 1500lbs divided by 2 equals 750lb. 750 divided by 150 equals 5. So the spring arch will decrease by 5" when installed. You can use that figure to get the center of the rear axle loaded. this will get you real close.

If using a used spring with an unknown rate, set the spring with the eyes on a flat surface, and measure to the center of the spring. Add 100 lbs of weight in the center of the spring, and measure the deflection. Then do the same with 200 lbs, and 300 lbs.  lets say the spring deflects 2" with 300 lbs, this gives you a rate if 150 lbs per inch, you can plug this into the equation, and figure it like a new spring.

[1FATGMC]

........................... Then take the weight of the rear of the car, for our purposes 1500 lbs...................

Good post Frank, using the spring rate is a good idea.  

Hopefully you know ahead of time what the vehicle is going to weigh and how much of that weight is on the back.  I didn't have a clue when I started with my truck.  Now with the internet it is probably easier for someone to find the weight from someone with a similar vehicle.

My truck at 4000-4100 lbs. (loaded and in travel trim) came in higher than I would have ever guessed in the first place.

As usual you came through   ,

Sum

[UGLY OLDS]

Boy ....that Frank guy is one smart cookie...  Can we save this spring info to the "Tech" section???  

[47 ragtop]

I always set the rear suspension first. BUY the Chassis Eng bolt on rear kit and it will center your rear  wheels PERFECTLY. The ride height will give you the rake you are after. I use P235/70 or similar size tires and they will fill up the rear fender opening. Now to the front. BUY the Chassis Eng bolt on front crossmember and guess what = it will center your front wheels in the wheel opening PERFECTLY. The ride height is adjustable - about 2 1/2 inches. THis will enable you to fine tune ride height and level the car from side to side. You said this is your first street rod build and thes kits will be perfect for you. YES they cost aliitle more but they are worth it, reguardless of your abilities and the end result,time saved,and added value will always be there. PLUS they are foolproof !!