[Green Hornet]

Was planning on using this 73 bird sub-frame.....but just realized that the shim packs are excessive on the right upper control arm...

Looks like about a 1/2" on the front.....and 3/8" on the back..

The other side looks normal with just one or two shims..

The right side frame horn doesn't look quite right so I'm guessing it may have gotten whacked at some point in time...

Any other reason...that might justify the extra shims on that side?

[dataway]

If it's a problem with the frame it could probably be tweaked enough to reduce the need for so many shims. Someone probably didn't want to go to the trouble when it was part of an assembled vehicle.

[amcmike]

Other than things being out of whack, maybe they were experimenting with more negative camber and just didn't get to the other side? Or it's setup for Circle Track racing.

["QUICK-SILVER"]

Are the shims from a previous alignment with worn out a-arm bushings and ball joints?

Clay

[Sirrotica]

It all depends on whether the car was aligned previously with worn parts, when I did alignments the first thing to do it properly was to make sure the wear items were withing spec. I am aware that not all persons doing alignments check all the wear items before they do an alignment. It's pretty much a waste of time to align the front end with sloppy parts, but it does get done.

As you said collision damage may be another reason, along with the sub frame being off when it was welded together.

MOOG has problem solver parts for cars that can't be brought into spec with stock parts, so there are some cars that are either bent from collisions, or just have factory parts that are out of spec. The good news is that as long as you can get the car to spec, it will usually drive fine.

[Skip Fix]

Depends if they were trying to get a lot of camber caster out of it too. My 78 I have enough to barely have 1 thread left on the rear to get more positive caster. Frames can sag some over the years too.

[dataway]

Always wondered about that frame sag .... some properly applied heat to a strip on the bottom center of the engine cradle should flame shape the sag right out.

[rohrt]

i would get a couple of Trams and printout of the dimensions and start measuring it. The shims may be normal or there may be something wrong. Is the other side the same?

[Green Hornet]

Ok...thanks for everbodys input....

I checked dimensions on spacing on flange where upper control arm shaft mounts to sub frame....and both front and rear compare with 2 other sub-frames I measured...so right side fat shim packs prolly were re-installed after front end was rebuilt....

Will cross measure sub frame before I continue...but am optimistic that it can be used..

[punkin]

I don't mean to hijack this thread but what would be considered too many shims? I realize this is a point of leverage on the frame and the bolts that hold the control arms on. Curious what the recommended max?

[Sirrotica]

As long as I aligned cars, and owned my own front end machine, there is no max that I ever heard of.

As I already have posted, MOOG Makes problem solver parts for cars that can't be easily aligned with the stock pieces, such as offset pivot shafts for the upper control arms on GM RWD cars. Not every car is made like all the others that run down the assembly line. You may align 50 cars that come in with minimal adjustments, then you get the one that is an oddball that may give you fits. Sometimes it's due to collision damage, sometimes it just wasn't put together same as it's twins were when new.

FWIW, I've stacked shims on stock cars to get the camber on the RF to at least 2 degrees, then the front end gets pounded hard on a rough dirt track for years, no bad experiences with any of the shims or bolts on any of the cars.

[necdb3]

A bent lower control arm would cause the need for excessive shims.

[roger1]

That photo looks well in the normal range to me. A lot of thread left on the bolts. I've seen shim stacked quite a bit thicker than that before. It's also normal to see one side be a lot different from the other.

[Skip Fix]

"As long as I aligned cars, and owned my own front end machine, there is no max that I ever heard of."

To get some negative camber(-0.5) and all the possible positive caster I have as many as will fit and the lock nut still work on the rear stud. Even got B body 1/4" linger studs when GM still carried them