to be sure I understand this correctly: does slotting the standard shaft and slide it to adjust caster change the camber too? (I would guess it does)

 

It shouldn't. I just simply used the shim pack and moved a shim from the rear to the front effectively moving the spindle BACK to increase caster. Then you go back and check camber and adjust as necessary. This WILL change toe, set it last.

 

I believe it will all be clear once I start working on it and have the geometry in front of me. Thanks! Step 1 is slotting the arms.

 

Anyone looking to do this type of modification is studying and putting engineering into their car (to better the sold as is flaws that are inherent in mass production. Basically if GM could originally rationalize a higher price point when these cars were designed, then alot more engineering would have been added. Thus I could tell that you were smarter than the usual Corvette owner. Thus I am glad that you now have some good shared "engineering" from Forum members.

We all hope that when the frames were jig welded together that you have the same on both side, that all of the suspension pick up points are correct, no previous damage that would effect that. I have seen too many Corvettes that needed different shim packs on each side. Thus it is entirely possible that that might still be needed.

There are very smart people on this forum, and alot that automatically assume that just because you asked a question, that you don't know anything (I don't, because even though I have been an engineer, I will bounce things off of a second brain and that never hurts!) Good luck!

PS I will even take back the idiot comment (shot toward others here)! The year has no bearing in your question. The fact that you are on a C2 forum, clarifies what suspension you are working with. The alignment specs that work for others doesn't mean anything to your car (maybe a starting point).

Also changing castor with just shims, will definitely necessiate reshimming for the camber almost every time. Thus slotting will minimize the need to shim for castor, but shimming might be needed to tweek and adjust that castor still based on dimensions of the frame and the mounting points. Ideally it would be a perfect world if everything was welded by the factory perfectly straight. Because there was a tolerance allowed, some cars came out the door better (straighter than others). Thus the interesting question would be, what is the maximum number of shims that has ever been seen at the end of the production line and has anyone seen a car that needed no shims?

Also I shoot, so in that discipline just a little wiggle in the where the barrel is pointed could send the shot wide, high or low. Thus just a 1/4 inch or a minimum degree in a suspension has the same effect and that amount has an effect on the thing truly going straight.

 

Good point, the more that I simply adore to change things anyway. After all, almost 50 years have gone by since the inception of the C2, and insight in car technology/dynamics has evolved too. I am not a long time car mechanic, however, I managed to build my own AC Cobra, not from a complete nuts and bolds kit, but starting from a chassis and a rough body. That was a challenge, but very rewarding at the end (2500 hours of work and study spread over 4 years after the chassis arrived....) ;-) Rebuilding the corvette feels kind of easier, because I am now more experienced, and because there is so much info and standard or specialty parts available . And this forum of coarse helps a lot too

 

One guy was smart enough to touch on toe! That is a big factor that effects handling and the sensation of how it rides and drives! What is done to the castor with shims would necessiate an adjustment to the tie rods! Also my ultimate recommendation would be to straddle the camber in between race and street. On high G's needing max camber, then it is bad on the street and the tire wear suffers. On street camber settings, you can't get the handling benefit with the high performance tires and trick suspension pieces. That is why I paint the shims. I have a set for street operation and a set for race.
The Cobra kit sounds like fun (building a whole car from scratch would be a dream, the kits I hear are pretty proven, but still need someone of a higher level of ability!). I almost purchased a real raw 1950's Devin project a few years back.

 

It could!!!!!!!!!!!!!!!!!!!!!! because of how the factory welded your frame together and the geometry of those factory assembled suspension pick up points and that would necessiate shimming as is suggested in this post by Pop Chevy, I also agree set toe last (very good suggestion)!

 

I think you meant the other way around - if you move a shim from the rear to the front, it moves the top of the spindle forward, changing caster to more negative.

 

[QUOTE=TCracingCA;1581960571]

PS I will even take back the idiot comment (shot toward others here)! The year has no bearing in your question. The fact that you are on a C2 forum, clarifies what suspension you are working with.




Not really, this is a C1/C2 forum, and many questions in the past have generated many responses before it was understood that the OP was actually asking about the C1 suspension. Year of the car has bearing on almost every technical question asked on this forum.


Regards, John McGraw

 

Thanks for chiming in John ! Right on both counts.

 

I was smart enough to check OP's thread history to see questions/topics are C2 specific. Also C2 race cars get slots in the a-arm shafts for castor. C1 confusion- Good cover by you and your buddy! I applaud!

The positive thing that happened, is that you did make a sincere effort to give advice and to be productive in the thread!

The idiot thing actually was just a general observation about what happens alot of times when you post up something and some attention deficient know-it-all tries to trash what others input.

Also if someone wanted to take that personally. Oh well! It wasn't thrown at anyone in particular or I would have thrown a quote from someone in with the general observation!

Done- take the last shot, I won't reply. Best wishes to all who work on their own cars and those that own them without thought of investment value!

 

 

Sorry to jump in and drag up and old thread, but I'm in the same boat and need to slot my upper shafts for more caster
The most I can get with shims is +1.5○ without indroducing way too much + camber
So how long should I make the slots ?
I checked this site http://www.guldstrand.com/index.asp to see if I could just buy a pair without any luck.
Thanks for any advice
Dave

 

try "Moog K-6104" (see earlier posts in this thread) on ebay and there is plenty available

 

Thanks, I looked at that, but where is it actually offset ? Did it fix your caster problem ?

 

Basically I didn't think Guldstrand's shop (great shop) would do custom machining work anymore (even something as simple as this). They will work on most anything and do a great job, but doing custom machine work, I think that ended way back and if they ever do any custom machining, they probably farm it out because at the newer shop, I really don't remember seeing that type of equipment there. I think that the Race Porsche shop that runs the building to the westside and has rented the front of the Guldstrand building has some higher end machine equipment (not sure). But you definitely don't want him to take them there at Porsche prices!!!!!

But Basically any machine shop with a simple mill can do this. My advice is you first want to find a patient type guy that is first willing to listen and will take the moment to think and isn't in a hurry to take some of your money, and who doesn't think what you want is stupid and definitely someone that isn't going to rush the job and would be willing to have you there to watch. The last comment is a requirement by me when I have something done to parts! I will never ask for something to be done and then leave the parts there trusting someone that I hardly know!

I am not sure, but I think that there are two shaft styles that have been used in 1963-82 cars. Someone else can confirm or deny that (square pad area and round pad area?) Because I have only square pad types of shafts, that is what I worked with, you want to mill out the bolt holes, but leave enough meat on the bone to maintain some sufficient volume of metal around the milled slot. To gain adjustability you don't need much, and going off memory, I want to say I took mine about an inch, because I did this more on feel and opinion, instead of a precise measurement. I pulled the mill to the point where I didn't feel that I was compromising the piece.
The shafts that I did are buried somewhere in a box, somewhere out in the garage. I threw them someplace when I bought the Pole position Race arms prior to the company becoming SPC. One of these days, I will probably throw these on my 1968 or use them if a racing organization wants stock based parts.

 

Camber Castor is like a 3D puzzle with the shims. Think in the terms that a 1/16, 1/8 or 1/4 shim front or back will or could give you movement fore or aft (castor either direction). Thus sliding the shaft is moving the top back or forward. Thus you are rocking the top of the spindle thru the length of the arm and the ball joint. The simpliest way to explain camber is to put (add) equal sized shims front and back or to remove equal sized shims. Thus you are moving the top of the spindle outward or inward. The Moog arm offset which gives you spacing in camber.

 

It is, for my cobra I ended up designing the suspension linkage/hinges in my 3D Cad/Cam package so I could simulate the changes on my Mac. Caster/Camber/Toe usually change together. When I got it right on the Mac, I transferred it to the real world and it was spot on.

I did not mount the new upper arm control shaft yet, it's still shipping on it's way to my place in Belgium.

 

I have a very compotent machine guy I trust, but I'm not 100% sold on milling out the holes yet.
They're the "round" version, with not alot of excess material to mill out.

Is this the beast from MOOG ? Because $40 isn't alot of money when they come with new bushes as well.

 

Getting camber is generally easier to get, than the castor being discussed. This shaft you show was meant for accident damaged cars, but could most likely be used in the application being discussed (but for camber is it's design), but with the slots castor gains could be obtained. Using this offset shaft would essentially minimize the need for shims for Camber as it is designed, but the only problem is that it could be too much, to where now you can't get a shim in there that would pull it back to the spec or it the pads could be too thick (offset effect) to get the spec that you want or may need. Don't know till you try it! Slotting it doesn't hurt anything! You can always set it back to the original position where the bolt hole is or was!