Caster / camber relationship

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Caster / camber relationship

Postby cjbiagi » Thu Jun 24, 2010 7:29 pm

Does anyone know what effect the rear caster cam has on the camber? I know it is supposed to have a slight effect on it and am trying to figure out if increasing the caster setting more positive will increase or decrease negative camber. I don't have a lot of camber adjustment left and it's already a little negative, which I am fine with but I don't want to make it worse. Right now my rear caster cams appear to be set for as much negative as possible, I want to try and get as much positive caster as possible but wondering if adjusting them is going to give me more negative camber or not.
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Re: Caster / camber relationship

Postby Monzsta » Fri Jun 25, 2010 8:56 am

Both the front and rear bolts equally affect caster and camber. You want to have your caster as positive as possible while keeping your camber in spec. However, given the limited adjustibility of our front ends, either slotting the upper arm bolt holes or buying adjustable upper arms sometimes is necessary to hit the number you want. I couldn't do any better than -3.0 degrees of camber on my right side so I dialed in -3.0 on the drivers side to even it out.

If you move one bolt, you'll alter both the caster and camber, as well as toe. If the rear bolt cams are facing in, turning it out will give you more positive caster, positive camber and a toe out condition. Adjustments are best done on an alignment rack. If you want to experiment, make sure you mark your parts so you can put 'em back after.
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Re: Caster / camber relationship

Postby cjbiagi » Fri Jun 25, 2010 9:05 am

Ok, so if I adjust the rear caster bolts for more positive caster I will end up creating more positive camber? If that's the case It may help my situation rather than aggravate it. Right now my rear cam bolts are adjusted almost completely inboard which is almost maximum negative caster. I know I already have a bit of negative camber because I can see the top of the tire lean in. So I am hoping not to make the problem worse by adjusting the alignment to try and get the most positive caster as I can. Based upon what you are saying increasing the positive caster should actually reduce the negative camber, right?
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Re: Caster / camber relationship

Postby cosvega76 » Fri Jun 25, 2010 9:54 am

Clyde,

Yes, putting more positive caster in will push the spindle out and give you more negative camber. From my experience, there isn't enough adjustment in the stock cams to give you any appreciable positive caster to make a lot of difference. In a good example, you may be able to get 1 degree positive, but I don't think that is enough of a gain to make it worth the hassle in the camber department. You could crutch the issue by getting the offset upper bushings to help out the camber, but you'd be better off by getting some adjustable upper arms. If you come up here for the alignment, I can bring you over to meet Dave!

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Re: Caster / camber relationship

Postby cjbiagi » Fri Jun 25, 2010 10:31 am

cosvega76 wrote:Clyde,

Yes, putting more positive caster in will push the spindle out and give you more negative camber. From my experience, there isn't enough adjustment in the stock cams to give you any appreciable positive caster to make a lot of difference. In a good example, you may be able to get 1 degree positive, but I don't think that is enough of a gain to make it worth the hassle in the camber department. You could crutch the issue by getting the offset upper bushings to help out the camber, but you'd be better off by getting some adjustable upper arms. If you come up here for the alignment, I can bring you over to meet Dave!

Chuck

Hmm, ok, that's just the opposite of what was said earlier that adjusting for more positive caster would create more positive camber. My only fear at this point is making things worse by trying to increase the caster cams. Right now they are all the way negative. :bang: I guess adjustable arms are an option if we can't get get things set satisfactorily, Chuck has been gracious enough to offer his services to help me get it aligned so I guess we'll can see what we can do with it as she sits and go from there.
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Re: Caster / camber relationship

Postby HAULIN' IT » Sat Jun 26, 2010 11:22 am

Monzsta wrote:Both the front and rear bolts equally affect caster and camber. You want to have your caster as positive as possible while keeping your camber in spec. I couldn't do any better than -3.0 degrees of camber on my right side so I dialed in -3.0 on the drivers side to even it out.
If you move one bolt, you'll alter both the caster and camber, as well as toe. If the rear bolt cams are facing in, turning it out will give you more positive caster, positive camber and a toe out condition. Adjustments are best done on an alignment rack. If you want to experiment, make sure you mark your parts so you can put 'em back after.

I have a couple things to add that may help you cj.
Monzsta, While you are correct on wanting as much caster as possible (within reason, on the stock h-body this would be correct). I'm not following you on a couple things...3* of Negative camber is very poor, the car really shouldn't be driven. Your only using the inside 1" or so of the tire! & when you turn it really goes goofy.
Also, on the part about the "rear bolt cams facing in..." You have that backwards, if you rotate the cam outward on the back only (the bolt/bushing would be more inward), you would get more positive caster & more NEGITIVE camber.
You want to look at it something like this: Viewing from overhead, your moving the upper control arm/ball joint compared to the lower. If you move only the back bolt cam so the bolt is in all the way (not the cam), the ball joint is in & back (more neg. camber/more positive caster). Hope this helps, Lorne
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Re: Caster / camber relationship

Postby cjbiagi » Sat Jun 26, 2010 12:29 pm

I think part of the confusion comes from if you are looking at, the cam itself or the bolt. I always refer to the bolt position for my comparisons. The point of reference for me is always the bolt since that ultimately determines where the control arm is. The rear cam "bolt" should be toward the outboard to get the most positive caster though, this pushes the lower balljoint forward in relation to the upper which produces positive caster. I do appreciate everyone's input. As I look more closely it appears if I want to keep my stock components I am going to have to tweak at least my right side control arm bracket in a little bit. Not sure how I want to go about it yet. I know someone used a chain around the pitman arm to pull it but that doesn't appeal to me. I think there is a little bit of play in the K member holes, I'd like to pull the brackets tight as far as they can go inboard and still bolt the K member on. Because the K member just bolts on once I do get it where I want I may even just tack weld it to the brackets for a more permanent fit. It would mean having to grind the welds off if I ever needed to remove that part of the K member but it wouldn't be that big of a deal. I'd still be able to unbolt the two braces going to the core support, just the cross brace would be permanent. 3 degrees negative camber is a lot on a street car, I could live with up to maybe 1 degree negative. I'd prefer maybe 1/2" negative.
On a good note I don't think I have to move anything too far, probably an 1/8" to 1/4" max. It's just a matter of figuring out the best way to do it. Does anyone know how much play are in those cross brace slots?
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Re: Caster / camber relationship

Postby my79monza » Sat Jun 26, 2010 1:42 pm

Would it pay to use the AJE adjustable upper a-arms?
The feedback on these arms is almost non existant so it makes it tougher to decide whether or not to use a set of them.
I have thought seriously about a set but what little feedback I did see mentioned premature wear on the Heim Joint and I sure don't need that.
Wish there was some good serious data on these arms.
Merle
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Re: Caster / camber relationship

Postby CableDroid » Sun Feb 08, 2015 1:59 pm

Digging up an old thread I found while searching.....


My Monza's front end is currently torn apart for bushing replacement and I have a lot of negative camber after my S10 spindle swap (used 2" drop spindles). Never drove it or had it aligned since I am not finished with the engine swap.

Anyway, my old school drag racing neighbor suggested I swap the upper control arms side to side in order to gain the much needed positive CASTER in these cars, but I am worried it might make the negative CAMBER issues worse. I searched the Internet and found it has been done with H-Bodies, but no comments on alignment issues following.

I am also going to have to cut a coil (or more) from each of my front coils because it seems I have removed so much weight (factory 350 AC car) since the entire HVAC system is missing along with the weight reduction of going from an iron headed and intake SBC to an aluminum headed, nylon intake LS engine. Right now the suspension sits completely topped out, as if the engine were still removed. I am hoping the cutting a coil will drop the front end enough to allow some travel and help the CAMBER issues too.

Hopefully someone is still around the can help out.

Thanks!!


Link to the thread I started, didn't want to side bust this thread too much....

viewtopic.php?f=10&t=42836.
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Re: Caster / camber relationship

Postby cjbiagi » Sun Feb 08, 2015 4:16 pm

What position are your lower cams in? There is a lot of variables involved without knowing where your alignment already is. Sometimes frame spread will also contribute to negative camber. Easiest solution (depending upon how much it's off) is to install offset upper control arm bushings. Otherwise you may be looking at adjustable aftermarket upper control arms. Swapping the upper arms does provide way too much caster and may put the balljoints at some weird operating angles. For a drag car maybe it's ok, it would most likely be way too much for normal street driving.
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Re: Caster / camber relationship

Postby CableDroid » Sun Feb 08, 2015 5:38 pm

No way to know where they were originally and I didn't note the position before removal. I am going to scratch the a arm swapping.

Would the fact the suspension was completely topped out cause the negative camber since both upper and lower control arms are aimed at a 45 degree angle pointed down?
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Re: Caster / camber relationship

Postby cjbiagi » Sun Feb 08, 2015 5:59 pm

The control arm angle will definitely affect the camber. As a general rule the lower control arm should be relatively parallel to the ground and ideally the upper arm should be be pointed up slightly or at least parallel with the lower arm at normal ride height. Having the upper arm pointed up slightly will give you a better camber curve although this relationship is pretty much built in to the car unless you change spindles. As the arms swing through their arc the camber will change and since the upper arm is shorter it will have more effect than the lower. I would suggest getting your ride height set first and then see where the alignment falls.
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Re: Caster / camber relationship

Postby CableDroid » Sun Feb 08, 2015 6:30 pm

Do you have to know how much drop per coil cut off stock springs?
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Re: Caster / camber relationship

Postby cjbiagi » Sun Feb 08, 2015 7:22 pm

Not exactly, it's a trial and error thing so you want to start slow. However, because of the A arm leverage on the front suspension it will drop more than you cut. So if you cut off 1" of spring height it may drop the car 1.5" or so. Do you really think you removed that much weight from the front end to have the car topped out? It would seem to take a lot to do that, just want to try and make sure there is not some other reason for the suspension to be topped out. Can you bounce the front end at all?
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Re: Caster / camber relationship

Postby CableDroid » Sun Feb 08, 2015 7:33 pm

Yeah, it moves if I really lean or push on the top of the fender. It only moves a lil, and rebounds hard enough to make a decent sound of the upper control arm smacking the upper spring perch section of the unibody.
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