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Author Topic:   Frame build-up question
blanep
Dirt Maniac

Total posts: 105
posted February 04, 2005 08:18 PM  
Starting on my 2006 car, an '84 monte. I have the frame sandblasted and ready to start work on but need input on something. I am planning on clamping the frame to large channels once I have it squared and leveled before I do the cage and everything else. However, I had also planned on relocating the front a-arm/shock towers right off the bat for my desired caster, camber, anti-dive and everything else. My question is, if I set all of these variables with the frame leveled, is it going to throw all of those settings way out of whack when I eventually set the frame to the correct ride heights? I mean you can't really set the ride heights correctly until you get the whole thing built and on the ground and scaled out, but these front end mounts seem like they need to be done now, while everything is stripped.

So, to sum it up, can these front end settings be made with the frame in a level state and still be close enough to be able to fine tune once the final ride heights are determined? Also, what baseline should I use for setting my front-end paramaters, the lower a-arms in a generally level attitude?

racin78p
Dirt Freak

Total posts: 333
posted February 05, 2005 02:11 AM  
Oh Man,...

First, the way you are talking about doing this is the way mods are built. But, yours isn't a mod. When you say front a-arm/shock towers I assume you mean upper control arm mounting locations? Are you just going to shift the angle of them? Do you have a camber/caster gauge to help you set it up?

Back to the A-arm top mounts: you can use an angle finder to set them where you want them exactly before welding them up. If you are going to run adjustable upper A-arms then camber/caster is a snap. If not then your back to using shims. Your ride height is determined by spring height and or spacers. You get that then you align the front end up (having it close is much desired before scaling of course). To answer your question, I think you will be fine setting it up while on the "jig". For kicks and re-assurance you might give Jet racing or Intimidator race cars a call and ask them too. They might be able to get you the correct angle for the mounts also.

I'm not sure what you mean by relocating the shock towers though. That is a whole new ball game! Do you mean just relocating the shocks? One of the cool dudes on this forum e-mailed my some pics of how he did just that. Really trick. Found out I can't do it this year though (rules).

Hope this helps. Race on.

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racin78p
if it ain't fun, then don't run

blanep
Dirt Maniac

Total posts: 105
posted February 05, 2005 07:46 AM  
You are correct in assuming that I am talking about the upper control arm mounts. However we aren't allowed aftermarket control arm mounts and must keep stock shock mounts so I was trying to convey all that by calling it the upper a-arm/shock tower.

I do have a caster/camber gauge and bumpsteer gauge as well as the numbers I would "like" to try to obtain (can't get everything just perfect with stock stuff as one thing always affects another as you well know).

I'm just trying to keep from having to cut and weld all of this stuff after the car is completely built.

racin78p
Dirt Freak

Total posts: 333
posted February 05, 2005 10:34 AM  
Okay. Well, I helped a buddy (who won the track championship that year) set up/remount his upper A-arm mount on just the LEFT side. He wanted more camber. He got it. Anyway the point is, if you are knowlegable in this area and not afraid to give er' heck, then do so while it is on the jig. Just make sure you measure and re-measure before you make it "perminent", dig? It's really not rocket science, but you still have to know what you are trying to accomplish and what you are DOING!. Two ways to look at this. If it is good, don't mess with it. And the other; you never know until you try it! I still suggest calling on of the premier chassis builders, or at least talk it over with a trusted race nut buddy who may have done this. Either way, good luck and be sure! Race on.

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racin78p
if it ain't fun, then don't run

thinker29
Dirt Newbie

Total posts: 1
posted February 05, 2005 11:28 AM  
I have started to do a lot of building on metric cars. On my last car, I did all of the upper a-arm mounting on a level "jib." I would then bolt on the lower arms and spindles and bolt the upper a arm to the spindle. I have always ran my lower a arm level on the left (same distance to ground pivot point and ball joint center) and then raised the right front 1/4" higher. Thus, I pretty much know where to put everything for ride height. After placing it there, I then started to mount the upper arms. I cut the stock mount completely of and in half and moved the mounts around to about the "right" spot. I have read to position the mounts parallel with the center line of the frame. Camber and caster can be put pretty close now too w/ a gauge. As far as the downward angle, I'm still trying to figure that all out. Camber gain and roll center has to be considered here. Also, I set the antidive just under zero now too not knowing whether or not higher ride height at the rear effects this. You may have to tack weld and move stuff around a lot but eventually you'll be able to get what you've decided to aim for.

snowman
Dirt Freak

Total posts: 241
posted February 05, 2005 11:53 AM  
Yeah, you can do it that way, no problem.....But I would reccomend placing some 1/4 in. shims between the uppers and mount.......this give you a little "wiggle" room to make adjustments.......and, the next set of stock parts you bolt on won't be exactly the same as your current set.....It just gives you a little room to work.....

Good Luck,
snowman

blanep
Dirt Maniac

Total posts: 105
posted February 05, 2005 12:14 PM  
That's exactly what I was thinking snowman. Just wanted to make sure that in working it through in my head that I wasn't overlooking the obvious. Thanks guys for the input.


Eljojo
Dirt Forum Champ
Total posts: 968
posted February 05, 2005 07:34 PM  
I spoke to Tony Ford @ TnT Racecars about this. His opinion was to first cut the end off the lower A-arms and relocate the ball joint (out about 3/4" on the right) By doing this you won't be moving the right upper mount in so close to the motor that you will be having problems with the stock upper a-frame getting into the header. Then shorten the upper mounts and allow for about a 1/4" of anti dive. Give yourself soe "wiggle" room as Snowman suggested and go to work with the caster camber guage. My plan is to set the right side at 2 caster and 3 camber. That's with the lower at static level. My target numbers will be achieved by shimming. Best to go ahead and fabricate an extra set of lowers so that in the event of a mishap, you will have a spare!

racin78p
Dirt Freak

Total posts: 333
posted February 06, 2005 01:34 AM  
You da man!! Eljojo!!

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racin78p
if it ain't fun, then don't run

neil rucker
Dirt Forum Champ
Total posts: 799
posted February 08, 2005 07:34 PM  
jojo! you tell em how us hillbillys do it!

    

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