clip question

[JELLY]

Originally Posted by 1-ton of fun

the longer the better. in my 3link design i did for my truck the upper and lower links are the same, 24". the longer the links, the less pinion angle change there is with suspension movement.

as for the geometry, from a side view, the links will intersect at an imaginary point called the instant center. this can be adjusted by changing the height from the ground that either end of the upper or lower links attach to the body or axle. for best launch characteristics, you want this point to fall on a line drawn from the contact patch of the rear tire with the ground to a line perpendicular to the ground, intersecting that lie at the height of the center of gravity of the truck. below this line will cause the rear of the truck to squat on launch, above will cause the rear to rise on launch. right on the line and you will have 100% anti-sqaut (a good thing) and the rear will not raise or lower on launch. there are other factors to consider such as the side view swing arm length (SVSA) and roll centers.

it is best if you are fabbing the brackets to design some adjustability into them so the suspension can be tuned once it is together and on the road.

1-Ton,

I watched my DVRed extreme4x4 show today and thats exactly what they said! I just need to find the center of gravity and roll center and i understand the rest.

As for brackets, i am fabbing everything. I bought threaded inserts and ends already for link length adjustment. I may make the axle and frame brackets with a few different mounting holes also.

[Houston54]

If your suspension is from a 78 G-body you can find drop spindles from most suppliers. If you retain your original spindles you will may have a harder time finding bearings as the 78 spindle design on the G-body cars is unique. The 79 and up spindles are different. The S-10 also uses the same spindles so if you want to simplify future maintenance you can always swap the 78 one out.

I found I did not need to use drop spindles as the way I installed the sub-frame got the truck to a good stance. Any lower and I would be scrapping going in and out of driveways/parking lots.

There are some pics of my install in the picturetrail link in my signature.

Have you fitted the core support to the frame yet? If not you will be in for a surprise.

[youngrodder]

Originally Posted by Houston54

If your suspension is from a 78 G-body you can find drop spindles from most suppliers. If you retain your original spindles you will may have a harder time finding bearings as the 78 spindle design on the G-body cars is unique. The 79 and up spindles are different. The S-10 also uses the same spindles so if you want to simplify future maintenance you can always swap the 78 one out.

I found I did not need to use drop spindles as the way I installed the sub-frame got the truck to a good stance. Any lower and I would be scrapping going in and out of driveways/parking lots.

There are some pics of my install in the picturetrail link in my signature.

Have you fitted the core support to the frame yet? If not you will be in for a surprise.

Huston--

I know what you mean about the core supprt (steering box). What radiator did you use? My frame set up looks different then yours. Did you Z the frame? My core support had to be shortened. When I bought it, it was a driver and had a 48 car radiator in in.

Nice truck

Marc

[Houston54]

Originally Posted by youngrodder

Huston--

I know what you mean about the core supprt (steering box). What radiator did you use? My frame set up looks different then yours. Did you Z the frame? My core support had to be shortened. When I bought it, it was a driver and had a 48 car radiator in in.

Nice truck

Marc

I used a Desert Cooler radiator for a V8 application with trans cooler. It is the same dimensions as the stock unit but is a three row design. I am running an electric fan from a Taurus and the temp does not get above 180 in Houston traffic. I got the radiator through Classic Parts for about $320 some years back. I do not know what they are going for now though. I researched the heck of it before deciding there really was not another radiator that would fit well.

The mounting of the radiator took some doing in that the steering box creates an extreme interference with the core support. I sectioned out the core support and welded in a brace that reconnected the side and bottom. Since the front sheetmetal is indexed off the core support any change in the height or front-to-back reference will throw the sheet metal off. I then sliced the front mounting surface of the core support from the top down to about one inch below the bottom hole used for the radiator mounting. This surface was then folded back at the top so it slanted forward from top to bottom. This effectively kicks the bottom of the radiator forward to clear the steering box while maintaining the top of the radiator as close to stock location as possible.

The attached pic show this pretty well.

[youngrodder]

Originally Posted by Houston54

I used a Desert Cooler radiator for a V8 application with trans cooler. It is the same dimensions as the stock unit but is a three row design. I am running an electric fan from a Taurus and the temp does not get above 180 in Houston traffic. I got the radiator through Classic Parts for about $320 some years back. I do not know what they are going for now though. I researched the heck of it before deciding there really was not another radiator that would fit well.

The mounting of the radiator took some doing in that the steering box creates an extreme interference with the core support. I sectioned out the core support and welded in a brace that reconnected the side and bottom. Since the front sheetmetal is indexed off the core support any change in the height or front-to-back reference will throw the sheet metal off. I then sliced the front mounting surface of the core support from the top down to about one inch below the bottom hole used for the radiator mounting. This surface was then folded back at the top so it slanted forward from top to bottom. This effectively kicks the bottom of the radiator forward to clear the steering box while maintaining the top of the radiator as close to stock location as possible.

The attached pic show this pretty well.

Thanks--

Simular obstical but different frame and core support set up. I might just go with a slightly narrower radiator and offset to one side to clear the steering box. I have all of my sheet metal fitting and I am close to paint so I don't want to start over by making a change to the core supprt.

Marc

[JELLY]

Originally Posted by Houston54

If your suspension is from a 78 G-body you can find drop spindles from most suppliers. If you retain your original spindles you will may have a harder time finding bearings as the 78 spindle design on the G-body cars is unique. The 79 and up spindles are different. The S-10 also uses the same spindles so if you want to simplify future maintenance you can always swap the 78 one out.

I found I did not need to use drop spindles as the way I installed the sub-frame got the truck to a good stance. Any lower and I would be scrapping going in and out of driveways/parking lots.

There are some pics of my install in the picturetrail link in my signature.

Have you fitted the core support to the frame yet? If not you will be in for a surprise.

So i should swap the spindle to a '79 or newer? The spindle shaft and bearings are the only difference?

The core support is in and the splice work looks alot like what is shown in your pics.

Thanks
Jeremy

[Houston54]

Originally Posted by JELLY

So i should swap the spindle to a '79 or newer? The spindle shaft and bearings are the only difference?

The core support is in and the splice work looks alot like what is shown in your pics.

Thanks
Jeremy

You do not have to swap but you might want to see if you can source the wheel bearings easily. For me it was cheaper to swap the spindles as the 78 bearings were several times more $$ than the 79 and up units. I also had some 81 spindles laying around. You can find replacements easily and cheap enough to make it worthwhile in the long run. If you are going to drop spindles this is a moot point.

As to using lowering spindles I do not think you will need them IF you are putting bags on each corner. The airbag retrofits I have seen have all required sectioning of the front spring pockets on the sub-frame to provide enough clearance for the bags.

[1-ton of fun]

Originally Posted by JELLY

1-Ton,

I watched my DVRed extreme4x4 show today and thats exactly what they said! I just need to find the center of gravity and roll center and i understand the rest.

As for brackets, i am fabbing everything. I bought threaded inserts and ends already for link length adjustment. I may make the axle and frame brackets with a few different mounting holes also.

one thing that will help since measuring the height of the center of gravity is difficult, especially on a project car that is in pieces, it to estimate a highest and lowest possible CG height, and then design your frame brackets to adjust to cover the whole range needed for those two different scenarios. as for the link lengths, see what will make fabrication and installation easiest of the frame brackets, then figure out what length works for that plan.

if you can give me the wheelbase, tire height, and the height from the ground (using the tire height that you will be using on the truck) of the upper and lower mounting points on the axle, i can help you with the calculations.