Spring behind wishbone front spring

[Jeff]

I thought I should get some opinions on the front spring on my build. I had a 31 1/2 spring that was for sure too long for the job. I measured the center of the spring pivots on the wishbones and came up with 33 inches with the bone mounting brackets in place on the frame. I talked to speedway and they convinced me to try a 29 inch spring in place of the 30 that I calculated by subtracting 3 inches. Ok I put the 29 inch spring in place. It pulled the wishbone bracket on one side while lining up the other side with the frame off by 3 inches and the shackles are straight out to the pivots with no real load on the chassis when i pull the 3 inches to position and it preloads the spring. So I think it's back to the drawing board. What do you think? I seen a drawing in Posies catalog that shows what i have in the center photo as wrong. So it must be wrong? Does anyone have any photos of a wishbone spring behind for reference that they can post here so I can get a better idea of acceptable? Thinking about trying a 31 the 31 1/2 was about straight down. Maybe a 1/4 inch from it on both sides but the bone brackets could be laid out dead on the frame due to no preload. I might add that I have a little wigel room moving the pivots in or out, but for the 29 I had them all the way out and for the 31 1/2 I had them a couple turns short of all the way in so i can gain a little in that direction. Thanks Jeff

 

[RPM]

How about some pictures of what you are trying to do?

 

[Jeff]

Here is a photo with the 31 1/2 spring. I know the weight of the axle is hanging down in the photo, but the shackles would be the same if reversed pushing up with bare frame. I know it will change once engine etc is loaded to the frame.

 

[choppedtop]

The spring end should be below the shackle mount, not above, if I am seeing this correctly.
Lee

 

[2old2fast]

were you not able to get a 30" spring ? You can re-arch the 29 , but that will lower the front end. with the 29 in place, did you try loading the chassis w/about 900# to see if the shackles drop to 45*. ? There should be tension in the front spring wlittle weight on it , that's what keeps the front axle centered.
dave

 

[Hot Rod Todd]

Was on FB the other day and saw pikkys of Ted Browns bucket front end. Hes always advocated for a very long spring (and hes done over 250,000 miles in the car so hes an authority on stuff like that). And he designed the CCR chassis so he knows stuff


https://www.facebook.com/photo.php?...37576232964.2076242.1041615800&type=1&theater


His front end has brackets going back from the tube axle and then bolts directly onto the axle without any shackles. Interesting for sure.

 

[choppinczech]

Hmmm, I kind of like that.

You could get pretty low with that set up by mounting the 4 bars at the top and bottom of the frame rails.

And no side to side movement.

 

[Jeff]

Thanks for the help got a 30 inch sping and worked out well. Here is an updated construction photo with TH400 case in place.

 

[Neshkoro]

I've never seen a setup where the shackles are up like that. I 've always seen them installed in a "W" fashion where the fixed end the shackle is higher than the end that is attached to the spring. I would be afraid that they would flip around and screw up your ride height.

 

[Jeff]

They will face up when the weight is applied. And I will have to remove them to tack weld the wishbone brackets on first before they will point the right way. Right now the bones can just spread and let them drop to where they are now. I am just getting it all laid out at this point. Waiting on engine mount brackets from Spirit right now to see how they fit. I got a full cross member that I from speedway but put a Heavy gauge Moroso rear sump Mustang pan on the engine so had to scrap that Idea after the fact. I have been collecting parts for this build for over two years now so bound to be a few errors and extra parts, over all it is coming together quite well. I am trying to find a couple TH400's for guts right now. Called a friend in indy about a couple today, but don't know if they are available. Thought about re-gearing the trans but don't think I want to spend the bucks on that right now. I need it rolling and the engine and trans in it. Got a line on a converter today. The guy put it in and totaled his TH350 behind 450 HP with it so he got a smaller one and rebuilt the tanny. It's a 3200 to 3500 stall. I think about all that is left for that is the rear tires and a set of rear coil overs. I got a set but can't use them they a buggy style coil overs of the rat rod the rear end came out of.