Bar angle on a retro Rocket

[MQueen]

I have a 07 Rayburn that someone put Rocket 4 bar brackets on. I have no way of knowing if they installed them at the correct height. So what I need to know is with the bars in the set up holes what angles are they at in degrees so I can compare that to what I have. Bar lenths do match the book. Also with the panhard level with pinion and 7" up on frame what angle is it at? From what I can gather this Rayburn front is basically the same as a black rocket and I am trying to copy the black front rocket LR behind Big RR spring set up. I have not ran this car yet just finishing it up and trying to get my ducks in a row.
Thank you for replies I usually don’t have to ask questions because I can find the answers on here but I couldn’t find this in a search.

[jedclampit]

BAr angles are going to be dependent on which brackets are on the car and the ride heights you are using.
I believe the rayburn spindle is similar to the blue/gray rocket.

Check here to id brackets first or post some pics.

http://www.rocketchassis.com/images/Catalog/23_4LinkBrackets.pdf

http://www.rocketchassis.com/parts.php This is the main parts page, not very current I believe, but it should serve you well.

You should be able to figure the rr ride height to use, based on the RR lower bar angle, in usually the center hole on the rr lower, being about level to 2* uphill to the chassis.

See what brackets you have and work from there.

[MQueen]

Ok I will follow up with pics or details. But I still need to know what it is on an actual rocket sitting at ride height so I can compare my mount height to an actual rocket. If rocket is LRL +10 LRU +20 and my set up holes have me at +5 and +15 that will tell me my set up holes are too low and i will have to start in the next hole up as the standards. ----->Jed I really respect your opions on here I can tell you have it together. I'm no nubie to the sport, been racing for the past 34 yrs but I have only been working with a 4 bar the past few years (01 swartz) and I am chasing my tail most of the time. I understand most of the concept and theory but cant hit on a combination that works for me. Cant afford a new car so I try and make do with what I can get ahold of.

[MasterSbilt_Racer]

I think what Jed is saying is just set your ride height where your lower bars are near level in the middle. Then put your lr upper in a hole around 20 to 22 degrees to start. Put your rr upper in a hole where you have 18 degrees. That is how I would attack the problem.

[jedclampit]

Yep, thanks MBR.
I don't think you will have any problems getting those #'s.
Your rr lower angle will let you determine the correct ride height to use @ the rr, the only thing that could be problematic is if the brackets aren't at the correct angle in relation to the chassis.
Don't sweat the bar angles, they will fall right into place! I can tell you which holes to put the bars in when I know what brackets you have, and the * reading you should get.
Where to put the rear end l-r and appropriate axle tube lengths will have to be determined also.

[MQueen]

Yep, thanks MBR.
I don't think you will have any problems getting those #'s.
Your rr lower angle will let you determine the correct ride height to use @ the rr, the only thing that could be problematic is if the brackets aren't at the correct angle in relation to the chassis.
Don't sweat the bar angles, they will fall right into place! I can tell you which holes to put the bars in when I know what brackets you have, and the * reading you should get.
Where to put the rear end l-r and appropriate axle tube lengths will have to be determined also.

Yes exactly, this is why I need the info. For an extreme example if my mounts are installed 4" too high then I would have to lower my ride height by 4" to be able to leave the bar in the setup hole in order to get the angle required. I have printed those off and will post back when I get home.

[MasterSbilt_Racer]

If your mounts are off on the vertical direction, you have essentially just raised or lowered your fuel cell.

Your ride heights are now determined by the geometry. If it takes 7" to make it right, that is your ride height. If it takes 8" or 6", that is your ride height. Geometry is all that matters. Your chassis builder gives you ride height measurements for simplicity and as a carryover from monoleaf and truck arm cars.

[billetbirdcage]

If your mounts are off on the vertical direction, you have essentially just raised or lowered your fuel cell.

Plus altered your rear shock mount heights!


You might also be able to do this:

Put 2 bars on the upper or lower that has the most holes or spread between them, make sure both bars are the same length and roughly the same angle side to side. meaning if you put them both on one side of the cage offset it the amount of a rod end width in the frame that way. Put one bar in the very top hole and one in the very bottom hole, this will lock the suspension at the ride height that is correct for the bracket heights, then measure and see if the ride height is correct for the car. The difference between the 2 is the amount he RR is off.

This really doesn't work on the left side as they don't take in account that the birdcage is an inch lower do to stagger. Most all cars are not built with the brackets right on the left side that is why wedge changes a lot with moving left bars and not so much on the RR. The more stagger you run the worse this will get.

Hope that makes sense!

But as Jed said put the RRL bar in the middle hole (if 3 hole bracket) and set level to 2 degrees uphill and measure ride height, if it's not correct then the brackets are off that much. Make sure to keep the rear end somewhat level when doing this. I would also plum bob the mid plate to the ground and draw a line on the ground and then plum the rear end tubes (far out as possible) and see how square the brackets where installed also. They likely aren't at the right hieght or square unless someone new what they were doing.

[MQueen]

Yes I understand completley. It has the newer style 6 hole double slot brackets. This was one of Brian Shirley's old cars.

[fox1162002]

I've built a couple of these cars and I always made sure ride heights were the same or within an 1/8 in. Honestly these cars really work I'm in the process of doing some changes to my friends car well the 1st one I ever done. I'm gonna try and change his front end geometry to help tighten up some more. These cars use the rocket blue front. Any Rayburn swingarm from 02 to 11 can be done this way. All you have to do is have a blue front rocket and jig it up. Then apply it to the Rayburn. I know we set his rear end by making sure the LF and LR was in line then the ride heights I'm not sure of the fronts have to get his book but on the RR the bar was in the center hole and was level. We made LR an 1/8 higher from frame to rear end than RR then we started scaling. Maybe this made sum since.

[MasterSbilt_Racer]

Plus altered your rear shock mount heights!

That could be good or bad.