1600 Front End Problem

[Wendell #527]

My 2/1600 front end isn't using all it's travel. I have Fox Position Sensitive Shocks that I bought from Kartek supposedly set up for 1600s. I think they were 15/15. I have a 6 spring pack and good trailing arms again from Kartek. After a race, there is still about 2" left on the shock that has not been used, like the shocks are too stiff, or the leafs are too stiff. I think I reamed the bushings enough, because when I jump on the front end, it seems to cycle easy enough. Should I change to 7 leafs, or re-valve the shocks?

[wstephens]

This may sound like a dumb question but here it goes...
What is the stroke length of the shocks, and based upon that, what is the stroke length of the arm?
A lot of people will run a 12" shock but the stroke / cycle of the arm is only 10" thus you end up with 2" of unused shock. In the past this was done on non-position sensitive shocks just for the purpose of having a higher oil capacity keeping the shock cooler. I don't know much about pos. sensitive shocks or how this relates.

Hope this helps a little, and good luck!

[cosmo]

Take out your leaf springs. Unbolt the bottom shock bolt. Cycle the suspension. Now you'll be able to see how 'free' the arms are. Next,bolt the shock back up,remove the gas from the shock. Cycle again,you'll now see how much travel you are actually are using.

[bajavwracer]

A lot of people will run a 12" shock but the stroke / cycle of the arm is only 10" thus you end up with 2" of unused shock.


Yupp thats true. My 5-1600 has 14" bilsteins up front and we only got about 11" of travel. thus leaving about 3"of left over.

[Ramsey_ElWardani]

Yupp thats true. My 5-1600 has 14" bilsteins up front and we only got about 11" of travel. thus leaving about 3"of left over.You shouldn't be able to get that much travel out of a 5-1600 or 1/2-1600. If you do you are over twisting the torsion leaves and rotating the lower arm from almost verticle to almost verticle. You need to cycle your suspension as Brian (cosmo) suggested and do some re-figuring.

[Superfab]

I used the 10" shocks on the last car I did and pretty much used all the travel. The car had a true 9-13/16" wheel travel with a little shock left over at each end to keep from damaging the shock at full droop and full compression. A 12" shock is just a waste. This was with standard 1600 arms. Also I allways check travel with the wheels turned to check for tie rod clearance. Amazing how many people dont!

[bajavwracer]

You shouldn't be able to get that much travel out of a 5-1600 or 1/2-1600. If you do you are over twisting the torsion leaves and rotating the lower arm from almost verticle to almost verticle. You need to cycle your suspension as Brian (cosmo) suggested and do some re-figuring.





Ok 11" might of be overdoing it jeje maybey about 10". But also im Using a 181 (thing) BJ front end.

[Wendell #527]

When I built it I had about 11" of shock travel, and about 10" of wheel travel. I measured it out so the 1" that I wasn't using was at the bottom of the stroke. Now I'm seeing the shock isn't completely closing, so I'm probably only getting 9" of travel. I'll take out the leafs, unbolt the shock, cycle it and see if it's hanging up somehow or I'm just too stiff. Thanks for the input.

[DailyPedal]

I have used stock German leaves on light single seaters and stock and/or 7pks on two seaters before so you may be just a little too stiff from what peole used to run...no two cars are the same though as the spring rate needs to be matched to front to rear weight, wheel and tire combo and driving style.

[la2baja]

If you cycle the front as said earlier and you are still not getting full use of the shock in the up stroke, I would check the shock position. Maybe hydro-locking the shock early. Maybe the extra inch at the bottom of the stoke is to much, or maybe it is more than an inch?

[Wendell #527]

Well, my wife just fixed this problem! In the MORE Powder Puff she broke both front king pins. They were kind of wimpy little king pins. This is a 1983 car, so we've been racing in 1300 class because it's just not competitive in 1600. Now I have the OK to go with coil overs. I'll get longer trailing arms, combo spindles, and throw in the coil overs. I'll make sure the bushings aren't hanging up, and I'll have to lengthen the steering rods. Any other things you think I should worry about? Thanks for all the advice.

[Erik Irvine]

The only other things I can think of is:

1. Beam width, if you want a wider beam in front now is the time to do it, because you will be building the shock hoops/tie-rod length around the beam.

2. Tie-rod clearance on the frame. My old car was setup to run 1-1/4 arms, when I put 4 inch over arms I didn't get much more travel because when the arms dropped out, the tie-rods hit the frame, I ended up going with a wider beam which helped that out. Make sure to check clearance pointed straight and turning the wheels side to side with the arm dropped out.

Also another thing to think about is drop spindles, you may want to check ino those.

What spindle/arm combo are you going to buy (if you know yet)?

[Wendell #527]

Good points--thanks. I was thinking 4" longer arms, but I will have a problem with the tie-rods hitting the frame. They're close as it is now. I would like to have a wider car any way, so maybe I better get a wider beam and re-do the shock hoops. Even then maybe I'll only be able to use 1-1/4 or so arms. I was planning on using regular combo spindles instead of the King Kong spindles so I could stay with my drum brakes (just to save $). Think I should upgrade that, too?

[Erik Irvine]

IMO I think those King-Kong spindles are overkill, unless your breaking the combo's too much. If it was me I would buy combo's and keep the drums until you start breaking things, especially with a light car like yours. You can cut out the existing bottom bars and add some with a bend at the end to help clear the tie-rods for the bigger arms (see picture attached...thanks Ryan P!). Also if you put a 6, 8, 10 , or 12 in. over beam that will buy you some clearance as well. It may not be that hard to figure out the tie-rod clearance so don't limit the length arms you get solely on that variable.

Links with some info:
http://www.desertrides.com/forum/viewtopic.php?t=7870
http://www.desertrides.com/forum/viewtopic.php?t=7337

[Wendell #527]

Thanks---that's a good picture that shows exactly what I need to do. I'm gonna tear it upart tomorrow, cycle it, sit back and drink a cold one and figure it all out. I have a good idea I'm going to do just like yours is and move that part of the chassis down and go with longer arms. maybe not 4" longer like I originally planned, but maybe half of that. I'm pretty sure the coil overs will be a lot better than the leafs.

Thanks for the help.

[Erik Irvine]

Pm me or post here before you weld the rack mount on the new beam. There are some tricks you can do to reduce bump steer, and put it where you want it in the suspension cycle. Also if you don't want to mess with the bend you can do an "X" pattern, that's what I did on the last car I built (see pic 1&2).

Couple of other notes to chew on:
1. Build it so the chassis ties into the front beam far enough out so you don't tear a corner off braking, hitting a rock, or running into another car (see pic 2). There should be enough room for the coilover, but not much more than that. I have seen guys with 12 over beams come straight out of bug bodies... it is best to tack everything and bolt up your arms, rack, tie-rods to make sure it's good

2. Be careful welding to the beam, stich weld it. If you run long beads you could possiblly distort the beam and make it a pain in the butt for bushings and if it is real bad screw up the geometry/alignment etc.

3. Make sure to lean the beam back, I put 7 degrees for non power steering and 9-10 with power steering. Puts caster into the front end (see pic 3)

Hope this helps

[Wendell #527]

I printed your drawings and agree with your comments. I think I better wait till next season to upgrade. I just got some combo spindles and I'm going to stay with the short arms for now. I see you race MDR in 1300. Maybe I'll see you out there next year. I'm racing in MORE now, but we used to chase for a 1200 truck in MDR, and some of those races were fun. Thanks again for your help. I'm gland I didn't upgrade until I can do it right.

[DailyPedal]

Well, my wife just fixed this problem! In the MORE Powder Puff she broke both front king pins. They were kind of wimpy little king pins.

Just curious, where did you get the pins? There are some imported pins going around that shops have sold that are junk. Always ask about the quality of parts that you are buying and check around for as much info you can get.

[Wendell #527]

I got the king pins that broke from Kartek. I didn't check where they got them from, but judging by the size of them I think it was a design problem rather than a quality problem. Those little pins are only about 5/8" diameter, and as fast as my wife was going I'm not surprised they broke. I should have upgraded to combo spindles when I rebuiult the car back in March. It's interesting to hear there are some junk pins going around. Hopefully the big distributors like McKenzies and Kartek are smart enough to stay away from the junk.

[DailyPedal]

If I remember right, Kartek makes their own pins and wont sell the imported crap so if you broke those...but again, are you running 45-year-old VW spindles? You said "I should have upgraded to combo spindles when I rebuilt the car." Dude it sounds like you had other issues, maybe bent arms and/or shims in spindles not properly set up. If the front end is not set up properly, parts will be put in a bind and things break.

[Wendell #527]

I got it fixed. Nothing was bent or in a bind or anything. Just old style spindles that aren't near as strong as combo spindles.

[Erik Irvine]

Cool!! When is the next race?

[Wendell #527]

December 1st in Barstow!

[Erik Irvine]

Cool, I am guessing the Toys-4-Tots race. Have fun, I can't make that one, I will be working that Saturday.

Let us know how it goes, who is driving you or your wife?

[Wendell #527]

I'll see you at another race then. I'll be racing this one. Laura says she's planning on just chasing till next Powder Puff. This is a cool race because you go 5 10 mile laps, and then I think 3 40 mile laps with a short intermission in between. Not sure of the specifics, but main pit is right behind Slash X, and that's a party in itself! See you out there sometime.