adjusting 4link woahs...

Old 05-24-2007, 12:30 PM
  #1  
jessejames79
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Default adjusting 4link woahs...

ok dumb question but i cant find the info anywhere... while adjusting the wheelbase on my car i find i must back the rod ends almost all the way out to get the wheelbase close to factory spec wich is 115" on all 55-57 chevy's i bought this chassis done already and got it cheaper than it would have cost me for the back half parts... figureing i'd have to do some work to it to get it right.... so here's my question what is the minimum thread engagement on a 4-link rod ends??? also the housing will not line up with the arch in the top of the framerails like the 4-link was from one supplier and the frame rails from another... man it probably would have been easier to just buy all the parts and start from scratch... well thanks for any help...
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Old 05-24-2007, 01:07 PM
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sp2816
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I definitely am along the lines of more is better, because I want to keep at least half of threads if not more of the rod end threaded into the bar. The diameter of the rod end shank is smaller that the tube that it is fitted into. If it is necessary to maintain the 115" wheelbase, you can buy the 1 1/4 Chrome Moly tubing and buy the threaded bungs (left and right hand threads) and have them custom fitted and welded to your length. Sometimes the wheelbase is lengthened from factory specs to help stability on the top end and sometimes it is shortened to help on chassis reaction. How do the rear tires fit in the wheel wells? Are they centered or are they too far back now? I would rather have the wheelbase set at 114" than not have enough threads for the rod ends.

You spoke of the arch for the rear frame rails. Is there clearance problems with the rear end, or anything hitting the frame? If properly braced the rear frame rails are only holding up the rear body and a spot to mount the shocks. And it needs to have good welds and be square in the car. The rest is really cosmetic in my opinion, because your suspension is being held by the front crossmember. By properly braced, I mean 2 bars going from the top of the hoop to the frame rails in the trunk area. And where the shock bar and shocks are mounted on the frame have a X-brace tying back into the main hoop. There are different variations on this, but this is the basics in triangulation. For the front crossmember of the 4-link, I like to add some extra bracing at the top of the 4-links plates rear frame rails to the bottom of the hoop and also some going forward from the 4-link plates at a diagonal over to your frame rails on the underneath side. This will try to keep the crossmember from bending in the middle and the top 4-link mounts from flexing.

There should be some other good inputs on this.

Bill M
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Old 05-27-2007, 06:30 AM
  #3  
mcracecars
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Do not use the 4 link bars if you have to back out the rod ends so much. I cannot tell you how many times I have seen control arms and 4 links and ladder bars were the rod ends seem to be only threaded in a couple of turns. And since rod ends never seem to be replaced or even checked periodicly, In my opinion it is an accident waiting to happen.
When I see this kind of stuff, I have to wonder about how the rest of the car was put together.
You should not see, on a 4 link bar more than about 7 threads showing beyond the jam nut. Any more and you need to make up new 4 link bars.
Any decent chassis shop can make them up for you, or go to www.chassisshop.com and buy the tubing and tube adapters, make them up yourself and take them to a good welding shop that can tig the adapters on. It is also a good idea to put a couple of plug welds on each end. Typical 4 link bars use 1.250 x .095 cm tubing.
As far as how the frame is configured over the rear end, it is not a big deal as long as there is no interference, as Bill stated, and everything is square.
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Old 05-27-2007, 10:38 AM
  #4  
edvancedengines
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For what it is worth;
I agree completely with McRacecars.

Those accidents that are waiting to happen with problems with rod ends usually show up at high speed or right past the finish line and result in crashing.

Never use anything but the best and most expensive rod ends in tension stresses. You can get by with a little lessor quality in compression stress. With ladderbars even with the good rod ends always have safety straps bolted on.

Ed
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Old 05-29-2007, 11:40 PM
  #5  
sc3314
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You have been given some real good advice. Load the car up, and take it to a reputable chassis man! You need the correct lenght on the 4 link bars for your chassis. Do you have the same problem with the threads on the wish bone? Ed wrote an excellent piece on 4 links, great infomation!

The wheel base maybe altered from stock with any chassis work. But not to the extrem you are speaking of. With the rear end problem you have. I would have to wonder if anything is correct?

I sent you a pm, I have some pics. that will show you what everyone is talking about.

Dave
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Old 06-01-2007, 05:24 PM
  #6  
edvancedengines
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Dave,
I thank you sir.
I do hope that many racers are helped in my writings. I have already heard from a few chassis guys that like what I wrote and they say it has been helpful for them.

Ed
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Old 06-20-2007, 09:24 AM
  #7  
RonOwensRacing
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Yes Yes Yes Please do yourself a Huge favor and do like these guy's have told you take your car to a good shop and have new 4-link bars made it is not that bad you cant put a price on safety .
Just look what could happen if they broke and you crashed if no one gets hurt or killed you still lost more than it would cost to do them right .
I know you will That's why you asked in the first place .
Take care and good luck with your build. Ron
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