Zero1Niner

Having some concerns about too much frame flex. Previously I had a pretty badly cracked frame on the drivers side rail, but I had the frame welded by, who I think, was a competent welder. We didnt add any extra material to stiffen the frame which may have been a mistake in hind site, however the way the frame is flexing, Im not sure if adding extra material to the frame rail side wall would have reduced the flexing all that much that I am seeing.

I cant remember the amount of frame flex that occurring before the Borgeson was installed, but clearly the Borgeson has significantly more torque than the factory box, and I am am sure its putting much more stress on the frame rail than the factory setup.

I did add a spreader bar...not sure how much that is strengthening the frame. Regardless, Im still seeing it flex even with the spreader bar installed.

When I turn from stop to stop, I can watch the frame rails twist. The most severe twisting occurs when its approaching the full left or right stop. I would say most of the twisting occurs in that last 5 or 10% of the range. When slight turns, the twisting seems minor in comparison to how much twist occurs once it hits the stop.

I guess I have a few questions. Ive heard a bunch of complaints about C3 frame flex, but wondering if what I am seeing should be highly concerning or is basically normal for this car.

Another question is what can I do to stiffen the frame up? Will I need to completely rip apart the front end to make the improvements?

I use this car as a daily driver, and not looking to win any restoration awards. Its more of a very slow restomod project. My primary mission is to make sure this is a strong, safe and reliable car.

Bad Bird

Why are you turning the wheel with the car not rolling? My old man would have smacked me over the back of the head for doing that, .

mysixtynine

Mine does the same thing.. I was concerned at first as well.

As mentioned above.... move the car before turning the wheel it takes a huge load off all your steering components ... I have to hammer this into my wife all the time.

But ... realize that a manual box will have the same effect its just not as easily seen because you cant do it as fast. I like the fact that I am not killing my steering column support and bearings trying to muscle the wheel in the car.

The factory power assist will have just as much pressure on it if not more as the assist RAM attachment point is on the bottom of the frame rail connected to an extension bracket instead of on the vertical side and is in line with the steering box and is at the same depth from the frame as the pitman arm.

Zero1Niner

Good question. I was just doing that to see how much flex was occurring. Its much harder to see the frame flex when the hood is open, driving down the road with my head deep in the engine compartment

mrvette

There you go, in any corner, the frame flex will be much greater due to loading than any static driveway test, but maybe not so great a difference when pushed to the stops R/L

you got a support between the upper A arms, that's about as much as you can do.....

fleming23

For what it's worth, RideTech is supposed to be releasing a Borgeson Frame Brace on or around 5/4. They used it on their 48 hour car and I have been in contact with them regarding getting on ordered.

74modified

I think all above are good reply's. I am using a Jeep box (what the Borgeson is based off of) and my mounting is a little different. The only things I can think of (that are fairly easy), if it bothers, you is to add solid motor mounts and add reinforcement gussets to the engine mount horns as outline in the Power Book. I have both and it stiffens things up a good bit. Most probably would not need this, but with your already compromised frame, it is something to think about.

Bad Bird

From suspension loading, quite possibly. However, not in the location of the steering box; when you drive a car with manual steering it's rare to ever have to apply as much steering wheel input torque as when you are stationary/barely rolling.

Equal and opposite reactions rule the day here; the more torque you apply to the wheel, the more the frame has to resist that torque.

ignatz

Speaking of forces at work here, the more caster you have dialed in, the more you are lifting one side of the car or the other up and down. Sit in the car and eyeball something close by as you turn the wheel.

mac79vette

For what its worth the Chevy power book shows to weld a plate over the large hole in the frame behind the box. I believe its there to access the bolts that hold the bracket on the frame that the hydraulic ram attaches to. I welded mine and have a borg box and don't thank that is too much frame flex, but did not have the borg box with it open so can not say if it makes a difference. Some one either at VB&P or Vansteel also recommended welding a plat in that hole.