shiftbyear

Has anybody welded in gussets or other supports while they had the body off the frame. I've seen some frames cracked on a-bodies. Don't know if this is a common problem or just from abuse. Pictures would be helpful. Thanks

joe_padavano

Unless you know what you are doing, welding in "reinforcements" can make the problem worse. A major cause of frame cracking is stress discontinuities. The entire frame bends under load. If you weld in a plate at a spot on the frame, the big change in stiffness where the plate ends causes a stress concentration, which will cause a crack sooner than if you had left it alone. Any reinforcements must be tapered so that the stiffness change is very gradual along the length of the frame.

Run to Rund

The convertible frame aka F35 HD frame would be a good way to get a reinforced frame.

jensenracing77

Yep! I seen that all the time with the MX race quads I use to build. People thought they were doing such a good thing by welding all these gussets all over the place. They would crack far worse like this than if they just left it alone. I even seen an engine brake because all the chassis flex was transferred into the engine (the engine is part of the structure on a quad). There are some places we would add a better weld where the factory welds would not hold up but the best race bikes I ever built had no extra material added to the frame other than maybe a thicker weld.

oddball

Depends on what car you have. If it's a 68-72 then you're in luck! There's tons of stuff made for Chevelles, all of which swaps to the Olds.Various companies make plate kits that more or less convert the hard top frame into the convertible frame. Some are cheap, some are expensive. The big difference is how they deal with the trans crossmember.


Or you can snag a stock convertible frame.


While I don't know what I'm doing, I did add gussets to the bushing mounts that are welded to the frame and just hanging out there (ie, front lower arm rear bushing) as I saw those cracking and trying to fall off. I also went whole hog and did the HPI Customs kit which adds K braces.

joe_padavano

Most of those aftermarket kits were NOT designed by anyone with any engineering experience. The kits were done with "eyeball engineering" and are very good at adding weight to the car and reducing weight in your wallet. Improving bending or torsional stiffness? Not so much.

TripDeuces

I narrowed my frame but I added gussets and reinforcements in a few places.