1st gen body flex, dse frame connectors

[BRIAN]

I bought a set of DSE connectors thinking for some reason they would make my life easier but in the end wound up modifying them to the point that I just should have started with 2x3 tubing. The DSE stuff is 1st rate by the way for someone looking for direct weld in deal.
I welded rear section and bolted on front using 9/16's bolts and crush sleeves. Out of curiosity I hooked up my Snap On ball joint dial indicator and jacked up car from front crossmeber. This is bare shell and bare frame. The measurement is taken mtg the gauge from the front apron support and placing the indicator at the nearest portion of the rail near the body bushing. I also had Global West solid bushings. I am a little dissapointed to say the reading was approx .040. That is with only one bolt in each connector end as I was short 2 bolts. The problem after looking at the situation is the frame connectors even if welded to the subframe do not connect to any part of the body for about 12" back. Even if welded that is about 16" without touching the body for support. You can see the connector acually move down at the front when jacked up as the floor pan flexes. I plan on running roll bar tubing under seat brace connecting to connector to stop front flex.
Has anybody ever measured a stock rubber mtd no frame connector car this way? By the way I am assuming the measurement would be higher if taken from the front frame horn. I know the sheetmetal will stop most of this but I am just curious. I will post more accurate readings when I get the bolts and after I modify front of connector.

[Salt Racer]

That's very interesting. Thanks for the info. To be honest, this doesn't surprise me much.


...The problem after looking at the situation is the frame connectors even if welded to the subframe do not connect to any part of the body for about 12" back. Even if welded that is about 16" without touching the body for support....

That's a lot of leverage. One thought is to fill in the gap between floor pan and subframe connectors with steel plates, stitch welding them all way to the front. I'd even take the subframe bushings off and weld the subframe on the body shell if I had no intention of swapping in a new subframe down the road.

To gain rigidity in longitudinal direction by significant amount, material needs to be added outside of two planes defined by the top and bottom surface of frame fails. This is why stuff like roll cage (complete with A-pillar bars), tall driveline tunnel, firewall-subframe down tubes, etc tremendously increase rigidity.

Have you checked the torsional stiffness? It's more important.

[BRIAN]

Not too many people interested but.. Finallly got some grade 8 bolts and tightened down subframe to actual connectors. Holes are dead on and a bit of a pain to get in but once they are aligned it is easy. By bolting them on I have eliminated the upward motion of the subframe connectors but only eliminated .010 of movement to .030. By the way I am using the crossmember that ties the two spring towers together. After some looking at it and actually by accident found that it is more in the actual subframe then anything else. I sat on rail to take a break and noticed dial indicator nose dived almost the exact amount. Maybe the .030 now is not a lot but the last car I built could lift three wheels of the ground by lifting at one suspension point with just about no movement so I am now obsessed on obtaing the same. The answer I guess will be forward struts from firewall. I do not want to run cage so I will also run bar across firewall tying into cowl. Will see what happens.

[Steve Chryssos]

but the last car I built could lift three wheels of the ground by lifting at one suspension point with just about no movement so I am now obsessed on obtaing the same. The answer I guess will be forward struts from firewall. I do not want to run cage so I will also run bar across firewall tying into cowl. Will see what happens.

Brian,
Interestig info. Sorry I don't have any hard data for you. But I do have a full roll cage with downbars to both front and rear framerails and fab'd sfc's in my 68. Plus the car's together.

Don't worry. You'll be able to jack one wheel and lift three off the ground. Judging by your Rambler pix, it looks like you are on Long Island. Come on out (jus' past Westhampton) and I'll show you. I just bought an aluminum jack, so maybe that's a bad idea--but what the hell.

[BRIAN]

Yes I am on beatiful Long Island in Nassau. I will try and hit some shows out East with Rambler this summer if all goes well. Just look for the ugly car with the uglier driver. Probably stuck on the side of the road in need of that jack.

[Steve Chryssos]

No way man, That Rambler's cool looking! I just realized I mis-read your post. You are not doing a cage, so my car does not offer a good comparison.