Careless Posted January 5, 2007 Share Posted January 5, 2007 I agree with Mike. It looks like you're making progress. I'm jealous...every time I look at my car, I wish I knew how to weld so I can stichweld my frame to stiffen up the chassis. My friend was just explaining to me that you can drill through existing spot welds, re-weld it, and grind down the excess weld to also improve stiffness. Trying to do more research on that process. or just weld the seam where the two metals meet. i don't think there is a point in taking out spot welds Quote Link to comment Share on other sites More sharing options...
johnc Posted January 5, 2007 Share Posted January 5, 2007 FYI... that scale on the steel comes from the rolling process. The lower priced steel plate and angle is hot rolled (and, surprisingly enough, called Hot Rolled (HR)) which leaves the bluish scale. If you can get it, cold rolled (CR) steel is free of mill scale and is generally a little better quality (1018 or 1020 vs. 1010). Quote Link to comment Share on other sites More sharing options...
heavy85 Posted January 7, 2007 Author Share Posted January 7, 2007 i don't think there is a point in taking out spot welds I believe it's the cheater way for classes that do not allow seam welding. Anyway here's the subframe. It connects to a 2x3 that sandwiches the factory subframe in the rear and the T/C bucket in the front. Overall I'm pretty happy with it other than it took forever to get square and level and symetric. Main thing I'm contemplating is how to lighten it as it's close to 25 lbs. As you can see I've drilled some holes but pissed the wife off in the process and killed a bit so no more big holes anytime soon for me otherwise I would have kept going. The rear crossmember is intended to add some strength by tying the two sides together and also double as a driveshaft safety hoop but once I get to the exhaust I realize it'll probably have to be modified or even made into a bolt-in. The front crossmember is just tacked in to keep it square while I welded the rest but it will be repositioned and will become the transmission mount. Hopefully in then next week it'll be welded to the car. Cameron Quote Link to comment Share on other sites More sharing options...
Careless Posted January 7, 2007 Share Posted January 7, 2007 I believe it's the cheater way for classes that do not allow seam welding. Anyway here's the subframe. It connects to a 2x3 that sandwiches the factory subframe in the rear and the T/C bucket in the front. Overall I'm pretty happy with it other than it took forever to get square and level and symetric. Main thing I'm contemplating is how to lighten it as it's close to 25 lbs. As you can see I've drilled some holes but pissed the wife off in the process and killed a bit so no more big holes anytime soon for me otherwise I would have kept going. The rear crossmember is intended to add some strength by tying the two sides together and also double as a driveshaft safety hoop but once I get to the exhaust I realize it'll probably have to be modified or even made into a bolt-in. The front crossmember is just tacked in to keep it square while I welded the rest but it will be repositioned and will become the transmission mount. Hopefully in then next week it'll be welded to the car. Cameron did u dimple those holes? because that's what makes them way more effective as lightening and strengthening holes at the same time. Quote Link to comment Share on other sites More sharing options...
tube80z Posted January 7, 2007 Share Posted January 7, 2007 You really shouldn't put holes in the top and bottom, those are the parts of the tube that are seeing the greatest loads when this is treated like a beam. The sides would be a better candidate. Cary Quote Link to comment Share on other sites More sharing options...
heavy85 Posted January 8, 2007 Author Share Posted January 8, 2007 You really shouldn't put holes in the top and bottom, those are the parts of the tube that are seeing the greatest loads when this is treated like a beam. The sides would be a better candidate. Cary I put them in the top since it's redundant steel with the floor .... kind of like the factory rails only had three sides to make most efficient use of the floor. Actually the only reason I did this at all was because my factory rails were trashed as it's not the most efficient way to add stiffness to the chassis. Regardless I'm not sure I agree with you for all load cases in this application. You are correct that the more the metal is from the center the stiffer the beam will be ... high moment of inertia .... however, I'm more worried by the yield case if you were to bottom out on a sharp object, jack in the wrong place, etc since the section is relatively thin vs the potential normal force that could be placed on it. I wanted to minimize the chance of screwing up (off road, slipped jackstand, etc) and kinking the beam. 1" tall tube is not much then start adding holes and well if you look up at my cracked factory frame rail pic and you can see where I'm coming from. This is the reason I went with 0.083 vs .065 wall was to prevent a jack or jackstand or curb from denting them otherwise this thick stuff is just dead weight. I just wish my factory rails weren't beat up so I didn't even have to mess with this ... and they didn't even have spec of rust on them. Cameron Quote Link to comment Share on other sites More sharing options...
johnc Posted January 8, 2007 Share Posted January 8, 2007 Originally Posted by Careless i don't think there is a point in taking out spot welds I believe it's the cheater way for classes that do not allow seam welding. Not enough or too many spot welds are an easy way to spot someone who's cheating. Good cheaters leave the factory spots welds alone. Using a 1/8" thick cut off wheel, grind a slot through the top layer of sheet metal until the bottom layer is exposed for about 1/2". Weld up the groove and grind it smooth. Repeat 600 times throughout the chassis. Quote Link to comment Share on other sites More sharing options...
katman Posted January 8, 2007 Share Posted January 8, 2007 "Using a 1/8" thick cut off wheel, grind a slot through the top layer of sheet metal until the bottom layer is exposed for about 1/2". Weld up the groove and grind it smooth. Repeat 600 times throughout the chassis." Caught me! Quote Link to comment Share on other sites More sharing options...
Careless Posted January 8, 2007 Share Posted January 8, 2007 Not enough or too many spot welds are an easy way to spot someone who's cheating. Good cheaters leave the factory spots welds alone. Using a 1/8" thick cut off wheel, grind a slot through the top layer of sheet metal until the bottom layer is exposed for about 1/2". Weld up the groove and grind it smooth. Repeat 600 times throughout the chassis. hehe, i was thining of something like that too. or even doing some rosette welds in between the factory spot welds. even using the brass silica wire so that it's easy to grind down (doesnt spark) and it's good enough for strengthening sheetmetal and is easier to use without warping it. Quote Link to comment Share on other sites More sharing options...
johnc Posted January 8, 2007 Share Posted January 8, 2007 Caught me! I caught a national level 240 autocrosser (who shall remain nameless) with a seam welded chassis. He didn't clean up all the bubbled out seam sealer and a thin putty knife found welds where there shouldn't have been any. I "suggested" that the competitor find a new chassis to use for subsequent National Tours because I would be there with my trusty putty knife and a credit card. He showed up at the next NT with a brand new C5 Corvette. I also noticed some nice, thick, and long "jacking pads" on the bottom of the front frame rails of Jim Thompson's old ITS 240Z. Were these also an idea of yours Keith? Quote Link to comment Share on other sites More sharing options...
heavy85 Posted January 16, 2007 Author Share Posted January 16, 2007 And the best for last. This is what happens when you are pushing down on your wonky floor trying to make it meet the rails and then proceed to spot them in from the bottom. You think your hand is not on top of the weld and well your wrong Quote Link to comment Share on other sites More sharing options...
LLave Posted January 16, 2007 Share Posted January 16, 2007 I see you suffer from the "someone thought it would be cool to cut a hole for a 6x9 here" syndrome too Quote Link to comment Share on other sites More sharing options...
mull Posted January 16, 2007 Share Posted January 16, 2007 I see you suffer from the "someone thought it would be cool to cut a hole for a 6x9 here" syndrome too Don't we all? : ) Nice update heavy85! Quote Link to comment Share on other sites More sharing options...
heavy85 Posted January 18, 2007 Author Share Posted January 18, 2007 K-member mocked up which will also become the base for the engine mounts. Should both add some rigidity as well as mount the engine. Cameron PS - I actually have a receipt from who knows how many owners ago in the early 90's for a $1500 stereo install followed closely by a repair bill to fix the damage when the stereo was stolen ... come to think of it maybe that's why my dash is perfect. When I got the car it still had fiberglassed in front speakers and a subwoofer box fiberglassed into the spare tire well ... there's still a few lbs of glass stuck back there. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted January 28, 2007 Author Share Posted January 28, 2007 Here's the front swaybar reinforcement. I welded 1/2" tube between the top and bottom of the frame rails with 14 guage plates. Haven't figured out the bottom side yet as not only are about 8" worth of spot welds cracked and seperated but the bottom of one frame rail has about an inch long crack. Overall shot of the engine bay. You can see the finished K-member which the engine mounts will attach to, the swaybar mounts, & strut tower reinforcement. The plates on the firewall will weld to the strut towers through a 1" tube assuming the tubes will clear the engine but I think they will. I chose that spot on the firewall since there is a vertical gusset backing it and it also ties into the top cowl plate so it seems to be about the strongest part of the firewall. To top if off there will be a bolt-in tube from strut tower to strut tower. I ordered JTR headers Friday so next weekend I should be able to stuff the motor back in and start fabbing the mounts. Cameron Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted January 28, 2007 Share Posted January 28, 2007 Do you know if the JTR headers will clear the K frame on the passenger's side? Because i don't think it would the way my LS motor is sitting. The driver's side header comes out behind the TC cups. But on the other side I would worry about header and starter clearance. Also I would think seriously about reinforcing the TC cups where the K frame pieces attach to them. I think the weight of the engine will flex that end of the frame. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted January 28, 2007 Author Share Posted January 28, 2007 Do you know if the JTR headers will clear the K frame on the passenger's side? ... But on the other side I would worry about header and starter clearance. I should know in about a week when my headers are delivered. I dont see any issues with the starter from my initial trial fit before the k-members were installed. We'll see but I hope I dont have to redo them. Also I would think seriously about reinforcing the TC cups where the K frame pieces attach to them. I think the weight of the engine will flex that end of the frame. I've been thinking alot about this. The back side of the TC cups are very heavily reinforced with the subframe (see pics) but there is nothing vertically to really add support where the cups attach to the frame rail. I'm open to suggestions here if you got ideas. Thanks Cameron Quote Link to comment Share on other sites More sharing options...
heavy85 Posted January 31, 2007 Author Share Posted January 31, 2007 Here is why I had to reinforce the swaybar mounts - you can see air between the framerail side and bottom .... enough you can measure with a yardstick. I already showed the top side so here is the finished other side. I split a 1" tube into two 1x1 angles and plug welded through the old metal to the new plate on the bottom. Here's the new plate on the bottom. Overall this is way overkill if it was caught many moons back before the parent material cracked up. But as you can see above there was not much left to work with so this is what I came up with to make sure it does not happen again. Hope people are enjoying the show and if you have personal experience please feel free to chime in with advice or other things I need to be aware of. Need to order some tubing for the strut towers and am anxiously waiting for the headers - man I hope I dont have to start over on the K-member. Cameron Quote Link to comment Share on other sites More sharing options...
LLave Posted February 1, 2007 Share Posted February 1, 2007 I notice many people who use 2x3 tubing lay it flat (2in high x 3 wide) I assume that this is to lessen the protursion through the floor, but wouldnt you actually want it the other way from a structural point of view? I imagine much more vertical load the horizontal. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted February 1, 2007 Share Posted February 1, 2007 I should know in about a week when my headers are delivered. I dont see any issues with the starter from my initial trial fit before the k-members were installed. We'll see but I hope I dont have to redo them. I've been thinking alot about this. The back side of the TC cups are very heavily reinforced with the subframe (see pics) but there is nothing vertically to really add support where the cups attach to the frame rail. I'm open to suggestions here if you got ideas. Thanks Cameron Well you probably don't want to here this but I would have tried to tie the K frame back into the frame rails and not the TC cups. A suggestion for you. When I clad my frame rails with 18 guage sheet, I cut long slots through the new metal so I could weld the center part of the new steel and not just the outer edge. Pretty easy to do and grind down smooth. It makes everything like it is one solid piece instead of two layered pieces. I am not sure what engine you are putting in or why you need a K frame, but here is an early pic of my unfinished LS motor cross member I have since welded some gussets between the sides and the motor mount brackets. I also double layered the whole frame rail from the TC cups to in front of the stock crossmember. I then welded in pieces of pipe through the frame rail to make bolt holes to secure the cross member. My header on the passengers side comes out just behind the motor mount on my cross member. In fact, you can see the left and right sides point in opposite directions. That is because I had to move the passenger's side mount forward an inch just to get clearance for the JTR LS headers. Quote Link to comment Share on other sites More sharing options...
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