I'm another fan of the CRS bolt in chassis having fitted one to my 355 powered LH. Another weak point for LH-UC Toranas is the firewall seam just above the transmission. I've seen this seam split on stock 202 auto LHs from body flex & have seen a factory 5.0ltr SS hatch split so bad you could reach under the dash & put your fingers out into the engine bay.
chassis twisting
Started by
_V6 UC_
, Jun 17 2012 10:08 PM
50 replies to this topic
#27
_V6 UC_
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Posted 18 December 2012 - 03:45 PM
Never heard of that one. My cars almost done, I still haven't done any form of strengthening. Il have to get under n do some measurements to box and strengthen a few things. Front bumper will have to go back on to hide the braid n cooler so that will help. Not sure how concerned I should be about the twisting. Few ppl say it ok. Others say sort it out
#28
TerrA LX
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Posted 20 December 2012 - 07:24 PM
I'm another fan of the CRS bolt in chassis having fitted one to my 355 powered LH. Another weak point for LH-UC Toranas is the firewall seam just above the transmission. I've seen this seam split on stock 202 auto LHs from body flex & have seen a factory 5.0ltr SS hatch split so bad you could reach under the dash & put your fingers out into the engine bay.
Het Matt,
I have never seen one like that, what would you think is the main cause, is it one rail lifting higher than the other opening it up?
#29
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Posted 21 December 2012 - 12:31 PM
When Boy's UC got crunched on the left rail that seam opened up.
#30
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Posted 21 December 2012 - 08:20 PM
So lateral and vertical movement, hmm, * goes off to triangulate the chassis rails*.
#31
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Posted 22 December 2012 - 07:46 AM
^^^That's it, in some cases when the seam splits, the transmission tunnel will crack too. I almost purchased a factory 5.0ltr LX SS hatch with 355 engine, M21, 9" etc for $6K a few years back, untill i inspected the body of the car. It had large bulges in the sill panels near the lower rear corners of the doors & the firewall had split open as i mentioned above. Basicly, the body had flexed so much from the weight & added power of a healthy 355 amongst other things & it had twisted. I knew from my experience in the trade that no matter how much work i put into that car, it would be difficult to achieve & maintain good panel alignment.
#32
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Posted 22 December 2012 - 05:13 PM
Het Matt,
I have never seen one like that, what would you think is the main cause, is it one rail lifting higher than the other opening it up?
lack of torsional rigidity along with inadequate spot welding on seam is why that one opens up imo, the first sign of it usually comes from a front bumper that goes out of alignment when you have not hit anything
At minimum i would add more spot welds along with stitch welding the ends together, the welds let go the metal has not gone through an inelastic deformation so stress levels are below the youngs modulus of the metal used.
The radiator support panel is what holds the front of the rails together,it should act like a bulkhead yet the hole for radiator also weakens it so it is not as effective as it could be,cutting the top to allow the engine to swing in easier is a huge mistake unless you are chasing more body twist, perhaps boxing this U section could help a little.
If someone could measure up a CRS kit which look rather crude imo i think they could be made lighter and stiffer/stronger, another benefit is the members here who can do fabrications can build their own if we have dimensions to work from.
#33
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Posted 22 December 2012 - 05:23 PM
Struggler should chime in here, when he and Warren had their big block Torrents they had no chassis kits in them for a long time and i don't recall them splitting and warrens was a regular 9 second car at the drags. Must be badly welded or lack of welds to do that.
#34
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Posted 23 December 2012 - 09:59 AM
Mine has RHS welded in to connect the front and rear chassis rails together not sure how how much it would strengthen it i also noticed the lower control arm mounts on the floor had being welded up after what looks like they started to tear out of the floor good possibly take some pics later if you want
#35
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Posted 23 December 2012 - 01:42 PM
Mine has RHS welded in to connect the front and rear chassis rails together not sure how how much it would strengthen it i also noticed the lower control arm mounts on the floor had being welded up after what looks like they started to tear out of the floor good possibly take some pics later if you want
Would be good to see just how much connecting the front to rear rail actually does, Im stressing abit about when my lh finally hits the road as im currently having a solid roller cammed holden 355 built with estimates of 550+hp at the flywheel. Plans are minitubbed with coilovers and if possible (subject to what my engineer says) at minimum a four point cage with a bolt on front section to turn it into a 6 point. Plans will be to race it as often as possible but still drive it on the street. Just worried about wrecking good door gaps and straight bodywork! Have spoke to my engineer briefly about connecting the front and rear chassis sections which he said is fine to do but made it sound as if it does not do alot strength wise. Like said we only briefly spoke about it and he did say do the tubs and coil overs first then discuss the chassis connectors. Maybe i just misinterpreted what he was saying about it. Would rather do the weld in style as it's cheap and i can do it myself plus it looks neater in my opinion than the bolt on kits. In saying that if there was no real gain from doing it that way i would just do the bolt in kit and hope that it dont stand out like dogs balls!
#36
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Posted 23 December 2012 - 08:27 PM
A bolt in chassis kit may not fit very well. A weld in kit you make your self can be made to fit. And of course the DIY job means you add as little or as much stiffening as you please.
#37
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Posted 23 December 2012 - 10:56 PM
I found kit on eBay from waddington's for $990 plus freight. Ill buy it next week
Just incase a few of you guys dont know, Waddington's have just bought out Castlemaine Rod Shop. So more than likely that Waddington's kit is the CRS kit.
#38
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Posted 24 December 2012 - 06:57 AM
Just incase a few of you guys dont know, Waddington's have just bought out Castlemaine Rod Shop. So more than likely that Waddington's kit is the CRS kit.
Waddingtons used to make them before they aquired CRS, would be interesting to see an original Waddington kit next to a CRS kit so you could do a comparison. After fitting different items from both places in the past (not chassis kits), if i was buying a kit it would be from Waddingtons for sure. More hope of it fitting as its "meant to"
#39
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Posted 24 December 2012 - 09:40 AM
Waddingtons used to make them before they aquired CRS, would be interesting to see an original Waddington kit next to a CRS kit so you could do a comparison. After fitting different items from both places in the past (not chassis kits), if i was buying a kit it would be from Waddingtons for sure. More hope of it fitting as its "meant to"
Didnt know Waddington's sold those kits I have never bought anything from them. It's good to know though that there stuff has been good in the past since they've taking over CRS, buy with confidence.
#40
A9X
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Posted 24 December 2012 - 10:17 AM
My hatch runs a very strong and torquey 8
We did Seam welding only and ditched the chassis connector idea in favour of the basic roll cage
No obvious body flex issues 6 years later
We did Seam welding only and ditched the chassis connector idea in favour of the basic roll cage
No obvious body flex issues 6 years later
#41
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Posted 24 December 2012 - 10:52 AM
My hatch runs a very strong and torquey 8
We did Seam welding only and ditched the chassis connector idea in favour of the basic roll cage
No obvious body flex issues 6 years later
How much seam welding did you do as a matter of interest? i'm at about that stage now, but not going to put a cage in the car if it can be avoided.
#42
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Posted 24 December 2012 - 09:57 PM
basic stitch welding of the chassis rails, and any suspension pick up points
#43
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Posted 25 December 2012 - 08:31 PM
Had a hatch years ago with a strong 350 sbc in it.
Twisted the left front rail up 3" on a really good launch one day. That was the end of that car as we striped it and transfered the running gear into another car. Gave the shell to my old man who turned it into a speed way car.
The new car had a 6 point cage and we stich welded the front and rear rails and mounts for the diff. We never had a problem after that.
With the new hatch i'm doing at the moment, i will be doing my own connectors, stich welding pick up points and a min 4 point cage to strengthen it up a bit. will be running around te 500+ rwhp in it.
Twisted the left front rail up 3" on a really good launch one day. That was the end of that car as we striped it and transfered the running gear into another car. Gave the shell to my old man who turned it into a speed way car.
The new car had a 6 point cage and we stich welded the front and rear rails and mounts for the diff. We never had a problem after that.
With the new hatch i'm doing at the moment, i will be doing my own connectors, stich welding pick up points and a min 4 point cage to strengthen it up a bit. will be running around te 500+ rwhp in it.
#44
enderwigginau
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Posted 29 December 2012 - 06:43 PM
We did Seam welding only and ditched the chassis connector idea in favour of the basic roll cage
The cage would basically do th same thing........
#45
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Posted 31 December 2012 - 02:10 PM
Cage is a good alternative to a bolt in chassis kit or weld in chassis connectors. Untill you go to engineer or road register the car. If you happen to reside in NSW in any case. The engineer i spoke to (RMS approved & recommended) had no issue with approving the CRS chassis, but will not engineer a roll cage. I also remember having rear seat passengers evicted by Police from an LH Torana i owned with a roll cage fitted & being given a $270+ fine for conveancing said passengers in a vehicle fitted with a roll cage.
#46
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Posted 31 December 2012 - 04:48 PM
I find when stitch welding the thin floorpan after a period of stress it can start tearing. It's caused by heating and thus weakening (when welding) such thin material, I prefer to plate inside over a much larger area and then bolt (or stud) to the thicker or double folds of the chassis or mount plates. Of course a cage and/or more solid 4-5mm full chassis from bumper to bumper is best. But heaven forbid you make a car safer for occupants. The fun police say you can't make your car safer because they get all confused and can't understand why you would do that to an old high performance car. Funny how the most horrific racing car crashes in history happen and the driver walks away looking back without seeing one straight panel, but yet that roll cage saved his life. As tricky dick johnson mowed down the trees at bathurst I bet (after kissing his own butt) he kissed his roll cage. We live in nanny country where rules are only about revenue raising rather than having rules to keep people safe.
#47
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Posted 31 December 2012 - 05:23 PM
Keep note people, when bracing the chassis, do it between the axles, not outside. Outside the axle lines is the crumple zone and this is a good thing. I'm pretty sure CAMS/FIA do not allow the safety structure to be beyond the axles.
#48
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Posted 31 December 2012 - 05:42 PM
Over time my LX hatch started to flex a bit more then I would like and I had under 400 hp at the fly wheel from what I have read on here if I was doing it again
Extend the chassis rails from where they finish by rear or gear box as far back as you can and box them in from the inside the car from cross brace to under rear seat
double plate the inside side of and bottom of chassis rails.
Stitch weld the body espesically critical areas
not sure how but would look at double plating inside around the bottom of the door opening and up into the footwell as this is where my car flexed, jack the car up and put stands under the chassis rails as near the firewall and see how much the front of the car droops.
just a caution I am no guru of body strenghtening but just looked on here over the years at what others have done and what I thought looked the goods and what didn't
Extend the chassis rails from where they finish by rear or gear box as far back as you can and box them in from the inside the car from cross brace to under rear seat
double plate the inside side of and bottom of chassis rails.
Stitch weld the body espesically critical areas
not sure how but would look at double plating inside around the bottom of the door opening and up into the footwell as this is where my car flexed, jack the car up and put stands under the chassis rails as near the firewall and see how much the front of the car droops.
just a caution I am no guru of body strenghtening but just looked on here over the years at what others have done and what I thought looked the goods and what didn't
#49
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Posted 31 December 2012 - 08:10 PM
My engineer will pass a half cage and he said possibly a full cage, so I'm only tack welding the front half in case he doesn't allow it. He's already done the paperwork for half cage, but not full cage yet.
#50
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Posted 31 December 2012 - 09:30 PM
Cage is a good alternative to a bolt in chassis kit or weld in chassis connectors. Untill you go to engineer or road register the car. If you happen to reside in NSW in any case. The engineer i spoke to (RMS approved & recommended) had no issue with approving the CRS chassis, but will not engineer a roll cage. I also remember having rear seat passengers evicted by Police from an LH Torana i owned with a roll cage fitted & being given a $270+ fine for conveancing said passengers in a vehicle fitted with a roll cage.
I have the same issue. Engineer I'm using will pass lots but will not pass a half cage if I have rear seat. I'm spewing as I want rego with rear seat
In NSW and QLD you cannot have a back seat with a cage. Under the NCOP all other states should be the same.My engineer will pass a half cage and he said possibly a full cage, so I'm only tack welding the front half in case he doesn't allow it. He's already done the paperwork for half cage, but not full cage yet.
Just watch which way RMS go, as they may disallow rego with a cage at all, no matter what your engineer signs off.......
Grant.
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