wjr85 Posted November 13, 2008 Report Share Posted November 13, 2008 Help and Advise needed I am attempting to get my chassis ready for blasting and painting over the x-mas holidays. All the restorations manuals advise that you should at a minimum weld another bar inside the rear spring hangers on either side which seems to be logical enough for extra strength. My question is what type/thickness of bar to use and the most importantly how long ie how far to you insert it into the existing cross bar/spring hanger ?? To all of those who have been there and done that, all advise and suggestions would be gratefully received. John Ramsey Quote Link to post Share on other sites
Menno van Rij Posted November 13, 2008 Report Share Posted November 13, 2008 Hello John, We did this during the Summer of 07. I used Roger William's 'How to improve...' and advise from seasoned (is that the term?) classic rally attenders. And yes, the chassis of my car has received the inner tube as well! If you click on the Photobucket link at the bottom of the posting (in my signature), you'll find 14 pages of restoration pics. On page 2 is a clear picture of the inner tube in situ. After measuring the chassis, we've tried to stiffen the chassis by adding triangle shaped pieces of steel on all 'junctions', thus adding strenght to the 'squareness' of the chassis. If you need more info or more pics, please feel free to PM me for more info! Menno Quote Link to post Share on other sites
G.Guiot Posted November 13, 2008 Report Share Posted November 13, 2008 Help and Advise needed I am attempting to get my chassis ready for blasting and painting over the x-mas holidays. All the restorations manuals advise that you should at a minimum weld another bar inside the rear spring hangers on either side which seems to be logical enough for extra strength. My question is what type/thickness of bar to use and the most importantly how long ie how far to you insert it into the existing cross bar/spring hanger ?? To all of those who have been there and done that, all advise and suggestions would be gratefully received. John Ramsey Hello, by experience, I would recommend 3 improvements on the TR3 chassis; at the front for the faixations of the lower wishbones on the chassis, at the back, to strenghten the back suspension fixation at tjh elevel of the chassis, and at the level of the central box of the chassi, to put at the rear of the box a similar piece of metal that at the front of the box. Obviously, you can do a lot more... but don't forget that a chassis has to be a litlle bit flexible. See artgicles on my web site : what I did page : http://www.trregisterfrance.com/meca/fiabi...bilisation1.htm and what cold be done page http://www.trregisterfrance.com/TR3rallye/...ye_chassis2.htm Rgds GG Quote Link to post Share on other sites
Ian Vincent Posted November 14, 2008 Report Share Posted November 14, 2008 The Revington solution to strengthening the rear spring hangers is to weld fillets into the corners between the tube where it sticks out and the chassis. To me that seems a better solution because a tube welded inside another tube has a much lower moment of inertia than the original whereas reducing the lever arm - which is what the fillet pieces do - reduces the stresses by a factor proportional to the square of the depth of the fillet. In other words you get more strengthening effect! Rgds Ian Quote Link to post Share on other sites
bob-menhennett Posted November 14, 2008 Report Share Posted November 14, 2008 John Following a TR Register Bodywork Seminar( which I atteneded many years ago up in Coventry ) I welded in the largest solid steel rods I could get into the spring hanger tubes on my TR4. Length...I was told it was only necessary to make sure the rod passed through the main box section of the chassis.You are of course prevented going all the way through because of the dip in the tube. Being solid metal you can turn up the welder ( compared to thin bodywork ) and make sure you get a complete seal around the rod/ tube joint to prevent any ingress of water. Good luck with it Bob Quote Link to post Share on other sites
Tr4Tony Posted November 14, 2008 Report Share Posted November 14, 2008 Hi The chassis strengthening conversation is one id like to add to based on my experience with 3VC and BST82B, both of which have different mods made 'in service' and lastly my own TR3a 2 SMC to which i have just completed a lot of chassis work on. There are some critical stress areas which need to be sorted out on the TR chassis because they are weak and some areas where additional stiffness is required to assist handling. Conversely there are parts of the chassis where additional strengthening may well induce stress, so you cant just tumble in and get welding. You do need to think about this quite heavily as its very easy to do something useless that just adds weight! There are a couple of experts out there who do this for a living, so well worth giving them a call. Neil Revington, Colin Mathews at CTM and Steve Hall at TR Enterprises would be top of my list. Generally, strengthening the main suspension pick up points is safe. So, driving a slightly smaller tube inside the spring hangers at the back and then welding it in place is a good thing. Tube has a better strength / weight relationship than bar in most applications. Doing the body mounts isnt a bad idea, but not critical. Filleting the joints at the rear is a good idea, just check spring clearances. This is what was done on the 'works' TR4's. Plating around the chassis pin mountings at the front of the rear springs is a good plan as these do get bent or detach. Similarly beefing up the suspension turrets at the rear by adding metal to where they attach to the chassis leg is absolutely necessary. Protection of the boxed section of the cruciform in the middle is also a good thing as repeated bashing causes this to deflect heavily. I have constructed a skid plate here. Similarly strengthening the angles and boxing in the cross member area between the front turrets is good. Filleting all the corners is also good and as per TR4. I use 3mm steel triangles of about 50 mm x 50mm to do so. Also do the same to the top and bottom of the strengthening bar between the top of the turret and bottom the front chassis member, forward corners of the main chassis rails etc about 8 corners in all. Filleting properly adds a lot of strength for a small weight increase. The works TR4's had strengthening to the lower front suspension fulcrums, effectively boxing in the centre section to stop deflection on impact. This is essential. If you plan to run a TR3B / early TR4 wide chassis and steering rack, strengthening of the mounts is required as per the works TR4 again. hangers are required from the rad. cross tube to behind where the rack bolts on and effectively links the steering tack mounts to the upper section of the turrets. Lastly you will undoubtedly want to run some sort of sump shield. The 'Customer' short bolt on sump guard is simply not adequate for rally use as it only provides 'bash' resistance to the base of the radiator and front of the sump. You need a heavier duty arrangement even for modern road rallying which covers at least the front of the sump (as per 3VC) or better still a full length tray extending to the back of the bellhousing. If you have any doubts about this requirement look at BST82B's guard and the damage underneath that it takes in protecting my engine and gearbox. The Stag filler shield on the overdrive is also a good compromise if you dont want to run a full length gearbox guard (which i suggest you wont). Hope this helps ..... if you want to look at either car or bare TR3a chassis let me know as ill be happy to help you outwith all I know. Regards Tony Quote Link to post Share on other sites
ianc Posted November 16, 2008 Report Share Posted November 16, 2008 One addition to Big Tony's excellent list: the TR2/3 rear damper mounting is pathetic and not infrequently has broken/breaks away from the chassis! Four large reinforcing strips (a pair either side of each captive nut) need to run vertically down from the top of the bracket and down the rear of the bracket as far as the bottom edge of the chassis. I believe Revington sells a kit of bits to carry out most of the strengthening found in the Works TR4s - but Tony has listed the mods and any competent person with access to various bits of sheet and tubular steel can DIY. Ian Cornish Quote Link to post Share on other sites
ianc Posted November 18, 2008 Report Share Posted November 18, 2008 A further thought on rear damper mountings. If they are damaged, why not upgrade to the larger size lever arm dampers, as fitted to the Works TR4s? You need a wider and stronger bracket, but you'll notice the difference! No need to carve the bodywork in order to fit telescopic dampers to the rear on a solid axle TR - these bigger dampers are the dog's whatsits! Ian Cornish Quote Link to post Share on other sites
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