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MG MGB GT V8 Factory Originals Technical - Spring hanger reinforcement?
|I've got bad rust in the support structure for the right side forward leaf spring hanger, this would be a good time to add reinforcement since this is *the* critical mount. Does anyone have suggestions for good ways of beefing up that area?|
I made some chasis rails that run from the spring mount area, to the center fixed crossmember. Similar to what the RV8 has. They are bead welded to the spring mount and crossmember areas, with spot welds to the floor pans. They seem to be doing a good job of stiffening up that section of the chasis.
|Yes, they make a big improvement to rigidity, as well as strengthening the spring hanger area, the bad news is that they would be difficult to weld unless you turn the car either over or on its side. I fitted them to a Heritage shell, along with tapered strengtheners from the box section to the cill ( theres a MG website with pics on somewhere ) .|
|Would appreciate any info with pictures anyone has. My '73 is going to need help. Plus, this will be the best time to relocate the springs inboard for narrowed rear/wider tire combo.|
You need to bring jackstands to ABFM se we can get your car up in the air and let everyone slide under and drool over your modifications!! It just might keep the drool splatters off that paintjob!!
I will be heading up to Bellavue Early Sat morning for the show. I hope to tag along with 2 other V8's and caravan up. I just had to rework the balancer and pulleys again, and they are still not right, but are runnable. I may have to make a pulley at work to solve the problem I am having.
|Tapered strengtheners to the sill? I'd like to see that. I'm working on a CB btw, so there's not a lot of height change.|
|Unfortunately I can't remember where I found the site, I know it was on a site which had a long list of mods carried out to MG's with pics of the work done.|
I may have some pics of my shell showing mods, at home, Im at Silverstone this weekend, but if I can I'll E amil them to you next week sometime,
|Rooting around in my bookmarks, I found http://www.theautoist.com/RearSuspension.htm that shows his "tophat" installation. This might be it.|
|<<Tapered strengtheners to the sill?>>|
Talking about what Nick Smallwood did?
Here's Tony Barnhill's article & pics about "top hats" as he calls them:
The info this V8 Fraternity shares on the 'net is outstanding!
|I've yet to try my 1974 GT, but I constructed box sections to reinforce the spring hangers by using half inch square section tube to make a framework from the transverse box section where it meets the front to rear box sections back to the spring hangers themselves. I then skinned the frame with seam welded steel sheet. I also made up the transverse box sections to tie the cills in with the front to rear main box sections. These were fitted at the forward end of the cills where the feet driver and passenger will be. I also double skinned the floor pans by spot welding flat steel sheet inside the car onto the tops of the ridges pressed into the floor pans. The voids between the two pieces of metal have been filled with an expanding foam. This last mod has as much to do with noise and heat transfer as strength. The experts always say that your suspension can never work correctly unless it's secured to a strong platform. Apart from welding in a full roll-cage, I don't think my GT could be much more rigid. When it does get on the road, I'll post a report. Good Luck.|
I am also working at my shell at the moment so its the best time to add these. Could you please let me know where you got those "top hats". If you made them yourself, please mail me a drawing.
|Peter van de Velde|
That's the one, I've tried it and it worked, did three laps at Silverstone yesterday, and the body seems much more rigid than the old one (mind you it's a new heritage shell so it blooming well ought to be).
Made the top hats myself, but had them professionally welded, they run from the crossmember backwards to the spring hangers, I made them just wide enough to go over the hangers, so the metal is double thickness where the bolt goes through.
I can measure them and send details if you like.
Thanks for your quick answer. You mention that the "top-hats" were welded. Does this means that you didn't bend the parts out of sheet metal but that you got these by welding it from parts cut out flat steel plate? It may have something to do with the thickness of the plate. Which thickness of steel plate did you take?
Could you also let me know about the tapered sections to the sill? How many and an idea about the shape and basic dimesions.
Currently i am replacing my sills and the body is in a rotator so this is the moment to fit these.
|Peter van de Velde|
I made mine out of three pieces of flat stock,them welded them together to form a channel section. The rear section of the channels were formed from 2"x3"x.250" box tubing for max. strengh, as this is where the anti tramp bars connect.
mine were bent from sheet, but my folder was not strong enough so had to go to a sheet metal workers, they are thick enough to support jacking, and seam welded along their length.
I will measure them (approx) tonight and E mail a rough drawing.
|What are peoples thoughts on improvements to the rear mount on the frame?, or are they generally thought of as being strong enough? I'm still working on fitting the engine to the car, but this thread has brought this topic, which I hadn't even thought about, to my attention. Looking at the original mounts though, I can see why this is important on these cars, there really isn't much there.|
Thanks for your advice but Mike send me some rough drawings and i prefer to go that way.
Thanks for E-mailing the drawings. Its a good idea to make some cardboard templates and dress these and then copy these on steel plate. I will go this way. The thichness of 2mm sounds good to me. I think all channels are made of 2mm steel plate so it should be enough.
|Peter van de Velde|
|If there is any confusion with my wording in my post, I mean the mount area on the body for the rear end of the leaf spring, where the shackle swings.|
sorry 'bout that.
Glad to be of assistance, I hope you can follow my rough drawings OK. The sections are plenty strong enough to jack the car up on,
|In my opinion you fellows are overdoing it just a bit. 2mm is reasonable enough, but there isn't a single point on that body where you can attach a piece of 1/4" plate and get adequate support from the body. The front spring hangers themselves are only maybe 3mm thick and that's a two piece laminate. The points I've found that need beefing up the most are the bolt holes. After that something consistent with the body panels it attaches to is appropriate. I used .031" for the channels, although I might have gone up to .061 if I'd had it on hand. Anything more is overkill and only adds weight and makes welding more difficult, although admittedly being able to jack on it is a plus.|
Most of the force transmitted to the body there is a combination of upwards and forwards. Adding the channel does not add a tremendous amount of strength to the vertical support no matter how stiff it is, since practically all of that support comes from the vertical wall in front of the batteries and there is only floorpan ahead of that. And since it's a straight shot to the center cross member a very light tubular support member is all that is needed to support more force than the vehicle will ever be able to develop in that direction. The weak area of the channel is between the bolt holes and the beginning of the closed bottom section, or the open area where the spring mounts and this is beefed up by the existing bracket, so with proper design and welding only a very thin section is quite adequate.
I just went down the route Rover used with the RV8, I assume that they found the original 40 year old design insufficiently strong to cope with the V8 power (that was MG's original excuse for not making a V8 roadster).
Adding weight really isn't a consideration as far as I am concerned , and as you say, it's very handy to have a sound jacking point just in front of the rear axle.
|Thanks, guys, for your kind words about my "tophats"....|
...I went with them as they are pretty close to what Rover used with the RV8...I folded metal that is about the same thickness as the spring hangers themselves & welded them along the length of the body to the cross member & then bolted them thru the cross member...I also welded a strap that's part of my "top hats" up through the spring hanger itself & seam welded them to the spring hangers....if you look at my set-up, you'll see that I designed them so that they make great attachment points for my Doug Jackson anti-tramp bars....
...you've already got a good link, but here it is again:
....sorry my welding isn't that of a professional, but they're secured in place, I guarantee...oh, &, yes, they're designed to allow water to flow out of them in case it gets in....
|Getting off original topic but picking up on Tony's thread: I'm also running Doug's antitramp bars; just put them on and haven't driven with them yet. They're beautifully fabricated like 'most all of his wares, and they fit like gloves. The one downside is they are pretty heavy. Anyway, I just had 1/8" steel reinforcing plates made up for the floor behind the seats, cut out the asphaltic soundproofing so those plates would rest right on the metal floor, then bolted the tramp bar front brackets through both the floor and the new plates, having rustproofed the heck out of everthing. Seems utterly bombproof ... only time will tell though. |
In a CB car, the spring eye hanger sticks down quite a bit less than on a RB car, and the front tramp bar brackets Doug supplies for CB vs RB cars are, accordingly, quite different (the CB ones are much simpler). On a CB, the force of the traction bar basically goes right into that fat spring eye plate, whereas I believe in an RB car the force is directed a couple of inches forward of it. Anyway, I didn't think going the tophat route was necessary and could be quite difficult to install on a finished car. Though of course fifteen years from now when I restore the car there's certainly no downside to beefing things up.
This thread was discussed between 19/07/2002 and 26/07/2002
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