MG Sports Cars

Looking good - Yer movin' right along, Jim!
.....the Dragon beckons in less than 10 months..........

Yep, and that might be a bit of a puzzle if everything gets done. No need to worry about that yet. Anyway the tranny cross member is done.











I spent a little time on the driveshaft, it has a humongous rubber donut on the front that there's just barely enough room for. But the problem I'm having is with the universal joint fitting the chevy yoke on the other end. Hopefully I can figure out what is up with that tomorrow.

JB

Edit: Actually, what I meant to say is that I've pulled out all the stops to get enough progress on this car so that I can take it down off the rack and start work on the MGB-Roadmaster. Progress is good, and I'm now far enough along to mount the steering rack, which is the one piece needed before the car can be moved. However, I also intend to sort out what's needed on the driveshaft and attach the lower radiator mount. Then I'll be happy with switching to the other car and can get back on mine once the sheet metal work is all finished, and maybe some fiberglass too. I expect that to happen in a couple days.

J



Edited 1 time(s). Last edit at 07/19/2010 12:28AM by BlownMGB-V8.

Jim,
Lookes really good. Can't wait to see it in the flesh in Sept.

Steve

Thanks Steve. Well, progress has stopped for now. I made up the rack mounts and when I went to fit the rack it became all too clear that the firewall cone is going to have to be lowered at least an inch. Consequences of lowering the engine I suppose. So at that point I decided I wasn't ready to begin that mod and took the car off the rack. I also had fitted up the driveshaft and marked it, boxed it up to send away for modification and then decided to get a 2 piece Lexus driveshaft first and see if I can use that. It has a big nut and tapered fitting over a spline, meaning it can potentially be collapsed to install, pulled back out and locked up solid. Real handy if you have a fixed differential.

So now the MGB-Roadmaster is up on the lift and work on this project will mostly be at a standstill until that one is squared away. In the meantime maybe I'll happen across some parts that have gone into hiding.

JB

Lower radiator support is completed.





I think this radiator, with the transmission cooler fittings, is a slightly better choice than the one we used in the Roadmaster, as the side tanks have a better shape and more clearance for things like the bumper mount bolts. Anyway, it looks like there will be just about enough room for the A/C and intercooler condensers in the front.

JB

Firewall mods are now complete and the rack is mounted.





Thanks to Ted Lathrop (Fast Cars Inc.) I now also have a set of 375 lb springs on the coil-over rear shocks, so, letting the car down to check it's stance it is very clear that I will need to go to a late model front cross member. In contrast to the MG-Roadmaster which uses the same size tires all the way around, this car will use the 315/35-17 rear tires which are about 26" diameter. The fronts are presently 24" and to go significantly larger I'll need to increase the distance between the hubs and the headers, as at full compression the existing tires come very close. So, a late model x-member it is then, and probably a little larger on the tire diameter as well. Maybe Pete has one...

The increase in ride height will make the car much easier to get into and out of and I don't think it'll hurt handling too much, considering that the stance is 6" wider than stock.

JB

If all goes to plan, by the end of this week I will have in my hands a pair of very special triple convolute suspension air bags that are supposed to fit in the space presently occupied by the original MGB front coil springs. This is something I've spent several years looking for and I've finally found a source, though delivery isn't real fast. So I'm keeping the old fingers crossed.

This modification should allow infinite height adjustment, and work just fine with the existing crossmember. In fact it should work fine with either early or late units, although for a given ride height the early unit should give a lower roll center.

In addition, I will be adding a spacer block under the front pivot mount for each of the lower control arms. This will give additional clearance between the steering rack and the lower control arm, and should slightly reduce the caster. If it has any effect on camber at all it may increase it very slightly.

So that's what's in the works right now. I also need to acquire some sheet metal and replace the missing bits in the front of the inner wings but right now I'm mostly excited about the air bags.

JB

I'll try to take some photos to post later on today but I've made some good progress. First about the spacer blocks. This turned out to be a bit of a surprise, as I had to space down the front pivot farther than I had expected. A full 1-1/4", and on the left side I still had to bend the upper flange of the control arm a bit for good clearance of the boot. I used a 1/2" spacer on the rear pivot so there is 3/4" of stagger. At some point I'll get it on an alignment rack and see how much difference that makes in the caster, but it looks like the camber change under suspension compression should be helpful. I used 1/2" and 1/4" spacers and stacked them to get the needed result. We will need to look at this on the MG-Roadmaster to make sure we don't have a problem there as well. The rack was not moved down as much on it and is positioned level, whereas on this one the left side had to dip a bit lower than the right side. RB cars have the rack oriented similarly, though in a higher location. It's possible that we may be OK on the other car, I'm pretty sure we checked it.

The spindle arms have been modified to correct for the new rack location by bending. Caution: do not attempt this if you are not at least somewhat familiar with metalurgy. Bending was accomplished with heat, followed by slow cooling to control crack propagation, then bead blasting and close magnified inspection. This gave satisfactory results. The end of the arm had to be lowered about 1 inch.

The triple convolute air springs finally came and will be a good match and line up better in a couple of ways than the double convolute ones. I will add a pilot to engage the upper spring locating cup in the crossmember, and there is a spot on the crossmember that could use some touch up with an angle grinder. This is a flat plate under the bump stop, the edge of which intrudes slightly. Shouldn't be difficult, and then the new air springs will pop right in I believe. More later.

JB

Air springs are installed. There is a little fine tuning to do but I think they'll work just fine. Initially I pressurized them to 100 lbs on the lift then let the car down. That made the front end ride too high so I let a little air out. Bouncing on the radiator support with my full weight, I concluded that the stiffness is pretty similar to the stock spring rates. I think it may be a bit more progressive, stiffer as it compresses but at this point it's hard to say, but my shocks are set pretty stiff so there should be plenty of range for adjustment. Of course, height is infinitely adjustable and easy to do. Here is the as-installed photo, you'll notice the schraeder valve for easy adjustment of pressure.



Next photo, the springs with valves and centering cups installed, pressurized to 40 psi and ready to fit into place. Once the top is centered, pressure is released and the upper convolute holds the spring up while the pan is installed. The only modification needed to make this work is seen below.



Here the lip on the crossmember is ground back to clear the top convolute. This is easily done with a 4-1/2" angle grinder. The edge is ground back all the way to the aluminum block and then smoothed and rounded so that there are no sharp edges to abrade the bellows.



Finally, in this last shot you can see how the groove between the convolute clears the lower part of the snubber bracket and the freshly relieved edge clears the bulge.



The whole process of swapping out the springs can be done in a couple hours or less, depending on how fussy you are and how fast you work. With the kits received ready to install, doing it in an hour would not be unreasonable. Cost will be more than a set of new coil springs of course, but there is more functionality too. If anyone wants a set I can fix you up. If there's any significant demand I'll make it a standard product line and talk to Curtis about setting up an advert on this site.

JB

Jim, the air springs look neat, nice installation there. As for the A arm spacers, I'm still trying to wrap my head around how you can essencially tilt the A arm a the inner pivot point without modifying the lower trunion on the king pin or the upper trunion to compensate for the non parallel axis. Seems like in a B or even my Midget suspension you essencially have 4 parallel pivots, inner A frame, lower trunion bolt, upper trunion bolt, and upper shock pivot that have to be parallel or you'd induce a lot of stress and friction.

Right, check out the last post on the A-arm spacer thread in the suspension forum.

JB

wow, that does not look right and as far as I know you will need to lower the top fulcrum the same as you did the lower, I would not suggest doing what you did, car is going to have excessive positive camber that will need to be compensated somehow, and the castor is going to be screwed, looks like a mess to me

This should properly be in the A-arm spacer thread, really I was posting those photos for the air springs. But, here's the latest:



Looking closely you can see the mounting points are compensated for camber, and I expect a 3 to 4 degree caster reduction as well which should work very well with the wider tires. The forward pivot is positioned outward slightly and the rear one spaced inward by the same amount, moving the bottom of the kingpin back, the difference in block thicknesses allowing for that swing. (Trunion is rubber mounted of course)

The net effect should be no static camber gain or loss, increased camber on compression, and additional steering rack clearance. However, moving the pivot point downward appears to cause camber gain on sag, something I'll have to look at more closely before I can approve the mod. Worst case, I may have to cut the rack mounts off and relocate them a bit. I'll probably run the wheel up and down tomorrow and measure what it does.

JB

Progress has been slow, partly due to a painful decision to re-locate the steering rack mounts. I was not happy with it sitting at a slight angle (even though the RB cars do also) and even less happy with the lack of clearance for the LCA. So I broke off the old ones, tearing holes in the crossmember in the process. At least that proved the welds were strong enough. The point at which these mounts attach is at an angle so I cut the sides off some channel iron, giving a pair of wedges which matched the angle and provided the desired thickness to move the mounts forward. Turns out I had used spacers under the mounts for the MG-Roadmaster but hot having it here for comparison I had inconveniently forgotten that detail. This spacer also caused the rack to be moved upwards as it moved forwards, giving a much more satisfactory position and attitude for the steering rack itself. So I welded it.



The spindle arms will have to be adjusted to match of course, but LCA clearance should now be adequate regardless of what I do with the LCA relocation blocks. I also put in the lines for the air bags.



They should be well protected from road debris and abrasion.

This does cause a small problem with the oil filter however as it now interferes with the steering rack. That could be fixed by moving the engine forward about 1/2" and if I had not already located the engine mounts I would probably go that route, But since I have, I have another solution in mind. With the frame extensions I should have plenty of room to use a later Buick oil pump cover which angles the filter forward. I just need to get one. So that goes on the to-do list, along with getting new panels to finish up the front of the inner fenders. Hopefully I have a lead on the latter. Then maybe I can get started on the new hinges for the bonnet and other things. In the meantime, Townsend looms and there is much to do to get there with the MG-Roadmaster.

JB

Good news. Swapping in a spare set of steering arms it looks like the spacers moving the LCA inner pivots downwards are a pretty close match to the distance the rack was moved down so an unmodified set of arms should work out just about right. Very helpful. Of course this also means that if you space down your inner pivots you have to either move your rack or bend your arms.

A source has been found for the missing body panels so within a few weeks I hope to complete that part of the metal work, and it also looks like I may have found a lower pump housing to try. If it works out I hope to finish up the front end work fairly quickly. Adding a sway bar can come later.

JB

Jim, you've went Hi Tech, in a good way,on much of this build, have you considered dynamic control of the bag pressures ? Of course, meaning anti-dive and roll ? Great work, roverman.

Haven't given it much thought Art, though there is always room for improvement. After I've gotten it back on the road and have driven it for awhile I will probably give it some more thought though since it wouldn't be too hard to do.

JB

Bill Young, If you're reading this you'd be proud of me. The following photos show the front sections of the inner fenderwells welded in place and as Bill knows I'd been having a tough time getting any kind of usable welds out of my Snap-On mig welder. But, as I had finally used up the last of the shield gas and wire I made a couple changes. First I bought a 12 lb roll of .023" wire, which my welder feeds much more reliably as it just handles the bigger roll better, but the big change was to use a different gas mix. You see, I bought the mig before I got my TIG welder and wanted to try using it to weld aluminum. So I bought as bottle of straight argon, reasoning that results with aluminum wire would be better. Well that never worked out at all, and with the argon the results on steel also sucked. I even went so far as to have the welder checked out by a professional welder repairman. So not too surprisingly, now that I'm feeding it standard mig mix it's doing a fairly respectable job. Doubtless not as pretty as Bill's work, but definitely good enough to mostly replace the use of my gas torch on sheet metal.







In the first photo you may notice the use of a Buick V6 "Metric" oil filter mount which angles the filter in a favorable direction for the wide radiator frame mod. However, I set the engine back pretty far and will need extra clearance for the standard V6 filter, even more for a standard diameter filter if there is one available to match the metric mount. So a notch will have to be added for that, and clearances provided on the sides for the radiator itself.

Oh, and I've decided I don't like the lowering blocks for the LCAs and instead will design a clearanced and reinforced front arm for the spring pan, making four of them as I do so I can sent a pair to Max for the MG-Roadmaster which shares this car's geometry. At some point I still intend to mock up a measuring jig to look at some geometry changes but first I think I want to get the car running again. Stay tuned.

JB

Looks good Jim. I didn't know that the welder was giving you trouble though. I've always used a mix for my MIG machine that was 75% Argon and 25% CO2 and had pretty good results. I reserve the pure Argon for my TIG welder. I'm still running .035" wire, but need to get some smaller wire for the body work on the MGA. 35 is fine for chassis work and the heavier stuff, but the smaller wire is better for sheet metal. Lately I've been practicing my TIG welding and really like the results. Someday I hope to be able to do aluminum work like you and Gary do. Right now I'm getting better on steel though. Found my main problem was that I couldn't really see the arc because I wasn't wearing my reading glasses under my helmet. Being able to focus on the arc made a ton of difference. I was able to weld a -12 steel AN fitting to a thin wall tube this morning without burning any holes so I was quite proud of myself after that. LOL

Amazing what a difference the reading glasses make isn't it? But be careful. I used a die grinder with a carbide bur wearing reading glasses and ended up getting steel bits dug out of my eyes. Bad thing was, I have a good full face shield that would have prevented it and it never even occurred to me to put it on. Some days we're just not even close to being as smart as we think we are I guess. That's a pretty good trick on the -AN fitting though. Two hints that can help. Rig up a way to back shield your welds, say by putting a "T" on your gas line to the torch and running a small hose to the back side. This will pay huge dividends by making your welds look purty on both sides. (I haven't set mine up that way yet but will next time I'm using it.) Secondly don't get in a hurry. Most problems with TIG are caused by too much heat. You can always add more heat but too much is hard to correct. The good welders I've watched always brace their forearms and minimize movement at the weld point. A foot controlled rotary table is a wonderful thing to have. I've accumulated some pieces but have yet to build one.

Last night I made some cuts and bends to allow the big radiator to fit. I'll be welding those up next and grinding down the weld beads. Add a pair of flat panels on the sides, and then a tight compound curve for radiator hose clearance. You'll never guess what I found for that piece... an MGB bumper overrider. Have to bend and trim it a little but I'm pretty sure it'll work. Photos in another day or so.

JB