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Mon Jan 20, 2014 12:02 pm

I'm resurrecting an old FiberFab MG TD kit car on a '69 IRS pan. As best I can figure out, the running gear has 53k original miles, but it sat in a barn for about 15 years before I bought it. Just finishing up an engine build for it, and want to address the suspension and brakes before putting it on the road.

It was originally lowered about 2" in front when built (early 80s is my guess) by cutting and rotating the lower torsion bar tubesin the front. Rear was lowered about 1" by rotating the swing arms by likely one notch. That's what the factory build manuals called for then...

I'm building a new-to-me used front beam with Sway-Away adjusters, and plan to remove all the short leaves in both top and bottom stacks, to soften the suspension. Adding a bolt-on disk brake kit at the same time. I'll also add camber shims to bottom tube.

Anyone have suggestions for shocks and swaybars to run on this light car, with an even lighter front end?

I've heard/read that used oil (non-gas) shocks work well on the front, due to the very light weight up there, but have seen very little discussion for the rear shocks. I'm considering either KYB Gas-Adjust or KYB GR2s on the rear. I understand the stiffer Gas-Adjust my raise my rear about 1/2" to 3/4" of an inch and certainly would give a firmer ride. Raising it a hair wouldn't be a necessarily bad thing, to provide added clearance for my 1.5qt sump and single quiet pack. How harsh would that ride be, compared to new oil shocks or GR2s?

How about sway-bars? All I have now is the stock front one. I've seen VERY little discussion of swaybars for these kinds of kits that will be entirely road-driven... Not sure that recommendations for a heavy bug sedan really apply to a much-lighter 1300 lb car with a totally different weight and balance. Similarly, not sure how usage on the shorter wheelbase of a dune buggy might be different from this full-length pan that's now driven from the back seat...

BTW, the new engine is a bit old-school:
88x69, using Berg's machine-in jugs & forgeed pistons, rebuilt stock crank and rods
Big valve (40x35) heads, with SS valves and HD single springs
Set up for 8.0:1 (or close) compression
Engle 110 cam and lifters, 13.5 lb 8-dowelled flywheel
Dual 40 HPMX carbs on CB space-saver manifolds, CB linkage
Scat solid rocker shafts and 1:1 swivel foot rockers, stock pushrods
CB Maxi filter pump and Scat 1.5 deep sump
Extractor and quiet pack
Scat fresh-air 36HP doghouse shroud with venturi ring, thermostat flaps, and thermostat for cooling
Rev-limited to 5400 RPM to avoid crank and valvetrain problems

Looking to turn this into a fun lightweight 75-80 HP (or so) sports car for cruising the winding roads in the hills/mountains of East Tennessee...

Mon Jan 20, 2014 12:27 pm

Best comparison is our Manx clone buggy. I run a stock diameter sway bar and it seems adequate. I do also run KYB GR2 on the front and its firm but not harsh. The only thing is shock length depending on how low you are in the front. Various places sell KYBs for lowered cars, but most of them are valved wrong. I have a proper set of GRs (Excel)from Aircooled.net on my wifes 61 and love them. I also run Gas Adjusts on the rear of our buggy for that slight lift and to help with the deep sump as well.

BUT I am running fairly large tire - 205/55 and 295/50s on the buggy, so not sure how much those impact the ride.

Most folks on here seem to prefer oil shocks in the front, but I don't.

Mon Jan 20, 2014 12:47 pm

Thanks for the reply!

I'm running P185x65x15s all around, on stock wheels.

I only want the front lowered by about 2" as it is now -- where I have plenty of fender clearance in turns. Not sure, but the addition of these bolt-on disks might kick the front wheels out a bit further, meaning that I can't go much lower, any way.

I'm adding the adjusters in a "neutral position" so I can fine-tune height as necessary. I certainly don't want to slam it... I want suspension travel.

Mon Jan 20, 2014 2:46 pm

Unless you are doing some serious driving don't worry about sway bars. In the front the stock one will be fine. If you put one in the rear it will make the front end want to under steer even more.

brad

Mon Jan 20, 2014 3:24 pm

I have the '55 MG-TF replica, very similar to your car. I run oil shocks all around and have been happy with them. On the rear the only change I made was adding a camber adjuster (swing axle), which helped a lot! Still a little stiff on the front, stock sway bar, but I will be removing some spring slats in hopes of remedying that situation. Tire pressure plays an important role in ride stiffness, also. I run 18 on front and 28 on rear, radial tires. Disc brakes on front and original drum on rear. Need to soften up the ride or you will begin to see stress cracks in the fiberglass, especially up front! Hope yours is as much fun to drive as mine is to me!

Mon Jan 20, 2014 3:49 pm

slalombuggy wrote: Unless you are doing some serious driving don't worry about sway bars. In the front the stock one will be fine. If you put one in the rear it will make the front end want to under steer even more.

brad

But, if I upgrade the front to a larger bar at the same time I add one to the rear, wouldn't it balance out?

I did that to a much-heavier KG convertible years ago, and it made a world of difference in how it handled...

Right now, the rear rolls in a curve because it is so soft, and the front is so light and firm that it pushes/scrubs badly. I don't have the softened front beam on it yet, so I'm not sure what that will do...

I started considering sway-bars because I must swap the original one I have onto the new adjustable beam -- and I thought why not upgrade at the same time...