switching from 1/4 to 1/2 elliptics

Started by pfordt, June 09, 2011, 12:59:09 AM

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pfordt

Not sure if this is best in mgs or healeys so I am cross posting.
Can someone tell me what is involved in swapping from quarter elliptic to semi elliptic springs? I am going to a narrowed rx7 axle so while I am at it I am wondering about trying semi elliptical springs from a donor midget  I have to try to get a better ride and maybe be easier to set up.

patrick
4age bugeye swap in progress

Bill Young

Patrick, the floor pan on the Bugeye doesn't have the spring mounts for the front of the springs so you'd have to fabricate those or get replacement panels from Moss or such.  In the rear the floor pan of the trunk area isn't formed for the bolts and those would be difficult to access from inside the rear of the Bugeye anyway. Personally I think that your best option would be to work with the existing spring mounts if they are in good condition and not rusted and go with some type of coil over shock arrangement and a three or four link. I think you'll be much happier in the end as well. Check out Brian Kraus' conversion for his rear end treatment. Very similar to what I'd think would work well in your chassis. http://www.britishv8.org/MG/BrianKraus.htm
Jim Begor also did a 4 link with coil overs in his Bugeye and it's well done and works great.
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Moderator

Bill's advice sounds good to me.

Personally, I know next to nothing about the quarter elliptic design or about how one would convert... but the topic also came up briefly a couple weeks ago when I was talking to Craig Chima about racing Spridgets for <a href="http://www.britishracecar.com/ChuckPitt-Spridget.htm">this article</a> and for another that's coming up about Harry Gentry's Sprite. Harry is lightning quick on quarter elliptics. I asked Craig if he figured Harry was giving up any performance by using the earlier suspension, and his answer was to the point: "Not at all." Now I need to get with Harry and find out if he has any set-up tips he's willing to share. Of course that's all within the context of vintage racing, where modifications have to fall within specific rules and where ride comfort doesn't matter.
1971 MGB GT V8
Buick 215 w/ Rover heads, custom EFI & crank-fired ignition.
Custom front and rear coilover suspensions.

roverman

Patrick,RX 7 rear, as in IRS ? Throw away SLA's and use semi eliptics ? When did RX 7's use non IRS ? Good Luck, roverman.

Bill Young

Art, the first and second generation RX7s used a live rear axle, then went to an IRS later on. It's a pretty neat swap into a Midget as they used 13" wheels and disc brakes so it will clear the original size Midget wheels as well. Jim's car pictured above uses an S10 rear but Brian's car uses a first generation RX7 rear.