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Slow, but a little progress

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motofiaccone

motofiaccone

Senior Member
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Hi Gents:

Life's conspired against me lately, but I managed to make some progress. So far, I almost have a front upper control arm fabricated. Hopefully, over the weekend, I'll have both the other upper control arm fabricated and the jig for the lower control arm.

It's been fun!

jig1.jpg


jig2.jpg


jig3.jpg


Please follow along the website. I write the descriptions, ect. there. Constructive comments are always welcome!

--Thanks, Chris
 
What is it for?
 
He is making a control arm to replace the front shock. The square tube is part of the jig.
 
Yep, that's right. I'm getting rid of the lever arm dampers. I forgot to take some pics of the actual control arm in the jig. It's 99% done. I just need to weld in a cross brace.

--Thanks, Chris
 
What a a learning experience.
 
OK, so I managed a bit more. Both upper control arms are now fully fabricated. I'm shocked by how strong they are! The weird looking bit bolts to the chassis. The control arms bolts to that. I used rod ends to allow a bit of camber adjustment. The upper arms are 16ga DOM.

customespridgetsuspension1.jpg


The welds look a bit crap, but the rest are fine. I love take pics of the bad welds :smile: Oh, I want to make sure there is plastic on each arm of the suspension. The upper side uses polyurethane bushes in the upright/whatever it's called on a midget.

OK, then I set about building a jig for the lower control arm. This one uses big, thick poly bushes on the chassis-side. On the outboard side, it uses bronze bushes. I'm thinking of pressing some bronze bushes into the upright/whatever it's called as well. However, I have to drill out the trunion first. Ah, small British cars.

customespridgetsuspension2.jpg


And another...

customespridgetsuspension3.jpg
 
Hopefully, this week will see the lower control arms fabricated. Tomorrow, I'll pick up a couple pieces of of steel for the spring pan. I'm going to keep the general bolt-on spring pan setup. This means there needs to be a big hole in some 1/8" steel. So I'll drop the bits off at the sheetmetal guy to plasma it out.

I hope to get the front tube dampers in this W/E as well. We'll see...

--Thanks for following along, Chris
 
BOOMER!

sorry. too excited about the outcomes of the football game this weekend!

Chris,

thanks for keeping us updated on your progress! learning to weld and fabricate is one of my long term goals...unfortunately the desk job is keeping me pretty busy right now.

atleast I get to live vicariously through this website......
 
Some more pics. I have the lower control arm pretty much fabricated. I'm considering putting a cross brace right in front of the spring pan mount.

Thoughts? My concern is that the control arm might twist during use. The spring pan, whilst strong, probably won't help this. My thought is to weld in a 3/4" square tube to both the control arm sides and the spring pan.

customespridgetsuspension4.jpg


customespridgetsuspension5.jpg


customespridgetsuspension6.jpg


Thanks for following along. Of course, a better description of what I did is on the website.

--Thanks, Chris
 
Darn, that thing looks like its gonna be heavy!
 
I know :frown:

That is really the downside to going with this design. It literally weighs twice what the stock bit weigh--which is frustrating because I hate unsprung weight.

I suppose the upside is that it will be significantly more ridgid than the stock piece. But still, point well taken.

I do have a cunning plan to remove some unsprung weight from the upright assembly, so perhaps (hopefully) it will all even out.
 
My thoughts: You've gone this far... might as well kill the spring pans and go for a coilover set up. You're half way there already.
 
That sure would save weight.
 
Gents:

All good points. The coil over set will be a phase two project. I want to keep the suspension design to a minimum. When I designed my se7en's suspension it took many hours of CAD. I'm grabbing low hanging fruit on this one :smile:

At this point, I want to get something safe, fun and reliable on the road for my wife. Think Miata but less 600 (or so) lbs and nostagic aesthetics. The Miata engine will provide twice the horsepower as stock, so components should be beefed up a bit. I realize those lower control arms worked well for years, but they aren't the strongest of things.

I can build light. I did a 925 lbs car from scratch. I could do this one light too. But I'd rather build it strong...and have the time of my life building this stuff.

Tony:

What do you estimate the weight premium of my control arms over the stock bits? Going to coilovers would save MAYBE 1/2 lbs.

--Chris
 
Exciting update!!!

You guys had me really worried so I went to garage to do the kiddo weigh method: place one component in each and and raise and lower slowly :smile:

I'm happy to report that the weight difference is about a 5-10% premium on my control arms. The stock control arms did not have any bushings, nor the spring pan (and associated hardware) attached. But my control arm did not have the bronze bushings pressed in.

Sooo...

Perhaps they will be closer in weight than my initial 2x esitmate. Still, I have to weld on the damper mount...and half the damper itself is sprung weight as well.

whew!

--Chris
 
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