LocostUSA.com

@JAMADOR
@Lonnie-S
Thanks fort he tips!

Build Table and First Tubes

Table is built from 3/4" MDO and 1 x 2 poplar ribs. It lives outside, and the MDO has held up surprisingly well and the surface is nice to work on. Not much rain to worry about in California, but it did get caught uncovered in a couple of storms and still remained flat through the crucial build stages. It's about 2 years old now and has about an 1/8" droop over its length, but is still usable as a level work surface. On hindsight, I'd make the section taller, but it's worked well as is.

After a lot of planning, the first few tubes have gone in place.

It's underway!

Cheers,

_________________
Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886

Yes!
I feel it's a lot like a house, you get it framed and it starts to look like something. You think to yourself, "Hey, I'm doing pretty good, almost done..." When in reality you're only 10-25% done!

A Few More Tubes

Starting to take shape.
Maybe I can us the heart for a roll bar...

First Engine Mock-Up

Getting the engine in place to verify tunnel dimensions and other related structures. After the first photo, I cleaned off all the surface rust and began spray canning as I go to try and minimize rust. It means having to clean each joint before I weld, and I plan to have the whole frame Media blasted when complete. Mock-up bonnet is a donor from a Caterham S3 owner who's car had been converted from a single downdraft carb to dual side drafts.




When I opened the 1967 engine up, I was surprised to find standard bores in decent shape. I thought maybe it had never been opened. On closer inspection, the crank has been ground, and the freeze plugs are made In USA!

Where did you get the hood (bonnet)?

Cheers,

_________________
Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886

If I recall correctly, someone semi-local to me was selling some used shocks on usa7s.net. When I went to pick them up, he had just received a new bonnet from Caterham. He had no use for the old one so he generously donated for my project. Since I had that bonnet, I've built some of the details to fit it, thinking that even if I make my own, I could potentially by a standard Caterham S3 bonnet in the future.
I've found a lot of parts just by asking people who happen to be selling, trading, or otherwise getting rid of something else.
Finding a lot of great people in these communities!

Jumping ahead a little...

Frame core is tacked up, but I've been avoiding the curved pieces: dash hoop, cockpit sides, and rear hoops. I shopped around a little, thinking I could get a local shop to do them, but had a hard time finding someone who would bend just a few tubes, and do it for an unreasonably low cost (Locost?). So, I used a cheapo pipe bender from eBay, along with my own super precision bending fixtures .

It worked out surprisingly well, I'm happy with it. Took a few tries to figure out the amount of spring-back. I tried to get the rear hoops and dash hoop each bent as one piece, but couldn't quite nail the width without burning through too much tube stock through trial and error, so I finally settled for a 2 piece dash hoop and 3 piece rear hoops. I was striving for a nice elegant arch to the dash, and the top rear hoop is gently curved in profile to blend with the cockpit sides.

Good going on the bent tubes. I think it was the weathering of the wood in the bending fixtures that made it work out [WINK].

Cheers,

_________________
Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886

I am going for a vintage look, so the weathered wood definitely helped!

Front suspension is coming together. Most of the frame welding is done and everything is still pretty straight and true so I started by leveling the frame and locating the lower mounting points. I used an extra long drill bit through the front holes to try and keep the rears parallel, and then an all-thread fixture to ensure everything was aligned before tacking the sleeves in place. From there, I made wood templates for the upper mounting points and cardboard templates for the brackets. I ended up getting the brackets made at SendCutSend.com for around $5 each, which saved a few hours of cutting and grinding. They still needed finessing for final fit, but they got me 80% of the way there. Used the all-thread fixture again to keep everything in line. A little more work on the left side, then it's time to get my steering rack back together and figure out the mounting.

Steering rack mods and mount.

I did some mocking up of steering rack placement. Without working out the geometry, I was hoping my Spitfire rack would be acceptable unmodified. Bump steer turned out to be pretty significant, which I guess I could have figured out ahead of time! So I ended up having the rack shortened based on my Vsusp dimensions. I had a local machine shop cut the shaft, weld up to fill the machined flat and re-thread the end. Rack tube was cut and re-welded, leaving the bushing in place.

With the new shortened rack, I started trying to dial in the height, it turned out to be much more sensitive to location than I expected. With the rig in the pictures, I would set toe at 0" at ride height, then check toe (with a tape measure) at 2" of bump and 2" of droop. Not as sophisticated as dial indicators at multiple intervals of suspension travel, but at least it's showing me extremes at this point, and I feel like I can read the tape down to 1/32" or less. Once I got it close, I started testing with .050" shims. The best I could do was to get it similar at full bump and droop, ending up at about 1/8-3/16" total toe out (difference at front and rear of tire centerline). Based on what I've read (no shortage of articles and threads on the topic!) it seems a little high, and that toe in would be preferred for stability. I don't want to start another bump-steer thread, but happy for any feedback. So with those numbers I decided to install the rack mount a little low to give me room for dialing in with more precision at final assembly. At that point, if needed, I may have to revisit rack length.

Ackerman at 10° of steering on the outside wheel results in +1°-1.5° on the inside wheel.

The rack mount center section was a SendCutSend piece with the side bracing added by me. Not the most economical route, but with limited time, it's helping me make some progress. After welding the mount in place I realized I forgot about lower radiator hose routing, but I think it will just sneak through, might need a little relieving to prevent any rubbing. Radiator mount is next, so we'll see.

Unmodified Rack:




Shortened Rack:

Tilt Front Nose

I'm experimenting with a hinged a tilt up nose. I haven't seen this done, has anyone seen it before? It needs a little finesse, but so far I'm liking it in concept. Part of the trick is getting it to pivot in the right place to clear everything as it swings open, and not have the pivot points hanging below the frame or nose where they are exposed to dirt and damage. The pins are easily removable, so the nose can still be completely removed if needed. The frame half of the hinge will be screwed to the frame. On the top, I can still use the standard Dzus method, or I may try just using small alignment pins and allowing the bonnet to do the hold down work. I'm going to add a clip-on check strap on either side to keep it from hitting the ground when open. I'll probably reinforce the nose at the mounting points.

The hinge parts are 16ga. stainless from SendCutSend.

To stabilize the nose side of the hinges, I suggest a 1x1/8 steel strip cross brace inside the nose to pickup the four screws and a wider attachment base (distance to the pivot provides leverage on the narrow base). It can also be bent to hug the slight curvature of the nose and pick up more fasteners in the fiberglass if you get any cracking. If the nose is going to be separate from the bonnet/hood, it will be less critical/weight that can catch the wind.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Good idea. The way the attachment at the nose is cantilevered out from the hinge pivot does cause the nose to flex, and I can imagine it cracking before long.