A really long-term Sprint Kart experimental build

[Tinkicker]

Welp...I'll go ahead and tell you up front that this project won't actually get going for a while yet. As I've mentioned elsewhere I've got some priority jobs at home to take care of before I can buckle down.

But paper tigers have always been cheap, and I'm pretty practiced at paper tigers since I've always been broke, so I will be posting my ideas here as I plot them out until such time as I can start laying hands on parts.

This isn't going to be your average yard kart. I've got a tendency to over-engineer things, but (as with a teardrop camper build I did a few years ago), I also tend to simplify as I go and get the kinks worked out in my mind.

If I told you I'm building a kart to see just how fast I can go, as in no set upper limit, you might think it's crazy, but doable. But what if I told you it's a wooden kart?

To get the ball rolling, here's a little seat idea I banged up in SketchUp earlier. I've started with the seat because everything else will literally be designed and built around it.

That seat looks like any of the plastic kart seats you can buy online, but it also looks like some school desk seats I've napped in before. My bride seems to think she knows where she might snap up one of these for me for little or no money. It's nice having a partner on your path to destruction, isn't it?

So this introduces you to another facet of this project. Let's list them now, for clarity:
1) Build a functioning, durable kart out of wood.
2) Achieve unknown and amazing top end speeds and survive.
3) Engineer the kart with the most efficient construction possible.
4) Do it cheap!

Some expenses are necessary, others are optional, and still others can be eliminated through repurposing other items. There ya' go.
Here's another shot:

You'll notice the tilt. The empty air beneath it would be occupied by structural uprights where the bolts go through the seat. Since plastic seats are kind of flimsy, I've thought of intersecting supports into that rolled lip that goes all the way around the chair.

The baseboard there isn't important. It's just there for perspective.

Since I'm a safety-first kind of guy, I'll post some pics after awhile of some of the braking components I researched before anything else. Oh...as I buy all this stuff I'm going to try to keep a rolling inventory and price list for the benefit of anybody who might be interested.

And last but not least, I'm no pro on SketchUp, even though I've used it for years. Up to now it's been used for simpler things, so sometimes I may have to get you to use your imagination to picture a component I can't figure out how to draw.

Thanks.

 

[Tinkicker]

Had some spare time before I go store away the rest of the Christmas decorations, soooo.....

I mentioned a bit ago about the brakes. That's my priority, right along with driver restraint and protection. There's not a whole lot of protection at all contributed by the kart frame in a wooden design, so anything at all you can do to bolster your health is priceless.

First and foremost, a QUALITY helmet and a fire retardant suit. Why the crap would anyone ride something so dangerous as a high-speed kart and then not wear a helmet, or maybe put on one of those rebellious joke-of-a-hat like bikers wear?! You know, the little black skullcap with the metal middle finger sticking up on top that's poised perfectly to drive right down between the left and right hemispheres of your atrophied little brain?

"Yeah, the state trooper tried to take his durn helmet off but it was nailed to his haid. Garsh."

ANYWAY...because of my job, I'm privy to the whole world of auto parts, and so the only challenge is to pick the best one for the job. The first item I dug up is a brake master cylinder. As slick as the Willwood units are, and all the billet aluminum jobs you can find out there, they basically all do the same thing...push brake fluid. So why pay more for the same goal, just for a name?

After looking at the most common units my store stocks (for ease of replacement), I went with the clutch master cylinder from a 1986 Toyota pickup. It fits several years, 4wd doesn't matter, and because it's so common, it's CHEAP. Here it is:

That's a Rhinopac M-1638, and it costs me a big ol' $14.20. Before you tell me you found it a buck cheaper on Ebay, just remember...defects happen. Try finding the foreign guy who doesn't speak English who sold you your cheap cylinder, six months from now when it pukes out. Sometimes it's worth a little more to shop local...as long as it isn't TOO much more.

My rule of thumb is that the more inconvenient to replace or the more wear-prone a given part is, the more likely I am to buy local and pay for a name brand over a cheap no-name brand.

Next up is the caliper. I had first thought that I'd use two calipers for redundancy, placing them 180 degrees apart on the rotor. Then I realized that if I used an automotive caliper, chances were it would last a lot longer and also be easier and cheaper to replace if it failed. So, I did some digging through all the calipers in my store's stock.

First wave of checking was me walking down the parts aisle, picking each caliper box up to identify the lightest (smallest) ones. I wrote those numbers down. Then I went online and checked the part numbers in the buyer's guide to see what they fit. Again, popularity is key if you want to easily find replacements later.

I ended up with a rear caliper on a 2000 Chevy S-10. As with the clutch master cylinder it fits several years, so it's going to be available for a loooong time. A-1 Cardone part number 18B4712 (B stands for mounting bracket), cost of $27.36 with a $27.00 core.

Now, I can go to the salvage yard and buy an equivalent core for a couple bucks, trade it in and save the core charge, or pony up and pay the core. It's a one-time charge anyway since if it goes bad I'll just be swapping bad for good from here on. And when you look at the total, it's still a good bit cheaper than the aluminum aftermarket kart calipers.

Here it is, though this is a picture of the same type caliper from a different vendor. It just looked better than the only Cardone I could find:

One note here: this caliper, like most late models, has metric threads. Believe it or not, the 1986 Toyota clutch master cylinder has standard 3/16" inverted flare brake threads. But no problem...I'll tap the 10mm hole out to the next larger standard and use an adapter to connect to a 3/16" metal brake line.

The pads for these calipers are cheap, and you get two sets in every box. I'll post the part number and price when I get the numbers.

I'm on the fence at the moment about the rotor. I can either fabricate shims to place the brake pads closer together so that I can use a standard kart rotor, research an automotive rotor that would be light enough for my purposes, or make one myself. Still got to figure that out.

Standard brake fluid in most things is DOT 3. DOT 4 is great to replace it with because it's chemically compatible, but has a good bit higher boiling point. I'm going with DOT 5 though because unlike the others, it's silicone-base, doesn't attract water from the air, won't eat the paint of anything, and has an even higher temperature rating. The only time you wouldn't ever want to use DOT 5 is in an automotive anti-lock brake setup because down on the molecular level it's more compressible than either DOT 3 or 4, and it makes the ABS computer go wonky.

As mentioned, the cylinders will connect with metal line. I'll use a standard metal kart pedal. And there's a boss right there on the tip of the body of the master cylinder where I could screw in a brake light switch if I ever wanted brake lights, or needed a pedal-controlled circuit of some sort. Maybe a cruise control cut out lol.

I've found some part numbers for the switch, but here at home I'm not sure what the cost is, so I'll post that if it becomes a necessity.

That's all I've got for now.

 

[Tinkicker]

Oh wow. Just read the entire build thread by Freerunner15 that has become such a cult favorite around here. I may have to just kill this thread now because I don't know if I can take the beating that he did lol.

It may take me a long time to build this thing, but I AM trying to hand out some useful information in the meantime.

 

[chancer]

Nah you are alright... So far LOL.
You would have had to see the now deleted vids to fully understand why he took such a beating.

 

[Tinkicker]

Thanks.

 

[Flyinhillbilly]

I actually like FR. Where he went wrong was busting in here like John Wayne telling everyone else they were idiots. If you're going to do something crazy then that's great, we love crazy around here, but at the same time you seem to be able to realize that what you're doing is unorthodox and admit it rather than calling everyone beginners while mangling everything in sight.

That said, FR has one of my favorite youtube channels.

 

[Tinkicker]

Well I guess I missed the more extreme points where he talked down to everyone. I saw a lot of himself building himself up with miraculous mind maneuvers, but he's really so much like my little brother in law in that regard that I guess I'm used to that lol.

And yeah, I definitely ride the bent train tracks. The scenery is so much nicer.

That said, I just discovered itsid's kart calculator. That's a cool little time-saver...but I'm definitely going to need jackshafts. More jackshafts even than FR. Maybe a whole cluster with his LED lighting all over it, twirling and swirling. I'm definitely going to have to sit back and do some hard calculating once I understand the good and bad of different tires and know my diameters.

And I just ain't sure the 212 will push it all without some radical mods. Guess I could mount two of them.

 

[mckutzy]

If you looking for your long term use/longevity in your build.... and predominantly the jackshafts......

It'll be a bit hard.... but try to source some( used even..) Adamantium shafting(keyed of course) for the jackshafts.....

Itlll also make it super-speedy too......