Fangdango! V8 drag car

[luke66]

I love it when this build gets updated. It's just so dang rad! Hoping for some street running video soon!

 

[WickedFog]

This weekend I had a lot of free time, and it got spent on this car. First thing I did was head out and get some proper fuel!
View attachment 209509
I love the smell of that stuff

Saturday, I took the car out and decided to drive it around an empty parking lot. Engine fired up, and I started tweaking the needles. After a bit, I got it running well, and started trying to just lightly drive it around. Man, it did not get far at all! Just giving it the slightest amount of throttle and the car was wildly spinning out. No doubt far too light in the rear and nose heavy. This is definitely a combo of things, but I clearly need to replace the axle housing with the heavier titanium one (on order). I also note that the front servo was jerking around a lot whenever I gave it decent throttle. This was likely due to 1) It being a cruddy 10 dollar servo, as my throttle servo was fine and 2) Loose wiring on the distributor/plugs causing noise. Minor stuff though. I was incredibly impressed with the raw power the engine has. My biggest question was how fast would this thing be, and I think my answer is that it's going to be very, very fast.

My next issue was when I got home, cleaning the car up, was just a hassle. The open headers inside the thing just get fuel and crud everywhere on the rear section of the chassis. It was high time to put my exhaust on! So I got to doing that...

View attachment 209511
Nothing fancy, just some gently bent copper tubing with a hanger. Heat shrink tubing to insulate the chassis and body. Didn't really lose any of the awesome open header sound either. Reminds me a lot of the exhaust I had on my 71 Camaro in my punk street racing days
View attachment 209512
I do like when a plan works out.

So now it was Sunday, and I was mostly interested in tuning the engine and figuring out why the servo might be acting whacky. I had the car in my driveway and on the street, just goofing around. Man, the way this thing sounds, it simply just roars like a real car. Even just lightly tooling around, the thing just sounds scary as hell. I fiddled around with carb settings had it purring nicely for a bit, then not, then purring. Thing just seemed all over the place. One thing, my ignition battery (9v rechargeable) was low, so I have two, and swapped it, and the car was happy again. I also noticed that the plug wire caps on the distributer, a few of them anyway, kept getting loose. I honestly hate the design. Look below, and tell me how is anything supposed to stay connected? Why in the word do they not have some kind of either threaded end, or snap end?
View attachment 209513

My wife said put clamps on the boots. Maybe not a bad idea, but there's no room to do it. I decided to try something, which was take an m2 nut, and bore out the hole some to make a contact that would tightly fit on the posts and solder it to the wires.
View attachment 209514
Then I shoved the nut up into the boot, and put it on the cap. Seems to fit really snug. Hoping this will work. For the plug ends, my buddy came up with an idea that was great, which was to take a section of the spring from the glow plug wire from a Traxxas car and see if it would snap over the spark plug ends, and sure enough, it's the perfect size. The wire just slips in (tightly) into the end of the spring section. Haven't done it yet because so far, I think that plug boots are staying quite snug on the plugs.

I also alleviated any fuel flow concerns. I was not seeing any air in the line when revving, and so I'm not going to bother with the pump. I did test to see if it worked, and it did build slight pressure in the tank. It's something I can worry about later under much harder acceleration tests.

I had planned on taking some video. My phone was set up, but I hit the wrong button, and did not check until I put everything away. I'll get some very soon though.

With the car on the jacks, I noticed the oil was getting funky after all that running over the weekend. Drained it, and inspected it.
View attachment 209515

Looks like a good mix of brass from the crank bearings/connecting rods, and carbon steel from the rings. I think that is to be expected as the engine breaks in, but no doubt it's a good idea to change the oil after each use. The engine still feels pretty tight when turning by hand, so it's got a ways to go yet before break-in is done.

The other problems I had was the throttle linkage binding slightly, and the carb needles. I think I'm getting closer on those, but it's hard to tell when you keep dropping cylinders due to loose wires. I also need to properly set the timing. I could do it by ear, but I'll see about getting a timing gun. The last thing is coolant spillage out of the overflow tank. Not much I can really do about that one, other than not put too much in the system. However, too low, and the system draws air, and tends to run too hot and blow steam out the little hole in the tank. I think I'm going to put a fitting in the hole and run a line somewhere less obnoxious that getting all over the front of the engine.

Cool fix on the plug wires. Wonder why they didn't make those pins on the distributor cap more like the real thing, so you could just use a spring clamp on them, just like 1:1 plug wires, with a groove in them to lock hold the wire clamp on.

If your fix fails, I guess you'll just have to 3d print your own cap, and insert your own, properly machined contacts in it

Actually, it wouldn't be terribly difficult to make a better one.

Another idea would be to remove about 1/8" of the plastic around each pin, grind a groove in each one, and make a spring clamp to snap onto the pins. Just a thought, if your wires don't stay on.

Another idea, replace those pins in the cap with little M2 screws or something. That is, if you could get the current pins out of that cap cleanly.

 

[johnnydmd]

Cool fix on the plug wires. Wonder why they didn't make those pins on the distributor cap more like the real thing, so you could just use a spring clamp on them, just like 1:1 plug wires, with a groove in them to lock hold the wire clamp on.

If your fix fails, I guess you'll just have to 3d print your own cap, and insert your own, properly machined contacts in it

Actually, it wouldn't be terribly difficult to make a better one.

Another idea would be to remove about 1/8" of the plastic around each pin, grind a groove in each one, and make a spring clamp to snap onto the pins. Just a thought, if your wires don't stay on.

Another idea, replace those pins in the cap with little M2 screws or something. That is, if you could get the current pins out of that cap cleanly.

I love the idea of replacing the pins with screws. Love it. If I knew that I could get a replacement cap in a reasonable time, I'd do it right now That said, I might order a spare and give that a go.

For now, I tested the fix, and the thing seemed to run smoother for sure. Nothing shook loose, but I think ultimately screw down terminals are the final boss

 

[WickedFog]

I love the idea of replacing the pins with screws. Love it. If I knew that I could get a replacement cap in a reasonable time, I'd do it right now That said, I might order a spare and give that a go.

For now, I tested the fix, and the thing seemed to run smoother for sure. Nothing shook loose, but I think ultimately screw down terminals are the final boss

3d print a replacement cap. That's not terribly difficult to model up.

 

[Brady Matthews]

This thread is making me want to finish building my wooden RC rat rod with my V8

 

[WickedFog]

This thread is making me want to finish building my wooden RC rat rod with my V8View attachment 209742

That is awesome! Have you seen @Tunedfrog's wooden masterpieces?

 

[Chubaka]

That is awesome! Have you seen @Tunedfrog's wooden masterpieces?

 

[Xraycer]

This thread is making me want to finish building my wooden RC rat rod with my V8View attachment 209742

WALL•E !!!!

 

[Brady Matthews]

That is awesome! Have you seen @Tunedfrog's wooden masterpieces?

Thanks, I haven't heen his masterpieces yet

 

[Brady Matthews]

WALL•E !!!!

You're the 5th person to said that

 

[WickedFog]

Thanks, I haven't heen his masterpieces yet

He posted some of them here. These are all made from popsicle sticks.

Post in thread 'The Woodworking Thread'

Feb 2, 2024

Here is some of my popsicle stick builds.
Most important tip of all, be careful sanding the wood, it's hard to replace mistakes.
The Semi tractor on the left won $500 worth of Ryobi tools in a contest.

• Tunedfrog

• 
• 

 

[Brady Matthews]

He posted some of them here. These are all made from popsicle sticks.

Post in thread 'The Woodworking Thread'

Feb 2, 2024

Here is some of my popsicle stick builds.
Most important tip of all, be careful sanding the wood, it's hard to replace mistakes.
The Semi tractor on the left won $500 worth of Ryobi tools in a contest.

• Tunedfrog

• 
• 

Wow, that's awesome

 

[johnnydmd]

Made proper clips for plug side.

Engine running so much better now! Misfires have stopped completely.

 

[johnnydmd]

Replaced the 1200mah receiver pack with a beefy 5000mah version This because the receiver pack powers the fan, and that drains it fairly quickly. With this one, it should run for hours. Conversely, it takes a long azz time to charge it, lol. I also got my new tach (this one actually worked this time). This is visible through the back window of the car. I also benefit from adding some weight directly over the rear wheels. Alloy axle coming this week will add more.

I also replaced the sketch dogbone driveshaft with a super beefy MIP CVD version. This also allowed me to get the rear axle better lined up with the body because now I have some wiggle room.

I also ordered a 12v rechargeable battery pack for the ignition. It's still pretty small, but definitely adding more weight in the rear, but mostly I should have better spark and longer lasting. The 9v battery doesn't last all that long (but I do have a spare that I keep charged). I just have to be able to mount it back there cleanly. If not, and I can't notice a difference in how it runs, I'll stick with the 9v.

I do want to rebuild the brakes, and instead of using the cobbled up Mad Crusher piece, fab it myself from aluminum and CF, something that I can reproduce accurately.

I did test the new steering servo with the engine running, and no glitching. That's a relief. Now my list of stuff is shorter that I want to do to this as Winter has fully set in, and testing is going to be hard to come by, but it's still a lot:

1. Replace rear axle with alloy.
2. 2100mah 12v ignition PS. Alternative - they do sell an alternator that can power the ignition once the car is started. Maybe...maybe.
3. Make the wheelie bar adjustable, and with dampers. This is pretty high on my list, and was the plan from the outset.
4. Fuel pump? Maybe. We did some testing on TG with it, but it's looking more like the carb is just really needing more fine tuning, or even modification.
5. Turbos? Again, this is probably something I have to see about, because 1) They are building superchargers for these, and 2) "all motor" might be more than enough, like WAY more than enough.
6. Better lifters. So far, no problems to report, but I probably will make some machined, one-piece ones. I think all other concerns I had about the engine I've resolved.

 

[WickedFog]

It looks like it has the same amount of wiring as a 1:1

Just awesome stuff man!

 

[CertifiedMike]

Working gauges on an r/c car!
Only cooler because its an r/c car that NEEDS gauges!

HERO! You are my hero sir!

 

[johnnydmd]

My GTB axles came last night. I bought a pair, because I saw originally that the design would allow me to Frankenstein the two halves into a narrower, centered pumpkin style without any cutting/trimming. I was completely astounded by the quality compared to the Hot Racing and RC4WD axles! These things are legit with a terrific design and precise machining. They are also a lot lighter than I expected, so while now having a bulletproof drivetrain, I'm probably still a little light in the azz-end. I do have my 12v battery pack for the ignition arriving this week (and I got a 1200 and a 2400 version), so that'll help add some. I just have to figure out a place, and how to mount it.

Now, can I just get a day out of the 30's or 40's so I can so some testing?

 

[Xraycer]

This rig just keeps getting cooler and cooler!

 

[johnnydmd]

Got the axle, and new 12v ignition battery added (note - it's worth mentioning that Cison offers an alternator that can power the ignition once started, so that could be something to try out at some point). Ran the car, and wow, what a difference the 12v and new plug wire combo made! So much smoother.

The empty space now by the receiver is where my Racebox micro will be going

I also designed new upper wheelie bar links to be spring loaded and adjustable, pretty much identical to the real deal 1:1 cars.

With all of that, I did have a 50 degree day Sunday to test. Sadly, the wire clip on the starter broke, and I couldn't find any small enough at the local HW store, so I had to wait until yesterday for some from Amazon to arrive. Testing and vids will have to wait...

I did get one last set "beauty" pics of the finished car with the window rivets, and exhaust system in place.

 

[WickedFog]

Got the axle, and new 12v ignition battery added (note - it's worth mentioning that Cison offers an alternator that can power the ignition once started, so that could be something to try out at some point). Ran the car, and wow, what a difference the 12v and new plug wire combo made! So much smoother.
View attachment 210905

The empty space now by the receiver is where my Racebox micro will be going

I also designed new upper wheelie bar links to be spring loaded and adjustable, pretty much identical to the real deal 1:1 cars.
View attachment 210906

With all of that, I did have a 50 degree day Sunday to test. Sadly, the wire clip on the starter broke, and I couldn't find any small enough at the local HW store, so I had to wait until yesterday for some from Amazon to arrive. Testing and vids will have to wait...

I did get one last set "beauty" pics of the finished car with the window rivets, and exhaust system in place.

View attachment 210907
View attachment 210909

RC build of the year award right there.