"Project Mario" - Testing Complete: A+

[Florida_Slotter]

One of the most interesting people in all of motor racing is Mario Andretti. I remember when he won the 1967 Daytona 500 driving a Ford Fairlane. One of our club members had one of the #11 Revell-Monogram versions of this car and a deal was struck. When I ran the car around, I realized that while it was a beautiful car, there was something lacking in the mechanical department. So I set out to rectify that situation.




The first thing I did was to remove the body from the chassis, then use it to set up the wheelbase on my jig. The blue things are my jig wheels. I use these to set the axle height so I can build the chassis when it is sitting flat on the jig's surface. Once I put my wheels in place, the car has the desired clearance under it.




Next I removed the stock Revell-Monogram motor from the chassis and did some measuring to find the dimensions of it. As you can see, it is .996 in length. Well that is quite nice as I have a wire bender that will allow me to bend a loop that is exactly 1.000 inside dimension. I am not going to worry about the .004 differece, solder will easily fill that when I mount the motor.




To make the loop, I simply bend the wire using the wire bender that I purchased from RGEO Products. It is set up to bend 1.000 and .750 inside dimension wire loops. I have added a .460, but we'll talk about that at a later time. I have also used this wire bender to do all sorts of crazy bends for other chassis types that I build. I find it to be a very useful tool in my arsenal.




After I checked the "U" shaped loop for 90 degree bends, I bent the rear of the loop up in the rear. This would be my mount for the rear axle tube. I make my axle tubes out of 7/32 round brass tubing. This allows my to solder either a 3/16 oilite bushing or a 3/16 ball bearing in place and mount my rear axle in that.




I added a piece of .064 thick x 1.000 wide piece of brass strip under the front axle. This is what I will mount my guide tongue to. It will also be place that I mount my front axle tube to. For the front axle tube, I used a piece of .125 round brass tubing. A 3/32 axle fits nicely inside of it. My next build will use a piece of 7/32 tubing as I want to use bushings or bearings in it and also make the front wheels rotate independantly.




This shot shows the relief I cut into the front of the 7/32 round brass tubing to allow the motor to be located for the optimum in gear mesh. A quick bit of work with the Dremel makes this an easy task. Then just clean it all up with a few touches of the file and you're good to go.




Here is the chassis with the front axle tube mounted, a pair of 'pans' (made from .064 x .250 brass strip) and a motor mount (also made from a .064 x .250 brass strip). Basically all I need to do is mount the guide tongue, solder the motor in place and mount the wheels, tires and gears.




Of course I just HAD to set the body on top of the new running gear to see if it made it sit more like the prototype's images I could find on the internet. I think it fulfilled that requirement.

The first test was to run some laps on my test track, which normally hosts Carrera "GO" racing. But with a 4 lane setup, I just use one of the middle lanes and I can run my 1/32 cars around to see how they work.

Something that came across loud and clear, or more correctly silent and clear, was the sound that was coming from the car. Gone were the noises that came from the car previously. The gear mesh was now spot on. The car ran very smooth, but without any screw on wheels, it was hard to true up the tires.

A quick shopping trip to Slot Car Corner rectified that problem. I bought a set of the C.B. Design Wheels Classic Steel Wheels - 15 x 8 for the rear and 15 x 7 for the front. Then I used their tire finder to come up with a set of Yellow Dogs to fit the new wheels. Once they came, which was like almost overnight - I swear those guys fill the orders and put them in the mail when the computer prints out what you ordered.

When the wheels and tires got here, I glued the tires to the wheels, then ran them up on my Hudy. When I put them on the chassis, the car was so smooth going around my test track, it was hard to hear it running. I was impressed.

So, how did it GO when put on our new mdf track? You'll have to come back to find out as I still need to take a few more photos to show how I mounted the new chassis to the body.

See y'all soon!

[HomeRacingWorld]

Very interesting, great job going here.

[Scatman1]

Thanks for the step by step build. Looks great. Any chance of a complete chassis photo and how you mounted the chassis?

[Florida_Slotter]

Scatman1,

There most certainly is:




The black plastic pieces you see on the front of the chassis are from the original chassis. I simply epoxied them to the chassis. This way I have a way of holding it all together with a couple of screws.

[Florida_Slotter]

Well here's the part where you need to send in a video of you performing the "secret handshake" that Bibbster had sent out for us to learn.

You will need to do that prior to looking at the following.

Remember, this is all on the honor system, so no cheating allowed!


To begin with, if you look at the photos in the post above showing the top and bottom view of the finished chassis, you will see a couple of black bits stuck to the front of the chassis. Those are from the orginal chassis. I simply epoxied them to the chassis pieces in the front. This way, I use them to secure the chassis in the body.

Now for the 'other half' of my system.




I took a piece of .032 x .250 brass strip and after soldering the .125 square brass tubing to it, affixed it to the rear body mounts with some CA glue.

The centerlines of the square tubing align with the centerline of the extension I added to the chassis at the rear. To mount the chassis, just slide the extension into the .125 square brass tubes, then screw it in place with 2 screws.




I like to isolate the body from the chassis by doing a mount like this. I hope to keep body movement from affecting the chassis in any way, shape or form.

Using the .125 (outside dimension with a .014 wall thickness) gives me about .032 of movement. If I find this too much, I will limit this movement by drilling a hole in the square brass tubing, soldering a 2:56 nut to the tubing and then putting a 2:56 hex head screw into the nut. I can adjust the chassis / body movement amount as we all know that track conditions change.

At this time, we do not race on ovals. But while building this chassis I had an idea. If I build an inline motor arrangement, then I can put the motor at about the left hand most portion of the chassis. That should help in turning left on those ovals. Or I can come up with other intersting arrangements like an offset anglewinder that will really turn left and go fast.

If I do that, then I can mount the body at all 4 corners with this round post in a square hole arrangement. I can then put the adjusters on it and you can tweak the weight bias and movement. I'll bet Bibbster can show Harry the way home then! Only time will tell.

Stay tuned, this could get even more interesting!

[Florida_Slotter]

[Florida_Slotter]

Bibbster,

I had forgotten to answer one of the questions you had asked, "How did it run?"

Well I do not have a timing system hooked up on the new track as of yet. One of those 'soon to be issues' that we all know we want but the budget lady says "not now!"

But there was a stock Revell-Monogram 1967 Ford Fairlane that one of the racers had with him. It has been tuned and we had a side by side race. The other car did not have Yellow Dogs on it. I think they were stock. In all fairness I am sure it would have put up more of a fight with updated tires, but the one with the scratchbuilt chassis had it's way with the stock chassis car. As we came out of the tight 180 that leads into the main straight, I was able to get on the throttle much quicker and I was pulling away from the other car. But when it came to running the turns, I don't think upgraded tires would have made much of a difference. The modifed car just handles so much better.

Remember this, it is the same motor and gear ratio (I had to change to another gear when I put the CB Wheels on as the stock axle is knurled for the gear and wheels. The stock gear had no way of fastening to the new smooth axle. I grabbed a Slot.It gear with the same amount of teeth and kept the stock pinion. So all was the same or should be considered the same.

[Scatman1]

Did you put Mario back in the car? Photo shows no interior. I sure hope we can post this somewhere on HRW website. Maybe all your photos and step by step without our inputs. (article format) Someone looking to build a chassis and using the search feature may never see this post. Just my 2¢ :think:

Once again, thanks for sharing.

Tony

[Florida_Slotter]

Tony,

During my testing phase the car started out as herky & jerky. When I looked, the interior was not letting the chassis move smoothly. So it came out. When I pulled it, the car just got very smooth.

It appears that I will have to shorted the depth of the interior by about 1/4 inch or so.

I hope to have Mario back behind the wheel here soon.

Thanks for asking.

[HomeRacingWorld]

We can do that Tony, if Marty says I can steal it :)

Think you have heavy enough lead wire there? I have some jumper cables here if those are too weak :)

[007jag]

Hello,
This is the aspect of slotting that I'm trying develop my skills in & this is one great example!!!
I simply can't say thank you enough for the clear and very helpful step-by-step photos & descriptions.
Your work is inspirational - Thank you,
Jack
P.S. What is the reason or use of the brass side pans???

[Florida_Slotter]

[Florida_Slotter]

[Florida_Slotter]

Scatman,

To truthfully answer your question about Mario being back in the car, I must answer a resounding "no". Not because I do not want to, but he will not fit.

In order to get the CG as low as possible, the original interior will not fit. I might have to take all the parts and "Dr. Frankenstein" it all together - severed body parts that is - on a shelf to make him fit back in the car.

Yesterday we were having a "NASCAR Day" and just having a ball. Basically we have chosen to divide out NASCAR into two distinct, easy to differentiate categories. That would be early and modern NASCAR. Early NASCAR has no window nets, Modern NASCAR does.

We were running Early NASCAR as most of us like that category more then the Modern era. There were Plymouth Belvederes, Dodge Chargers, Ford Fairlanes, Plymouth Superbirds and Ford Torinos all over the track - literally.

However Mario always wound up being the top dog.

Yes, it seems a bit unfair to compare a car with a brass and wire chassis and a lot lower CG to a car that sits high on a plastic chassis, but I do not know what is more demonstrative of how much better a car is with a brass and wire chassis under it.

The car is just so forgivable that it invites you to drive it deeper into corners then you would do with a different car. It will slide in a turn when you drive it too hard rather then 'turtle flip' and lay on it's side. I would say that this is as much a "Stock Car" in it's relationship to what a stock Monogram strock car is to it as a stock 1967 Fairlane is to what the car Mario drove in the 1967 Daytona 500 is. Kind of interesting.

Perhaps we need to have a comparison done by Harry to see just how much better this car is then the stock Monogram car is. Remember, it uses the stock Monogram motor in the wire and brass chassis.

Only time will tell.

[ourwayband]

Marty
Thanks for all of the info and pictures on your great build.This is one part of the hobby I hope to expand my Knowledge and skill on .I've got a long ways to go too..
Thanks again

rusty