Things Heat Up Again (Namely, Dave's Stomach!)

Well, we got the steering levers and linkages all set up and bolted in place using a plate my dad made up with a pivot for each lever.

While making the steering levers, the project's second fire related incident occurred when, while grinding one of the levers, my dad's shirt ignited. It burned holes through all three of his (polyester) shirts, left a minor burn on his stomach, and burned one of his fingers where the polyester melted to it while instinctively beating out the fire. After changing shirts and bandaging it up, it was back to work.

We rigged cables for the throttle, the brake, and the clutch, hooked up a throttle trigger on the right hand steering lever, and rigged a pedal to act as a brake and clutch.

After a very successful test drive using a 2x4 as a seat, we mounted the seat I've been saving for a tank seat for quite some time. After another relatively successful test drive we brought it back in to make a few minor changes to the clutch cable and to move the shift linkage up next to the driver's seat (seeing as the linkage broke during the last test drive anyway.) We noticed that we needed to adjust the throw on the idler pulley arm so all the tension was taken off the belt when the clutch pedal was in. We also decided to eliminate the dual purpose clutch/brake pedal and to make the pedal just a clutch, and to rig a brake trigger on the left hand steering lever.


Running the throttle trigger.

My dad taking the first test drive with the brake pedal and steering levers hooked up.

Track Work and Flooring

This is not what anyone wants to see when they look at their tank! Wednesday, we were having trouble when driving the tank in 2nd gear, if you turned right it would often lock up on you and you would be stuck there turning until you backed up a short distance. We came to realize a loud thunk from the right front bogey wheel that would only happen before and after this phenomenon.

Much to our dismay, but as we had assumed, both bearings were wiped right out, most likely due to the fact that these are the only 2 sets of bogeys out of 12 that don't have any grease fittings, and at high speed the bogey wheel was jamming sideways and not allowing the track to turn. We discovered this of course after disconnecting the track and jacking up the right side of the PPT.

Luckily, the bearings were just 1" inside and 2" outside, and our local auto parts store had them in stock, so we pulled it all the way apart.

You can see what was left of the two ball bearings, seized right to the shaft.

When we put it all back together, we reinforced the track with some conveyor belt rubber, since the connection point was pretty weak.

Today we sprayed down the crossmembers that would be exposed under the tank with rubberized undercoating, and put the marine grade plywood floor in.

We also began machining the steering levers, and debating the interior design. I threw up the white flag today and admitted that this is going to have to be a one man show.

We didn't have much time to work on the tank towards the end of the week, but here are a few videos of what we ended up with. We did get it steering right AND left, and put a much smaller 3" pulley on the engine to slow it down, which worked beautifully. I shot these videos of my dad driving it around, working the steering free. Due to the lack of a brake on the transmission pulley, we have been using our boots to stop it to prevent it from grinding. As you will hear, that doesn't always work! But, it climbs well, so well that it will climb until it bottoms itself out, and it does real well going across the snow.

It's Alive!

Well, large scale tank production was put on hold today, due to the need to do some actual work. However, last night my dad rigged up an idler pulley to keep tension on the drive belt, and started on finding a good place to tuck the battery. We did work on the tank for about an hour and a half this afternoon, as I was anxious to at least see if it was capable of moving under its own power. We rigged used a makeshift fuel tank, rigged up a clutch lever on the ldler arm, and rigged up a tiller for steering. Looking and handling much like some form of land boat, it was finally time to see if we were as smart as we thought we were.

I was 90% sure it would drive with little or no problem, but it was the steering I was worried about because of how frozen up the brakes and throwout bearings had been. We fired up the engine, and to out amazement, it drove. It also steered. Right. After several minutes of playing with clutching techniques, which gear was which, and using my hand on the governor arm to control the engine speed we were...driving in circles! But, driving in circles is better than not driving at all! I think after a little work freeing up the lefthand throwout bearing it will be steering no problem. The only other thing we need to change is the engine pulley. It is gear a little high for a tank, and stalls out if you don't give it enough throttle at first. Putting a smaller pulley on the engine should solve that problem.

At least we can prove it runs!

The only known video in existence of my PPT/tank driving. Hopefully more tomorrow!

Progress Is Being Made

Today started off with me finishing freeing up the steering, giving the transmission one more cleaning, and putting it back in the PPT. Steve and I then pulled the Kohler out of the Simplicity.

After a few mock up attempts, we came up with a way to mount the engine on top of the transmission using some scrap metal. This is where we ran into an issue I had sort of expected to run into. By flipping the PPT around and make the front the back and vice versa, we needed to find a way to turn the engine around so that we didn't end up like a Polish Army tank, with one speed forward and two speeds reverse.

The nice thing about the Kohler Magnum horizontal shaft engines is that you can take power off the flywheel by attaching a coupler into already drilled holes in the flywheel. This makes the drive belt turn clockwise as opposed to counter clockwise if we had used the crankshaft side of the engine. This also leaves the crankshaft available for another trick we have up our sleeves.

We then welded the engine mount together, managing to only ignite the waste oil tank one time, but some quick footwork on my dad's part solved that problem.

Steve and I then aligned and squared up the engine before my dad laid the final beads. This thing will run tomorrow, and possibly even drive.

Ripping and Tearing

Well I started today fully expecting to have the steering and drive system of the tank in working order. Silly me. First thing first I pulled the cover off the gearbox, expecting to find sludge, rust, and metal shavings. Much to my surprise, all we found were some little worn gears, an intact chain, and no metal splinters whatsoever.

There were about 5 ounces of water and three ounces of oil/sludge in the very bottom of the gearbox, but that was easily turkey-bastered out.

We put two full tubes of 00 grease, some 90 weight oil, and a full can of silicone grease inside, smeared it all around, and then I sealed it up with silicone gasket.

Then the brains of the operation, Steve realized that by pulling eight bolts and undoing the chains from the drive sprockets, we could pull the entire drive system out of the PPT, which left us with an empty PPT shell. This made cleaning out the inside of the PPT, and the inside of the drive much easier.

Then I could resist the temptation no longer. I took the seat that will soon be my driver's seat, put it inside, and tried it on for size. Something tells me I might have to shorten that seat up, or find a new one! My dad is insistent that we will not be able to make this a two man tank, but I am convinced we can make it happen!

I put the drive on my lift, and began freeing up the three brakes (one main brake, and one on either track for steering) and continued to clean the never engine crud out of every crevice. Steve and I then brought in my engine and gas tank donor, a 20 year old Simplicity commercial mower with a 20hp Kohler opposed twin cylinder engine with hopes of getting it running. A little carb cleaner, a battery boost, and a few carburetor adjustments later and we were in business. At this point it was 5 o'clock, and we retired for the evening, and some blueberry pancakes and sausage. More will surely ensue tomorrow.

Finally the Project Begins

Well, it's been 284 days since I brought my PPT home, but who's counting right? We've had a few weeks of no snowstorms, so at the Emporium we are enjoying the roughly two weeks of down time we get a year. Today I took the tractor and cleared myself a path out to my PPT to bring it in out of the snow bank. When we put it on a pallet in the spring, it looked like this:

It looked very similar today, besides being under about a foot of snow. I pulled it out, and up to my bay door, and got to work. Steve and I pulled the hood off, yanked the wiring harness out, and pulled what was left of the seat out. We then used the tractor to bring it into my bay and put it on the lift. Here is where the real surgery began. I pulled the engine, amazed that not a single bolt snapped as rusted as they were. My dad and I then used the cutting torches and die grinder to remove the gas tank and what was left of the rotten floor. After messing around with it for a few minutes, we were amazed to see that if we put it in forward or reverse and turned the pulley on the gearbox, it actually moved, and surprisingly smoothly. We put it up in the air, and again to our amazement found that all the bogey wheels were free. There was a lot of dirt, ice, and just plain sludge around the two brakes that act as the steering, so we pushed it outside and pressure washed the engine and drive compartment out. After pushing it back on the lift to continue to unthaw over the weekend, we spent a significant amount of time looking it all over, trying to figure out exactly how this will work. Of course, only time will surely tell.

My Dad pressure washing out the engine and drive compartment.

Me cleaning out around the gearbox.

The gearbox and brakes. The PPT is steered by a brake on either track. This area was the front of the PPT, but is now the back of the tank.