The continuing saga of Niksons 1402 IMP sn 129

[turbinator62]

Finished the new belly pan today. I riveted on 2 flanges that are .050 apart to sandwich the bottom of the forward bulkhead. I bent an entry angle on both to make it easer to install. This will stop any hot air from flowing forward under the engine.

Also finished up the clutch lever where it exits the side of the airbox.

The hand throttle is a self locking unit from a propeller control. The governor on the Wisconsin has vey high return to idle force. I tried a simple lawn tractor throttle but it would creep back to idle unless the friction was set so high that it was unusable. This unit allows motion when applied from the lever, but locks if the force is applied from the cable end. I was originally a reversing type, so I had to make an adapter to pull the cable when the control is pushed forward.

I was not real happy with the rubber hose fuel line with all the heat in the airbox so I replaced it with a stainless AN 4 Aeroquip hose with fire sleeve.

I think I'll pull off the exhaust manifold and wrap it with insulation like the exhaust pipe also. Every little bit helps.

[turbinator62]

Today I assembled and tested the new air box. IT WORKS! I ran it for about a half hour at max governor speed (2800 RPM No load) and the cowling was only warm to the touch. Before it would roast you out. There is good airflow out of the defrost vents but almost none from the back one that is intended to blow warm air into the rear cab. I used a manometer to check the pressure at the rear vent and it is almost ambient. This is actually a good thing because it means there is no back pressure on the cooling air. (I thought there would be a little) To correct this I ran a 2 inch scat duct up to the top of the engine to pick up the higher pressure air and that corrected the problem. I wrapped part of the exhaust manifold with insulation but ran out so I had to order more. It should be even better when the manifold is fully insulated.

There is now a flow of warm air out the back of the tunnel around the rear end.

I will have to wait for winter to see how effective it is. There will still be a lot of radiant heat from the engine but I may have to add more heat vents.

There are a few more details I have to finish up and this thing will pretty much be done.

[Snowtrac Nome]

the scat tube works well for heater duct that was the ducting of choice for my snow trac heater tubes

[Cidertom]

With the engine so well buttoned up, have you given thought to a remote extinguisher bottle? I've been in an Imp that caught fire... no fun

[turbinator62]

I have a Halon bottle with a remote nozzle from a plane that I plan to use but I have to get it refilled. (Expensive) Fire is always a concern in a tightly cowled engine. That was why I went to high temp fuel lines and fire sleeve.

[Snowtrac Nome]

if you plan to Keep up with Bid Al and his kt-7 you're going to have to get a wet bar for that thing and some cardboard cut out chicks to prop up next to it

[turbinator62]

The air box is finished and all buttoned up. I wrapped the manifold with 1" exhaust tape. All I have left is to rebuild the brake system.

[turbinator62]

The next thing on my list is to fix a leak in the rear end. I had determined earlier that it was leaking from the input shaft seal. I ordered one from the good people at Spryte Improvement in Wallace Idaho. The seal is a common size, and easily available, but their price was as good as any and I believe we should patronize the people who are supporting our machines.
I did not want to have to remove the rear end from the chassis to do this, but the bearing retainer/seal housing cannot be removed due to interference with the rear end mount. Since the seal is bad anyway, I decided to allow it to get trashed as I drove the housing off the shaft at an angle.

I then determined how deep the new seal had to go into the housing in order to clear the splines. A seal driver was machined with a boss of the proper depth to seat the seal. I used a piece of 2- 1/2 " nylon for the job.

The new seal is somewhat thinner than the old one so it can be installed deeper in order to clear the shaft spline. That may have been the problem that caused the leak.

I can check that one off the list.

[turbinator62]

Both slave cylinders were leaking badly as is evidenced by the damaged paint on the rear end. Since there are no new cylinders of this type left in captivity, the only option is to rebuild them. After disassembly, both were found to have extensive corrosion inside. The pits were too deep to hone out. The only option is to sleeve them. New cups are available from NAPA, United PN 14451.

I ordered a 1 foot length of 1.375" .065 wall 4130 aircraft tubing. The ID is 1.245". 4130 is very close tolerance and resistant to corrosion. With a light honing it is ready to go.

The cylinders were chucked up and bored to 1.380". (A slip fit for the tubing) Two lengths of tubing were cut to about 3.400", deburred and a notch cut in one end to prevent blockage of the bleeder hole. They were then installed into the cylinders with JB Weld, a common high strength epoxy. Cleanup is done with rubbing alcohol before the epoxy cures. Should this ever need to be done again, (hopefully not in my lifetime) the cylinders can be heated to 350 degrees or so and the sleeve pulled out and a new one installed.

The pistons were serviceable, but the aluminum cup retainers were pretty badly corroded so I machined two new ones from 6061 T651 bar stock.

Tomorrow I'll reassemble the brakes and replace the master cylinders.

This thing is almost done!

[Nate b]

The craftsman ship and abilities you have are phenomenal. Absolutely enjoy reading and seeing the work you are doing.

[turbinator62]

Thanks. It is my wish that posting on this forum will help other guys facing the same problems to find solutions.

A side note: Right after I stated that there are no slave cylinders available I found these http://www.powerbrake-drivetrain.com...WAGNER-/Detail by Googling FE 21637

At $534 each, the few hours and 20 bucks to rebuild the old ones still looks good.

[Nate b]

The craftsman ship and abilities you have are phenomenal. Absolutely enjoy reading and seeing the work you are doing.

[nikos]

Check up Operation in the 1402 IMP
SURGERY Treatment
Nikos

[DAVENET]

Originally Posted by Nate b

The craftsman ship and abilities you have are phenomenal. Absolutely enjoy reading and seeing the work you are doing.

I'm sure you are ready for it to end, but I think the rest of us are going to be sad about it! I really do enjoy seeing these updates and your solutions to the problems. After this, you are going to need to find another one to go thru to keep us entertained!

[turbinator62]

Thanks for the compliments. It has been fun posting the progress on this project. I don't know about doing another one but I plan to continue to post our adventures with it. I hope to haul it to its new home in Eastern Washington in a few weeks. if everything works out, I would like to go to the Snowcat Jamboree in Leavenworth Washington in January.

I hope to get back to work on the airplane soon. I think it is feeling neglected after 5 months.

[turbinator62]

When I rewired the cat I reused the fuse block that was in it. (first picture) The problem was it was too big and only had a single buss. It was kind of in the way down on the floor panel. So I took it out and replaced it with two 6 circuit fuse blocks I got on Amazon.com for about 5 bucks apiece. I divided them into a battery buss, accessory buss and ignition buss. The floor is now clear.

Sometimes you have to do it wrong to know how to do it right.

ON (IGN): Ignition, fuel pump

ACCY: Wipers, search light, gauges, intercom, winch, 12 volt outlet

BATT: High beam and low beam, fog and back up lights, dome lights, fan

The battery buss is hot all the time. The Accessory buss is hot when the key is in ACCY and ON but off while cranking. The Ignition buss is hot with the key in ON and while cranking but off when in ACCY.

[anthonydoldd]

Great job!!

This cat was a neat concept when you bought it but you have done a wonderful job completing the project. Your engine shroud looks great! I hope that it is the cure. Watching Nixons videos it was quite apparent that the cab got awful warm when running. It is always fun to watch these projects unfold and see the quality of the workmanship that members here have.

[turbinator62]

Thanks! The little bit I have driven it the cab has been way cooler inside. I hope it will be warm enough in the winter. I can always add some more vents if I have to.
We're used to going to our cabin on snowmobiles so just being in an enclosed cab will be an improvement.

[turbinator62]

Finished up the steering cylinders today. The final honing and polishing was done on the lathe.

[turbinator62]

One of the steering brake master cylinders was leaking. I had planned to rebuild them but after disassembly found them both to be unsalvageable. The bores on both were very badly corroded. Fortunately, I found two new Wagner PN MC 36313 master cylinders on eBay for $80 each. The castings were a little different than the original but I was able to mill them to accommodate the steering levers. The webbing on top of the unit interferes with the lower part of the steering lever and must be narrowed to clear it.

I want to thank all of the people who have done this before and posted the part numbers and sources for these hard to find parts. I would still be trying to figure this out if it weren't for this forum.

Now I just have to fill it with fluid and bleed the system. Just a couple of small details left and it is DONE!