1898 Nash Two Cylinder Build

[raveney]

Screen Cooler Tank

I didn't seem to come across an empty can that matched the dimensions I wanted, so I salvaged a heavily tarnished foot of 2" copper pipe and a coil of 1/8" icemaker line to see what could be done.

Slit the copper pipe lengthwise with a hacksaw in the vise, and then heated it cherry red with the turbo torch and firebrick hearth. Carefully pried it open and then flattened it using the vise jaws while turning over end for end. I have aluminum soft jaws in this vise. Then I was able to form the semisoft copper over a stub of 3" pipe to form a 3" tall by 3-1/2" OD cylinder for the tank. I then silver brazed this and cleaned it up in the lathe on some wooden formers.

The leftover copper had enough for the floor of the tank so that was silver brazed in next, and then again, and one more time until it held water.
I am using Kapp Zapp 3.5% silver solder in a half pound roll as it is much cheaper per foot compared to the Harris brand. It does work okay with the white flux, but does not seem to work at all on ferrous metals.


I had planned to make three hoops out of the 1/4 OD copper tube, but only ended up using the one as a clamp for the screen. It was too large for the scale, and I ordered 1mm x 4mm half round online to replicate the "bulges" that are found on galvanized tubs and barrels. I was able to mill the tubing into half round pieces after clamping it in an aluminum jig that has a 1/4 ball end mill groove to hold the tubing flat.


Not really sure how the top sprayer part is made, so I sketched a few ideas and ended up with a 1/4" by 3/4" ring with 12 1/16 spray holes. The "hood" is a loose fit over this ring and will hopefully allow the cooling water to cascade down the screen/funnel shape. The screen material is 20 mesh copper.


I wrestled with the screen material enough until I chose to make a wooden former on the lathe. This has a base the same size as the tank (3-1/2") and tapers at 26 degrees. Pinned the screen on the wood and will attempt soldering it another day.

 

[kuhncw]

Nice work on your coolant tank. Also, your Nash looks great based on the recent photos you posted.

Thanks for all the detail in your build thread.

Regards,

Chuck

 

[raveney]

Thank you Chuck

Fuel Tank

I would like to try a different kind of fuel tank for this engine. I remember the old steel fuel oil tanks that people had inside their basements up North for heating. Just so happens that the dimensions are available online so I could get the correct aspect ratio for the typical 275 gallon type. It was scaled to match a piece of 1-1/2 copper pipe I had, and to use up a bit of glass tube for a sight glass.

The copper pipe was sawn in half and the other slabs squared up in the mill. Made the radius for the bulkheads using a compass/scribe and a 6" table top disc sander. I silver brazed it together so it wouldn't come loose later when the fittings and bulkheads were added using softer silver solder. The sight glass fittings were too thin to braze without melting/distorting them. The zinc melted. On the second attempt, I brazed solid pieces and plan to thread and bore them afterwards.

The Kapp-Zapp 3-1/2% solder didn't take well when using the white flux on the large end piece. Had to stop, reclean and use regular plumbers flux. Still need to finish up soldering and add the fill and vent ports to it. What do you think so far?

 

[raveney]

The fuel tank work continued very well using the plumbers acid flux and 3-1/2% silver solder. Hardest part was the two gauge glass fittings. I would fabricate these parts using solid round bar and thread everything before drilling the internal passages next time. I had to use a 3/16" transfer punch inside the two 1/4" OD brass tubing bits in order to prevent collapsing them.

The fill and vent ports are threaded 5/16-24 with 7/32 across flats squares milled onto the plugs. The glass tube is sealed using small bits of graphite packing in compression. Water tested it both before paint for the solder joints, and afterwards for the glass gauge fittings. I am hoping this tank will be able to set at the base of the engine and not have to elevate it. It may need a structure built to raise it closer to the carburetor level.

looking at these pictures, the sight glass is not to scale but it looks okay in real life setting next to the engine.

 

[raveney]

Cooling Pump

There is a plan for a centrifugal pump included in Doug Kelley's book. I started the build by drilling the bearing cavity, tapped mounting plate holes and the radius' for the feet. Then centered it in the 4 jaw and machined the shaft bearing profile. I was then able to flip it and use a mandrel to counterbore the areas for the pump shaft lip seal and volute. The pump suction plate was then made in a similar fashion on the mini lathe. The impeller is fabricated from brass bits soldered and then loctited to a shaft. I used a 8 x 16 x 7 metric lip seal as I couldn't find a 3/16" size one anywhere I looked.



I tested the pump using a small drill and may have partially ruined it as the pulley is used to set the end play. I removed the pulley to grip the shaft in the drill chuck. It still pumps but feels "crunchy". I think I will make some brass or bronze washers to fine tune the impeller clearance.

The pump test was used in conjunction with the screen cooler tank and it wasn't a real good showing. Quite a bit of the water ran down the screen as intended, but it overflowed the clamping ring and went onto the ground. This will need improvement and I'm thinking that the screen cone needs to be recessed below the lip of the tank to be successful. I will also remake the upper spray hood out of aluminum and feed it from the side as the weight and the hose wants to tip it over.

 

[raveney]

Plumbing & Gaskets

PM Research sure does make some beautiful cast bronze fittings so I purchased the 90 elbow trees to eliminate some of the silicone hose on the cooling circuit. I made an aluminum fixture to hold the elbows and ensure perpendicularity when drilling and tapping.



Sealed the threads with blue loctite and also used high temperature red gasket maker on the exhaust manifold and cooler head plates. The red dye gets everywhere, so I switched to gray gasket maker for the lower temperature parts. The only true gaskets used are for the heads and I made these from some 1/32" Garlock blue sheet gasket. I tried something different on these and was pleased with the results. Used a tube of blue check and just pressed the head onto the sheet gasket while on the granite surface block. I had tried it on a scrap of plywood and it didn't work. Also tried clamping and the clamp shifted while tightening and smeared . Third attempt was a keeper. For the holes I had a SS punch already made up for #6 screws. Really surprised how accurate eye balling this worked. I hope it doesn't leak.

I had spent the better part of a day making several types of throttle plates for the Traxas carb. The tricky part is that the throttle arm rises (or lowers) as you rotate it. The piece that worked the best uses a thin sheet that deflects or bends to compensate for this. It may not be necessary, but the lever seemed like it would have moved on its own with the vibration of a running engine. They surely designed it to be silky smooth for a servo to move it in an RC plane or car.

I will tackle the timing and ignition next

 

[LorenOtto]

Plumbing & Gaskets

PM Research sure does make some beautiful cast bronze fittings so I purchased the 90 elbow trees to eliminate some of the silicone hose on the cooling circuit. I made an aluminum fixture to hold the elbows and ensure perpendicularity when drilling and tapping.
View attachment 154492View attachment 154493View attachment 154494


Sealed the threads with blue loctite and also used high temperature red gasket maker on the exhaust manifold and cooler head plates. The red dye gets everywhere, so I switched to gray gasket maker for the lower temperature parts. The only true gaskets used are for the heads and I made these from some 1/32" Garlock blue sheet gasket. I tried something different on these and was pleased with the results. Used a tube of blue check and just pressed the head onto the sheet gasket while on the granite surface block. I had tried it on a scrap of plywood and it didn't work. Also tried clamping and the clamp shifted while tightening and smeared . Third attempt was a keeper. For the holes I had a SS punch already made up for #6 screws. Really surprised how accurate eye balling this worked. I hope it doesn't leak.

I had spent the better part of a day making several types of throttle plates for the Traxas carb. The tricky part is that the throttle arm rises (or lowers) as you rotate it. The piece that worked the best uses a thin sheet that deflects or bends to compensate for this. It may not be necessary, but the lever seemed like it would have moved on its own with the vibration of a running engine. They surely designed it to be silky smooth for a servo to move it in an RC plane or car.
View attachment 154496

I will tackle the timing and ignition next

 

[LorenOtto]

I like you fixtures to finish out the elbows, I intend to copy them. Thank you for posting.

 

[raveney]

You are welcome. I believe I saw it being used somewhere else and thought the same.
For 1/4 fittings this holding fixture is 5/8" square and the holes are 5/16 through, and 23/64" for 1/8 deep at three places. The side hole is 5/16" from the end. I used two #8 SHCS to hold it together while flipping. Had to relieve some of the internal radius for the elbows using a small burr bit.
These dimensions allow removing the fixture and flipping each side when using a vise stop. It saves a fair bit of time compared to clamping the elbows individually and finding center each time.

 

[raveney]

Good News
I got the engine running fairly reliably and shut it down because I didn't have the cooling system connected and the ignition was just laying on the benchtop with alligator leads connecting everything.

Fabricated an MDF baseplate with a raised area to support the water pump and screen cooler and the battery and ignition below. Solder and heat shrink on everything so no electrical buggery would happen.

Bad News
Wouldn't start. Pulled the spark plug wire and waggled the crank back and forth to check spark and wasn't getting any. Then I got a huge blue one and that was it.....let the smoke out of the ignition module. Pried the cover off and it's "potted" with yellow epoxy so not repairable.

I hate electronics

 

[raveney]

The replacement Rcexl twin fire ignition module is on the slow ship from China making it over to Florida. I was really tempted to go a different way and buy a dual output coil with a TIM-6 CDI box. I'll give this Rcexl another try though. I'm pretty sure I shouldn't have tried sparking it with such a large gap. I was holding the spark plug lead and checking for spark against the head studs. I have read other people's stories that this is a no-no. Nothing else to do, so I tidied up the engine's cosmetics and made a wooden display base.


I used 3/4 plywood as the floor and 3/4 red oak for the frame. Instead of plain wood, I added some texture by using my table saw sled and a strip of wood drilled 1/4" x 0.5" on center. This strip indexes the base to the saw blade and cut kerfs to create tile and grout lines. Painted everything gray and then swabbed stain across the surface to make it look like terra cotta tiles. I sealed it all with a matte topcoat so cleanup wouldn't be too bad after dripping oil, gas and coolant in the "grout lines".

The baseplate studs are 8-32 epoxied into the plywood with acorn nuts on top. I think that I will use the new ignition and battery without attempting to hide it under the base.

If anyone reads this and has experience with Rcexl burning out, please chime in.

 

[kuhncw]

Very nice work. I like your base.

PM sent.

Chuck

 

[raveney]

Thank you Chuck,

The ignition module arrived and I transferred the soldered wiring over to it similar to what I did before. I added an aluminum clamp and grounding block (yellow arrow) to make sure I didn't forget to ground the SS sheathing and burn out another module.






The engine likes a lot of advance to get started. I mean 30 BTDC advance. So it runs again, but more refining is necessary. The bronze wtaer pump bushing did not seem to take oil very well and wore out quickly. Once the shaft got sloppy the impellers dug into the pump volute and got crunchy which started the o-ring belt to slip and stop pumping water. I trimmed the blades and adjusted the end clearance again, but a new design is needed.

Also have quite a bit of oil blowing out every non gasketed joint on the crankcase. The oiling doors especially. I drilled and tapped two breather pipes right above each door and thought that would give a path for any blowby to escape. Helped a little, but still leaking like crazy. I didn't think the rings were seated so I kept running without the cooling system, but they aren't getting any better.

I will have to disassemble and inspect. Maybe that's why the ignition needs to be so far advanced? Leaking out most of the compressed fuel mixture by the time the piston gets near TDC?


I will try again next weekend.

 

[Ghosty]

Did you install the resistor that is in the plug end of the fitting, if not you will burn out the secondary coils in the ign box.
Cheers
Andrew

 

[ninefinger]

Excellent work, not sure how I missed your progress previously.

For the crankcase oil leakage issue, can you sneak in a one way valve into the breather pipes, making them PCV valves (i.e. let the air out but not back in)? It should help by making the case pressure much lower or even negative, hopefully making any flow at the leaking joints move into the crankcase and not out.

Cheers,
Mike

 

[Rustkolector]

Sounds like too much blowby. I would remove the cylinders and the rings from your pistons and give your rings the Mayhugh test. Make a stepped plug with an OD slightly larger in diameter than the inside diameter of your compressed rings. The plug step should fit closely in the ID of the compressed rings. Install each ring squarely in the cylinder, and install your plug. You should have small space between the OD of your plug and the cylinder bore. Turn down/off the lights and shine a bright light in the top of the cylinder. Look through the bottom for any light showing around the circumference of each ring. Bad rings will often show light near the gap or opposite the ring gap. Keep the ring gap about .003”. Reject any ring showing any amount of light other than at the ring gap. They will not get better with usage. If the rings are determined to be a good seal then it may be the ring groove clearance. Try to keep it >.001” and polish the sides of the rings.

You are still going to need a crankcase vent. Placement is important and a check valve helps. Also, the engine rotation should throw the oil against the non-inspection door side of the crankcase. Don’t dip the rods in the oil. A tiny rod cap dipper rod is all that is needed on a slow speed engine. Don’t score your cylinders by running dry.

You might want to try a brass gear water pump like the one Jerry Howell designed with tiny ball bearings and add a lip seal on the shaft. Positive displacement gear pumps solve a lot of cooling system flow and design problems.

Jeff

 

[raveney]

Did you install the resistor that is in the plug end of the fitting, if not you will burn out the secondary coils in the ign box.
Cheers
Andrew

Thank you very much for sharing that.

Sure enough I had 1000 ohm resistance when checking across the discarded RCEXL boots. I cut them open with a abrasive wheel and salvaged the two resistors. Unsoldered the spark plug ends of may wires and installed them at the brass split sleeve. It seems to start and run smoother now. First I heard of this and I've searched this forum and others for hours it seems. I suppose that's why I let the smoke out of the other box.

A few photos to help others below

 

[raveney]

Sounds like too much blowby. I would remove the cylinders and the rings from your pistons and give your rings the Mayhugh test. Make a stepped plug with an OD slightly larger in diameter than the inside diameter of your compressed rings. The plug step should fit closely in the ID of the compressed rings. Install each ring squarely in the cylinder, and install your plug. You should have small space between the OD of your plug and the cylinder bore. Turn down/off the lights and shine a bright light in the top of the cylinder. Look through the bottom for any light showing around the circumference of each ring. Bad rings will often show light near the gap or opposite the ring gap. Keep the ring gap about .003”. Reject any ring showing any amount of light other than at the ring gap. They will not get better with usage. If the rings are determined to be a good seal then it may be the ring groove clearance. Try to keep it >.001” and polish the sides of the rings.

You are still going to need a crankcase vent. Placement is important and a check valve helps. Also, the engine rotation should throw the oil against the non-inspection door side of the crankcase. Don’t dip the rods in the oil. A tiny rod cap dipper rod is all that is needed on a slow speed engine. Don’t score your cylinders by running dry.

You might want to try a brass gear water pump like the one Jerry Howell designed with tiny ball bearings and add a lip seal on the shaft. Positive displacement gear pumps solve a lot of cooling system flow and design problems.

Jeff

Thank you Jeff,
good advice and I will fix the water pump first and try it again, but I think at least one of the rings is cracked or stuck. I can gauge the amount of blowby using a low pressure air test (recycled refrigerator pump/compressor) on each cylinder through the spark plug port. It does sound a little excessive, but not terribly so. I made spare rings in case I need to go that route.

 

[Ghosty]

The engine likes a lot of advance to get started. I mean 30 BTDC advance.

`Its not the engine that needs the 30deg BTDC, its the ign unit. The rxcel units have the ability to advance and retard the ign timing.

 

[raveney]

Thank you Ghosty,
That makes me feel better about all that advance.
I remade the water pump impeller using a stouter 1/4 drill rod shaft and tried again. The pump would work for a brief time and then slip the belt again. Open up the pump casing and there would be small bits of raised aluminum. I did this several times opening the clearances each time by reducing the diameter of the impeller blades 0.004" at a time. Finally I theorized that the aluminum bits were caused by cavitation due to low NPSH. I raised the coolet tank up high and that seemed to solve the problem. This looked really stupid so I ditched the screen cooler tank and made a tall reservoir tank instead. I only had SS pipe in a size fat enough to look somewhat realistically scaled so I silver brazed that to a 2-5/8" square base and then added a 5/16" suction and 1/4" discharge pipe.
It will run forever now and the blowby seems to have gone down a lot. I think that I'm nearly done now.