Micro 12VDC Generator with a Cox .049 Sure Start Diesel Engine

Cribbs74 wrote:It's an interesting topic.

Probably best to take a break for a couple days and revisit.

I know Admin already dropped the hammer, but I would like to add that folks need to also refrain from profanity (in any form) It's against the forum rules.

Ron

Your advise is appreciated. I am much better after a break. As mentioned, I would not spend more than 30 minutes per log in and mainly on PC and not on cell phone. The targeted log in period is 15 minutes. 30 minutes is the maximal. Hope I manage to do this.

Because Cox International is temporarily out of stock of their diesel crankshaft awaiting a new order, I have ordered a Davis Diesel crankshaft. Here are the concerns with the Davies Diesel crankshaft :

I have not yet received the Davis Diesel crankshaft and I have only seen pictures thereof. From what I have seen of the pictures, I have these concerns with the Davis Diesel crankshaft :
1. The crankshaft eccentric ( the flywheel ) looks narrower than the original Cox crankshaft. I wander whether the Davis Diesel crankshaft can generate the same suction as the original Cox crankshaft.
2. The axel of the Davis Diesel crankshaft lacks the middle narrowing which the original Cox crankshaft has. I wonder I wander whether the Davis Diesel crankshaft axel can be oiled enough.
3. The crankshaft eccentric ( the flywheel ) looks narrower than the original Cox crankshaft. I wander whether the Davis Diesel crankshaft can have the same inertia ( momentum ) as the original Cox crankshaft.

How to repair a broken crankshaft pin :

DISCLAIMER : THIS HAS NOT BEEN DONE BUT IS A STANDARD, NON ENGINE GLOBAL PROCEDURE DONE IN MANY INDUSTRIES AND PLACES AND, THUS, SHOULD WORK.

The idea is to place a specially made screw in lieu of the broken crankshaft pin. The most important rule is to make such a thread, so when the engine works, i. e. when the piston drives the crankshaft, the screw gets tightened by the friction between the screw and the piston rod to crankshaft pin assembly.

When one looks at the working engine, started with a right hand spring starter, the engine rotates counter clockwise. Thus, looked from the pilot’s seat, the engine rotates clockwise. This means, during the working and exhaust cycle, when the piston drives the crankshaft, the piston will exert friction which will act counter clockwise. This means the thread must be left thread, opposite of the normal thread to ensure tightening. During the compression and loading cycle, when the shaft drives the piston, the friction will be of the opposite direction. The force during the working and exhaust cycle is stronger, therefore, an opposite thread is needed. The same direction apply during start up but the force of the compression and loading cycle is greater yet not as high as the force during the working and exhaust cycle.

1. Thread must be made at the same point where the old pin has been. This can be made with a watch repairer set.
2. A screw must be found or cut to match the thread and the direction of the thread. The screw must have a non threaded portion which will be the only visible portion after installation. The head can be cut and a tiny slot for a normal screwdriver can be cut in the middle. Alternatively, a round head Allan key screw with smooth head with the same length as the pin can be used. Obviously, the diameter of the screw or the head must be the same as the pin.
3. Micro welding of the screwed in screw with a laser or a micro plasma welder is welcome.
4. High temperature Lock Tight ( the super strong one ) is welcome.
5. Strength depends on materials and thermal processing.

This may or may not be possible to be made by a general person. Very fine thread maker is needed. Very high accuracy in making the thread perpendicular to the crankshaft eccentric ( flywheel ) is needed. Finding such a screw may be next to impossible : remember : the diameter must exactly match the diameter of the pin.

The best people to do this job are watch repairers. They also have the tools and headless screws, hopefully, with a flat section.

Got a jar with a lock and a long glass. Hope to be able to store Ether in the jar. Hope the jar is air tight. Hope the Ether does not evapourate.

The Internet says :

1. Ether must not be sprayed from a spray can into a container but, instead, the can must be punched at the bottom while upside down and propellants musy be waited to escape. The remaining is almost pure Ether not mixed with propellants unlike when sprayed.

2. Once the Ether is poured into a non plastic container, the container must be kept open for a few minutes for any leftover propellants to evapourate.

3. Ether must not touch plastics.

4. The container must be kept in a freezer to even more prevent Ether evapouration.

Jar and stainless steel canisters, jars, thermos, etcetera are welcome and no plastic containers of any kind.

Rubber gaskets cannot be avoided. Must be air tight.

Glass syringes must be used and not plastic.

Only specialised neupren fuel lines must be used although the automotive stores sell specialised Silicone hoses and lines which withstand all fuels.

I have also found poured Ether to be better, start easier and burn easier as well as give more power than the squeezed one. Air tight storage, however, is imperative.

You would not normally use any "screw" fitting for the crankshaft pin. It is far quicker and simpler to use a rod (usually a drill rod) of the correct size and drill and ream a hole to produce a very tight press fit.

Crankshafts are not comparable by sight. The strength of these depends on the steel used and the degree of tempering employed.

The Davis crankshafts I have are made from a chrome steel alloy. I am not sure that the lack of narrowing of the middle of the shaft would make any difference to lubrication. The Cox crankcases usually carry a groove for lubrication. The narrowing may have been done to reduce the friction of the bearing area but, then again, the reduced area could induce wear leading to the crankshaft wobbling.

The standard Cox crankshaft seems to be made from a free machining carbon steel that has been ground, polished and heat treated.

Often the pin breaking is not through the weakness of the material but because of flooding and/or the ball and socket joint in the piston loosening and creating a hammering action.

ian1954 wrote:You would not normally use any "screw" fitting for the crankshaft pin. It is far quicker and simpler to use a rod (usually a drill rod) of the correct size and drill and ream a hole to produce a very tight press fit.

Crankshafts are not comparable by sight. The strength of these depends on the steel used and the degree of tempering employed.

The Davis crankshafts I have are made from a chrome steel alloy.  I am not sure that the lack of narrowing of the middle of the shaft would make any difference to lubrication. The Cox crankcases usually carry a groove for lubrication. The narrowing may have been done to reduce the friction of the bearing area  but, then again, the reduced area could induce wear leading to the crankshaft  wobbling.

The standard Cox crankshaft seems to be made from a free machining carbon steel that has been ground, polished and heat treated.

Often the pin breaking is not through the weakness of the material but because of flooding and/or the ball and socket joint in the piston loosening and creating a hammering action.  

This is very good information, thank you.

A rod would be OK as long as the rod can be stable and not move. A screw would be much more stable. Rod or screw with micro welding and high temperature Lock Tight ( in case such is available to withstand the working temperatures ) is even better. Thus, in case there is a way to weld the rod with micro welding, this would be very stable. Tempering can be carried out thereafter to either harden or soften the assembly. The welding point may have different qualities, depending on the tempering after welding.

Micro welders are either plasma or laser welder which pin point the weld spot with lower than a millimetre precision. They look like a pen or a pencil and are very easy to work with. May still be expensive though.

Every person on the internet swears by the Davis crankshaft, therefore, they must be very good. Steel Alloys are better than steel. Hopefully, the Chromed steel used does not rust unlike the simple steel.

When the engine rotates, a tiny part of the fuel, containing oil, goes between the crankshaft axel and the housing. The narrowing acts like a buffer, a fluid capacitor, which stores more oil in between the narrowings as well as creates a lower resistance towards the coming oil into the axel and axel housing. Thus, the engine would be always oiled well and more oil would come into at the expense of fuel loss which is negligible. In case Davis Diesel crankshaft allows for a good clearance between the axel and the housing, then the axel will be oiled OK and the only difference is the lack of storage of oil to be used whenever needed and whenever the crankcase cannot pump fuel into the axel and axel housing.

Because many people on the Internet are extremely happy with the Davis Diesel crankshaft, maybe, the clearance is good enough and the oiling is good enough.

True, the friction of the Cox crankshaft is concentrated on the two wider points but these are very long to create any significant damage. True, the Davis Diesel crankshaft spreads the force throughout the whole axel but this may also mean more friction.

However, the main concern with the Davis Diesel crankshaft I have is whether the crankshaft can generate a good suction which is the most important consideration for this design. The Cox crankshaft generated such a wonderful suction, I was able to start the engine in less than 10 seconds, just 2 to 4 spring starts. I am afraid to even think what happens with the Davis Diesel crankshaft but I hope the suction is OK. Please, note, people who do model airplanes do not care as much how easy their engine would start and most of them use electric starts.

Regardless of this post, the best way is to wait and see how the Davis Diesel crankshaft performs.

Received the order from Cox yesterday.

Ordered glass syringes and lab glasses from AliExpress.

Got stainless steel canister and bottle from Walmart. Airtight. Can be made even morebairtight with O rings from the automotive shops. Silicon squeezed gaskets not recommended. Do not work very well even when well installed. Leak.

Whatever difficulties I have pointed out do not apply for airplanes. Cox crankshaft OK. Cannot be broken.

Spring start OK. Takes 10 seconds under correct circumstances as noted. Starts with any propeller for 10 seconds.

This clarification is necessary so people are not mislead on the engine. The engine is perfect for airplanes.

Methanol is better than Kerosene for airplanes. Seems to start eadier as well as provide a fuller burning, hence higher power and even higher at huge RPM.

Membrane pressure sensors are available. Used in explosive evaluation. Membranes made of metal. Various pressure ratings available. Depend on size and support.

May be possible to be used as protection gaskets. Break in pressure unknown and depends on counter piston pressure.

Counter piston and metal may fall into and damage the cylinder and the piston.

Can be chosen to an extend when the shatter pressure for the Teflon gasket is known, yet, empirical test and see cannot be avoided becausevof the dependence onvradius and counter piston pressure. Can be chosen for maximal counter piston pressure as this is the most likely circumstance for high RPM or compression.

The best would be for a manufacturer to install them on the side of the chamber, replaceable.

StevenStanleyBayes wrote:

ian1954 wrote:You would not normally use any "screw" fitting for the crankshaft pin. It is far quicker and simpler to use a rod (usually a drill rod) of the correct size and drill and ream a hole to produce a very tight press fit.

Crankshafts are not comparable by sight. The strength of these depends on the steel used and the degree of tempering employed.

The Davis crankshafts I have are made from a chrome steel alloy.  I am not sure that the lack of narrowing of the middle of the shaft would make any difference to lubrication. The Cox crankcases usually carry a groove for lubrication. The narrowing may have been done to reduce the friction of the bearing area  but, then again, the reduced area could induce wear leading to the crankshaft  wobbling.

The standard Cox crankshaft seems to be made from a free machining carbon steel that has been ground, polished and heat treated.

Often the pin breaking is not through the weakness of the material but because of flooding and/or the ball and socket joint in the piston loosening and creating a hammering action.  

This is very good information, thank you.

A rod would be OK as long as the rod can be stable and not move. A screw would be much more stable. Rod or screw with micro welding and high temperature Lock Tight ( in case such is available to withstand the working temperatures ) is even better. Thus, in case there is a way to weld the rod with micro welding, this would be very stable. Tempering can be carried out thereafter to either harden or soften the assembly. The welding point may have different qualities, depending on the tempering after welding.

Micro welders are either plasma or laser welder which pin point the weld spot with lower than a millimetre precision. They look like a pen or a pencil and are very easy to work with. May still be expensive though.

Every person on the internet swears by the Davis crankshaft, therefore, they must be very good. Steel Alloys are better than steel. Hopefully, the Chromed steel used does not rust unlike the simple steel.

When the engine rotates, a tiny part of the fuel, containing oil, goes between the crankshaft axel and the housing. The narrowing acts like a buffer, a fluid capacitor, which stores more oil in between the narrowings as well as creates a lower resistance towards the coming oil into the axel and axel housing. Thus, the engine would be always oiled well and more oil would come into at the expense of fuel loss which is negligible. In case Davis Diesel crankshaft allows for a good clearance between the axel and the housing, then the axel will be oiled OK and the only difference is the lack of storage of oil to be used whenever needed and whenever the crankcase cannot pump fuel into the axel and axel housing.

Because many people on the Internet are extremely happy with the Davis Diesel crankshaft, maybe, the clearance is good enough and the oiling is good enough.

True, the friction of the Cox crankshaft is concentrated on the two wider points but these are very long to create any significant damage. True, the Davis Diesel crankshaft spreads the force throughout the whole axel but this may also mean more friction.

However, the main concern with the Davis Diesel crankshaft I have is whether the crankshaft can generate a good suction which is the most important consideration for this design. The Cox crankshaft generated such a wonderful suction, I was able to start the engine in less than 10 seconds, just 2 to 4 spring starts. I am afraid to even think what happens with the Davis Diesel crankshaft but I hope the suction is OK. Please, note, people who do model airplanes do not care as much how easy their engine would start and most of them use electric starts.

Regardless of this post, the best way is to wait and see how the Davis Diesel crankshaft performs.

Sorry. Forgot. I do not mean ti fight but to say the truth which is NOT known by most of the people.

Regardless who says what, Cox diesel crankshafts CANNOT be damaged by flooding. I say so with 100% certainty. I have been doing thousands of floodings under all posdible circumstances even whe forcing with a powerfull high RPM drill on full power without pulsing FOR 4 MONTHS.

In case this is not a proof, I do not know what is.

how is your generator

does it still run?
or
does it run again?

mine is at a standstill
i ran out of fuel

robot797 wrote:how is your generator

does it still run?
or
does it run again?

mine is at a standstill
i ran out of fuel

I am still waiting for the crankshaft. Please, see the status report I am now to write.

DID YOU RECEIVE THE ITEMS FROM COX INTERNATIONAL? This is important in order to figure out what action to take in case you have not. Maybe to contact the Dutch customs and postal service?

I have not received the crankshaft yet but I would wait a while because yesterday was the first long weekend of the summer and nothing has been working for a long while.

Davis Diesel is based in Florida, hence, I would clarify : the first long weekend in the summer is a very big deal in Northern countries and states with cold and long winters. Consider this very close to Christmas.

Also, US mail is considered more like domestic here than foreign. The post office considers international mail with priority over domestic. This is why, I expect robot797 to receive mail from Canada and, probably, US to The Netherlands faster than I.

Thus, a good idea is to wait until next week.

StevenStanleyBayes wrote:


I am still waiting for the crankshaft. Please, see the status report I am now to write.

DID YOU RECEIVE THE ITEMS FROM COX INTERNATIONAL? This is important in order to figure out what action to take in case you have not. Maybe to contact the Dutch customs and postal service?

yea i have the package

it was at my neighbors home
they forgot to give it to me

robot797 wrote:

StevenStanleyBayes wrote:


I am still waiting for the crankshaft. Please, see the status report I am now to write.

DID YOU RECEIVE THE ITEMS FROM COX INTERNATIONAL? This is important in order to figure out what action to take in case you have not. Maybe to contact the Dutch customs and postal service?

yea i have the package

it was at my neighbors home
they forgot to give it to me

The most important think is you got the package. What was the problem? Was the address wrong or the postman made a mistake?

here in holland when sombody is not home they deliver it to one of the neighbors
and i get a little note were my package is

my neigbours are not always home
that is what it boils down to

robot797 wrote:here in holland when sombody is not home they deliver it to one of the neighbors
and i get a little note were my package is

my neigbours are not always home
that is what it boils down to

This is a good arrangement. In most countries this is not allowed because of privacy. Again, the most important is you got the mail and you can build a second generator.

Davis Diesel crankshaft just received. Local post slow. Not yet opened but hope OK. Happy to receive the crankshaft.

Davis Diesel demonstrated an excellent service. Price OK. Shipping excellent. Not seen the product yet but sure to be excellent as every one says.

Just opened the mail. Looks perfect. I was most afraid whether the crankshaft plate where the pin is attached was the same. Looks the same. This means the suction generated by the Davis Diesel crankshaft would be the same.

The material looks like a strong stainless steel alloy which is OK. As Davis Diesel mentioned, Crome and steel alloy. Must be OK.

So far, I am very happy with the crankshaft. Hope the teeth fit the drive plate. Cannot say for sure because the different colour makes the visual comparison difficult. The teeth and the pin plate as well as the pin are black in the Davis Diesel crankshaft and whitish in the Cox crankshaft.

I hope they made them the same.

As previously mentioned, the only visual difference is the axel narrowing which is available on the Cox crankshaft axel and not on the Davis Diesel one. Also as mentioned, this is not a big deal. Either way is OK.

The Davis Diesel crankshaft is an excellent product and they have an excellent and immediate service.

StevenStanleyBayes wrote:Just opened the mail. Looks perfect. I was most afraid whether the crankshaft plate where the pin is attached was the same. Looks the same. This means the suction generated by the Davis Diesel crankshaft would be the same.

The material looks like a strong stainless steel alloy which is OK. As Davis Diesel mentioned, Crome and steel alloy. Must be OK.

So far, I am very happy with the crankshaft. Hope the teeth fit the drive plate. Cannot say for sure because the different colour makes the visual comparison difficult. The teeth and the pin plate as well as the pin are black in the Davis Diesel crankshaft and whitish in the Cox crankshaft.

I hope they made them the same.

As previously mentioned, the only visual difference is the axel narrowing which is available on the Cox crankshaft axel and not on the Davis Diesel one. Also as mentioned, this is not a big deal. Either way is OK.

The Davis Diesel crankshaft is an excellent product and they have an excellent and immediate service.

Also : Because the Davis Diesel crankshaft is made of Chrome or Chrome Nickel or Vanadium or all these and steel alloy, the axel is incredibly shiny, polished like a mirror,. This will reduce friction slightly.

Robot797 is right. There is no any delimiter to stop the piston from going up. There is only a seat for the Teflon gasket which is a delimiter for the Teflon gasket to go down. Because the Teflon gasket is very thin, very thin Aluminium may do the job of protection but, because Aluminium does not shatter but bends, this can go into the cylinder and scratch or damage unlike the soft Teflon or shattered Teflon pieces.

Sorry. Mistake. Admitted.

The engine has been reassembled with the new Davis Diesel crankshaft which fitted perfectly.

The engine has not yet been attached to the generator chassis.

After the pin of the original crankshaft was broken, the crankshaft was replaced by a Davis Diesel strong crank made of stainless steel alloy, most likely steel and Chrome and or Nickel and Vanadium. The new crankshaft is perfectly the same as the old one. Unable to tell whether the axel teeth are the same because these are black in colour on the new crankshaft and white on the old one and this makes visual evaluation impossible. The axel of the new crankshaft is perfectly glossy and mirror like finished to reduce friction which should compensate for the lack of narrowing which would act as oil retainer too.

Although the drive plate can be press fit by simply installing a propeller and tightening the propeller screw, this is not recommended because of the force needed. The Cox engine assembly tool available from Cox International is great and does the same job yet allowing for a higher tension of the tool’s nut which pushes the propeller which pushes the drive plate whose teeth go in between the teeth of the crankshaft axel. This tool consists of a couple of washers which push the propeller, a fully threaded strut ( rod ) which goes a quarter in into the propeller screw hole of the axel and acts as a propeller screw to install the propeller onto as well as the washers and then install the tool’s nut onto the strut to be tightened either by the general purpose Cox wrenches ( recommended ) or a large standard ( not Philips ) screw driver.

One must be careful with lining up the gasket which is between the opposite ( to the propeller ) side of the crankcase and the plastic backplate which contains the Reed Valve, the mesh, the fuel and air intakes. Best, use 4 needles or straightened paper clip instead of the four screw at the beginning to easily lift the plastic backplate and ensure the pins go through the holes of the gasket. Use Castor oil to “ glue “ the gasket for lower amount of movement. When the gasket is positioned OK, Remove the pins one after another and position the corresponding screws immediately after removing a corresponding pin. Do not tighten them up. Just a quarter turn to be able to stay. Then, because the screws are not yet tightened, one can lift the backplate a millimetre or two to examine whether the screws go through the ears of the gasket. Check this on multiple occasions to be sure. I have done this a lot and has always worked.

DO NOT OVERTIGHTEN THE BACKPLATE SCREWS NOR ANYTHING ELSE. DO NOT OVERTIGHTEN THE TOOL’S NUT. NOTHING WITH THIS ENGINE MUST BE OVERTIGHTENED. Will resist vibrations OK even when not overtightened. Just finger tight with low torque precision screwdrivers ( the ones for watchmakers sold in dollar shops ).

I also successfully reset the piston which was the same as when purchased but the factory did not reset the piston well leaving a huge tolerance. This may have been the reason for many problems such as crankshaft pin, Teflon gasket piston touching, etcetera.

I have wrongly mentioned here and there, there has been a delimiter ring to limit the movement of the piston. This is not true. The delimiter only disallows the Teflon gasket to fall into the cylinder but does not disallow the cylinder from going up. I even put the piston through the cylinder upside down, through where the head is to lubricate the cylinder with Castor Oil better and to push the excess Castor oil down.

Oiling the crankshaft axel and the cylinder and the piston with Castor Oil is IMPORTANT! Otherwise the cylinder moves through the piston with a great difficulty and one may be mistaken something is wrong with the tolerances. Nothing is wrong. Just the piston and the cylinder need some oiling.

Resetting the piston was now done very carefully with a very tiny hammer hammering while rotating for a very long while, ten fold or more, each rotation just resetting the piston very slightly, almost impossible to detect. IMPORTANT : THE RESETTING TOOL WAS KEPT AS CLOSE TO THE PISTON CENTRE AS POSSIBLE WITHOUT TOUCHING THE PISTON. Touching the piston even slightly while hammering may deform the piston to become useless which, as someone has said, is known as “ mushrooming “ the piston.

The Teflon gasket was almost flat and twisted slightly yet, I think, I was able to “ determine “ where the “ dome “ of the gasket was which I was not sure whether available at all. I think the dome is where the gasket is smoother ( well finished ) to the touch. This “ dome “ side must be positioned down towards the cylinder and piston and not up towards the counter piston and the head.

Once I realised there was no any delimiter and the piston can go up as high as possible, I found the reason for Teflon gasket burning problems ( which I had known before but was more sure now ) : a non reset piston as well as high compression screw setting, despite the downward pressure and mainly when starting a hot engine, can touch the gasket. Again, the logic is the compression and the combustion do always push the piston down and thus a non reset piston cannot touch yet there is a lot of vibrations and wobbling which may throw the piston up mainly when starting. A non reset piston would also affect the timing yet this can be compensated with the mixture and compression as standard.

The same wobbling and vibration of a non reset piston ( mainly when down ) can affect the crankshaft pin and create a great deal of fatigue.

Thus, I think I may be right to say : always reset the piston, mainly a brand new one which comes from the factory which with one purpose or another does not deliver pre reset pistons and these need resetting by the user.

Cox claims another resetting may be necessary after breaking in and, once this done and with the engine broken in, a necessity for a new reset is not expected but may or may not happen.

Once everything installed, hand turn the engine for a while without the compression screw to push the Castor Oil, used for oiling the cylinder up and down. Also, do use initial Ether priming, say, through the Air Valve intake to initially dissolve the Castor Oil which may remain in the cylinder and create an initial drag.

I have found the hard way heavy Ether priming does help start the engine. This can be preceded by a slight blowing of fuel from the tank into the crankcase while rotating the propeller. This blowing can be done with a mouth through the tank aeration duct or hose in case of any. Avoid flooding. With an initial fuel in the crankcase and heavy Ether priming in the Air Valve, the engine would start more easily and be more settings independent ( insensitive ). Obviously, correct settings are necessary for the engine to sustain the start.

Although some people advise against Air Valve priming and for priming through the exhaust, I advise for because Ether cleans the air intake mainly from Castor Oil and any other contaminants. Avoid flooding, though.

Easy start is also important to prevent the spring from braking and so is avoidance of flooding. I have broken many springs.

Spring breaking, however, is an important protection for the crankshaft and mainly the pin : during spring start, in case of flooding or dragging or any other reason, when the engine does not want to easily rotate, the spring breaks eliminating the push on the crankshaft and pin. Again, to rely on the spring is not the best thing to do, thus, ensure easy rotation and start to spring start by rotating the propeller over one compression or less for a while before going over more than one compression in case needed. Staring with one compression only is a good idea.

The lack of delimiter and the possibility for the piston to go up the cylinder freely up to where the crankshaft and the piston rod and the piston rod assemblies would allow is also a good protection of the cylinder and the piston from hitting a delimiter and breaking although, as mentioned, the compression and the combustion act against this, To rely only on compression and combustion may not be a good idea.