Sunday, September 23, 2012

EL Bonnie - Flywheel Balancing Act

Yeah, OK, I know Bonneville is over, but I am going to go ahead and write this just as I would have had I not run seriously short on time leading up to it.  So with that in mind, here is the next installment.

Balance the flywheels. Simple enough.  In fact if you are familiar with the process you know its normally only about a two hour process. The key word here being normally. Really nothing normal about this motor though. Turning a 1939 engine of any type into a Bonneville racer is not a simple task, but add to the antiquated design, we are also dealing with a small (by Harley standards) displacement which needs to stay that way to remain in the chosen class. In this case, what I am trying to do is make up for displacement with RPMs, and RPMs call for strong and light parts.

Well, we already had some strong parts in the S and S 3-1/2 inch stroke flywheels, and while these flywheels start out considerably lighter than their OEM counterparts at 26-1/2 pounds for the pair of bare wheels, they still needed to be put on a serious diet for this special application.  So... to the lathe!
I lightened the shiny new flywheels - a lot!  In fact, as sometimes happens, I got a little carried away.  Knowing that I was dealing with these tiny little 3-5/16" bore pistons, I "mis-underestimated" how much of the counterweight I could remove.  Oops.  Well, I had planned to make the pistons as light as possible anyway, so....

First thing was to track down a pair of .080" wall tool steel wrist pins.  It seems that I obtained the last set on the planet from Axtell by way of Zippers.  Of course they were for a Evo so I had to shorten them as well as hone the pistons for the .001" larger diameter pins.  Weight savings on the pins alone was nearly 50 grams.  The pistons also went on an extreme diet, with enough material removed from the insides to make any piston manufacturer cringe.  I was careful to try to leave at least .180" thickness in the dome though. 

I went with 55% for the flywheel balance factor, chosen because that is what the factory used for the XR750.  Small motor, short stroke, and high revving - those were the characteristics I hoped EL Bonnie would share with an XR. To get there, not only did the pistons go on a diet, but even such small things as the crankpin nuts were cut down, not to mention adding an internal bevel to the ends of the pin.  Before all was said and done, the finished crankshaft assembly (with rods and shafts, ready to run) weighed but 20 Lbs 5 Oz.   obviously this motor borders on anorexic.

Before final assemble and true, the flywheels received the same oil shedding, heat dispersing coating as the interior of the crankcases.  The underside of the pistons also received the same coating (the idea is to keep the oil moving off the inside of the piston to aid in cooling it.  The domes got a ceramic coating as well as an oil retaining skirt coating. 

Oil pumps on these old motors are becoming a little problematic.  Back in the good old days, it seemed that a guy could always sort through a drawer full of spare oil pump gears to find pairs that would give acceptable protrusion from the body.  As time goes on though, the pickings are getting pretty slim.  The solution actually results in a better pump than what one might come up with if the drawer of spares was still well stocked.  By surface grinding the oil pump gears so that the pairs are of matched thickness, and then surface grinding the pump body, the protrusion of the gears from the body can be "blueprinted" while compensating for the thickness of reproduction gaskets.  Bear in mind that we are talking about doing this on a precision surface grinder, not a belt sander.  EL Bonnie's pump was in medium poor shape, but the surface grinding treatment brought it back - that and some welding and re-machining on the cover.

That pretty well wraps up the story on the bottom end. The heads had been re-worked by Ron Adamson before the motor came to me, so I'll just comment on the rocker arms.  They too received the lightening treatment; or maybe we should call it the "lightning" treatment, since we are dealing with an early Knuck.  Once lightened and spec'd for shaft clearance, all that was left was to resurface the pads and treat them with the same oil shedding coating as the bottom end parts.

After all the trials and tribulations which accompanied prepping the engine parts, final assembly was somewhat anticlimactic - in other words it went smoothly.  And all finished with nearly a week left for the team to install the engine in the bike and dyno it before leaving for Bonneville!

Thursday, September 6, 2012

The Fiery Furnace

The book of Daniel was written in the 6th century B.C., that is; between 500 and 600 years before the birth of Christ. Soon after Jerusalem was conquered by Babylon and its king Nebuchadnezzar, four young men were taken from the tribe of Judah to Babylon. Here they were to be raised in the Babylonian culture so that they would be useful in dealing with the Jewish captives who were also brought there. In today's terminology we might say that they were to be brainwashed. But this brainwashing did not really seem to work as planned. While the four young men did grow up in Babylon and were promoted to positions of authority, they never forsook the God of Israel.

The four young men were named Daniel, Hananiah, Mishael, and Azariah, but they were given Babylonian names. Daniel became Belteshazzar, Hananiah became Shadrach, Mishael became Meshach, and Azariah was renamed Abednego. These last three; Shadrach, Meshach and Abednego, are the focus of our story.

Daniel chapter 3 begins with a description of a 90 foot tall golden image that king Nebuchadnezzar made. The king commanded that at the dedication of the image, when they heard the music play, everyone must fall down and worship the golden image or else be thrown into a fiery furnace. That is where we pick up the story in verse 12:

 There are certain Jews whom thou hast set over the affairs of the province of Babylon, Shadrach, Meshach, and Abednego; these men, O king, have not regarded thee: they serve not thy gods, nor worship the golden image which thou hast set up. Then Nebuchadnezzar in his rage and fury commanded to bring Shadrach, Meshach, and Abednego. Then they brought these men before the king. Nebuchadnezzar spake and said unto them, Is it true, O Shadrach, Meshach, and Abednego, do not ye serve my gods, nor worship the golden image which I have set up? Now if ye be ready that at what time ye hear the sound of the cornet, flute, harp, sackbut, psaltery, and dulcimer, and all kinds of musick, ye fall down and worship the image which I have made; well: but if ye worship not, ye shall be cast the same hour into the midst of a burning fiery furnace; and who is that God that shall deliver you out of my hands? Shadrach, Meshach, and Abednego, answered and said to the king, O Nebuchadnezzar, we are not careful to answer thee in this matter. If it be so, our God whom we serve is able to deliver us from the burning fiery furnace, and he will deliver us out of thine hand, O king. But if not, be it known unto thee, O king, that we will not serve thy gods, nor worship the golden image which thou hast set up. Then was Nebuchadnezzar full of fury, and the form of his visage was changed against Shadrach, Meshach, and Abednego: therefore he spake, and commanded that they should heat the furnace one seven times more than it was wont to be heated. And he commanded the most mighty men that were in his army to bind Shadrach, Meshach, and Abednego, and to cast them into the burning fiery furnace. Then these men were bound in their coats, their hosen, and their hats, and their other garments, and were cast into the midst of the burning fiery furnace. Therefore because the king's commandment was urgent, and the furnace exceeding hot, the flames of the fire slew those men that took up Shadrach, Meshach, and Abednego. And these three men, Shadrach, Meshach, and Abednego, fell down bound into the midst of the burning fiery furnace. Then Nebuchadnezzar the king was astonied, and rose up in haste, and spake, and said unto his counsellors, Did not we cast three men bound into the midst of the fire? They answered and said unto the king, True, O king. He answered and said, Lo, I see four men loose, walking in the midst of the fire, and they have no hurt; and the form of the fourth is like the Son of God.  Then Nebuchadnezzar came near to the mouth of the burning fiery furnace, and spake, and said, Shadrach, Meshach, and Abednego, ye servants of the most high God, come forth, and come hither. Then Shadrach, Meshach, and Abednego, came forth of the midst of the fire. And the princes, governors, and captains, and the king's counsellors, being gathered together, saw these men, upon whose bodies the fire had no power, nor was an hair of their head singed, neither were their coats changed, nor the smell of fire had passed on them. Then Nebuchadnezzar spake, and said, Blessed be the God of Shadrach, Meshach, and Abednego, who hath sent his angel, and delivered his servants that trusted in him, and have changed the king's word, and yielded their bodies, that they might not serve nor worship any god, except their own God.

There are a lot of thing we might learn from this story, but I'll only touch on a couple. The first thing I would like to point out is that Shadrach, Meshach and Abednego found themselves in this predicament because of their obedience to Almighty God. The 2nd Commandment, as found in Exodus 20 says: Thou shalt not make unto thee any graven image, or any likeness of any thing that is in heaven above, or that is in the earth beneath, or that is in the water under the earth. Thou shalt not bow down thyself to them, nor serve them: for I the LORD thy God am a jealous God...

In fact, these three obviously were not trouble makers; verse 12 tells us they had been put in a position of authority over the affairs of the province of Babylon. It seems that they grasped the principles laid out clearly in the New Testament, that they were to subject themselves to government ...right up until the point where government demands disobedience to God. Then, as Peter states in the book of Acts:  We ought to obey God rather than men.

These three displayed their faith in the face of almost certain destruction. In verses 17&18 they say this: ...our God whom we serve is able to deliver us from the burning fiery furnace, and he will deliver us out of thine hand, O king. But if not, be it known unto thee, O king, that we will not serve thy gods, nor worship the golden image which thou hast set up.

In other words, Shadrach, Meshach and Abednego had faith that God could deliver them if he chose to, but even if God did not chose to deliver them from the furnace, they would not bow down and worship the image that Nebuchadnezzar had set up.

One other thing I would like to point out is that in verse 25, when Nebuchadnezzar notices that there were four men walking in the furnace, rather than the three they threw in, he states that the form of the fourth is like the Son of God. I would like to suggest to you that the fourth was not only like the Son of God, but that he was the Son of God.

Because Shadrach, Meshach and Abednego had faith in God they had this promise from Deuteronomy 31:6 Be strong and of a good courage, fear not, nor be afraid of them: for the LORD thy God, he it is that doth go with thee; he will not fail thee, nor forsake thee.  In the New Testament this same verse is quoted in Hebrews like this: I will never leave thee, nor forsake thee.

I think it is interesting that Shadrach, Meshach and Abednego faced the penalty of being cast into a fiery furnace here on earth because they refused to sin. We face the penalty of an eternal fiery furnace because we choose to sin.

Rev. 20:11-15 And I saw a great white throne, and him that sat on it, from whose face the earth and the heaven fled away; and there was found no place for them.  And I saw the dead, small and great, stand before God; and the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works.  And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works.  And death and hell were cast into the lake of fire. This is the second death.  And whosoever was not found written in the book of life was cast into the lake of fire.

These three men from our story, Shadrach, Meshach and Abednego, had the Son of God with them in the great trial of their obedience and their faith. They had a promise that he would never leave them or forsake them.  But do you know what the good news is? If you are a Christian, then you have that same promise. God will never leave you or forsake you.

Just as the Son of God kept these three men from being harmed by Nebuchadnezzar's fiery furnace, he will keep you from the lake of fire. Why? Because your name is written in the book of life; that is, your name is written in the book of life if you will turn from your sins and believe on the Lord Jesus Christ, trusting that he made the payment for your sins by dying on the cross. Then you too will have God's promise of never leaving nor forsaking!