Friday, October 29, 2010

Justice Vs. Mercy

Websters 1828 defines justice as "The virtue which consists in giving to every one what is his due." In contrast it gives the definition of Mercy thus: "That benevolence, mildness or tenderness of heart which disposes a person to overlook injuries, or to treat an offender better than he deserves."

Justice and Mercy are two concepts that are normally in opposition to each other. In fact, it seems that they may be polar opposites; natural enemies, so to speak.

But there is one place where these two concepts meet and neither does violence to the other. That one place is at the cross of Jesus Christ! No other place is such perfect Mercy displayed than in Christ paying the penalty that is due for our sins, treating us far, far better than we deserve. And no where is such perfect justice upheld than in that same act of our Lord and Savior taking the punishment in our place, for without the payment, mercy would not have been possible; justice would have demanded that we pay our due.

Psalm 101:1 I will sing of mercy and justice; To You, O LORD, I will sing praises.

Something to ponder as we gather to worship our great God and King this weekend.

Sunday, October 17, 2010

Porting the 45 Inch Flathead, Conclusions, Conjecture, and Caveats

In part one of this series, I did a flow test on a stock Harley 45" Flathead cylinder and published the results here. In part 2 I added porting work utilizing stock size guides, again publishing the results. Part 3 saw the addition of larger intake valves. In this concluding piece, I would like to show the before and after results, along with my interpretation of those results.

First the overall results:

Exh stock .100" lift - 41.9cfm / finished 58.3cfm (+16.4)
Exh stock .200" lift - 82.4cfm / finished 99.8cfm (+17.4)
Exh stock .300" lift - 104.4cfm /finished 120.3cfm (+15.9)
Exh stock .350" lift - 110.6cfm /finished 128.3cfm (+17.7)
Exh stock .375" lift - 113.3cfm /finished 132.0cfm (+18.7)
Exh stock .400" lift - 115.7cfm /finished 133.8cfm (+18.1)
Exh stock .450" lift - 119.3cfm /finished 135.2cfm (+15.9)

Int stock .100" lift - 48.2cfm /finished 53.3cfm (+5.1)
Int stock .200" lift - 83.8cfm /finished 90.5cfm (+6.7)
Int stock .300" lift - 98.7 cfm /finished 112.4cfm (+13.7)
Int stock .350" lift - 102.6cfm /finished 119.0cfm (+16.4)
Int stock .375" lift - 103.8cfm /finished 122.1cfm (+18.3)
Int stock .400" lift - 104.3cfm /finished 124.0cfm (+19.7)
Int stock .450"lift - 104.4cfm /finished 128.0cfm (+23.6)

That gives an overall increase at .350 lift of 16% on both the intake and the exhaust. Not too bad, but is that all there is to be gained in porting work on the Flathead 45? Certainly not; in fact I already have some ideas in mind for the next set.

So, what have we learned? First off, the exhaust side of the equation requires a minimal amount of work to get it up to snuff. A good valve job blended into the port, with the ports "cleaned up," and a 30 degree backcut on the valve are about all that are required. I personally would not sacrifice any compression ratio by relieving the exhaust side.

On the intake side, the results were just as good, though perhaps not so clear cut. A larger intake valve is obviously worth while. It provides several advantages. The first is the most obvious. The flow potential is greater on a larger valve. Second, the larger diameter puts more circumference on the bore side where the flow is easier to achieve. The third advantage of the larger intake valve, is that it moves that circumference closer to the cylinder bore. That means you will actually be removing less material when relieving, which in turn leaves more compression ratio.
The possible drawback to using a larger intake valve is the increased shrouding by the wall of the head on the back side. Any airflow from the "back" side of the valve is going to have to travel around and over the top of the valve to get to the cylinder. The question becomes, what is the ideal valve size, keeping in mind that the increase in flow on the bore side from the largest valve may outweigh the small gain a smaller one would provide on the back side. In the picture below, the pencil is pointing out the area in the head that shrouds the intake valve. Incidentally, I opened up the small portion marked in black which corresponds to the edge of the head gasket in the area around the intake valve.

And that leads us to the question of seat angles. I spent a little time (very little, obviously) making a drawing to help explain what I believe to be the difference in flow characteristics between the 30 degree and the 45 degree valve seats. Note that the drawing is not to scale whatsoever.

Notice the difference in the shape of the green line which indicates my interpretation of airflow tendencies between the 30 and 45 degree seats. The 30 degree seat and valve tend to direct the air in a "flatter" trajectory toward the cylinder bore on the bore side, at the expense of a sharper turn to get around and over the top of the valve on the back side. In contrast, the 45 degree has a slightly better flow path on the back side, but is directing the flow higher in the chamber on the bore side.

With these paths in mind, here are some thoughts;

  • A 30 degree seat is probably much more effective in a Flathead than it would be in an OHV, since you would want the airflow directed deeper into the cylinder on the OHV(cylinder directly below the valves; flip the drawing upside down).
  • A smaller valve, with less shrouding would flow better on the back side with a 45 degree seat. Whether or not this might make up for the 30 degree's better path on the bore side would require more testing.
  • A 45 degree seat would benefit less from relieving than a 30 degree. That is not to say that a 45 degree will not benefit.
  • Depending on the amount of clearance between the top of the valve and the head at full lift, flow from the back side of the valve may actually decrease as the valve nears full lift. This could be alleviated by taking material out of the head at this point, at the cost of lowering the compression ratio.
  • A 30 degree valve seat theoretically would flow best with a smaller choke diameter than a 45 degree in order to allow room for more angles, resulting in a gradual redirection of the flow (the choke is the smaller diameter in the port just below the valve seat)

A word (or three) on the transfer port:

I have heard it theorized that the reason relieving works is because it increases the area of the transfer port (the transfer port being the "window" between the top of the cylinder bore and the roof of the head). I tend to think this is incorrect. I do believe that it would be relatively simple to test though. A well ported and relieved intake should show a significant increase in flow by relieving the exhaust valve IF the transfer port is the restriction. Similarly, the intake should show an increase by removing material from the roof of the head in the transfer area. Easy enough to test, however either method risks needlessly lowering the compression ratio.

Here is a tip if you are having trouble visualizing the transfer port. Lay a head gasket on a piece of light cardboard and trace the outside and headbolt holes. Open up the headbolt holes in the cardboard and place it on a cylinder using bolts to align. From the bottom of the cylinder trace the bore onto the cardboard, remove from cylinder, and cut out the round circle you just traced. Now by laying the cardboard cutout onto the head and aligning it with bolts, you will be able to see the actual transfer port size and shape. Just eyeballing it would lead one to believe that the transfer port (at least on a normal 45) is probably large enough. A few measurements should either confirm or dispute this. Unfortunately time restraints precluded me from checking it this time around.

This finishes up my series on porting the 45 inch Flathead, at least this particular one. There is more porting work on Flatheads on the horizon though, so if I get some positive feedback on this series, I may do another. And by positive feedback, I don't mean that you necessarily agree with my conclusions, just that you found it worth reading.

Friday, October 15, 2010

David and Goliath

(Once again I chose a familiar story from the Bible for the devotional portion of Valley View Baptist's ministry at our local nursing home)

The story of David and Goliath is one of the best known in the Bible. The army of Israel under King Saul, and the army of the Philistines were faced off against each other in somewhat of a stalemate. Most of us remember how that the Philistines had a giant by the name of Goliath among their number, who was over 9 feet tall. He would come out each day and provoke the army of Israel, saying that he would fight their best man, and the winner of that fight would determine the fate of the two nations. No one except the young lad David was willing to accept the challenge.

1 Samuel 17:38-40 And Saul armed David with his armour, and he put an helmet of brass upon his head; also he armed him with a coat of mail. And David girded his sword upon his armour, and he assayed to go; for he had not proved it. And David said unto Saul, I cannot go with these; for I have not proved them. And David put them off him. And he took his staff in his hand, and chose him five smooth stones out of the brook, and put them in a shepherd's bag which he had, even in a scrip; and his sling was in his hand: and he drew near to the Philistine.

then went out to meet the giant on the field of battle, where they exchanged insults.... well, not so much an insult as a prophesy on David's part:

1 Samuel 17:46-47 This day will the LORD deliver thee into mine hand; and I will smite thee, and take thine head from thee; and I will give the carcases of the host of the Philistines this day unto the fowls of the air, and to the wild beasts of the earth; that all the earth may know that there is a God in Israel. And all this assembly shall know that the LORD saveth not with sword and spear: for the battle is the LORD'S, and he will give you into our hands.

that the "battle" was on:

1 Samuel 17:49 And David put his hand in his bag, and took thence a stone, and slang it, and smote the Philistine in his forehead, that the stone sunk into his forehead; and he fell upon his face to the earth.

There are a multitude of lessons to be learned from this event in David's life. The point I would like to elaborate on is found in verse 47 where David says "And all this assembly shall know that the LORD saveth not with sword and spear: for the battle is the LORD's, and he will give you into our hands."

Even the part of the story where David took off Saul's armor testifies to this. Whether or not David was wearing armor would not have changed the outcome of the battle one little bit, except for this. If David had been wearing armor, it would have disguised what a youngster he was. The Philistines would have looked on him and seen a warrior, maybe a little on the small side, but a warrior none the less. No, by going out to meet Goliath as a young shepherd boy, armed with only a shepherd's sling, it was very obvious that David did not stand any kind of a chance against the giant warrior. It was painfully obvious that only God could deliver him and the Israelites.

You see, God could have provided a strong experienced warrior to fight Goliath. Perhaps even King Saul, who was taller than the other Israelites and was known for his military feats. But if God had allowed Saul to fight and defeat Goliath, who would have gotten the glory? Certainly it would have been Saul and not God. God chose an inexperienced youth to fight the battle so that everyone would know it was God who determined the outcome, not man.

The situation is much the same when it comes to salvation. Matthew 5:20 For I say unto you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven.

In Jesus day, that was a really eye opening statement. The scribes and Pharisees were the religious leaders of Israel. They did everything they could to follow every commandment of God, every law, and even every religious tradition of the Jews. They did everything they possibly could to avoid even the appearance of sin! We only tend to look down upon them today because Jesus rightly chastised them because many of them were relying on their own righteousness. But if their own righteousness was enough to earn them a place in heaven, who would get the glory?

David faced insurmountable odds when he fought Goliath. He didn't stand a chance. He couldn't save himself from the giant; only God could save him, and that was obvious. So God received the glory for it.

When the Spirit of God shines the light of the Bible on our sins, and we see that we are facing insurmountable odds, then we understand that we don't stand a chance. Only God can save us from our sins, and that is obvious. If you have not already done so, won't you put your trust in Christ's payment for your sins? God will receive the glory for it!

Wednesday, October 6, 2010

Porting the 45 Inch Flathead : Big Valves

So, what about those bigger intake valves? As we saw in part two, we finished with a 13% flow increase just from porting along with a backcut on the valves. Just how much more is there to be gained from bigger intake valves?

Before I go any farther, I'd like to mention that a reader left a comment stating that the legendary tuner Tom Sifton would actually reduce the valve size to reduce shrouding (close proximity of portions of the chamber to the valve which inhibits air flow). To clarify, I assume that Mr. Sifton was dealing with WR engines and their already oversize intake valves. The normal 45 has a valve size of 1.625" on both intake and exhaust. A WR had a 1.810" on the intake and 1.560" on the exhaust. Another difference on the WR, is that the valves were "tilted"such that the edge of the intake valve was much closer to the cylinder bore than the standard 45. There are reasons that this was an advantage, which I will come back to that later.

It is a valid question, though. If a bigger valve is better, then when, or does it ever, become too big. Unfortunately, due to time considerations, I will not provide a definitive answer to that question at this point. Testing multiple valve sizes was just not practical on this particular project. I chose to use a readily available oversize valve marketed expressly for 45 inch motors. This valve has a 1.875 head diameter, which is about all that will actually clear the head gasket on a 45.

Now, let's see if I can put this diplomatically. I was somewhat taken aback upon receiving these oversize "performance upgrade" valves. My first thought was "these are nothing but antique tractor valves with a hard tip installed." OK....I may be wrong on that. They may have been made for an antique auto engine, but the fact remains that they have all the modern technology of a 1920's Minneapolis Moline. Conveniently, instructions included with the valves detail how to back cut, shape and polish the valve head as per the factory KR manual. Finished valve is shown below.

Where was that promised diplomacy you ask? Let me get to that. My guess is that these valves have been available from this supplier for quite some time, and as such they have been a valuable resource for many hot rodders over the years. What I am trying to say is that, before custom made valves became affordable, these were the best way to get a big intake into your 45. And as long as you have the equipment and ability to do the mods to these valves, then they will be a cost effective alternative to their custom made modern performance counterparts. But if you have to pay someone (like me) to do the modifications to the valves, well, then not so much. Next time around, I will probably have a pair of valves custom made to spec. In fact, if I were to get some indication that there is enough demand, I would probably have multiple pairs made and offer them for sale. The price might be slightly higher for the custom valves, but they would be a high performance valve right out of the box.

But enough of that; on to the results. The oversize valve has a 30 degree face rather than the normal Harley 45 degree. This has an advantage for this application, which I will discuss later. For now, I began the seat by opening the "choke" to 85% of the valve diameter. This was an arbitrary figure I selected (very conservative) and in retrospect I wish I had opened it up more after initial testing, because it may have provided further gains. Truth be told, by the time I had all the other testing done, I had forgotten that I had started with such a small choke until I looked at my notes to write this. The next step was a 30 degree seat cut, which I narrowed on the port side with a 45 degree, and then added a 60 degree also on the port side. Had there been room, I would have added a 75 degree cut, but opted to hand radius the 60 into the choke.

On the top side of the valve, since I lacked a stand alone 15 degree cutter, I opted to use a "flat" cutter to provide a top cut and thus some unshrouding on the back side (away from the cylinder bore). I made this about .090" larger diameter than the valve, which took it just about to the gasket.

For this set of tests, I switched over to the front cylinder, so a comparison between these figures and those from part 2 will not be apples to apples.

.100" lift - ported 1.625 valve 50.3cfm / add 1.875 valve 57.0cfm
.200" lift - ported 1.625 valve 85.5cfm / add 1.875 valve 88.9cfm
.300" lift - ported 1.625 valve 104.7cfm / add 1.875 valve 105.9cfm
.350" lift - ported 1.625 valve 106.7cfm / add 1.875 valve 111.9cfm
.375" lift - ported 1.625 valve 108.1cfm / add 1.875 valve 113.1cfm
.400" lift - ported 1.625 valve 109.0cfm / add 1.875 valve 113.6cfm
.450" lift - ported 1.625 valve 109.7cfm / add 1.875 valve 112.8cfm

As you can see, it came out to a nearly 5% gain at .350" lift. Next up was to unshroud the valve on the bore side (there is no where to go on the back side since we are already to the gasket.

The results of unshrouding (as shown in above picture) are as follows:

.100" lift - previous test 57.0cfm / add unshroud 60.9cfm
.200" lift - previous test 88.9cfm / add unshroud 94.0cfm
.300" lift - previous test 105.9cfm / add unshroud 111.3cfm
.350" lift - previous test 111.9cfm / add unshroud 115.6cfm
.375" lift - previous test 113.1cfm / add unshroud 116.7cfm
.400" lift - previous test 113.6cfm / add unshroud 117.3cfm
.450" lift - previous test 112.8cfm / add unshroud 116.1cfm

About another 3% increase at .350" lift. So what about relieving? That's next. There are plenty of resources available that describe the process, so I won't attempt to describe it here. I just want to add a couple points. Since I was already satisfied with the exhaust flow, I relieved only the intake side. Also, you could think of the relieving as extending the unshrouding that I did in the previous test all the way to the cylinder bore. In other words, if you are going to relieve, then skip the unshrouding step. I did them one at a time for testing purposes. The relief is shown in the picture below.

Flow results were:

.100" lift - previous test 60.9cfm / add relieve 58.8cfm
.200" lift - previous test 94.0cfm / add relieve 94.3cfm
.300" lift - previous test 111.3cfm / add relieve 115.5cfm
.350" lift - previous test 115.6cfm / add relieve 119.6cfm
.375" lift - previous test 116.7cfm / add relieve 120.8cfm
.400" lift - previous test 117.3cfm / add relieve 120.8cfm
.450" lift - previous test 116.1cfm / add relieve 118.9cfm

That shows a 3% increase from the relieving vs. unshrouding, or a 6% increase from relieving as opposed to installing the larger valve alone. The last change was to modify the face of the valve as per the KR instruction sheet ....well almost. The sheet suggests cutting the face down to until there is only a .025" margin left. That seemed too narrow for my taste, so I cut it to .050". The results were:

.100" lift - previous test 58.8cfm / add face mod 60.5cfm
.200" lift - previous test 94.3cfm / add face mod 95.0cfm
.300" lift - previous test 115.5cfm / add face mod 113.5cfm
.350" lift - previous test 119.6cfm / add face mod 118.8cfm
.375" lift - previous test 120.8cfm / add face mod 120.3cfm
.400" lift - previous test 120.8cfm / add face mod 121.0cfm
.450" lift - previous test 118.9cfm / add face mod 120.8cfm

Somewhat inconclusive on this modification. Small gain at .100-.200 and a small loss at .300- .375, and again a small gain at .400 and above. I was happy that I didn't make the margin any smaller than .050".
In my next post on this subject I plan to go back to the rear cylinder to give a direct comparison from the stock readings to the finished product, along with some analysis of what caused what. Incidentally, I am not happy with the readability of the "charts" I put here on my blog, so if anyone is interested in having a better version emailed to them, contact me at and I will be happy to send out something.

Saturday, October 2, 2010

Indoctrination vs Conscience

In the news this week is the sad case of a young university student who took his own life after a homosexual encounter that he took part in was made public on the Internet. This comes at the end of a month that has seen at least three other teen suicides thought to have been brought on by taunting due to their sexual orientation. The Rutgers student was 18 years old, one of the others 15, and two of them only 13 years of age.

The media, of course, is all abuzz with what should happen to the students responsible. A near consensus among liberals is that the perpetrators should be charged with a hate crime.

But maybe its time to take a look at the real culprits in these tragedies. Who's really at the bottom of this rash of deaths. After all, kids have been bullying other kids for as long as there have been kids. Teasing is often a much more cruel act than the name implies, but are we really ready to charge children with hate crimes for it?

No, the real criminals in these cases are those groups which rabidly promote a gay lifestyle. Every Gay/Lesbian/Transgender/Perversions-You-Have-Never-Even-Heard-Of group had a big hand in driving these young people to their death. The prime time television programs that reek of sex, sexual innuendo, and always feature a really cool gay guy are accessories to the crime. Yes, and every school teacher who has taught young people that homosexuality is perfectly normal, may have blood on their hands also.

Thirteen years old and already out of the closet? Seriously? Does anyone really believe that a thirteen year old would let anyone know that they had such tendencies unless they were constantly being told it was normal, right, and most of all cool?

The problem is, even with all the indoctrination of young people into accepting homosexuality, they still have to deal with a pesky little thing called a conscience.

Romans 2:14-16 For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves: Which shew the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the mean while accusing or else excusing one another; In the day when God shall judge the secrets of men by Jesus Christ according to my gospel.

Let me give you a rough paraphrase of that: Even those who don't know God's law have it written on their hearts, so that there will be a sense of shame when they transgress it, and they will stand in judgement due to that knowledge.

The homosexual activists cry foul when anyone is "outed" even as they preach that there is absolutely nothing to be ashamed of in the act. If that were true, then how can it be a hate crime to reveal something that they claim is normal and right and good? In the mean time, the poor victim falls for the propaganda calling homosexuality proper, only to have their conscience overrule their wish for guilt free sin, said consciences having not yet been seared by years of debauchery. Obviously for some of these youngsters the shame is so overwhelming that it leads them to take their own lives.

And that is indeed a tragedy ....but let's put let's be honest about who the real guilty party is.