By: Carl Amundsen Date : January 18, 2000
The Case: To produce the best crankshaft ever.
The Jury: Engine builders, car owners, chassis builders from our customer base.
The Material to be used
Much to do has been made about what kind of material should, could and would be used to make a crankshaft. Manufactures tout theirs are made of 4140, 4150, 8690, Stressproof, or other high mucky muck number designations. We investigated all of these options, but when the smoke cleared we came back to a material we had been using for 20 years. The material does not have a number designation because it is proprietary to the manufacturer and is patented. The brand of the material shall remain anonymous for our own reasons. The biggest user of this material is the mining industries, where it is used in augers, blades, conveyors or anything that requires a hard wear resistant material. We have used this material for 20 years in impeller blades for steel shot machines. Through its manufacturing process and mineral content it requires no hardening before it is used. It comes in the door with a hardness of 44 to 46 on the Rockwell "C" scale and the more it is used the harder it gets. This is all accomplished without it becoming brittle. The only negative side of this is that it is a nightmare to machine. It took about 6 weeks of trial and error to come up with the right feed rates and spindle speeds. The only tooling material that is compatible is solid carbide. Tool life at best is very expensive.
Design and Engineering
Instead of taking a brand new crankshaft out of the box and starting the process of cutting and grinding. This is not necessary with ARC cranks for most applications of camshafts and lifters etc. You will also find that there is no note in the box instructing you to deburr sharp edges, this has already been done. This was one of the more important items that we addressed in the manufacturing process. At least 15% 0f the machining time is spent removing sharp edges. This is an absolute must , this is also the reason other manufacturers simply leave you a note in the box. A sharp edge is an invitation for a crack to start, and no matter how small it is, it will grow just like cancer. I am sure everyone has seen the old trick of tearing a telephone book in half, same principal. We borrowed technology from NASCAR in designing the (airplane wing ) airfoil style counter weights. NASCAR has proven that it improves windage in the crank case and increases horsepower. The crank pin even has a true 1/8" radius for added strength and durability. Other crankshafts advertise that they are already balanced, NOT. We went through a very pain staking design process to make sure we could and should advertise a balanced crank. You will without a doubt notice the difference. ARC provides two differently balanced models of the +.563 stroker, one is balanced for the smaller bore up to .190 over and the 3 x 3 for the large 3 inch bore. Appearance, cosmetics and detail have always played a major roll in parts produced by ARC. I think we raised the bar on this one. Besides our logo, all ARC crankshafts are engraved with the part number and the date the part was manufactured. Little more can be said until you hold one in your hand, this crank is truly a work of art. Its worth mentioning , if you haven't already noticed, ARC has a habit of not following what the industry thinks or does. If we can't do it better, we just don't do it.
The latter part of August 1999 we made our first live test. You might think this is a crazy way to start testing, but we needed to build a motor that would come apart fairly easy, I mean explode! This was done with a blockzilla block, our new +.563 crank, an old .190 over piston with new rings, a used 4.225 rod with old rod bolts and a used 436 lift camshaft. We knew from the start that the rod bolts and/or the rod should break, they just had to much time on them. If our crankshaft was going to live it would have to withstand this. The tension and anxiety is growing. Over the next four weeks we made over 250 passes down our local 1/8-mile drag strip, seeing RPM's in excess of 9600. Nothing happened. Not being able to break it was becoming very frustrating. The next test we felt sure "The old wore out rod and bolts" would fail, and we would have our desired results. We put the motor on a kart chassis and ran it on the local 1/4 mile asphalt oval. This is the hardest test on any motor because you are constantly in and out of the throttle. We now had shipped a number of crankshafts to select customers with their promise to have them in motors very quickly, and report to us with results.
The results from the field are as follows:
"That's a beautiful part, works great.""Smoothest running motor I have ever seen, what did you do to it ?""I can't believe this , it's great !" "How soon can I get five more?" And so on. Everybody loves it and no one has had any problems.
We were now getting well into October and getting a little curious , what will break it ? We have over 125 laps on the kart and the motor just purrs. The only maintenance we had done was keeping oil in it. It was even suggested that we run it without oil, dumb idea of course but we were desperate for some results. We didn't do that obviously. At this time we turned the motor over to a local drag racer to finish the job. Finally some results. One of our crank shafts had made it through one of our renowned engine builder customers well west of the Mississippi and back to San Antonio , Texas. Charlie Bass Sr. and his son Charlie Bass Jr. are kart racers that race an outlaw class against the highly touted 2-cycles. However they use a Briggs Blockzilla. Over the past year they were using a 563 stroker crank of an origin I will not mention. They had the power they needed to lead and win races but kept breaking crankshafts. NEED I SAY MORE ? YES, I WILL! THEY WHIPPED EVERYONE AND WENT ON TO BECOME POINTS CHAMPION! A footnote to this is he always used ARC rods.
CONGRATULATIONS TO THE BASS FAMILY, WE LOVE YOU !
Texans have always laid claim to being a little different and I wouldn't debate that. Charlie Sr. had a strikingly different approach for checking for burrs and rough edges on our crank. He wiped the crank down with a pair of panty hose, and did not get a run in them. I didn't ask who the panty hose belonged to.
"We no longer have to hold the kart down on the rack when we run the motor, it just sits there and purrs." " I can read the temp. gauge and tack now, I can see the flags." Charlie Bass Jr. " Is this smooth or is this smooth "
At their request we have put the Bass' in the unprotected witness program.
Charlie Jr. Leddfutt24@worldnet.att.net
Charlie Sr. DrBriggs94@worldnet.att.net Home phone 210-923-5730
THANKS AGAIN TO THE BASS FAMILY
Now back to our test motor. We were closer than we thought, it only took two more weekends of racing to do it. When we tore it down the rod bolts had broken along with the rod (as we predicted) and chunked the whole mess out of the side of the block. FINALLY RESULTS WE WERE WAITING FOR. WHEN WE BUILT THIS MOTOR WE INTENTIONALLY USED AN OLD ROD WITH OLD BOLTS, THAT SHOULD HAVE BEEN JUNKED. WE KNEW THE ROD WOULD BREAK , WE JUST DIDN'T KNOW WHEN. The crank was still straight, the crank pin was still in perfect shape and the only damage was some scuff marks on the counter weights. We checked the hardness of the crank pin and it had gone up 5 pts. on the Rockwell scale. Magnaflux revealed no stress or cracks. Anyone in his right mind would think surely this is enough, NOT US. What everyone wanted to see now was just what would break it. GET THIS, the stage was set, the crank was placed in a hole in our heavy duty welding bench which is two inches thick. The crankshaft was vertical with one counter weight resting on the table. Our weapon of destruction was a 10 lb. sledge hammer with a 36" handle powered by Randy Amundsen. Smashing down on the exposed counter weight, we wanted to see if the counter weights would touch before breaking the crank pin. To me this seemed cruel, it reminded me of the turkey losing his head Thanks Giving morning. This crank surely didn't have a chance.
LET THE CONTEST BEGIN
After 5 or 6 hits the crank was holding up fairly well. After about 12 hits the crank was bending but still refused to crack. Someone muttered " that crank thinks Randy is a wimp". After more than 25 over the head death blows the crank finally gave up. Before Randy could catch his breath another brand crankshaft was set up ready for the same challenge. Two smashes latter we knew who had the toughest crankshaft on the market. This was ARC's real world extreme testing at it's best and our new crankshafts finest hour.
1. Its design and engineering is well thought out. 2. The appearance and cosmetics leaves the competition in dust 3.The balance is superb. 4.The strength is probably beyond necessary. 5.The price is higher but well worth it. 6.Go to market.
ARC has created a crankshaft with limited sales potential. It is going to last the customer too long and greatly reduce repeat sales. It may create for the first time in history, a USED CRANKSHAFT MARKET.