From:Kris Thompson
Subject:RE: Cannonball firing order 1-3-4-2 Date:Sun Oct 3 21:16:03 2010
Response to:3062
Great Accurate Discription of the Cannonball 4 Cylinders. Mark was an absolute "must have" during the duration as his efforts to make sure all was well was unbelievable. I can certainly attest to the "new" designed rods Mark provided. They are with out a doubt the reason I was able to finish the run with no additional lower end issues. It was a fantastic adventure and well worth a few (ha) great memories. Thanks again to all those people who made the the run possible. Kris

I thought I would provide a brief (if I can) explanation of the performance of the three four-cylinders that competed in the Cannonball Rally. I hope to explode a few myths about four cylinder engines and their ability to perform.

Let me start by saying the stock connecting rods that teens-era four cylinders come with are completely inadequate for this type of endurance run at close to modern speeds. In preparation for building the two engines that I did that competed, I became obsessed with cycling oil through the rod journals to cool the journal itself and lubricate the cylinder walls. I designed and developed a connecting rod that would pressurize the rod journal and throw oil all over the side of the cylinder wall. I then used thin wall centrifugally spun cast rod bearings so that the heat from the rotating shaft could be dissipated to the bronze lining through the connecting rod.

Of the three four cylinders on the run, one used these new rods and bearing inserts. It traveled 2,820 mechanically trouble free miles. Low and behold, the other two machines suffered - guess what? - catastrophic rod bearing failure. The 1915 Henderson failed within a day and a half, at which time the owner and I came to an agreement that he would purchase a set of the rods, bearings and pistons. Dimensions were taken, I phoned home to my shop, where the one guy in the country at that time who could have gotten it going, Mike Fockler, machinist extraordinaire and four cylinder convert, got the parts machined and sent to us in time to get the 15 Henderson back in the run. The motor was assembled by the owner and me at Foster Harley Davidson in Alabama and never suffered a lower end issue again.

Chronic magneto failure plagued all of the four clyinders throughout the run. Around day 4, the Militaire's rod bearings 3 and 4 failed. We couldn't cycle enough oil through the stock design. The rod journals got so hot that the original soldered in rod dippers fell out and then starved the cylinder walls and overheated the engine. I was devastated about this. I had warned all four cylinder riders that if we had failure, it would be rod-related. My students at the University had worked so hard to build a bomb-proof bottom end and we had suffered the same fate as the 15 hen.

Meanwhile, Westfall's Henderson, when not plagued with magneto issues, was marching across the country. As luck would have it, the 15 henderson that had blown up had two good pistons in it and the bore size and pin height was identical to that of the Militaire. That Militaire broke at the only spot in the country where I knew someone with the talent and willingness to help us put it back together - Russell Hughes, Master Pattern Maker and lover of four cylinders, 70 miles north of Hot Springs, Arkansas. We took two pistons from the 15 hen, fitted them to the Militaire bores, and headed for Russell's place. The Hughes family welcomed us with a traditional Arkansas catfish dinner, then Russell opened his shop and we worked into the night boring two new rod bearings, bushing the small end to accept a different sized wrist pin. I cannot thank Russell and his family enough for helping to get us going again. We assembled the motorcycle the next morning at Landers Harley Davidson in Hot Springs. Great people again who helped all the Cannonballers. We were able to coax another 1,400 miles out of the Militaire by picking our spots and avoiding prolonged hills (mountains). It was an incredible accomplishment for the owner of the Militaire for such an unproven design. My only wish for the Militaire was that we had had more time to test before the run. The Militaire is headed back to the University to undergo proper repairs and to give the owner and me a chance to test cam timing, carburation and cylinder flow.

Westfall's Henderson was awesome. I never set the exhaust valves and I had to adjust the intake pockets 4 or 5 times. We broke one chain and burned through 4 magnetos. I have to thank Clyde Crouch who kept mailing us magnetos and having them show up, remarkably, when we needed them.

There was a day when the 3 four cylinders, along with Slo Joe on his 14 Harley, finished in the first 4 spots. Total Nirvana moment for a four cylinder builder.

With the exception of down times on the mag, we just witnessed a single speed Detroit Hen traverse the country. Great stuff. I hope this becomes an annual event. Folks on the Cannonball were extraordinary people. The willingness to help one another was my favorite part.

I need to thank my students from the class of 2010, especially Matthew Wach, JaDon Spooner and Christopher Browning. We intend to start a new blog on the disassembly, measurement and inspection of the Cannonball engines of Westfall and the Militaire. Students will perform precision measurement and will provide a comparison of the wear patterns from the original set-up of the engines. If Cannonball is run again, I will be there. And it will be firing order 1-3-4-2.