Recent content by Jim Allen

Bob, When replacing bearings in an engine we press the crank shaft out first. This part of the disassembly is done in a press because both bearings are a shrink fit in the crankcase. If this cannot be done, then the shrink fit in the crankcase is not enough! Once the crankshaft is removed...

The inner & outer races of radial ball bearings are not designed to support themselves. Not only is a shrink fit required on the outer race, a press fit is required on the inner race. All Nelson .45 pylon racing engines have the inner races of both front bearings pressed onto the crankshaft. I...

Terry, You will be amazed at how easy tuned pipe development becomes once you have a working test stant. Keep up the effort! Jim Allen

Robert, Where is the lake you're running at? Jim Allen

"Note to self. If your shaft will not release when you untighten collet nut & you must pry the shaft out of the collet you already got a collet nut problem." This is not always true Joe. The split collets I use are split from end to end. The 5/8" hex on the collet nut will lock this type of...

Looks great Mic. Can't wait to see its acceleration at the start of the race getting to that #1 bouy. Have you had a chance to test it yet? Jim Allen

I must agree with Brad & this explains why any collet used on a cable MUST be split from "end to end". The photos show the simple heat sink fixture that allows the cable's end to first be silver soldered for .125" at its end. Next, the cable is soft soldered, solid, for 1.250" on that same end...

Terry, When you are using a stainless steel bag to prevent decarburization of steels, the bag must be very airtight on the folded end. The entire bag should be placed in the hardening oil & then holes are punched into the bag while it is completely immersed. You will notice that a sealed bag...

Terry, The Untitled Document under "running in" refers to the MB-40 FAI speed engine & what the piston should look like after running in is completed. The FAI speed fuel is still 80% alcohol, 20% castor oil as far as I know. This engine operates in the 31,000 to 33,000 RPM range. The reason the...

Terry, The pictures of your pistons look very strange! I have posted both brand new & used for many hours, pistons from pylon racing engines operating in the 29,000+ RPM range. The "wear band" (area where the piston rubs on the cylinder) is clearly visible on both new & used pistons. Notice...

Terry, It is not necessary to make a ball on the male end, but some shape besides a straight shaft. If you draw this up at a 10 to 1 scale, it can easily be seen that a round shape does not touch where the slots are cut in the female end. Take a look at the type of universal Tyler mentioned...

Terry, Do you remember what I told you would happen if you attempted to use anything that resembled a HEX. Imagine how long a hex would survive at 7 HP+, turning 30,000 RPM+. The reason this happens can easily be shown with the diagrams I sent to you showing where the torque force is applied...