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The shaft will be pressed into place, and right now I'm not planning to harden either. The max lift will be .100". - Terry

That resistor is to reduce the emi radiated by the plug wires. It's purpose is to reduce the Q (quality factor) of the inductance associated with the plug wires which can radiate interference to nearby electronics. It's more important in RC applications where the radios are susceptible. In our...

So many little parts ... One last revision of the rocker arms was prototyped before machining them en masse. They were then machined in batches of five with each from its own little 7075 workpiece. Small batches aren't very efficient, but they allowed fine tuning of the process without the risk...

As an interesting aside I recently watched a Youtube video of a guy trouble shooting a misfire in a particular cylinder in a new (full-size) engine. He was pretty experienced and suspected a compression problem in just that cylinder. The engine sounded normal and the battery current draw looked...

Tony, Yes, I've done it twice before. I really don't think it's a problem in a model, especially one that's using splash lubrication. But, we'll see. The question you should be asking is if an oil pump is really needed. If you could look through the oil pan of a running engine you'd wonder why...

Work started on the valve train, and with a couple hundred parts ahead of me I'll be a while. The valves' 5/16" diameter was locked in by the already machined heads. The intakes could have been bigger, but with the engine's huge plenum and long runners I was concerned about flow and manifold...

photos? ... video?

Yes, I've used this on four of my engines and have been happy with the results. I didn't invent it - just offering an explanation of how it works. Terry

More Photos ...

Fixing the rub ... The bottom ends of the liners which stand .040" proud of the block created a couple thousandths interference with the sides of the rods that went unnoticed in the live assembly model. With the block stripped down and set back up in the mill, a quarter inch wide strip was...

Split bearings in a pressurized oil system, especially those with oil grooves, need a full 360 degrees of coverage around their journals to avoid leaks and pressure loss. In a splash lubricated system, full coverage isn't necessary and may not be desirable. Shop-made model bearings designed for...

Continuing on with the rods ... The bores for the small end bearings were drilled and reamed next. The bearings themselves were turned from 932 bronze and preinstalled in the workpieces where they would later be blended into the rods during their machining. I considered it a good sign that...

Good idea! Wish I'd thought of it ...

I agree it can be wasteful. It becomes a trade-off between material and time, and sometimes between material and machining precision. If you want to CNC machine a part with minimum hands-on and the fewest number of setups, you have to allow space around each part for the cutter as well as...

After laying in the crankshaft, work began on the connecting rods. Gage pins in conjunction with a simple shop-made fixture were used to measure the actual rod journal locations with respect to the centerlines of the cylinders. These were checked against the assembly model which had been using...

The individual bearings were parted from the workpiece and another sanity check made with each resting in the block and the test shaft running through them. Witness numbers was engraved on either side of each bearing's parting line to prevent mixing up the halves. The crescents were machined in...

The tenacity of the super glue really surprised me. My original plan was to augment it with a pair of pressed-in pins at the front and rear of the workpiece for back-up until the threaded fasteners were added. Adding these pins though would have meant that I wouldn't have had room for the spare...

The crankshaft mains include a pair of outer ball bearings and three inner bronze clamshell bearings. The diameters of all the bearings are the same, and the recesses for them were machined into the block using the Tormach. For all practical purposes they're equivalent to having been line bored...

With my unknown grit Harbor Freight beads, I can usually bury .001" machining marks, and a little more if I'm willing to dwell long enough. I wouldn't be able to hide .004" though. What happens is that on a finished surface with .0005" scallops directly off the mill, the surface is so reflective...

By scraping, I meant there was some epoxy left in some of the corners that I needed to scrape out with a sharp stick. Bead blasting doesn't do a good job of removing epoxy as it seems to bounce off it without cutting. The finishing passes were set for a .0005" maximum scallop height, and those...