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Mark, Yes, I have the module. It's a spare that I kept on hand since I've used so many of these in my other engines. That being said, Roy had one last PCB that he's making up for me to replace my spare. - Terry

Dave, George, Thanks for the responses. I'm planning to use one of Roy's magnum CDI modules, and so dwell shouldn't be an issue. I won't be be able to rev to 7800 rpm, but that's ok. I suspect my rpm will ultimately be limited by my intake valves. - Terry Terry

https://www.homemodelenginemachinist.com/threads/quarter-scale-merlin-v-12.24153/

The full-size engine's distributor was fully mechanical with extended-dwell dual points. The model's distributor will be electronic and based upon a Hall effect device. Trigger possibilities include eight magnets mounted on a non-ferrous disk or a single stationary magnet mounted behind an...

I sketch out all my machining steps and correct them along the way if I find issues with my original thinking or find a better way. They all go into a big 3-ring binder for that project so I can refer to them later on a future project if I'm doing something similar. More importantly though if...

minh-tanh, Not sure what you're asking, but the lifter bores are .002" larger than the lifter bodies, and one of the holes in each strap is slotted to allow the vertical motion. The shoulder bolts were machined so there's enough clearance for the strap to freely move with the bolts bottomed out...

Charles, there wasn't any step, but turning a chamfer on the end of the shaft would probably have helped a lot. Can't help but think the dimensions of the seal were off for some reason. The o.d. measured .820" (I had to actually bore the recess to .780" to press it into the timing cover, and a...

Before beginning work on the distributor, a few checks and loose ends involving final assembly of the camshaft and crankshaft sent me down a rabbit hole. A few thousandths interference between the camshaft hub and the timing cover was discovered and cleared up with a slight counter bore inside...

The front mounted distributor is driven from the camshaft through a helical gear set. Specialized equipment is used to manufacture commercial helical gears, but usable one-offs can be made in a home shop using conventional or, if necessary, shop-made gear cutters. Involute cutters are designed...

The compression ratio using the measured combustion chamber volume worked out to be 6.9. I was hoping for a little more so the pistons could be simply dished to provide the needed valve clearance. At five to ten thousandths interference the goal was a clearance of .050" to insure there would be...

Some twenty valves and valve cages were completed, and so there were plenty of spares. Cage leak-down times measured using the test valve were surprisingly consistent at some 15 seconds plus or minus a few. Ten seconds of polishing with extra-fine Timesaver smeared on a felt bob improved the...

Peter, I may have worked with 416 but my memory is foggy and most of the material I use is recycled scrap and machine shop drops with no pedigree behind them. It's possible I have some 416 in my shop as I have some drops that are bright and shiny like 303 with no corrosion but are magnetic. The...

Sparky, The valve heads are 3/8" in diameter and the stems are 5/32" in diameter. If I understand your question, the leak check isn't trying to measure a component of leakage between the cage and the valve stem because it doesn't affect the main seal of the combustion chamber. I typically leave...

It's difficult to separate the design and machining of the valves from those of the valve cages. In addition to sealing the combustion chambers they affect their volumes (and C.R.) as well as the rocker arm geometries and pushrod lengths. Even with their CAD models playing nicely together...

My last photo showing the 'assembled' camshaft may be misleading. The camshaft parts was really just stuck together for the photo. The body with all the lobes is separate from the front hub. These two pieces have tenon'd ends which will be Loctite'd together inside a sleeve which will be...

The camshaft was tackled next. Ninety degree heads, offset cylinders, interleaved pushrods, firing order, direction of rotation - all these combine to make the scratch design of a V8 camshaft a challenging mental exercise. First up was the selection of the camshaft's duration and lobe...

Petertha I used the term hi-rel to mean high reliability. The bearings are .250" dia and .223" wide including the shoulders. I've never before seen bearings with these raised shoulders, and that was one of the reasons why I bought them. They were a one-off lot purchased from the CDD Surplus...

Although I hadn't yet gotten to the valves and valve cages, I needed a break from the mind-numbing valve train parts production. To ease the monotony, I prototyped a pair of roller lifters to see if a roller camshaft could be made to work in this engine. Of course the lifters gained some...

https://www.homemodelenginemachinist.com/threads/draw-tech.29067/