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Welcome Arnaldo. We'll have you building your own engines soon!

"One of mine leaks so much oil it doesn't even get oil changes anymore because the oil doesn't stay in the bloody thing long enough to need changed in the first place! " This is a common misconception. The leaks in the engine are all acting like filters, so while oil is leaking out, the sludge...

I was recently looking at and discussing a 'full size' (200 bhp) water brake dyno which is owned by a friend. Cavitation is a significant issue, especially with higher revving engines. It is necessary to have a substantial head of water at the inlet to ensure that the pump does not pull vacuum...

I have an ESP32, but so far I've been playing with code on a PIC18 dev kit just for practise with no consideration of execution speed. I should add that I am very much an amateur programmer, but we seem to have arrived at the same mathematical solution. I have wondered whether to keep the...

Excellent work, Ray! I have some half baked code to run the ignition for my radial, using an ESP32 PIC. It will be interesting to see whether my PIC shares the foibles of your Arduino.

Congratulations on your first turned part. There will be many more firsts. Almost every project I undertake involves some technique I have never used before.

I have an adaptor which allows me to hold a 6mm shank cutter in my boring head, so I can run the cutter off centre for odd sizes.

I will also be learning! I'll report how I get on with test parts.

Hi Awake, I'm short, no. I am using the weld to lock the dowel pins against rotation to prevent the assembly from twisting. The primary strength of the assembly should be in the interference fits, so the weld should only be loaded in torsion, which spreads stress around the entire circumference...

Hi Ken, My timing gears are pinned exactly as you show, but the crankpins are hard dowels and drilling is not practical. The TIG weld was only a tack on the ends of the dowel, at their least stressed location. It was the weld itself which failed, so my proposal is to add as much material as...

Hi Ken, Standard fits are applicable when the bore is in a relatively large section of material. My crank webs are of irregular section, so I calculate on the basis that the thick bits are essentially rigid and all the strain occurs in the thin sections. This is, of course, an approximation, so...

Thanks John, I am always happy to hear how others have done things. I would be a fool if I thought I knew how to do everything. I think you have described what I am intending to do with the weld prep. I will Tig weld it, because I feel I have more control of the heat and filler than with MIG.

Thanks Ken. My crank is a pressed assembly, because my rods are one piece. The big end pins are 6mm hard dowels, pressed in to the crank webs and secured with a spot of Tig welding. The welds failed, allowing the crank to twist. I will make a new crank with more interference in the press fits. I...

The engine has run again. With a new timing cover, with clearance for the gears, it fired up easily and ran at about 1/4 throttle with the first guess needle setting. The engine was turning a 12 X 4 prop, which I had guessed on the basis that it is likely to achieve power comparable with...

For my model aircraft, I use clear Epoxycote.

Really? I would like to have the time (and patience) for a lot more perseverance! To my mind, this has been a fairly rapid design and build.

The engine ran for the first time on Saturday morning. And I broke it after just a few seconds. Nothing serious, the timing gears were contacting the inside of the timing gear cover and generated enough aluminium debris the jam the gears. I shall make a new cover with more clearance. I wanted to...

+1 for Drummond lathes. My roundbed is close to 100 years old and I can still produce parts to the precision required for small IC engines on it. See my thread "A 15cc sidevalve opposed twin" for some photos of my Roundbed in action.

When plating, the formation of bobbles indicates that the current is too high. It is possible to file bobbles back to a smooth surface, but if they develop early in the process, there may not be enough thickness of plating to support itself against filing forces. In such cases, it is best to...

Another couple of points worth mentioning... The warm electrolyte and the larger water bath will both evaporate at a significant rate. I found it necessary to top up the electrolyte with distilled water and the larger bath with tap water every day. If you want to interrupt the plating process...