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Here is the plan for the gear train. There are 2 idler gears in the gear train for 2 reasons. First, the idlers are offset and adjustable so that the backlash between the gears can be controlled. Second, the The crank, cam, and balance shaft gears are only 50 teeth with the idlers installed. If...

I like that wax idea for temporary leveling. I have used a hot glue gun, too. Here is a link to Roto metals who is a big seller in the US of all sorts of light weight and low temp and babbit alloys. I don't know if they have any distribution in the UK...

Agreed! There was one large complex spherical shaped gimbal frame that we bought for over 20 years from the same vendor. About 5 years into the deliveries they switched from green sand to resin bound. WOW, what a difference in the dimensional consistency and accuracy!

Where I worked for many years we used lots and lots of castings made by different vendors by different processes. Sometimes it wasn't until the 3rd or 4th order, after feedback to the vendor about how the casting needed to be adjusted, and after adjustments to our fixturing, that we got...

minh-thanh. Thank you (and everyone else) for following along on this journey (death march?? 👿 ) I agree with you about the thermocouple, but I was hoping that the temp might increase like the pressure does.

Yes, I already reduced it by filling the depression at the top of the piston. I will eventually have to make a new piston. I was fortunate enough to talk to a diesel mechanic who has been working on 2 stroke diesel longer than some of us have been alive. His first suggestion for "hard to start"...

Rod, To machine a casting you have to think like a casting. Bad joke, I know, but only partly in jest. That is a fairly complex casting and as you said getting it set up correctly is critical. Look at the parting lines on the casting. The main outside shape with the fins has a single main...

TIME TO CHARGE AHEAD! I have gone thru a couple of iterations today with varied success. The window is now machined for the inlet to the air chest for the scavenge ports. The picture shows 2 of the 14 scavenge ports. After doing that I taped a 1.5" x1.5" x .75" 12vdc fan over the hole and tried...

Wow Ray, you are quite efficient at this, and the results are exciting! Of course, I have a couple of questions. I believe you said you used o-rings on the pistons instead of conventional metal rings, correct? What compound do you use (Viton ??), and how long do they last before burning or...

MORE COMPRESSION AND TEMPERATURE TESTING I have been trying to come up with a better set-up to drive the engine to do some testing. This testing is just something that I "have a need to know" the results of, even though it might be slowing the forward progress. Right now it is set up to be...

You are a smart guy. You will figure something out. 😖 Lloyd

Hi @Roger B Getting instantaneous pressure &temp readings is difficult. But the both have a period of several revolutions to build and stabilize in this situation. In the past I have read the values directly on an oscope to avoid the processing lag for the standard display. It might be...

Hi Roger, I agree that leaks can be a real source of frustration. Here is the type of check valve design that I use whenever I can. It is commonly used in high pressure airgun fittings and will work from 2 bar all the way up to 300 bar. The simpler check at the top is my favorite. It is very...

Nerd !!!! That is a lot of news, and I hope the move goes well, but I have really enjoyed your project and posts. They will be missed, and I mean that sincerely. May I suggest a last ditch effort for your injector? I know how you must feel. Since the leak is at the back of the plunger, have you...

Hi Roger, Thanks for that info, but I do believe he was referring to the build of my 56cc diesel (this topic) and I answered that question in post #281. Here is more info about the water jacket arrangement for the diesel. Here is a view looking into the bottom of the outer jacket, with the...

Roger, thank you for the lap info. That looks like a nice system. Lloyd

Hi Roger, Actually, that was me who built the prony brake dyno with data logging capability. It utilized a load cell, a reaction arm, and a hall sensor, and an arduino micro, and recorded the data in an excel spreadsheet. Here is the build thread and demo for the dyno...

Ahhh, good point. There is about 8" of 1/8" O.D. steel tube coming from the head, then an adapter with a several cc's of volume, then a Schrader valve as a check, then 16" of rubber air hose, then some standard air fittings adapted to the gauge and then a check and pressure relief button at the...

Leaky compression Test Data I attempted a prelim compression and temperature test yesterday to see if the test equipment was functioning. The test setup was ok, but the compression in the engine is not yet up to par, and the drill that I am driving the engine with is not up to the task. It only...

COMPRESSION RATIO, TEMP, PRESSURE, ISOTHERMAL, ADIABATIC, and GAMMA TESTING @Nerd1000 already has the "nerd" name claimed, and he has proven to be worthy of that title, but it is my turn to throw in some nerd/geek stuff myself. I love spreadsheets and calculations and do a lot of...