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The single uses a different arrangement to hold the post as the plug is on the opposite side of the head to where the rocker post and push rods are. The twin has them both on the same side so that the plugs are high up and less likely to be a problem if the engine floods. The single also has a...

Most of the hit & miss engines are fairly low compression. I don't have the 1/3rd scale PMD one that I built but it was possible to bounce the flywheel back against compression if you did not pull it hard enough to overcome the compression.

Sid that would probably be an option just have to make sure the counter bore did not break out the lower face particularly if it needs to be enlarged to get a wrench to fit. Maybe angle the hole a bit too

Andrew, I think there may be a note on the original Upshur drawings to do what I suggested. EG a stud that stays loctited into the head that the post screws onto and a shorter screw to hold the pivot and cap to the post not as it is shown on the MEB drawings with a screw through the lot. Just...

I've seen a few model IC engines built with Hydraulic tube, the pre honed bore can be used as is and is ideal for anything with a long bore, these have been steel rather than stainless but with Viton rings on a slowish running display only engine I should think the stainless would be fine. It...

Another option may just be to drill the post with a clearance hole Or do as you say adjusting the end until things line up. But I would use a short length (about 5/16") of threaded rod which can be loctited into the head and not taken out again that the post can be screwed onto. You can then...

I see two little fishies 1. The thread into the head is quite shallow so you need to make sure you avoid the spark plug thread and also don't overtighten things and strip the shallow thread. 2. If the rocker post is also threaded as shown you may find it hard to get things to line up You...

Funny enough I drew an alternative liner a couple of days ago for Timo and put a 1mm x 1mm chamfer on that as it just looked right to me and is the sort of size I would have done if designing myself as it makes it easy to get the piston with it's rings into the bore. What do you know that just...

Timo, see my comments about the conrod hitting the liner and my suggested fix https://www.homemodelenginemachinist.com/threads/upshurs-opposed-twin-engine.36037/post-410429 9mm at the bottom and 6mm at the top would also work

It seems Andrew Whale wa susing teh MEB drawings so less likely to be a difference between the ones from Mrs Upshur and the ones from MEB so I drew a few parts to take a look. Steamchick this is what can be done with CAD. I should say there are a couple of variables on the drawing as the width...

That may explain why I can see differences as I am looking at the plans that were in Model Engine Builder. I have marked the sizes they give for the big end which are clearly different to yours and they also have the screw holes in the middle not breaking out the side. With your conrod having...

Almost, 450mm long with near 11" flywheel. All engines have the basic sizes in the last photo or on the product data sheet

Brian's rods don't look quite the same as the original designer drew them so it was probably OK on the original. Rods should not be offset from ctr line of their respective cylinder Cad makes it very easy to check as you can rotate the virtual crankshaft and see how all the parts move

The latest issue of MiM dropped on the mat today and I thought I would just take a look at the website of one of the small adverts in the mag for www.steamofsteel.de and found that they are now producing casting sets for the many steam engine models that I have seen over the years originally...

There is an io group for Emco lathes which is worth joining, although it says V10 in the name it does cover the other machines. I used to have the Emcomat 8.6 which is very similar to the 7 https://groups.io/g/emcoV10lathe

Just be aware that the solder you say you have got is not 4% silver / 96% Tin as spec'd on the drawings so may affect the joint strength. The 4/96 is a high tensile solder often used for HVAC as a replacement for silver braze. Oatey don't give strengths for what you have but I would think it...

Tinning is quite a common way to solder parts together, I was first shown how to do it at school. Basically it is the application of a thin layer of solder to both parts so that you can see they are fully coated before assembly. It does need to be thin, just enough to put a film on the surfaces...

Really? From the parts I have made from Delrin I would not have thought there was a problem with distortion due to being weak or flexible. Given the overall size and wall thickness there should be plenty of strength there to resist abuse let alone normal use.. Have a read about Delrin The...

Brian, can you enlighten us as to why the adaptor is needed? I can't see it serves any special purpose and just making the rotor hub a bit longer so it runs against the crankcase would fill the gap if it were not fitted.

Have a look at drawing 13 if you are using the MEB plans. "Cam Shaft Layout" 102deg