I ran across some photos of a scale model of an Olds Type "R" hit and miss engine, perhaps 1.5 or 1.75 hp, and I really like the looks of this engine.

It is produced in 1/2 scale (subject to castings availability).

At one time it was available as a 1/2 scale casting kit labled "Briesch Olds".

In researching this engine, apparently the patterns changed hands a few times in auction, and it appears that the 1/2 scale Olds patterns have been either lost or set aside under a lot of dust in someone's garage or barn.

I inquired around as to whether there were any 1/2 scale Briesch Olds casting kits or drawings available, and apparently those who have the drawings don't want to share them for copyright reasons, which I fully understand and appreciate.

So what is a person to do who would like to make a 1/2 scale Olds Type "R"?

Well, all it takes is a few good photos, and one can recreate many of the old engines. This particular engine is not too terribly complicated, luckily, and so I am on a Monty-Python-type holy quest to recreate the Olds Type "R" in 3D modeling, print patterns, and then make iron castings at a scale slightly larger than 1/2 scale (so that the flywheel diameter is an even 10&quot.

Perhaps a good exercise in 3D modeling.

All of the 3D models for this engine have been created with the appropriate draft angle, which makes them a bit more tedious and difficult to handle, but well worth it in the end whey one is trying to pull the patterns from the sand.

So far I am pleased with the progress I have made, working on and off over about 1 week's time.

Here are a few screen captures of the 3D models.

Screencaps.

Thanks for the kind comments.

I have to agree with the fact that a lot of old model engine designs are disappearing.

All I can do is work diligently to reverse that trend.

My thoughts are if someone made the drawings originally from looking at an old engine, then someone else can do the same thing, and recreate the engine again. Many assume it can't be done, and at one time I assumed it could not be done either, but I have since learned how to do it, and have successfully recreated an engine from three photos.

I am not sure about the exact copyright dates for engine drawings, but my plan is to start from a clean slate, and thus avoid any and all future copyright issues.

I have always been a bit unorthodox in my engine scales, and have never felt like I need to adhere to any particular scale factor. Call me crazy, but that is my approach.

The good thing about creating a 3D model though is that they can be 3D printed at any scale, and so people can create whatever size scale model they desire.

I hope one day to share the 3D model files for this engine, so that others can perhaps build it, and it won't be lost forever.

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Edited By PatJ on 20/04/2022 14:00:37

I think JasonB posted a photo a while back of machining an engine bore using a boring bar in the lathe, with the engine crankcase bolted to the carriage.

That is how I would machine the bore.

The Detroit Diesels used sleeves very successfuly in their engines, and it makes rebuilding a snap, but my philosophy is to cast it as it was originally cast, for historic accuracy.

Many casting kits depart from historically accuracy, in order to simplify the design, but I can't bring myself to do this.

I guess that puts me in the obsessive-compulsive category, but I have to cast it like the original, so no sleeve.

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Here is the Seager Olds Type "R".

Some slight differences from the Reliance Olds.

I am going more by the Reliance configuration, but not entirely.

To some extent, I am morphing the Seager with the Reliance design, which may be sort of a faux pas.

Oddly enough, the Reliance is listed at 1.75 hp, and the Seager is listed as 1.5 hp.

Edited By PatJ on 20/04/2022 16:30:17

For a model engine this size, I don't really see a need to have the water jacket extend under the cylinder.

The problem with scaling down engines is that sometimes parts and pieces become too thin or small.

And one more reason to make models as large as possible, so as to preserve as much detail as possible.

I will have to look at how small the water jacket space becomes on a scale model, but if the space is too small, I would just eliminate it.

The engine won't overheat if the water jacket is only on the top of the cylinder.

I won't sleeve the cylinder, although no doubt that is an excellent option in many cases.

No sleeve is just my preference.

There is much that can be accomplished with resin-bound sand, but as Jason mentions, there are limits as to how far gray iron will flow in small spaces.

You can generally get a complete fill on intricate work by adding phosphorus, but I never add phosphorus to my metal, but prefer to use untainted scrap iron from electric motor end bells.

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Edited By PatJ on 20/04/2022 18:43:37

I think I would use knife gates on both sides of the hopper, and then have gates on either end of the cylinder too.

The bore would have to be casts pretty thick in order for it to have a chance to fill; perhaps 3/8" thick walls or a little more. Omitting the bore core would cause too much shrinkage.

I am not sure if a 1/4" thick water jacket core would hold up to iron temperatures, but it is possible.

Some folks imbed a steel wire in thin cores to help them remain intact during the pour.

Another approach would be to cast the cylinder thicker than normal, and drill long holes in from the head end down the sides of the cylinder, and let them join the water hopper via slots in the head.

Thin cores are definitely a tricky thing to cast.

The Speedy Twin passage cores used a lot of chaplets to hold them in place, and if you look at the top of a Speedy Twin, you can often see the tops of the chaplets imbedded in the cast iron.

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