When One Cylinder Isn’t Enough: The Briggs And Stratton V8

The Briggs & Stratton single cylinder sidevalve engine is one that has been in production in one form or another for over a century, and which remains one of the simplest, most reliable, and easiest to maintain internal combustion engines there is. The little single-cylinder can be found on lawnmowers and other similar machinery everywhere, so it’s rather easy to find yourself in possession of more than one. [Lyckebo Mekaniska] evidently had no shortage of them, because he’s produced a V8 engine for a small lawn tractor using eight of them. A small air-cooled V8 sidevalve is something of a unique engine to be made in the 2020s, and the series of videos is definitely worth a watch from start to finish. We’ve been keeping an eye on this build for a while now, and we’ve embedded it below the break for your entertainment.

A CAD view of the V8 engine
Clearly a lot of CAD work has gone into this build.

For an engine which uses mass-produced engines for its construction, this one still relies heavily on parts machined from first principles. The cylinder blocks, valves, pistons, and crank rods are Briggs & Stratton, the rest is made in the workshop. It’s a design with the valves on the outside — so instead of the single camshaft you might expect from experience with OHV engines nestling in the V above the camshaft it has two camshafts at the bottom of the crankcase.

The crankcase is cast in sections first, followed by the machining of the crankshaft and camshafts, then the preparation of the cylinders.. The engine is assembled with a home made alternator on its flywheel and a conventional distributor from a donor vehicle. The lubrication system is another work of the machinist’s art, and the simple straight-through exhaust system is more at home on a drag racer than a lawnmower. Finally we see it running, and it sounds the business. Most recently he’s had to deal with a seizure and a replacement cylinder, but now it’s back together and he’s working on an improved cooling system.

All in all this is one heck of a build, and we wish we had some of those skills. We’re not sure whether he’ll mow the lawn with this thing, but one thing’s for sure, lawnmower hacking has quite a past.

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Vintage Bike Gets Briggs And Stratton Power

eBay made the process of motorizing a bicycle popular, with cheap engines from China combined with a handful of parts to lace everything together. If your tastes are a little more vintage however, [Oliver]’s build might be more your speed.

Starting with a real Briggs and Stratton liberated from an old rotary tiller, this engine has legitimate vintage credentials. Looking resplendent in brown, it’s paired with a bike in a similar shade from yesteryear. Drive from the engine is transferred by belt to a jackshaft, which then sends power through a chain to the rear wheel. The belt tensioner serves as a rudimentary clutch, allowing the engine to be disconnected from the drivetrain when disengaged.

The retro components, combined with an appropriate color scheme, make this a wonderful cruiser that oozes style. While it’s probably not suited for downtown commuting due to its lack of a real clutch and noise, it would make a great ride for taking in some country roads on a sunny day. We’ve seen similarly styled e-bikes, too. Video after the break.

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The DIY Open Crank Engine Moped

Anyone can strap a two-stroke engine on a bicycle to create a moped. But [robinhooodvsyou] has created something infinitely more awesome. He’s built an inverted open crank engine on a 10 speed bicycle. (YouTube link)  As the name implies, the engine has no crankcase. The crankshaft, camshaft, and just about everything not in the combustion chamber hangs out in the open where it can be seen and appreciated.

[robinhooodvsyou] started with an air-cooled Volkswagen cylinder. He filled the jug with a piston from a diesel car. Camshaft, flywheel, valves, and magneto are courtesy of an old Briggs and Stratton engine. The cylinder head, crankshaft, pushrods, and the engine frame itself are all homemade.

Being an open crank engine, lubrication is an issue. The crankshaft’s ball bearing is lubricated by some thick oil in a gravity fed cup. Even though the engine is a four-stroke,[robinhooodvsyou] adds some oil to the gas to keep the rings happy. The camshaft and connecting rod use Babbit bearings. While they don’t have an automatic oiling system, they do look pretty well lubricated in the video.

Starting the engine is a breeze. [robinhooodvsyou] created a lever which holds the exhaust valve open. This acts as a compression release. He also has a lever which lifts the entire engine and friction drive off the rear wheel. All one has to do is pedal up to cruising speed, engage the friction drive, then disengage the compression release.

We seriously love this hack. Sure, it’s not a practical vehicle, but it works – and from the looks of the video, it works rather well. The unmuffled pops of that low 4:1 compression engine reminds us of old stationary engines. The only thing we can think to add to [robinhooodvsyou’s] creation is a good set of brakes!

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