Has anyone ever cast their own engine blocks? Even as a hobb

>>1064082
Casting an engine block is easy once you get the tempature control settings and formula for the cast aluminum... Machining all the bits and pieces is the hard part.

Not impossible tho.

If ur serious and I strongly doubt you are. But making and casting 500cc straight 4 two stroke motors. I can promise you now its an untapped market because muh environment.... (even tho a two stroke harnessds 50% of the fuels optimal power. Unlike a four stroke that only harness 30%)

Gokart, marine, ohv, street motorcycles, and possibly the snowmobile market (tho they are still some of the reminding two stroke engine markets actually making them left.) are all untapped.

https://www.youtube.com/watch?v=QsmiIeAkE-o

>>1064085
God damn, I wish I had access to a CNC machine, and knew how to program them...

Google sheet metal engine block

"sheet metal" is probably misleading, but the process is more DIY than casting, I would think. At work we occasionally make replacements or modifications parts for old machines.... most of what we are replacing are very large cast parts. We actually layer laser cut 2" plate welded together to make a rough part and then grind and machine the replacement. Its a little more complicated than that but that is a simplified version. So the process in sound and totally DIY.

>>1064084
Isn't that backwards? The two stroke has twice the power per volume, but the fuel efficiency is less due to the exhaust.
I velieve so at least.

>>1064313
Yeah, I've heard of that as well - I'd probably start off making small single-piston engines by machining from stock metal instead of casting everything myself, just because I don't know how strong of a cast part I could make. The appeal casting has to me is that I could make engine blocks and heads that would be suitable for a car, without having to machine away a massive amount of material.

>>1064332
You're pretty much - two stroke petrol engines aren't particularly fuel efficient unless they're running at a certain (often very narrow) RPM range. They also make fuck all power until they hit high RPMs, too.

For emissions, 2 strokes are awful - the amount of unburnt fuel and oil they spit out means that they haven't been seen in cars (which have far stricter emissions requirements than motorbikes) since the 70s/80s, and that's not even getting started with the other emissions they put out.

>>1064082
some machinist forums have sub-forums dedicated to engine building.

the main problem with building piston engines from scratch seems to be getting the valves and cams done to where they are reasonably durable and work right. everything else is not that difficult to do well enough, even with manual milling equipment.

this is the reason that a lot of people who build miniature piston engines just build compressed-air engines.
it spins when you connect air to it, but they build them in such a way that they can skip building the whole camshaft/valve parts.

>>1064429
Valves should be doable once I have a decent metal lathe, but camshafts are pretty tricky, yeah - that lobe shape doesn't strike me as something easy to machine, but hey, people have been doing it for centuries. It can't be impossible.

>>1064086
For like 5-10k you can get a decent used VMC with 40x20x20" travel, more than enough for most anything you'd wanna do. Then another couple thousand for tooling.
Then another couple grand for the 480v three phase line and a nice air compressor.

>>1064488
Fuck that, I'd consider myself lucky if I ever had 10k in my bank account in the first place. I'll be doing this on the cheap.

>>1064493
Same, having my own VMC and a nice lathe is a dream of mine though. Maybe in 10 years it'll be feasible.

>>1064084
The major bonus is power to weight. Two stroke engines make about twice as much power for a given size but use more fuel. There's actually a very interesting engine that uses a turbo to overcome some of the loss. It's used in the aprilia sr50 ditech scooter. It's a 50cc engine that can propel the scooter to 70mph with the governor removed.

>>1064332
>>1064406


You two are thinking I meant MPG or running time. No I meant the two stroke engine harnesses more energy from its fuel per stroke.

For ease of explaining sake I'm gonna bs some numbers. Gasoline has 500btu of energy, a two stroke will use 250btu of that energy and the rest is wasted one way or another. A four stroke is only gonna get you 150btu of energy and the rest wasted. There for the two stroke is actually more efficient in terms of useable power.

Oh and modern two strokes require no oil mixing.. And can run on 94 octane with direct injection.... There is some sort of mechanical pump or electric pump that flows oil onto the hot bits on the engines. Plus they are kept even cooler with water jacketing...

And according to engineering explained broski a form of two stroke slash diesel style engine is litearlly the end game for petrol engines with current technology and knowledge. But that's a different ball game.

>>1064598
>per stroke
Who cares
Mpg and emmisions are all that matter as a measure of how "good" a vehicle/engine is

>>1064598
>engineering explained
D I S C A R D E D

>>1064694
>mpg
absolutely
>emissions
who gives a shit

I always thought it would be cool to cast a Block that uses GX200 or or clone parts to make sourcing internals cheap and easy instead of having to make them all myself from scratch. Like just cast a Block & head and use whatever stock or upgrade Parts you can find online. Maybe one day when I have more money and time to figure it out

>>1064694
>Mpg and emmisions are all that matter
No, you're a fucking loser. An engine needs to do WORK which requires power from each stroke. Do you know what torque is and why you want it?

>>1064313
>>1064406
See this, the best version I've seen explained plus quality pictures, but someone with actual engine building experience.

http://www.hotrod.com/articles/how-to-build-your-own-sheetmetal-engine/

>>1064493 To get your hopes up a little, you can overbore a cylinder with a honing tool.

>>1064598
>You two are thinking I meant MPG or running time. No I meant the two stroke engine harnesses more energy from its fuel per stroke.

Those are the same thing. There is, ultimately, only ONE measure of energy efficiency; energy in, work out.

If, for the same energy input (in this case, the chemical potential energy in gasoline), you get more work out ("MPG or running time"), it's more efficient. Period.

A two stroke produces more power not because it burns its fuel better, but because 4-strokes only produce power for 1/4 of their cycle, while 2-strokes produce power for double that.

Perhaps what you mean is not that they produce more power per stroke, but more power for a given RPM.

>>1064406
>>1064332
>>1064084
What lesson all of you are missing is one from slow speed engines. Two strokes can be, and are, the most efficient engines on earth. Wartsila Rt96 flex

Long story short: big giant stroke for relatively little bore, use cuts/ports in cylinder for air supply and exhaust. Turbocharged and fuel injection (injection timing for gasser can be horrendously early, because it isn't compression ignition engine). It would be more feasible to go supercharged (even if electric fan driven) due to difficulty of sourcing turbos so small. Big cup (if you can find one) in the head of the piston so as to keep compression ratio small whilst keeping ports closed and keep making power.

Wankel engines are the real untapped market. Their power to weight ratio is fucking amazing. For example, the Mazda RX-7 mk3 had an engine that weighed about 247lbs, output 217 lb-ft of torque, 255hp and had a really high redline, which makes things interesting for modifications.

0.87 lb-ft per pound and 0.85 hp per pound.

To compare, the VG30DETT weighs 489lbs for 283 lb-feet of torque, 300hp.
0.57 lb-ft per pound and 0.61 hp per pound.

>>1066482
seems like something attainable eventually. it would be cool to make something weird like a 4 banger that uses a crossplane crank or some dumb shit like that

There was a guy at the Reno Air Races, oh... two years back, I think, who had miniature V8 engines he cast himself. It was pretty neat. Some of them were even supercharged, and he had the wood patterns he used for the supercharger rotor and housing castings.
>>1066482
>>1064313
Holy shit, that's awesome. Do you suppose an air-cooled sheetmetal engine could be possible?
>>1066660
I'm a big fan of Wankel engines, but with the lubrication issues and all that, I really don't see them ever being competitive with four-strokes. They just aren't as good as 4-strokes at any of the things 4-strokes are good at (reliability, efficiency, pollution, noise, etc.).

HOWEVER, I do think simple, fuel-lubricated (premix) Wankels could find a happy little niche in markets that 2-strokes currently occupy, such as chainsaws/weedwhackers/leafblowers and similar lightweight handheld power equipment, and perhaps light vehicles like go-karts, dirtbikes, outboard-motor powerboats and so-forth. In such applications, Wankels can match or surpass 2-strokes in nearly every respect except cost, without any of the major drawbacks associated with 4-strokes (again, except for cost). Plus, by using fuel lubrication (which is already standard practice with most 2-strokes) instead of a more complex closed oil system, you eliminate many of the major headaches associated with Wankel engines.

>>1067412
>HOWEVER, I do think simple, fuel-lubricated (premix) Wankels could find a happy little niche in markets that 2-strokes currently occupy, such as chainsaws/weedwhackers/leafblowers and similar lightweight handheld power equipment, and perhaps light vehicles like go-karts, dirtbikes, outboard-motor powerboats and so-forth. In such applications, Wankels can match or surpass 2-strokes in nearly every respect except cost, without any of the major drawbacks associated with 4-strokes (again, except for cost).
That was my thought. They're lighter for the same power and if you can fix the lubrication issue, you can have a badass quad/snomobile that's lighter than the competetion for a bit more money, and a chainsaw that sees lots of torque at lower rpm. The application for towing shit with a quad would be pretty neat too.

Check this out. Ignore the edgy music.
https://m.youtube.com/watch?v=H2LT2OQd8n0

>>1067545
Also this.
https://www.youtube.com/shared?ci=7LDaZTNHv5U

>>1064082
I've always dreamed of a small displacement v12 and stuffing it in a Miata.
Just like Ferrari used to be in tnt 50's and 60's

>>1064493
>Fuck that, I'd consider myself lucky if I ever had 10k in my bank account in the first place. I'll be doing this on the cheap.

Then you will not be doing it. Sorry, but some projects require more than dedication. If you are that poor your effort is better spent building a shop to give you a lifetime of options. Then you can tackle big projects.

Put shop and tools before toys, and the toys will follow. Toys before tools gets you very little.

Learn how to buy used machine tools cheap (liquidation auctions etc). You don't require CNC for (most) one-off work and large conventional lathes and mills often go cheap because current scrap prices are low and hobbyists are intimidated by moving them. It's easy to put most machine tools on casters or wheels to get them onto a car trailer without paying a rigger. I've moved mills and lathes that way.

BTW most machine tool motors are smallish and you can build phase converters to run them off single phase supply. Practical Machinist has a great forum you should spend time on.

Shipping containers are commonly used for mobile workshops and are very easy to work with. I use two High Cubes joined at the sides.

>>1064082
Casting can be a bit hit-miss, lot of the problems that even manufacturers face is the formation of air bubbles and making sure enough of the metal gets to where it needs to be.
Some race teams opt for billet blocks and heads... which I guess is an option if you're a wiz with CNC, not as economical with material, but its ridiculously fucking strong

>>1067548
Hey Vincent, double check your options when you share videos. Jewtube made some changes to where now you can share with your name attached

>>1064598
>And according to engineering explained broski a form of two stroke slash diesel style engine is litearlly the end game for petrol engines with current technology and knowledge. But that's a different ball game.
https://en.wikipedia.org/wiki/Two-stroke_diesel_engine
It's not the end game, its just convenient to build BIG two-stroke diesels because they don't require a valve train at all.
Instead of using a camshaft and poppet valves or reed valves to make air move through the engine, they use a blower (a supercharger) but in this use it doesn't really create much "boost" like it does in a normal 4-stroke engine.

2-stroke diesels are a long-time thing because in addition to not needing any camshaft or valve train, they also don't have issues with spark advance since they combust at the top of the compression stroke all the time anyway.

They are much more simple mechanically and electrically, but they have fuel efficiency drawbacks as well.
Some normal-sized commercial trucks are offered with 2-stroke diesels. I've never heard of any car that came with one.

>>1064084
>aluminum block
Stay memed.

>>1069852
Why is that a meme? Certainly it has drawbacks but a meme?