TheNeedForZ

They are talking about gluing the body parts, not the head. Read before you post. ""The best solution would be to weld the passages and then cryo treat it to even the metalurgy of the aluminum, so you would have stress cracks between different densistyies of aluminum."" Are you sure what you are talking about?

http://www.twistmachine.com/

If that, then the peak inertial load comes to 2570G His setup will extend the redline to 7290rpm(if inertial load is kept the same)

L24 redline : 6500rpm rod : 133mm stroke : 73.7mm maximum inertial load at redline : about 2220G -------------------------------------------- Chewievette's setup rod : 140mm stroke : 69.7mm if maximum inertial load (the load rod and bolt sees) is to be kept the same, the new redline is moved to 6750rpm. A 250rpm gain, not much. If the LD28 or FJ rods are very strong(I am sure they are), and the pistons/pins are very light, then redline rpm can be extended higher. That only takes care of the con rods so they don't break. To get really high rpm, there's tons of work to be done. Oil alone is a lot of trouble. To rev Chewievette's setup to 9000rpm, the rods must withstand 3900G of inertial load.

Cewievette, You sure you have a L20A crank, not L20B crank? Cuz L20B is a 4 cylinder crank. Don't count on it unless you already have it. TheHelix wrote this, it's better than Lengine http://www.ozdat.com/ozdatonline/enginedesign/

the site has some slightly porny ad's but here's the video. http://www.thatvideosite.com/view/2282.html Race car trailing in the vacuum behind another race car....and then....

You can see the pistons thru the spark plug hole, if you are lucky, two of them will be near TDC, bring a flash light. The pins will require hydraulic press to get out. You'll have to make a jig to prevent pistons from being damaged or pay someone to do it. I guess you ask this because you want to buy as few parts as possible since the engines involved all have L28 rods. You have to get them as a set. If you want to remove the head to get the pistons/rods out thru the top, remember to clean out the ring of fouling around the top of the bores. You have another option : The other option is to sand down(or turn down if you have a lathe) your dished pistons a bit and use L24 rods. It costs you some labour and around 120$ for the L24 rods, but you get better rod/stroke ratio. The L24 rods are 3mm longer so you have to sand the pistons down until deck height is near zero. You can leave the pistons sticking out of the block a little bit to improve quench. If you are interested in this route, I'll tell you how to identify L24 rods so you don't end up buying L26 or L28 rods on eBay. A lot of eBayer's call their L26/L28 rods L24....

I don't think L20A is available here. The spec you listed gives too little room between head and piston anyway(0.25mm) what up with that?

lol who the hell made that?

Magnets clamped over fuel line again? BS.

There is a company that makes DOUBLE/single action 1911 called Para Ordnance in Canada. Ever heard of them? They sell in North America and have good reputation, very smooth trigger pull I heard. If you ever thought about carrying 1911 but is conservative about carrying a chambered+cocked+locked gun, then you should take a look. It's been too long since I touched guns, can't remember if it's ParaOrdnance or Para Ordnance...

zeiss150, Are you going to kick my a$% if I tell you to The AZC pistons are 87mm pistons only. It's listed on their website. 24ounce, When you have a few millimeters of air fuel charge sandwiched between piston and the quench pad, it degardes fuel mileage and increase tendency to knock. If you have the freedom to choose, bring the pistons close to block deck instead of several mm down the bore.

Well in Canada we aren't allowed to carry handguns. Our handguns are limited to 10 round capacity; our semiauto centerfire rifles are limited to FIVE rounds. But unlike in the USA, our semiauto rimfire rifles can have unlimited round capacity. I have a ruger 10/22 with 50 round drum mag....feels almost like a Thompson, plinking without aiming

I always wondered why Norm got the boot after the gas price thread. Afterall he's the 12 second SU carbie guy. I guess I do now. For the record, the admins do a much better job on this site than some forums I used to go to.

mtcookson, I've read your reply. The compression and power stroke will cushion some of the inertial load, but the danger zone is in the exhaust stroke where there is pressure pushing the leading piston counter-clockwise, since the leading piston is decelerating, the inertial load is also counter-clockwise. The two loads overlap and gives the highest inertial load in ccw direciton. Ditto intake stroke, except in cw direction and less. To put things into perspective, a stock SBC engine at 6500rpm has a peak inertial load of 3200G(that's G for gravity, not grams), or 7000lb given the mass of stock piston, pin, and small rod end. The bottom end has no problem with 7000lb of inertial load because the load is a stretching load, pulling everything up. Can one imagine pulling the rods with 7000lb of force and the rod not breaking? If the rod is strong enough like the stock rod, then I guess one can. The problem with MYT is not that inertial load exists, but the fact the load is in the form of rocking load. Suppose the MYT inertial load is ONLY 10% of that, 700lbs. Can you imagine standing four 175lb guys on one piston and have it not failing? And that's just 700lb of static load. The real inertial load is rocking it sideways, happening with every stop and go, with the load growing rapidly as rpm increases. True, the MYT engine can be designed with a small bore and stroke(radius) so the pistons don't fall off, but then the engine will not have enough displacement or rpm to beat four-stroke engines. The fuel combustion...there is never a lack of time to burn fuel, the reason some of the fuel doesn't burn is that it is not atomized well, not mixed with air well or just too cold/rich/lean to burn. The mixture that provides most power is a mixture with excess fuel anyway. The fuel droplet doesn't have time to go toward the outside....that is not quite accurate. The droplet itself doesn't really go anywhere, it's the pistons and chambers that swing. The pistons slap on the droplets, then the liquid is flung to the outside. If you slip a ring over a smooth stick, you'll see no matter how fast you swing, the ring can always find enough time to slide outwards. But that is not to say all the fuel will go to the outside, just some of it will be biased toward the outside. 4 stroke engines can have lousy fuel distribution too so it's not any better than MYT. The main problem is inertial loads, all other problems can be fixed with small fixes. The inertial load is what is limiting the engine. Imagine the engine running at 200 times the speed in animation/video, then you'll begin to feel the inertial loads tearing the pistons off the base.

nice work!!

I bet the sticker in the back says "Hey treehuggers! look what I got done"

lol, ok I've seen it actually.

Rocking load...ok you see how 4 pistons move as a set and two set of pistons = 8 right? Each set of pistons connect to something...a disk or rotor of sorts so essentially, there are two parts looking like this : ...| --O-- ...| the ... means nothing, just have to put them there to keep the spacing correct. When you accelerate/decelerate the assembly rotationally, the inertia of the piston rocks the piston at the base, where it is attached to the rotor. It's like when the bus accelerates, you are shoved towards the back and when the bus brakes you are pushed toward the front. If you stand in the bus and your feet are planted on the floor, the accel/decel will feel like someone is pushing you back and forth, that's what I am refering to. If you glue a standing piece of wood on the bus floor, the inertial load accompanying acceleration and braking will eventually tear out the glue, and the wood will detach from the floor. Suppose the rotors do not really stop at any time, but inertial load exists with acceleration and deceleration of the assembly. If the rotors never really stop, it only helps a bit, but inertial load is there as long as acceleration/deceleration is there. Their website also states that the pistons "stop and go", just like in their animation. How highly efficient is the MYT engine? It's what they are telling us for sure. When rotary engine came out, highly efficient was what they called it. Besides, they can't run any fuel in MYT, the inventor said it is best run with vegetable oil since the fuel lubricates the engine. If it is to run with gasoline with seperate oil lubricant(and suppose they find a way to lubricate the engine), oil will get transported to the outer wall of the doughnut cylinder eventually. Let's not forget crud, mud, soot and any kind of fouling will be swept to the outer wall as well due to centrifugal force. Which bring up another point, fuel droplets will tend to gather near the outer wall (air can move easily, but fuel droplets want to go in tangent direction), if the cylinder fillings have one area rich, one area lean and a fraction of it just right, how efficient can this thing be? I say it is most likely a diesel engine with fuel injected before combustion or a gas fuel engine, but is it reliable? To me, the fact that a single stray debris can ruin the whole engine that requires special machinery to rebore defeats the engine's advantages. Anyway, I want to stay skeptical. I missed dinner typing these, lol.

Ever ride in a fast train? The kind that has a 75mph initial speed?

Gearing or leverage is one thing, but they can't help with the stop and go inertial load. And inertial load is the major problem, more than torque loads. When the inertial load is a rocking load against material it's even worse. When the material is hot it's worst because it is probably aluminium and aluminum gets a lot weaker hot, and then aluminum is not known for its fatigue resistance, it's going to break. Rotary engine do not have this problem because the "piston" and "rotor" is one triangular piece. Is there anything MYT engine can do but a stack of wankel cannot do? I don't see it. If the MYT engine can rev to 5000rpm with any fuel and hold the rpm for 5 minutes without failing instead of putting with compressed air then I am convinced this engine is ok. However the question still stands : what can this engine do that a stack of rotary engine cannot? They do share similar problems, except the rotary engine do not have problem with rocking loads or anything rocking back and forth like the two set of pistons in MYT. There is nothing that stops the developers from showing us a real fueled engine running, but they just don't show it.

It's OK to assume "instant acceleration" math-wise since a real train can accelerate to 5mph faster in less than 10 secs. The difference between "instantly accelerate to 5 more mph" and "accelerate to 5 more mph in 10 secs" over a 3000mile trip is neglectable. To interprete the question word for word, it would mean the speed/time graph is stepped. Any object at speed is observed by their frame of reference to have slower time flow. So remember to throw that relativity thing in there. TECHNO BABBLE TIME!

What happened at zcar.com stays at zcar.com. I for one don't need to know any verbal jousting going on there.

The one thing I don't trust is how the pistons attach to the round disks. The stop and go motion of pistons create a lot of rocking loads to the disk they are attached to, the pistons is likely to break off from the disks and once something breaks in the engine the whole thing is destroyed since they share one common cylinder.