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Internal Combustion Engine

ciechanow.ski

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Re: Internal Combustion Engine

#171

Post by specialp »

gtvwill wrote: post #166
specialp wrote: post #15

I just built an engine for my car. One thing I gained an appreciation for was how CHEAP cars and engines are. There's probably nothing else with as precise machining that is as inexpensive. Engine cylinders are honed to accuracies that are less than 1 thousandth of an inch. Crank journals as well and rod journals. This is all precise machine work with metal. I use inches here because in machine work thousandths of in…

> "I use inches here because in machine work thousandths of inches is the language du jour." Yeah not in Australia unless your machinist is >50 years old. Metric is more accurate/easier/less prone to mistakes. Metric is what we use.

I'm not denying the metric system. Just in the USA it is thou period. and if the measurement is a consistent unit of whatever it works. Also GM (and Holden in oz) are inch based. So using metric will subject you to mistakes possibly. I agree though in science SI is the way to go

Re: Internal Combustion Engine

#173

Post by TheSpiceIsLife »

kingsuper20 wrote: post #10

It's a lot scarier when you see things going under load at speed. Lots of wiggling, twisty magic, waves. Smokey Yunick (blessed be his name) used to make see-through timing covers, oil pans, valve covers + strobe light + some sort of oscilloscope setup to watch the craziness. I think I remember seeing the results for small block Chevrolet timing gears on sprint car engines as the teeth wiggled more and more with rpm.…

How much of that was really metal elasticity and how much artifacts of the camera technology used, eg. rolling shutter?

I work with metals all day every day, and damn can it flex, but would have imagined the high carbon steels used in engines would he fairly still.

Re: Internal Combustion Engine

#174

Post by specialp »

philg_jr wrote: post #168
specialp wrote: post #41

Earlier quoted context omitted.

I built an LSX (Aftermarket GM) iron block engine (V8 LS) for a CTS V. I had to get some very precise tools (Have to measure to 10,000ths) or they were useless for bearing clearances and verifying cylinder diameters. My cylinders were 4.155 bore, and the bearing clearances were around 1.8 thousandths. Forged pistons, rods and crank. I had cracked a cylinder/piston on the original LSA. I did not trust anyone to do the…

Damn, dropping a new engine in a CTS V? What year? NA? How much power are you shooting for? The CTS V is definitely one of my favorite cars, I'd love to own one one day, but the ones with the manual trans hold their value pretty well :)

It was and still will be supercharged. It was 650 crank Hp, and will be over 800 conservatively . and its manual ;)

Re: Internal Combustion Engine

#175

Post by gtvwill »

specialp wrote: post #171
gtvwill wrote: post #166

Earlier quoted context omitted.

> "I use inches here because in machine work thousandths of inches is the language du jour." Yeah not in Australia unless your machinist is >50 years old. Metric is more accurate/easier/less prone to mistakes. Metric is what we use.

I'm not denying the metric system. Just in the USA it is thou period. and if the measurement is a consistent unit of whatever it works. Also GM (and Holden in oz) are inch based. So using metric will subject you to mistakes possibly. I agree though in science SI is the way to go

Yeah I cut my teeth on Subaru engines (helped having a gf who was a subi then telsa mechanic walking me through it). Subi are all metric tho. My workshop is a mix of metric for new gear and imperial from my old mans days running a farm.

We even have some stuff thats neither metric or US imperial, but is british witworth imperial...so different again and just enough to make a difference. Makes for some confusing repairs when your working with stuff that's had a mix of all 3 systems due to a long life of repairs.

Re: Internal Combustion Engine

#176

Post by s5300 »

gtvwill wrote: post #166
specialp wrote: post #15

I just built an engine for my car. One thing I gained an appreciation for was how CHEAP cars and engines are. There's probably nothing else with as precise machining that is as inexpensive. Engine cylinders are honed to accuracies that are less than 1 thousandth of an inch. Crank journals as well and rod journals. This is all precise machine work with metal. I use inches here because in machine work thousandths of in…

> "I use inches here because in machine work thousandths of inches is the language du jour." Yeah not in Australia unless your machinist is >50 years old. Metric is more accurate/easier/less prone to mistakes. Metric is what we use.

Still widely used and taught in the machine shops of highly reputable universities over here in the U.S.

If you're under 40 and can't use metric and imperial jargon without a second thought in the shop here that's a different problem. I personally enjoy doing machine shop-esque metal fabrication in metric and woodshop type things in imperial, but all machine shop instructors I've met through several good stem uni's that look even slightly middle aged love to talk in thou of inch, some to the point of getting quite physically frustrated when asked where the metric drill index/reamer set are in otherwise highly stocked shops...

Also, I've noticed and heard the same from others in surrounding states - Fluid Dynamics professors love to include absolutely unecessary boatloads of strange units and conversions in coursework/exams to apparently "prepare us for the shitshow that is industry"

Re: Internal Combustion Engine

#177

Post by globular-toast »

Over the years I've learned how most parts of a car work at a basic level. Engines, clutches, gearboxes, differentials etc. I can't help but feel a bit sad that it might all go away within my lifetime. Electric cars are essentially just a battery and a motor. They're just not very interesting.

Re: Internal Combustion Engine

#178

Post by rsj_hn »

outworlder wrote: post #108
rsj_hn wrote: post #68

Earlier quoted context omitted.

The Tesla can go 300 miles by making it light, aerodynamic, brakes that recharge the battery, not turning on the heater, etc. Yes, it's a significant engineering accomplishment, but in the heavy long haul world when analyzing break-even points what matters is range improvements due to an increasing energy/weight ratio, not range improvements due to reducing air resistance and inertia. This is because the form factors…

> by making it light If there's one thing that EVs are not, is "light". Model S ranges from 4,561 to 4,941 lbs. A model 3, 3,648 to 4,250 lbs. A Nissan Leaf - 3,538 to 3,946 lbs. In comparison, a Honda Civic weights 2,771 to 3,012 lbs. Regenerative breaking is nice but it's very dependent on the particular drive and terrain. Heaters are power hungry as there is very little waste heat that can be used (again, due to t…

> If there's one thing that EVs are not, is "light". sigh

Obviously we are not comparing about the weight of an EV compared to an apple or vehicle that doesn't require a battery. We are talking about extreme measures taken to make the car lighter so it can improve range. Replacing cheaper steel with more expensive aluminum, reducing even surface area of plastics, reducing wires. Truly amazing steps were taken to reduce weight.

> No it doesn't! It has horrible energy density per volume,

volume? Seriously? "The energy in 2.2 pounds (1 kilogram) of hydrogen gas is about the same as the energy in 1 gallon (6.2 pounds, 2.8 kilograms) of gasoline." https://afdc.energy.gov/fuels/hydrogen_basics.html

Re: Internal Combustion Engine

#179

Post by elihu »

the_cat_kittles wrote: post #77
elihu wrote: post #47

Earlier quoted context omitted.

The raw materials may continue to cost more for EVs. Motor windings are generally copper, and batteries contain lithium and (usually) cobalt and nickel. Permanent magnet motors sometimes contain rare earths. One could make an EV with aluminum motor windings and electrical cabling, no rare earth magnets, and lithium iron phosphate batteries. That would keep expensive materials to a minimum. EVs don't need a catalytic…

cmon man. the total weight of pricey metals in a car is so low, there is no way its going to offset the cost of precision machining. tolerances < 1 thou and callouts for surface finish and perpendicularity are expensive!

Somehow car manufacturers are able to make engines, transmissions, transaxles, and differentials really cheaply, so apparently all that precision manufacturing doesn't really cost all that much when producing at high volume. This should be equally true of EVs and combustion-engine cars.

Raw material costs might still be less than the manufacturing costs, but they're pretty hard to avoid. Also, materials that are cheap now might not be if demand grows faster than supply.

Re: Internal Combustion Engine

#180

Post by Bubbadoo »

elihu wrote: post #107
esaym wrote: post #96

Earlier quoted context omitted.

Note to replace copper wiring with aluminum, you have to go up at least one gauge size.

Yeah, aluminum is a worse conductor so you need thicker cable. It's less dense, though, so I think it usually comes out as being lighter. Thicker cables can be more inconvenient. I think aluminum also tends to have more problems with oxidation causing too much resistance at electrical contacts. I think for motors generally you just end up with a larger motor for the same amount of power.

All points you make are very true. In addition, aluminum tends to crack as it ages and you'll find aluminum wiring is usually a culprit in electrical fires. In the world of mobile electronics, it's usually looked down upon as the cheapest alternative when compared to real copper conductor used in higher quality automotive wiring.
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