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Internal Combustion Engine

ciechanow.ski

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Re: Internal Combustion Engine

#121

Post by elihu »

esaym wrote: post #93
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…

> EVs don't need a catalytic converter, so that's a big thing in their favor. I feel there is some sort of scam going on with catalytic converters for the last few years. I actually worked in a small family owned auto shop in the early 2000's. If a car came in with a clogged cat, we'd first fix the source of the issue (usually a mis-firing cylinder allowing raw fuel into the exhaust) and then we'd cut out the cat, an…

I don't think cats are to address greenhouse gasses; they're focused more on reducing pollutants that affect local air quality and human health.

The main greenhouse gas from a car is carbon dioxide. The amount you create is directly proportional to the amount of fuel you burn.

I don't know why modern cats are expensive; it might have to do with the price of platinum, palladium, and so on, and the relative amount of those materials. A cheap generic cat might have the bare minimum amount of catalyst, and might not do a very good job.

Re: Internal Combustion Engine

#123

Post by tmh88j »

esaym wrote: post #106
tmh88j wrote: post #55

Earlier quoted context omitted.

>I had cracked a cylinder/piston on the original LSA. I did not trust anyone to do the work so I did a lot of research and did it all myself I love working on cars so I totally get wanting to do that, but why didn't you trust someone else to do the work? There are probably more reputable LS builders across the US than any other engine family.

It sounds like he wanted some very precise work done. Quality in the blue collar trades has gone to nil in the last decade. And if you do find someone that is very detailed and "by the book" level of quality, you are going to pay 3X the normal labor rate. For instance, this is a performance transmission shop [0] that regularly takes apart "precision" rebuilt transmissions only to find they were not done right at all.…

LS engines are among the most common engines in custom built cars, and there are countless shops out there who specialize in them. No offense to him or you, but it's quite ridiculous to believe you can do a better job building an engine on your first try than shops like Texas Speed who have been doing it for decades with full blown R&D labs and regularly build 2000+ horsepower motors, all with highly skilled machinists and engineers using professional equipment that the average person would never be able to afford.

Edit - For reference here's a video of the shop I'm referring to. They're far from a podunk operation. https://www.youtube.com/watch?v=8HgwF5dISmU

Re: Internal Combustion Engine

#124

Post by kingsuper20 »

mgarfias wrote: post #109
kingsuper20 wrote: post #81

Earlier quoted context omitted.

Very cool. Although I own an LS, I've never touched an LS. The Sloppy Mechanics guy is impressive though. Since a short block is mostly just a short block, I'll be interested in seeing if LS heads/intake manifold/headers takes off in the SBC community.

Huh? What do you mean "takes off". Do you mean do we build LS motors now instead of gen1/2 SBCs then yes. If you mean "do the LSx heads drop onto a gen1/2 SBC", then no, not at all. only thing common between them is the cylinder spacing. The LS uses 4 bolts per cylinder like a ford, instead of 5 like the SBC, the firing order is different, the valve layout is different (ports are symmetric vs mirrored), etc.

Firing order is something of an arbitrary thing, it's been done on SBC for some time.

There are small block Chevrolet blocks that accept LS heads (Bill Mitchell maybe?)

(note: I wasn't referring to box-stock LS heads on a box-stock SBC)

Re: Internal Combustion Engine

#125

Post by buran77 »

esaym wrote: post #93
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…

> EVs don't need a catalytic converter, so that's a big thing in their favor. I feel there is some sort of scam going on with catalytic converters for the last few years. I actually worked in a small family owned auto shop in the early 2000's. If a car came in with a clogged cat, we'd first fix the source of the issue (usually a mis-firing cylinder allowing raw fuel into the exhaust) and then we'd cut out the cat, an…

On the other hand the quality and performance of those $80 catalytic converters are questionable at best. They have neither the longevity, nor the performance of the original part. They might last even 10 times less, and they're usually just barely good enough to pass the emissions tests, which is already the lowest bar to pass given how all manufacturers optimize for that. Real life emissions are far worse.

And the purpose of the catalytic converter is to make sure the CO, NOx, and unburned fuel are rapidly oxidized to CO2, N, and water before leaving the exhaust system. The outcome is that you will produce more greenhouse gases but fewer compounds that are more immediately dangerous to people, especially in cities. So it reduces localized pollution at the price of more CO2.

Re: Internal Combustion Engine

#126

Post by kingsuper20 »

esaym wrote: post #116
zeusk wrote: post #83

Earlier quoted context omitted.

Any race or high power engine, especially those that rev quite high will need rebuild - not just in bottom end but often with piston rings and valves as well. You don't really hear about those other engines much because their buyers understand that a race engine needs more maintenance than any other road car. Also, not beating on the engine until oil has warmed up to temp will elongate the bearing lifespan quite a bi…

> Also, not beating on the engine until oil has warmed up to temp will elongate the bearing lifespan quite a bit. I am curious if there is proof to this. I've always felt the same way. I know in the "old days" with iron pistons, if you you simply started up a cold motor and and drove it hard without a warm up period, the pistons would expand quicker than the block and would start to scour the walls and/or lock up. Bu…

It wasn't so much locking up or anything but cast vs. forged.

Re: Internal Combustion Engine

#127

Post by keanebean86 »

toxik wrote: post #79

This was excellent, but should perhaps be clarified that this is a gasoline engine - diesels don’t ignite by spark, but by immense pressure in the chamber. This also invalidates the “you cannot add fuel to increase power” of gasoline engines. Diesels can (and should!) run at lower rpm; they don’t stall because the ECU can add fuel to increase power output.

What I want to try is replacing valves with electric iris mechanisms. The computer would signal the iris to open or close depending on the situation.

No more complicated variable valve stuff. Just hold the iris open longer. Also no more interference engines and timing chain/belt changes.

Iris: https://commons.m.wikimedia.org/wiki/File:Iris_Diaphragm.gif

Edit: fixed typo, added link to iris gif

Re: Internal Combustion Engine

#128

Post by akiselev »

kccqzy wrote: post #92
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…

> 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. Not to denigrate the amount of engineering that went into car engines, but literally, what about chips? Devices that contain billions of transistors, arranged precisely on the order of nanometers. Yet they cost only hundreds of dollars.

They're apples and oranges. Chips are not machined, they're etched in batches. Their "tolerances", so to speak, are limited by the wavelengths of visible or UV light they use for creating the masks and exposing the photoresist that protects the wafer from hydrofluoric acid and other etchants. There's no mechanical force involved, except to spin wafers to apply coatings and move them between each stage of the process.

Engine blocks, on the other hand, are CNC machined one at a time and the force of machining steel causes vibrations that move the cutting tools thousands of nanometers back and forth. Placing both in the same building, for example, would likely cripple the semiconductor fab. Having a machine shop in China make a one off would likely cost as much as a luxury car.

Re: Internal Combustion Engine

#129

Post by tmh88j »

zeusk wrote: post #117
tmh88j wrote: post #102

Earlier quoted context omitted.

The S65 and S85 are road car engines, not racecar engines. They're also hardly BMW's highest performing motors. Even Dinan built engines don't suffer from that problem.

They're meant to be dual duty. There aren't any road car engines I'm aware of that use individual throttle bodies or 12+ compression without direct injection.

The S54 engine which came before the S65/85, was also high revving, had 11.5:1 compression ratio and didn't have any of the rod bearing issues. The 20v Toyota 4AGE also had them too with a high compression ratio.

Re: Internal Combustion Engine

#130

Post by formerly_proven »

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.

Only in the USA ;)

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