|
spiny posted:is this an american car thing ? As I used to regularly coast down hills in my '78 VW van (it's currently off the road for welding) and have done the same in pretty much 20+ other cars over the last 20 years I've had a licence, all with no exploding anything. The mechanics of being in gear with the clutch in are not the same as the mechanics of being in neutral.
|
#
?
Jul 23, 2014 23:36
|
|
|
|
| # ? May 14, 2024 06:50 |
|
|
Just do it in the correct gear is what he's saying. Or in neutral not holding the clutch down. You ever notice how you can't engage first gear unless you're near stopped in most cars? That's because, even with the clutch in, you're still engaging syncros and dogs and spinning poo poo up to get ready to transfer power. It's not like a linear motorcycle gearbox.
Queen_Combat fucked around with this message at 23:38 on Jul 23, 2014 |
|
#
?
Jul 23, 2014 23:36
|
|
|
It's mostly an offroad thing - with the transfer case engaged in low-range, your gearing is MUCH deeper. For instance, my transmission gears are all 2.72 times lower in low-range than they are in high-range/on-road mode. Most transfer cases have a low-range gearing of somewhere between 2:1 and 4.xx:1. Basically, it shifts your gearing down two gears, i.e. third gear in my truck in low range is about the same as first gear in high range. So picture what would happen to your clutch if you stuffed it in second gear doing like 80.
|
|
#
?
Jul 23, 2014 23:38
|
|
|
Krakkles posted:No. You're probably doing it either not that fast or in neutral, he did it fast and in gear. I'd do it at 60-70 MPH with the gearbox in 4th - the nearest surfing beach to me involves lots of rolling countryside, and as my bus gets 24mpg on a good day, coasting down two miles of hill for a few minutes saves money  my current daily driver is a dull diesel, so just hums along in top gear no matter what.
|
|
#
?
Jul 23, 2014 23:45
|
|
|
spiny posted:I'd do it at 60-70 MPH with the gearbox in 4th - the nearest surfing beach to me involves lots of rolling countryside, and as my bus gets 24mpg on a good day, coasting down two miles of hill for a few minutes saves money
|
|
#
?
Jul 23, 2014 23:47
|
|
|
kastein posted:It's mostly an offroad thing - with the transfer case engaged in low-range, your gearing is MUCH deeper. For instance, my transmission gears are all 2.72 times lower in low-range than they are in high-range/on-road mode. Most transfer cases have a low-range gearing of somewhere between 2:1 and 4.xx:1. ah, I think I'm getting it now, its the same as when you see the exciting pics of big motorhomes towing small runabouts which get left in first, that sort of thing ?
|
|
#
?
Jul 23, 2014 23:49
|
|
|
Basically, but possibly even worse due to the extra gear reduction. Here's a 2.5 ton Rockwell (deuce and a half 6 lug axle) axleshaft that got its rear end handed to it. Nice spiral fractures. They get harder to see past the somewhat rusty section of shaft, but they apparently go all the way to the steering joint in the axleshaft.     And this is why it broke.  It gets romped on pretty hard in the Alaskan wilderness... with a 408ci stroker in it.
|
|
#
?
Jul 24, 2014 00:19
|
|
|
Just to demonstrate how much energy is in flywheel explosions, here's a Ford 429, stroked to 557ci: https://www.youtube.com/watch?v=vq5cjNhN_po Sounds like it's just a little over 6000 RPM when it goes; the billet flywheel they had ordered was delayed, so they used the stock flywheel for the dyno runs. Stock they couldn't rev much higher than about 5-5.5k, so the powertrain was probably rated for about that. A description of the energy involved, from here: quote:The exploding flywheel went through the bellhousing (blowing it up), cracked the engine block (ruining it), went right through the headers (destroying those), and then went through a wall and into the next room. That’s one hell of an explosion. Now imagine that right next to your feet, with only 1/4 inch or so of steel/aluminum to contain it.
|
|
#
?
Jul 24, 2014 00:45
|
|
|
InitialDave posted:I seem to recall someone going off-roading in the US, Moab, maybe? They were bimbling along in low second or first, and came to a nice, wide run down a slope, so just dipped the clutch and rolled down it, getting up to a reasonable speed and modulating with the footbrake. They told us about this in Dyno class at MMI. You might be tempted absentmindedly to clutch in and shift down into 1st while the dyno just whines away after doing a 4th gear pull up to something like 120mph, but don't. It's bad.
|
|
#
?
Jul 24, 2014 01:57
|
|
|
Give me back my truck, dog. You can't even drive, you are a dog.
|
|
#
?
Jul 24, 2014 02:07
|
|
|
Crotch Fruit posted:That trucker is living the dream right there, deep down that is what I really want to do when some rear end in a top hat cuts me off. That is the happiest day of that trucker's life. Given that it's most likely That's one thing where you're wrong (and a bit of a mechanical/human failure thrown in): Russian cops loove taking licences, mostly because it involves a shitton of paperwork/money/bribes to get one back. They'll use any excuse to go "well we're taking your license" because it usually leads to getting a hell of a bonus to overlook whatever it was. Now for the mechanical failure part: My uncle had a beat-rear end old toyota *something* minivan in Russia-loving thing was falling apart to the point where the windshield fell out at one point. This is not that story, though. Something failed in the power steering or something, no one is sure which, and the car ended up off the road a little ways and stuck on something. So my uncle puts on the e-brake, gets out to see what he's stuck on. Pretty predictable from here since, again, beat-rear end piece of garbage: e-brake fails, car rolls forward, nails my uncle in the knee and traps him under the bumper. Cops come, get my uncle out, and take his license away. Because well, he was the driver and he hit a pedestrian.  Took about 2 months to get the license restored.
|
|
#
?
Jul 24, 2014 02:23
|
|
the authorities won't even consider revoking his license.
|
InitialDave posted:The clutch disc, being attached to the input shaft of the gearbox and therby driven regardless of the pedal being dipped, did not like seeing what was later calculated as nearly 20,000rpm, and made its escape in exactly the way you would expect. Huh -- I never considered this. Fascinating. I don't think I've ever coasted down a hill in first with the clutch in, mostly because the transmission whine when I'm going too fast for the gear is disconcerting to me, but now I have an extra reason not to do it. Just a couple weeks ago in CA we were talking about another reason not to do it, specific to motorcycles: the majority of bikes share the oil between the transmission and the engine, so if you're coasting downhill at 60 with the engine idling, the transmission is spinning at 60 but only seeing idle oil pressure. Bad move. Something I did do, though: When I was in high school and learning to drive, I once made a really overzealous downshift on the freeway and went from fifth to second instead of fifth to fourth, while travelling 60~ miles an hour. As I dropped the clutch back out and saw the engine rev up past the redline, there was a loud BANG and a cloud of white fog. After much panic and freaking out on the side of the road and driving home at 20 miles an hour and so on, it turned out to just be a freeze plug blown out the bottom of the engine (I assume because of overpressure in the coolant system as the water pump got going a million miles an hour). No other damage -- that old Ford SPI 2000 was unkillable. Could have been far, far worse, apparently...
|
|
#
?
Jul 24, 2014 03:00
|
|
|
Fucknag posted:A description of the energy involved, from here: One of the legends around the physics department at my undergrad university was about an accident they had with some type of flywheel device a few years before I started. I don't remember the exact function of the machine, but from descriptions it was about the size of a washing machine, had a flywheel inside the size of a beer keg but solid steel, and spun it at upwards of 100,000 RPM in a vacuum. One day, due to a previously undetected hairline crack, the flywheel let go as they were spinning it up through 75,000-80,000 RPM. It demolished the machine, demolished the lab, and threw a 200-kilogram "containment shield" on top of the machine through the ceiling into the classroom above. They later found pieces of the equipment in a parking lot 200 yards away. Miraculously, no one died or was seriously injured.
|
|
#
?
Jul 24, 2014 03:05
|
|
|
Sagebrush posted:No other damage -- that old Ford SPI 2000 was unkillable. Could have been far, far worse, apparently... Mine needed me to do a 3 pedal dance on the winter because the awful ford idle air tube was leaky. And at under 100k miles the exhaust manifold was leaking at the block which made the of sensor think it was misfiring. I'd call the engine and the car that it was attached to a mechanical failure. In under 10 years Fuel pump dead one morning Rear door opened one day while driving Front spring broke while driving (luckily I was doing like 5th slowing to a stop) Fan resistor died. Real wheel bearing went bad Most was luckily under tsb and recalls.
|
|
#
?
Jul 24, 2014 04:06
|
|
|
Sagebrush posted:One of the legends around the physics department at my undergrad university was about an accident they had with some type of flywheel device a few years before I started. I don't remember the exact function of the machine, but from descriptions it was about the size of a washing machine, had a flywheel inside the size of a beer keg but solid steel, and spun it at upwards of 100,000 RPM in a vacuum. One day, due to a previously undetected hairline crack, the flywheel let go as they were spinning it up through 75,000-80,000 RPM. Not surprising, there are documented cases of that sort of thing happening. Here's one from Cornell with an ULTRACENTERFUGE (I love equipment names). http://www.chem.purdue.edu/chemsafety/newsandstories/centrifugedamages.htm Here's one at MIT (which seemed to be safely contained) http://web.mit.edu/charliew/www/centrifuge.html
|
|
#
?
Jul 24, 2014 04:07
|
|
|
Fart Pipe's cousin nuked two of those loving asstastic motors in under 6 months. They're hardly bulletproof.
|
|
#
?
Jul 24, 2014 04:08
|
|
|
tater_salad posted:You must have gotten a mistake one. These engines are notorious for dropping valves.
|
|
#
?
Jul 24, 2014 04:09
|
|
|
kastein posted:https://www.youtube.com/watch?v=4F53zdTU850 Another A-904 bites the dust  
PainterofCrap fucked around with this message at 06:09 on Jul 24, 2014 |
|
#
?
Jul 24, 2014 04:58
|
|
|
PainterofCrap posted:Another 340A bites the dust Id drive the living poo poo out of that.
|
|
#
?
Jul 24, 2014 05:41
|
|
|
tater_salad posted:You must have gotten a mistake one. These engines are notorious for dropping valves. Was that in a Focus or an Escort? If the Escort, that's kinda sad, as the car it's based on, the BG Mazda Protege / Familia is a really solid car overall.
|
|
#
?
Jul 24, 2014 05:42
|
|
|
The platform can be good all it wants, but the engine was developed in-house at Ford; Mazda had nothing to do with it.
|
|
#
?
Jul 24, 2014 05:58
|
|
|
I had a SPI powered Escort and it was unkillable. Sold it with 275k on it and the next owner took it to 300k and beyond. As far as I know it's still clattering away being harsh and lovely. I guess some SPIs were better than others.
|
|
#
?
Jul 24, 2014 05:59
|
|
|
8ender posted:I had a SPI powered Escort and it was unkillable. Sold it with 275k on it and the next owner took it to 300k and beyond. As far as I know it's still clattering away being harsh and lovely. I guess some SPIs were better than others. Likewise -- the one we had was a 97 Escort wagon, and I think we sold it with around 220,000 miles. Still running and still on its first clutch :iamafag:
|
|
#
?
Jul 24, 2014 06:09
|
|
|
Sagebrush posted:Likewise -- the one we had was a 97 Escort wagon, and I think we sold it with around 220,000 miles. Still running and still on its first clutch :iamafag: Mine was also a 97' Escort wagon. Maybe that was a great year for the Escort. (It wasn't, all the years were bad for the Escort)
|
|
#
?
Jul 24, 2014 06:51
|
|
|
Fucknag posted:The platform can be good all it wants, but the engine was developed in-house at Ford; Mazda had nothing to do with it. Right I meant the other miscellaneous stuff complained about :P
|
|
#
?
Jul 24, 2014 07:02
|
|
|
CharlesM posted:Was that in a Focus or an Escort? If the Escort, that's kinda sad, as the car it's based on, the BG Mazda Protege / Familia is a really solid car overall. Focus. I guess the engine was okay but I sold it at around 120k because I didn't want to deal with a dropped Valve or a preemptive head change. Ford did a great job making sure I didn't buy a Ford again. My 2 previous cars were older and had less issues. One died in an accident. And the other died due to salt in hindsight I should have just gotten the mazda's fuel and brake lines re-done.
|
|
#
?
Jul 24, 2014 13:53
|
|
|
I have owned 5 3rd gen Ford Escorts/Mercury Tracers. Daughter totaled two and I flipped two for profit, other daughter still driving the last one. Surprisingly easy to work on, I love the fuel pump access door under the back seat. Bought one cheap because it had dropped intake valve seat #4 and another with a bad head gasket but the combustion gasses had melted a trough in the head. The Pick N Pulls were full of them at the time. The first car I lucked out and the first head I pulled was good. When I was fixing the second a year later after wasting time pulling the first two heads I perfected the art of pulling the valve cover, head bolts and the alternator mount that bolts to head and block then pry bar and lift up the entire head, intake and exhaust manifold to check the head. The intake valve seats in the number 4 cylinder had dropped in every single one I checked, I pulled all 7 heads in the yard. I ended up buying a rebuilt head. After I had installed the head and it was drivable I was looking for a jack and in the back of a 98 escort wagon I had pulled the head off was a brand new remanufactured head. Their seat dropped they bought a head and either couldn't find a mechanic cheap enough or or it got ticketed and towed for being inoperable. The beauty is that Pick n pull has fixed pricing they do t care the make or model or condition, so I got it for $48 or so. Everybody else in the yard was jealous. I was was just pissed I hadn't noticed it three weeks before instead of spending $250 on the rebuilt one. I still have it and next time a daughter wrecks their car I'm looking for another with dropped valve on craigslist for cheap. Apart from the valve seat issue they are pretty mechanically reliable and because of that issue there are plenty of unwrecked ones for parts. The relay module that controls both the cooling fan and ac compressors are prone to going out. Overheating can trigger the valve drop. I opened one up and I think standard relays could be soldered in to rebuild but at this point I have spares of that and every other sensor on the car.
|
|
#
?
Jul 25, 2014 02:01
|
|
|
tater_salad posted:You must have gotten a mistake one. Godholio posted:Hahaha, goddamn. the little clip that held the fuel door closed, and I stripped the threads on a spark plug hole and had to helicoil it. Currently at ~180k miles and am totally planning for a total powertrain swap within the next 50k miles. Also on my 3rd or 4th set of struts (Belle Tire, yes they are crap but everything since the first set has been warrantied). And gently caress the timing belt system in those. Non-keyed camshaft gears suck rear end. Also screwed up on the first replacement and threw the belt (NO DAMAGE!), took another 2 tries before I was good to go. First timing belt was replaced 7 months ago which was slightly late, but at least now I can replace it within 2 hours if the various bolts aren't rusted stuck.
|
|
#
?
Jul 25, 2014 02:54
|
|
|
I had a spare timing belt in the trunk for probably the last 4 years I owned it, but never wanted to dig in to get it installed. On a previous car (89 Taurus) I got to where I could replace the 3.0 Vulcan's alternator in under 15 minutes. A bad/undiagnosed voltage regulator will offer plenty of practice, it turns out. 
|
|
#
?
Jul 25, 2014 03:45
|
|
|
How come the bad voltage regulator would cause damage to the alternator? Shouldn't it only affect the downstream components?
|
|
#
?
Jul 25, 2014 04:18
|
|
|
Sagebrush posted:How come the bad voltage regulator would cause damage to the alternator? Shouldn't it only affect the downstream components? If it fails closed, as in max current to the field windings (which increases the induced voltage coming from the rotor windings), it can burn them out faster, in addition to whatever excess voltage is output.
|
|
#
?
Jul 25, 2014 04:24
|
|
|
Sagebrush posted:How come the bad voltage regulator would cause damage to the alternator? Shouldn't it only affect the downstream components? What fucknag said. The charging system is like a closed loop circuit, the regulator/rectifier turns the generator's AC into DC, and then it regulates the amount of voltage going into the field windings based on demand/supply. This is why your charging voltage doesn't skyrocket every time you rev the bike, the RR notices the voltage going up so it reduces the field coil current (voltage? not sure which one it uses) so as to make the output lesser.
|
|
#
?
Jul 25, 2014 04:36
|
|
|
Sagebrush posted:One of the legends around the physics department at my undergrad university was about an accident they had with some type of flywheel device a few years before I started. I don't remember the exact function of the machine, but from descriptions it was about the size of a washing machine, had a flywheel inside the size of a beer keg but solid steel, and spun it at upwards of 100,000 RPM in a vacuum. One day, due to a previously undetected hairline crack, the flywheel let go as they were spinning it up through 75,000-80,000 RPM. I was once in a room with enough flywheel UPSs (Flywheels hooked to generators) to power an 11MW datacenter for 16 seconds. I was fairly terrified. I'm not entirely sure my city is aware of how much mechanical energy is being stored in that building.  Can't find the weight of the flywheel but found that they spin at 36,750 RPM. I want to say it was in the 100-150lb range. Containment was gauge sheet metal. [e] The flywheel weight may have been much higher, the entire enclosure weighs 1500lbs. FatCow fucked around with this message at 05:59 on Jul 25, 2014 |
|
#
?
Jul 25, 2014 05:47
|
|
|
Holy poo poo. Which way do they spin? Tell me it's not horizontally at least.
|
|
#
?
Jul 25, 2014 06:04
|
|
|
slap me silly posted:Holy poo poo. Which way do they spin? Tell me it's not horizontally at least. Looks like it is. 
|
|
#
?
Jul 25, 2014 06:19
|
|
|
slap me silly posted:Holy poo poo. Which way do they spin? Tell me it's not horizontally at least. It's not a flywheel like you would imagine, as a disk. It's more of a cylinder.  
|
|
#
?
Jul 25, 2014 06:19
|
|
|
What's the benefit of having a flywheel based UPS? Faster response time or more output for the physical UPS size?
|
|
#
?
Jul 25, 2014 06:24
|
|
|
FatCow posted:I'm not entirely sure my city is aware of how much mechanical energy is being stored in that building. The equivalent of forty‐two kilograms of TNT.
|
|
#
?
Jul 25, 2014 06:25
|
|
|
Mr. Despair posted:What's the benefit of having a flywheel based UPS? Faster response time or more output for the physical UPS size? Batteries degrade. most fuels have a shelf life.
|
|
#
?
Jul 25, 2014 06:36
|
|
|
|
| # ? May 14, 2024 06:50 |
|
|
Carbon composite flywheels decompose in a ball of fluff basically. No shrapnel. They originally developed them for use in Postal Service jeeps back in the 70s.
|
|
#
?
Jul 25, 2014 07:12
|
|
