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Phy posted:When you think about it in terms of energy storage it's not that surprising. Because water is so incompressible, it doesn't take very much energy at all to build pressure. If it's air, you're pumping a lot of energy into it to cram a whole bunch of volumes into one volume. Volume has something to do with sustaining the pressure when you release some, too. Common rail diesels run 15,000psi in the business end of the fuel system. You would think that if you crack a nut open with it running you would get a laser of diesel shooting out and cutting through everything in it's path. In reality (I'm told) you get a small but extremely powerful squirt of diesel. You'd lose the end of your spanner, but not much else. I worked out the total amount of high-pressure fuel in a 1KD-FTV fuel system is less than couple of hundred ml, so it makes sense.
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Sep 28, 2014 00:53
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My NAPA axle survived 2 whole AutoX's... 
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Sep 28, 2014 01:12
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Slavvy posted:Volume has something to do with sustaining the pressure when you release some, too. It'll also inject enough diesel or hydraulic fluid under your skin to cause severe necrosis and death unless debridement and/or amputation are performed, so be careful with that line of reasoning. Real careful. 
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Sep 28, 2014 01:18
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Shooting scuba tanks with an M1 garand https://www.youtube.com/watch?v=vWivPYuLiOE
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Sep 28, 2014 01:31
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MOVIE BY KYLE
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Sep 28, 2014 01:33
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kastein posted:It'll also inject enough diesel or hydraulic fluid under your skin to cause severe necrosis and death unless debridement and/or amputation are performed, so be careful with that line of reasoning. Real careful. Oh for sure; I don't feel like losing a hand to gangrene. Cracking the high pressure system while it's running is like the biggest no-no there is. I'd love to see what happens first-hand, though. Just not with my own hand 
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Sep 28, 2014 02:04
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Slavvy posted:Oh for sure; I don't feel like losing a hand to gangrene. Cracking the high pressure system while it's running is like the biggest no-no there is. I'd love to see what happens first-hand, though. Just not with my own hand An RSG waterjet mach 2 runs at 55,000 psi, and can cut stainless steel at 60% A 6.7 powerstroke fuel rail runs at 30,000 psi. https://www.youtube.com/watch?v=pte7F1gmm4Q How much harder is your finger than stainless steel?
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Sep 28, 2014 02:10
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 This came from the oil dipstick.
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Sep 28, 2014 02:28
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The guy who did a lot of work on the engine in my 1997 Audi A6 (C4) forgot something when replacing the timing belt. I'd had it on the road for a week when suddenly one day there was a rattling from the engine. It lasted a few seconds before there was a loud bang and the engine stalled. Didn't start again, of course. After having the car towed home I took a quick peek. I just bent the plastic cover for the cam sprocket a little, and found some metal pieces. The timing belt didn't look good.  The timing belt tension wheel. Broken vs new.  To me this is a horrible mechanical failure since the wheel should have been changed when the timing belt was. Now I have to hope the belt didn't skip too much and cross my fingers when starting the engine today. Perhaps there will be more horrible mechanical failures involving explosions (or at least bent valves).
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Sep 28, 2014 08:07
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JazzmasterCurious posted:timing belt stuff Don't waste your time. That engine's hosed. SUSE Creamcheese fucked around with this message at 15:02 on Sep 28, 2014 |
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Sep 28, 2014 14:49
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zundfolge posted:Don't waste your time. That engine's hosed. Yeah, if the tensioner went that badly & the car stalled out there is a 0% chance the belt didn't slip to some degree. Cheapest option is probably going to be swapping in a second hand engine.
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Sep 28, 2014 15:18
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Yeah that engine is done, my condolences. The rattling was probably your valves tapdancing on the pistons. In general, a loud bang means "its hosed"
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Sep 28, 2014 15:24
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So would the mechanic be paying for your new engine?
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Sep 28, 2014 17:26
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Slavvy posted:Oh for sure; I don't feel like losing a hand to gangrene. Cracking the high pressure system while it's running is like the biggest no-no there is. I'd love to see what happens first-hand, though. Just not with my own hand And to make it even more fun any kind of atomisation will have the same effect. The boiler igniter only runs about 2 bar and I went to test the nozzle and held a rag in front. The first's hand broke the speed of sound with how quickly he pulled my hand out of the way. gently caress I'm glad he was thinking and saved my dumb rear end.
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Sep 28, 2014 19:08
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Two Finger posted:And to make it even more fun any kind of atomisation will have the same effect. The boiler igniter only runs about 2 bar and I went to test the nozzle and held a rag in front. The first's hand broke the speed of sound with how quickly he pulled my hand out of the way. gently caress I'm glad he was thinking and saved my dumb rear end. I don't know if your post/username combo is appropriate or not, as it implies the opposite outcome. Edit: on a similar note, on Thursday I didn't open my trunk enough to prevent it from falling closed, tried to catch it. Caught it before it slammed my fingers, but not early enough to prevent the power-assisted closing from kicking in and slowly pinching my fingers as it pulled the latch in. I was stupidly lucky that I had the keys in my pocket to open the trunk back up. When I work on my car I normally either leave them in the car to prevent the doors from auto-locking, or sit them >20 feet away so the car will actually shut off the electronics. I had thin but very dark purple bruises across the tops of my index, middle, and ring fingers on my right hand, along with a noticeable crease in the skin. They all seem to have healed up now though. ApathyGifted fucked around with this message at 03:29 on Sep 29, 2014 |
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Sep 29, 2014 03:23
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GoodbyeTurtles posted:Yeah, if the tensioner went that badly & the car stalled out there is a 0% chance the belt didn't slip to some degree. Would it turn at all if the belt slipped, timing went haywire and the valves bent? Say if a new timing belt, wheels etc was installed, would there not be some kind of horrible noise from the engine upon trying to start it? I'm asking seriously 'cause it would seem I got lucky on this one. No, the mechanic will not replace the engine / car / whatever. He's just a friend, and kindly let me have the car on down-payments. After changing the head gaskets (coolant leak) and other service parts (dampers, end links, etc) the car ran fine, was solid and passed the periodical. I then took ownership, and had it on the road for one week before this happened. Just my luck. But he's not getting any money until I have it running again. Car's solid in all other aspects. Low mileage, no rust. I'll not be the goon in the well here so it might be new engine time. Sad, it's rare to find ones below 200,000 Km these days. F4rt5 fucked around with this message at 11:55 on Sep 29, 2014 |
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Sep 29, 2014 11:51
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If the head has been off, he should have changed the belt and tensioner, unless he knew 110% that they were brand new. And the tensioner doesn't usually fail without some kind of noise unless it wasn't installed properly - a defect should usually be pretty obvious during installation. As someone who's been through a broken timing belt that involved engine damage - no, you don't always hear noise when trying to start it, beyond the starter spinning a bit faster then usual. In my case, all of the damage was over and done before the engine even stopped spinning. And it turned over just fine like that - again, aside from the starter sounding a bit faster. I didn't hear anything unusual when it died, aside from the engine stalling. I've also had an interference engine poo poo out a tensioner months after the timing belt was done, skip a tooth on the belt, and not suffer any damage - beyond the expense of having it towed to a shop, and the shop owner calling me and saying "whoever did the timing belt on this was a loving idiot - by the way, you're only out the cost of a new tensioner and an hour of labor." That car sounded perfectly normal when I tried to crank it, starter didn't sound any faster than usual. If it's lined up correctly, and there was no damage, go buy every lottery ticket you can find. But it would be starting and running if it was lined up. If he's letting you have it with monthly payments, hopefully you can come to some kind of agreement to get it running again. Neither of you want a broken car, but those are parts he really should have changed while the head was off - timing/cam belts are one of those things you really don't reuse unless you know it was brand new (and even then...). If he did change them, it's possible he got a defective tensioner, and might be able to make a claim with the manufacturer (haha not happening unless he owns a decent sized shop). randomidiot fucked around with this message at 12:17 on Sep 29, 2014 |
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Sep 29, 2014 12:06
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some texas redneck posted:If he's letting you have it with monthly payments, hopefully you can come to some kind of agreement to get it running again. Neither of you want a broken car, but those are parts he really should have changed while the head was off - timing/cam belts are one of those things you really don't reuse unless you know it was brand new (and even then...). If he did change them, it's possible he got a defective tensioner, and might be able to make a claim with the manufacturer (haha not happening unless he owns a decent sized shop). Thanks for the help and info, I'll quit whining now.
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Sep 29, 2014 12:22
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some texas redneck posted:If the head has been off, he should have changed the belt and tensioner, unless he knew 110% that they were brand new. And the tensioner doesn't usually fail without some kind of noise unless it wasn't installed properly - a defect should usually be pretty obvious during installation. I recently did the timing belt on an 07 legacy using an aftermarket kit. The new tensioner failed after around 200km (it had some kind of leak) and one of the heads skipped around 4 teeth. Did some compression tests and changed to an oem tensioner and belt and the engine has been fine, same amount of power and fuel mileage. What I'm saying is there is a chance that jazzmaster's engine could still be good.
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Sep 29, 2014 18:31
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JazzmasterCurious posted:Timing belt was changed when the heads were done, but not the other service items (tensioner and runner wheels + pump + thermostat). The dumbass. And the tension must have been a bit too tight, there'd been a whine which is a symptom of that, apparently. Thus it broke. I changed everything over the last two days, now the climate control panel (diagnostics easter egg) gives me a "17.0 engine speed sensor malfunction" (camshaft position sensor) — this will cut the spark and fuel supply to the engine. I'll try and reset it with VAG-COM from a friend and see if the ECU will give out some spark and fuel, if that doesn't work it's off to a reputable shop and more money out the window for either replacement heads or a replacement engine. It still could have jumped time when the tensioner broke. That would lead to a cam position sensor code, because the cam position sensor would disagree with the crank position sensor. Since you seem pretty handy, you should be able to manually crank the motor with a breaker bar to line up whatever timing marks exist on that engine, see if it really has jumped time. Since you have it all apart to do the tensioner etc, it shouldn't be too much hassle to get it back in time. If it does run, do a compression and leakdown test to make sure you didn't smash anything.
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Sep 29, 2014 21:30
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Can we not just look up the engine model and see if it's interference or not? What engine was it? The '97 A6 (C4 chassis) came with 8 gasoline and 3 diesel engines.
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Sep 29, 2014 22:05
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get a compression tester, spin the engine over on the key, if the tester shows zero psi, your engine is probably knackered. my BMW e30 B20M25 snapped its belt, but 'luckily' while I was idling in stopped traffic, so it 'only' bent all the valves, no piston damage or snapped rockers etc. replaced the valves and its running fine now. But if you were moving when the belt slipped, the momentum will have probably smashed something solid against something else, not good. Unless you have a non-interference engine, in which case, fit a new belt and feel smug 
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Sep 29, 2014 23:26
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ShittyPostmakerPro posted:Can we not just look up the engine model and see if it's interference or not? What engine was it? The '97 A6 (C4 chassis) came with 8 gasoline and 3 diesel engines. His picture looks like the passenger side bank of the 2.8l V6 which is an interference engine. The 5-cylinder gas engines were non-interference but weren't available in 97(?) http://raauto.com/pages/timing%20belt%20replacement%20guide.pdf
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Sep 29, 2014 23:54
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I've done a few belt services on the 2.8s. I vaguely remember that if they're 1 tooth off it'll eat itself. the bi-turbo is the most fun.
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Sep 29, 2014 23:58
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https://www.youtube.com/watch?v=OhfZlznuaVE not really a failure, now watch as i make the cab of this truck...DISAPPEAR
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Sep 30, 2014 00:36
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razorscooter posted:https://www.youtube.com/watch?v=OhfZlznuaVE The best part is watching the engine cradle collapse at 1:20 and toss the engine safely out of harm's way. There's gotta be one really proud engineer pointing to that and going "SEE? SEE?"
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Sep 30, 2014 00:50
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spiny posted:get a compression tester, spin the engine over on the key, if the tester shows zero psi, your engine is probably knackered. If the timing belt isn't fitted and tensioned, then some valves will be open, giving a 0 reading.
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Sep 30, 2014 01:56
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razorscooter posted:https://www.youtube.com/watch?v=OhfZlznuaVE looks ok to me. https://www.youtube.com/watch?v=TPpU5azjCB8
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Sep 30, 2014 02:00
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joat mon posted:His picture looks like the passenger side bank of the 2.8l V6 which is an interference engine. The five cylinders may or may not be interference, the 20v turbo definitely is.
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Sep 30, 2014 02:11
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ShittyPostmakerPro posted:If the timing belt isn't fitted and tensioned, then some valves will be open, giving a 0 reading. Valves would be held shut by the valve springs, if they've been bent then they wouldn't seal and you'd get a reading of 0 for the cylinder compression. Without a timing belt the cam would rotate to a position where the valves are closed (especially easily in a dohc engine) since the valve springs are applying force to close the valves, and you'd get a proper compression measurement by just rotating the crank though a cycle. Without the timing belt, I'd use the reading in a pass/fail sense, rather than the actual compression numbers.
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Sep 30, 2014 04:15
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Bajaha posted:Valves would be held shut by the valve springs, if they've been bent then they wouldn't seal and you'd get a reading of 0 for the cylinder compression. Without a timing belt the cam would rotate to a position where the valves are closed (especially easily in a dohc engine) since the valve springs are applying force to close the valves, and you'd get a proper compression measurement by just rotating the crank though a cycle. Without the timing belt, I'd use the reading in a pass/fail sense, rather than the actual compression numbers. I don't think either of my (4 cylinder) cars have a cam position where all valves are fully closed. Either way, the cam isn't going to keep spinning to find the perfect place where everything is closed and nothing is pushing on it, it's going to stop as soon as there's enough opposing force, which isn't necessarily a closed valve.
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Sep 30, 2014 04:25
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just remove the cam 
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Sep 30, 2014 05:28
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Raluek posted:It still could have jumped time when the tensioner broke. That would lead to a cam position sensor code, because the cam position sensor would disagree with the crank position sensor. Since you seem pretty handy, you should be able to manually crank the motor with a breaker bar to line up whatever timing marks exist on that engine, see if it really has jumped time. Since you have it all apart to do the tensioner etc, it shouldn't be too much hassle to get it back in time. Everything's put together with new parts. I did manually crank it to line it up correctly, managed to do it without the special camshaft holder tool even. But I've been an idiot and not disconnected the battery while working so I'll have to try that to see if the error code clears. If not it's VAG-COM time, compression test etc. ShittyPostmakerPro posted:Can we not just look up the engine model and see if it's interference or not? What engine was it? The '97 A6 (C4 chassis) came with 8 gasoline and 3 diesel engines. joat mon posted:His picture looks like the passenger side bank of the 2.8l V6 which is an interference engine. cursedshitbox posted:I've done a few belt services on the 2.8s. I vaguely remember that if they're 1 tooth off it'll eat itself. Well it's my birthday tomorrow and people have been asking me if there's anything special I would like or wish for. Well, that's pretty much a given now. 2.6 ABC or 2.8 AFC engine is on the wish list. Or a few shop hours to check the heads and pistons. An engine from a graveyard is going to be between $800 and $1800 depending on mileage. F4rt5 fucked around with this message at 11:32 on Sep 30, 2014 |
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Sep 30, 2014 09:54
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Thought I would share the pics of my horrible mechanical failure.    Was sliding at about 60mph in a right hander at a nice big open autocross when I heard a bang and thought I lost a tire. Turns out I didn't. Now it looks like all new bushings, aluminum adjustable control arms and sub frame reinforcement kits are in order.
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Sep 30, 2014 14:13
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Citroen 2CVs vanish when crashed into: https://www.youtube.com/watch?v=LUIxMIyExqE
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Sep 30, 2014 14:22
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Bajaha posted:Without a timing belt the cam would rotate to a position where the valves are closed (especially easily in a dohc engine) That is highly dependent on cam profile and should not be counted on as a valid test, especially one that you're going to believe as a pass/fail for "time to rip the head off!" It's easily gotten around with a leak down test and tweaking the cams until it's a sealed as it's gonna get, then run compression on that cylinder.
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Sep 30, 2014 15:36
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Sadi posted:Thought I would share the pics of my horrible mechanical failure. Holy poo poo.  But new parts! 
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Sep 30, 2014 15:47
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Sadi posted:Thought I would share the pics of my horrible mechanical failure. Sucks, but let me just say that is a loving gorgeous color.
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Sep 30, 2014 16:33
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peter gabriel posted:Citroen 2CVs vanish when crashed into: That's frightening. Even more frightening is that there are appears to be a fetish channel for girls failing to start cars: https://www.youtube.com/watch?v=v8keJXjguM0
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Sep 30, 2014 17:02
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spog posted:That's frightening. Hadn't heard of that, but stuck cars has been around for awhile. https://www.youtube.com/watch?v=UA2YvVPpDNc
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Sep 30, 2014 18:28
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