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xzzy posted:Would have been a cool idea if it hadn't been VW doing it. Fixed.
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Jun 20, 2016 08:18
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Handy with a welder (and mastic)? You too can enjoy an OEM quality water jacket retrofit!
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Jun 20, 2016 08:20
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Cakefool posted:Handy with a welder (and mastic)? You too can enjoy an OEM quality water jacket retrofit! Weld the cylinder head to the water jacket. Problem solved.
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Jun 20, 2016 10:03
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A friend gave me a nearly pristine snowblower that he had run out of oil until it seized. I tore down the engine this weekend, and think I found the problem: Is it common with these engines (305cc B&S) to have an aluminum con rod directly on a steel crankshaft with no bearing? The piston, cylinder, and everything else seem ok, so my plan is to take the smeared aluminum off the crank with some lye and see what shape the journal is in. If it looks good, I'll take my chances with a new con rod and the couple gaskets needed to put it all back together. A brand new engine is only $350-400, so it's not worth replacing the crankshaft @ $130 for a new one. Hillridge fucked around with this message at 15:02 on Jun 20, 2016 |
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Jun 20, 2016 15:00
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Yes, very common. They are splash oiled as well, so no tipping them up to run over a snowbank, as it'll starve the crank of oil, leading to a snapped rod.
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Jun 20, 2016 15:44
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spog posted:I heard second hand that a RAF maintenance guy got killed when working on a plane because he didn't bother to fit the mechanical lock-outs that prevented the ejector seat mechanism from going 'bang' while he was working in the cockpit. In 1980 a 7-year-old kid died during an airshow at Willow Grove. He was touring the cockpit of an S-3 and they were letting him fiddle with the controls, figuring there was no way he'd be able to do anything dangerous like both arm and fire the ejection seat. They were wrong.
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Jun 20, 2016 15:49
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There's a chance this could have lead to a fairly horrible mechanical failure. Decent crack in the front rotor of the race car. After taking the picture I found a couple more, one was much closer to the hub.
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Jun 20, 2016 16:27
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NitroSpazzz posted:There's a chance this could have lead to a fairly horrible mechanical failure. Decent crack in the front rotor of the race car. After taking the picture I found a couple more, one was much closer to the hub. How does that happen? Cooling too fast? Or just bad metallurgy?
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Jun 20, 2016 17:07
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Production car rotors used for racing just kinda do that sometimes. It's not "bad" metallurgy, per se, but a lot of steps applied to racing brakes that aren't bothered with for production stuff. You have a huge amount of heat input and maybe there's unrelieved stresses in the cast iron, or stress concentrations from machining or something ... nothing that would show up at temperatures seen on public roads, but pushed hard, there ya go. What's really loving scary is some cars like 1st gen RX-7s where the bearing carrier is part of the same casting as the rotor. One SCCA roadrace class called E Production ends up with slicks, widebodies, reaonably good power NA... and stock calipers and rotors, so everything pushed pretty drat hard. After A couple incidents where cracks from rotors made it to the bearing carrier and made the wheel depart the car (saw one at Road America at turn 5) they legalized stock sized but 2-piece rotors.
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Jun 20, 2016 17:22
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mekilljoydammit posted:Production car rotors used for racing just kinda do that sometimes. It's not "bad" metallurgy, per se, but a lot of steps applied to racing brakes that aren't bothered with for production stuff. You have a huge amount of heat input and maybe there's unrelieved stresses in the cast iron, or stress concentrations from machining or something ... nothing that would show up at temperatures seen on public roads, but pushed hard, there ya go.  Holy gently caress. Nothing like having a wheel leave the car coming into one of the hardest braking zones on the track. Yikes.
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Jun 20, 2016 17:37
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Ya S2000s crack rotors so regularly on track it's pretty much standard practice to have spares on hand to replace them when (not if!) they crack. Tires keep gettin stickier and stock brakes are just undersized now. More people running big brake kits and/or two piece rotors to deal with it
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Jun 20, 2016 17:45
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We see cracks pretty regularly but they're usually smaller and less of them on the rotor. We always bring a full set of spares for race weekends and check them every morning. We're not even running that aggressive of pads with the Hawk Blues. This was at Atlanta Motorsport Park which has a very hard braking zone for turn one, hairpin at the end of the longest straight. We were going from the top of 5th gear (~100mph) down to 2nd gear (~30mph). I also boiled the fluid about 15 minutes into a 2:45 stint and had variable brake pressure for the rest of the race. 
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Jun 20, 2016 18:06
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NitroSpazzz posted:We see cracks pretty regularly but they're usually smaller and less of them on the rotor. We always bring a full set of spares for race weekends and check them every morning. We're not even running that aggressive of pads with the Hawk Blues. You were that close to me and didn't say hi 
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Jun 20, 2016 18:10
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CommieGIR posted:You were that close to me and didn't say hi  Another failure from this weekend was the shift linkage. I went for fifth, it felt vague and took a couple tries to get it in. Radio'd pit and told them the linkage was failing and I would be doing the remaining hour of the race in third gear. Next lap forgot and went to fourth then as I went to fifth it broke as I passed the pit in point. Coasted down the straight to the pit out and they towed me in. Ten minutes to replace but an hour to track down a replacement. 
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Jun 20, 2016 18:54
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NitroSpazzz posted:Sorry man, I'll be back because I need to run that track in something a bit more fun That's what you get for granny shiftin' when you should have been double-clutching. 
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Jun 20, 2016 18:57
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mekilljoydammit posted:Production car rotors used for racing just kinda do that sometimes.
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Jun 20, 2016 18:59
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Boaz MacPhereson posted:
Yeah. EProd rules give me a headache. 2250 pound car (with driver) making about 230hp at the wheels through a dogbox, with about 10" of tread width of honest-to-god slick on the track... with 10 inch rotors and stock cast iron calipers. Then again, it always provides a point of perspective for all those people who go on about the absolute necessity of big brake kits. BlackMK4 posted:This happens to race rotors over time too Oh sure, but you have to admit the odds get a bit better when the parts are intended for their use.
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Jun 20, 2016 20:02
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NitroSpazzz posted:There's a chance this could have lead to a fairly horrible mechanical failure. Decent crack in the front rotor of the race car. After taking the picture I found a couple more, one was much closer to the hub. You should have been cooling them down with a hose spraying Onto the track from your pits as you drove by. tater_salad fucked around with this message at 21:45 on Jun 20, 2016 |
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Jun 20, 2016 21:38
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i bought a personal mister from home depot and plumbed it into my custom dryer hose brake coolers it works pretty well with my ebay slotted and drilled rotors
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Jun 20, 2016 21:49
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Does it handle the extra power from your electric turbo?
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Jun 20, 2016 22:06
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imo it does because i bought one of those breeze fans with integrated mister nozzel in center from home depot also and replaced the contents of the mister with methanol pulls air and cools the intake charge
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Jun 20, 2016 22:14
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tater_salad posted:Does it handle the extra power from your electric turbo? electric turbos are for chumps, my turbo runs off a solar hardwood gasifier-fueled Stirling engine worst part with this setup is it's hard to keep the flame from blowing out at high speeds, also the Stirling engine makes hell of torque steer
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Jun 20, 2016 22:19
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Splizwarf posted:also the Stirling engine makes hell of torque steer Well that's because you mounted it crosswise instead of axially, DUH. Your Stirling heatpump turbo power source should always be engineered to turn such that the flywheel's rotational direction is towards whichever wheels are driving the car, so that it is constantly adding downward force to those wheels and increasing traction for acceleration. I mean, this should be obvious to anyone familiar with the physics, but I guess not everybody is.
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Jun 20, 2016 23:16
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NitroSpazzz posted:There's a chance this could have lead to a fairly horrible mechanical failure. Decent crack in the front rotor of the race car. After taking the picture I found a couple more, one was much closer to the hub. This is what my rotors look like after every weekend. I replace them when the pulsing in the pedal gets bad. I'm the horrible mechanic failure.
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Jun 21, 2016 00:37
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IOwnCalculus posted:Group B also didn't care so much about cracking rotors or consumables as a whole, really. Calling drivers "consumables" is pretty crass.
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Jun 21, 2016 11:18
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SNiPER_Magnum posted:This is what my rotors look like after every weekend. I replace them when the pulsing in the pedal gets bad. I'm the horrible mechanic failure. CharlesM posted:Calling drivers "consumables" is pretty crass. 
NitroSpazzz fucked around with this message at 12:49 on Jun 21, 2016 |
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Jun 21, 2016 12:43
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CharlesM posted:Calling drivers "consumables" is pretty crass. Well, obviously there was a limit on consumables, else the series wouldn't have been canned.
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Jun 21, 2016 17:14
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CharlesM posted:Calling drivers "consumables" is pretty crass. I figured he was referring to the spectators.
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Jun 21, 2016 17:38
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Boaz MacPhereson posted:I figured he was referring to the spectators. Spectators are self clearancing.
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Jun 22, 2016 04:33
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What do you do when you're E28 524TD is overheating? If you answered continue to drive it you may be my brother or his wife... Things got a bit warm, good thing a bare replacement head is only $1550. Poor car will be sitting for even longer.      
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Jun 22, 2016 16:39
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Why does the metal inbetween the valves look....removable? Not the crack, but around it....
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Jun 22, 2016 16:44
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That's why I have drilled rotors, the holes let the cracks out.
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Jun 22, 2016 19:11
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CommieGIR posted:Why does the metal inbetween the valves look....removable? Not the crack, but around it.... netwerk23 posted:That's why I have drilled rotors, the holes let the cracks out. Our rears are drilled for some reason, we had bad luck with front drilled. They killed pads and liked to fail catastrophically
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Jun 22, 2016 20:01
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NitroSpazzz posted:Not sure, it looks weird in the pictures and even stranger in person but it's just the way it's designed. Sadly it isn't removable. Tracked down a known good, recently rebuilt replacement engine from a friend...that's 1000 miles away. VW 1.6l D/TD motors often get cracks between the valves, but for the most part were not a major concern. Those cracks look way bigger.
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Jun 22, 2016 20:05
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CommieGIR posted:VW 1.6l D/TD motors often get cracks between the valves, but for the most part were not a major concern. Those cracks look way bigger. That one appears to crack into the water jacket, given the "stuff" around some of the breaches. I'm with Commie, though. It looks like a plug was pressed in and then machined, almost like valve seat on a gas engine. I wonder if that's exactly what happened due to casting limitations for the water jacket?
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Jun 22, 2016 21:54
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Dodge 5.2/5.9 heads crack often between the valves but no one notices until it hits a water jacket, which most of them never do. So it's really not an issue.
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Jun 22, 2016 23:12
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Could be a pressed plug, that would make sense. These are all clear through to the water jacket, think there was one cylinder that didn't go through to the water jacket. The head is thoroughly hosed, we're getting it so I'll probably put up some pictures later if there's interest.
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Jun 23, 2016 00:08
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Cracked rotor chat? That is from the left and right of a DA Integra during the VIR 24. One cracked at 2am(15hrs in), other at 6am (19hrs in).
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Jun 23, 2016 01:45
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Could you reduce the cracking rate if you put the rotors on a lathe and smoothed out the corners? Not much, as it looks like most rotors have the pad surface right up to the edge, obviously.
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Jun 23, 2016 02:49
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EightBit posted:Could you reduce the cracking rate if you put the rotors on a lathe and smoothed out the corners? Not much, as it looks like most rotors have the pad surface right up to the edge, obviously. If you look closely, you can see there are other cracks around the big ones that start in the middle. When you put a ton of heat into the entire rotor, then the outside cools rapidly, it cracks from the inside out. repeat that a couple hundred times, and the cracks extend to the edge.
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Jun 23, 2016 02:57
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