I suppose he could learn the slow way - by doing things himself and seeing if they work or fail. The downside of that is that he misses out of hundreds of years of prior experience. I believe Blueflame is now at the level of Neanderthal tools, and his lifetime aspiration is to 'discover' how to cast bronze.
You learn by sound, hearing, and your own experience, after all this is all a man can do. Reading a book doesn't prove theory, practice does, and experience is the proof (if anybody believes you)
Um... Reading will allow you to learn from other peoples experience and proofs.
How do you know how tight to torque up cylinder head bolts? Do you read the manual and learn from the manufacturer, or do you re-engineer the design and calculate the torque settings from first principles?
Reading is cheap (free if you borrow books from friends and libraries) and can give you hundreds of years worth of experience and knowledge in a few days. Why pass that up if you want to be good at something?
Reading a book can tell you how a theory was proven by someone else. You don't, surely, solve every theory in every problem yourself, do you?
As tight as you can by hand I'd imagine, I would use the manufacturers stats as a guide, but I'm not going to believe it until I see it with my own eyes on a dyno (which I will probably never do anyway).
I don't like to use other peoples knowledge and take it as my own, that is often how I find myself looking like a fool, because someone told me something that is crap and I've believed it and passed it on.
A dyno won't tell you if you've done the head bolts up properly, with the correct preload, stretch, lubrication etc.
As tight as you can by hand - is that finger tight, or using a 50ft lever?
You see, you learn from other people all the time. Reading is just an efficient way of learning from the findings/mistakes/proofs that people have spent hundreds/thousands of years determining. If you refuse to read to learn about engines, then how will you ever know enough to even cope on a sim racing forum discussion, let alone in the trade in the real world?
Another skill with reading - be the source on Wikipedia, a university journal, a letter from a friend or a memo from your boss is to use common sense and other knowledge to determine if it's correct. You might get a letter from your boss telling you to put your head in a toilet to clean your hair. You've never tried it, so in theory you don't know if it would work. But you can determine that it probably wouldn't be a good idea from seeing what goes into toilets, perhaps even discussing it with sewage experts if you wanted to be sure. If I told you to torque your wheel bolts to 200lb.ft then you might either choose to believe me, or you might say "wait a minute. That seems a lot. I've not done much torquing of bolts, but there aren't many on cars that go above 80lb.ft. I'll phone a friend/garage (or ask on the internet, or go to the library and read a Haynes manual for, well, any car) to see if 200lb.ft is realistic."
Just saying you learn on your own - presumably by one day not tightening your wheels enough and having them fall off, then on the second day going a bit tighter (they still fall off), tighter the next day.... until one day they stop falling off. Is that still enough? What about fatigue? Eventually they might fall off because the studs break. Was that because they were undertorqued or overtorqued. So you carry on the experiment, getting tighter and tighter, until finally, 60 years from now you determine that for that car about 80lb.ft is about right.
You are still moving the lever by hand. No body weight, as head bolts are usually vertical (so the lever is moved on the horizontal plane). If tools are not allowed when doing it 'by hand', then you must believe that cylinder head bolts are just finger tight then?
Manufacturer figures are surprisingly accurate these days. Obviously there is variation in each engine (and in eah condition), but they are testing under very specific conditions. Gone are the days in the 50s, 60s and 70s when power figures were massaged "a bit".
But that's got nothing to do with head bolt tightening torque.
If you are pulling or pushing a 50ft lever you are no longer using only your hands. Also, manufacturers figures are still very much manufactered, most people don't bother to go have a dyno run and check their outputs, so they will never know the exact truth, and it's the same with mpg, the cars mpg stat is probably based in perfect conditions with tyres that are extremely hard with no weight in the car whatsoever.
If you are pushing a 1ft torque wrench, are you using your hands? Can you tighten a cylinder head bolt without using a tool to a specific torque?
Manufacturer figures for CYLINDER HEAD TIGHTENING TORQUES are not guessed, but worked out based on a combination of experience, clamping pressure on the head gasket, load cycling (fatigue resistance).........
There are ISO and DIN (and other) standards on IC engine power/torque quoting. They are carried out on production engines, with ancilliaries like alternators and power steering pumps fitted. In some cases none, some or all of the standard exhaust system is used on the dyno as well. They are reliable and corrected (within the limits of experimental error and manufacturing tolerances). Cars are frequently tested after manufacture by non-related companies (magazines road tests for example).
MPG figures are also controlled, using defined journeys, in standard condition. Yes, they'll be new tyres, but they'll be the ones you'd get when you drive it off the forecourt. Whilst many MPG figures are inaccurate, that is because real world drivers vary so much (see a post by me yesterday that touches on this). But they are consistent with each other - i.e a car that is quoted as being more economical than another car will probably prove to be so, even if the real world MPG isn't as quoted.
I prefer the 4th-gen one with the aggressive-styled headlights and better weight distribution. I gather that none of the Preludes are as comfortable as the Civics or Accords of the same age. But I much prefer the look of the Prelude.
Yes you are using your hands. I was just being pedantic, I don't know, I can physically tighten any bolt, with anything :P untightening is a different story though but does that mean you need a specific type of torque wrench to tighten head bolts?
I am assuming the head needs to be torqued as tight on each bolt of the cylinder head?
Well I didn't know this, to be honest, I didn't even think of power-assist or power steering, nor alternator, and would never of thought of the basically everything internal of the chassis, but most BHP/TORQUE numbers are based from at the flywheel as a general rule right?
Well, I thought the manufacters would bend the truth as much as possible. Afterall, it's not like anybody can find out for real before they buy the thing, once they have bought it the car company already have all their money.
That strategy would only work for a few weeks or months at most but car companies want to sell the models for years. Once people find out about the "truth bending", bad press would prevent other people from buying it. Also the public image and reputation of the brand would be damaged and even selling other models in the future will be harder. So if you think about, lying is bad for business.
Hey Blueflame. You said you knew something. Sadly, you were wrong. You could've done research before you made a statement, but you didn't. Even when others proved you wrong, you didn't believe them. And when you finally did confess you were wrong, you indirectly stated it wasn't your fault. You're one thick guy..
You should've been man enough to not make any mistakes. Also, when experts correct you, don't think they're wrong.
I'll leave the technical discussion to the experts, unless I can add something to the discussion. You should too.
well i guess the usual wot runs under load on a dyno will show you quite quickly if youve undertorqued the head bolts at least if theyre only finger tight
anyway im getting the distinct impression that he hasnt got the first idea what torquing a bolt actually means
also im confused whether i should feel honoured or terrified that my oppinion posted on a rather insignificant web forum is apparently more believable and worthy of parroting than anything in a physics textbook
