hagar Posted February 1, 2012 Share Posted February 1, 2012 i recently bought a lightened set of pulleys for my 92 1jz gte and was told that if i tried starting the engine with the smaller lightened pulley on the crank it would snap the crank. is this a problem with the 1jz? if it is why would they sell them. this is what i have bought. are these lightened wheels dangerous? Quote Link to comment Share on other sites More sharing options...
garethr Posted February 1, 2012 Share Posted February 1, 2012 (edited) General opinion is that Mr T's engineers probably know what they're doing, so it's not worth the risk. http://en.wikipedia.org/wiki/Harmonic_balancer http://en.wikipedia.org/wiki/Torsional_vibration#Crankshaft_torsional_vibration Edited February 1, 2012 by garethr (see edit history) Quote Link to comment Share on other sites More sharing options...
David P Posted February 1, 2012 Share Posted February 1, 2012 http://www.atiracing.com/products/dampers/damper_dinan.htm Quote Link to comment Share on other sites More sharing options...
Hellstrom Posted February 1, 2012 Share Posted February 1, 2012 The longer crank the more need for a damper. --- I am here: http://maps.google.com/maps?ll=57.729307,11.786122 Quote Link to comment Share on other sites More sharing options...
Nic Posted February 1, 2012 Share Posted February 1, 2012 The crank pulley/harmonic balancer plays a very important role, have a read of THIS THREAD They sell them because people will buy them Definitely bin it and fit a brand new OEM one instead. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 1, 2012 Share Posted February 1, 2012 I would always recommend a stock damper. I personally do not believe ATI spend the development money running every engine they do a damper for through a full R&D (expensive) harmonic oscillations test. I DO believe Toyota did though.... Quote Link to comment Share on other sites More sharing options...
hagar Posted February 1, 2012 Author Share Posted February 1, 2012 i think it's time to look for an alternative. Quote Link to comment Share on other sites More sharing options...
Nic Posted February 1, 2012 Share Posted February 1, 2012 The part number for a new OEM Toyota one is 13407-46020 Quote Link to comment Share on other sites More sharing options...
dr_jekyll Posted February 1, 2012 Share Posted February 1, 2012 what ive never understood is at the other end of the crank its bolted to a solid flywheel with no damping that then takes all the wheelspins, clutch kicks and thrashings you can throw at it without snaping the crank? Quote Link to comment Share on other sites More sharing options...
Nic Posted February 1, 2012 Share Posted February 1, 2012 what ive never understood is at the other end of the crank its bolted to a solid flywheel with no damping that then takes all the wheelspins, clutch kicks and thrashings you can throw at it without snaping the crank? The stock flywheel is dual mass. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 1, 2012 Share Posted February 1, 2012 what ive never understood is at the other end of the crank its bolted to a solid flywheel with no damping that then takes all the wheelspins, clutch kicks and thrashings you can throw at it without snaping the crank? Err! the std flywheel is damped, and if you fit an aftermarket solid flywheel, the clutch plate is spring damped, anyway the front pulley is damped in order to stop resonate vibrations that can feed back along the crank at certain loadings and RPMs that could cause damage. Quote Link to comment Share on other sites More sharing options...
Lee P Posted February 1, 2012 Share Posted February 1, 2012 I would always recommend a stock damper. I personally do not believe ATI spend the development money running every engine they do a damper for through a full R&D (expensive) harmonic oscillations test. I DO believe Toyota did though.... I agree, a new standard one is the best option Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 1, 2012 Share Posted February 1, 2012 You have really answered your own question, without realising it The crank at the front gets the impulses from just the no 1 cylinder, and as you move back along it the crank gets the torque pulses from more and more cylinders, until the last main bearing section is seeing all six firing pulses. So you have differential torque loadings along its length. Add to that the pulses are sometimes unequal, but a straight six is pretty much OK in that regard, which is why they are normally such sweet running engine formats. Then, and this is the bit you answered yourself, you have differential inertia. The front of the crank just "spins" and maybe drives some ancillaries. the back end has a dirty big flywheel to give inertia to the engine for added smoothness and easy starts, both as in firing the engine up from stopped, and driving smoothly away from a standstill on the road. Add the pulses, the unequal torque loading along its length, and the unequal inertia, front and rear and the crank is constantly twisting and untwisting (literally, but fractionally) all the time the engine is running. At certain RPM's and loadings it will twist a LOT relatively speaking. These are the crank harmonics, a BAD thing. The front damper's job is to calm these motions to stop the thing fatiguing and eventually failing catastrophically. Now, that's a pretty simplistic explanation, but basically the damper tries to damp down twisting movements, the same as the dampers on the road springs dampen the car body's oscillations up and down. If you have knackered, or no dampers (shock absorbers as they are so often wrongly called), the car's body vertical motion is violent, uncontrolled and potentially dangerous and unstable. By removing, or sometimes just altering the crank damper, you are basically doing the same to the engine, albeit the results are not usually immediately obvious. HTH. Quote Link to comment Share on other sites More sharing options...
hagar Posted February 2, 2012 Author Share Posted February 2, 2012 definately time for a new one. are there any aftermarket performance ones that are damped? Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted February 2, 2012 Share Posted February 2, 2012 Just get a Toyota one. Quote Link to comment Share on other sites More sharing options...
Kirk Posted February 2, 2012 Share Posted February 2, 2012 definately time for a new one. are there any aftermarket performance ones that are damped? Did you not read ANYTHING that has been posted Just get a Toyota one. Quote Link to comment Share on other sites More sharing options...
Hellstrom Posted February 2, 2012 Share Posted February 2, 2012 There are a few aftermarket ones like ATI and some more from what ive heard the ATI is not really good. How Well it dampens i wont say anything about that But the wheel is bigger for the aux and maked PAS and alternator and possible A/C rev more then needed and at high revs the belt is more likely to slip off. Id go for an OEM. Or for an aftermarket that has the same size wheel. --- I am here: http://maps.google.com/maps?ll=57.729170,11.785942 Quote Link to comment Share on other sites More sharing options...
Nic Posted February 2, 2012 Share Posted February 2, 2012 definately time for a new one. are there any aftermarket performance ones that are damped? See Chris and Lee's earlier posts, they both know their stuff. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted February 2, 2012 Share Posted February 2, 2012 (edited) Did you not read ANYTHING that has been posted Edited February 2, 2012 by Swampy442 (see edit history) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 2, 2012 Share Posted February 2, 2012 if they are going to alter the auxiliary belt pulley diameter they'd be better off making it smaller to slow the water and PAS pumps down on enthusiastically revved engines, and also reduce parasitic losses. How odd to make it a bigger diameter, but they are American, and bigger IS better Quote Link to comment Share on other sites More sharing options...
dr_jekyll Posted February 3, 2012 Share Posted February 3, 2012 You have really answered your own question, without realising it The crank at the front gets the impulses from just the no 1 cylinder, and as you move back along it the crank gets the torque pulses from more and more cylinders, until the last main bearing section is seeing all six firing pulses. So you have differential torque loadings along its length. Add to that the pulses are sometimes unequal, but a straight six is pretty much OK in that regard, which is why they are normally such sweet running engine formats. Then, and this is the bit you answered yourself, you have differential inertia. The front of the crank just "spins" and maybe drives some ancillaries. the back end has a dirty big flywheel to give inertia to the engine for added smoothness and easy starts, both as in firing the engine up from stopped, and driving smoothly away from a standstill on the road. Add the pulses, the unequal torque loading along its length, and the unequal inertia, front and rear and the crank is constantly twisting and untwisting (literally, but fractionally) all the time the engine is running. At certain RPM's and loadings it will twist a LOT relatively speaking. These are the crank harmonics, a BAD thing. The front damper's job is to calm these motions to stop the thing fatiguing and eventually failing catastrophically. Now, that's a pretty simplistic explanation, but basically the damper tries to damp down twisting movements, the same as the dampers on the road springs dampen the car body's oscillations up and down. If you have knackered, or no dampers (shock absorbers as they are so often wrongly called), the car's body vertical motion is violent, uncontrolled and potentially dangerous and unstable. By removing, or sometimes just altering the crank damper, you are basically doing the same to the engine, albeit the results are not usually immediately obvious. HTH. every days a school day Quote Link to comment Share on other sites More sharing options...
hagar Posted February 3, 2012 Author Share Posted February 3, 2012 clearly you folks just don't know me. are you trying to tell me that 1000 bhp supra's are running the standard oem pulley. i plan on a new engine for my car next year and it will be insanely powerful so i want something better. how do the titan one work, has anyone here had one? Quote Link to comment Share on other sites More sharing options...
Kirk Posted February 3, 2012 Share Posted February 3, 2012 clearly you folks just don't know me. are you trying to tell me that 1000 bhp supra's are running the standard oem pulley. No but I bet they could. Just some people seem to be brainwashed into thinking that just cause the part says 'uprated' on the tag means its superior in every way. Titan is the same as all the other ATI's just with a Titan logo printed on it. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted February 3, 2012 Share Posted February 3, 2012 Insanely powerful eh? Quote Link to comment Share on other sites More sharing options...
hagar Posted February 3, 2012 Author Share Posted February 3, 2012 No but I bet they could. Just some people seem to be brainwashed into thinking that just cause the part says 'uprated' on the tag means its superior in every way. Titan is the same as all the other ATI's just with a Titan logo printed on it. what a wonderful world we live in, all these unscrupulous people not interested in money but trying to make our lives better! as for toyota doing a better job than anyone don't forget i come from the mk3 world (my 5th mk3, actually it's the 3rd of 5) and i have seen the toyota idea of an adequate head gasket and bottom end on the 7m's and as for the strength of the original turbo's on the twins, the less said the better. it's not always about upgrading but just removing the bad bits sometimes. Quote Link to comment Share on other sites More sharing options...
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