Question on Lighter Crank Pulley

tacoskim · 10-01-2008, 02:42 PM

does anyone know if a lighter (but same size) crank pulley is safe for a daily driver truck?? to me it sounds like since its the same size it will be a good investment, but i dont think in the long run if u want ur engine to last as long its not a good idea. am i wrong?

whats ur guys thoughts??

1-3-2-4 · 10-01-2008, 06:25 PM

The size (diameter) of the crank damper will have a minimal effect on performance. The only real reason to make the pulley smaller is to underdrive the accessories (spin them slower) and to make it lighter.

Will the new pulley adversely affect engine life? Could. I've used lightened crank pullies on two of my cars with good performance gains. However, I never owned the car long enough to see any real damage. There is one reason and one reason alone OEMs install crank dampers: crankshaft durability. If the engineers who designed that crankshaft weren't concerned with the life of the crank, they would have saved the money. Every crankshaft has a different resonant signature (I4's are different than V6, V8, H4, etc.). I can say that V6 engines are not an inherently smooth running engine.

That being said, YMMV because it really depends on your drive cycle and expectations. If your driving doesn't involve running the engine at the crankshaft's natural frequency, you won't have much of a problem. Or, if you only plan on keeping the truck for a short amount of time, you probably won't have any issues. If you are concerned with either case, save your time and don't worry about the few ponies.

tacoskim · 10-01-2008, 07:25 PM

thanks 1234, im guessing its more of a gain for the manual folks to make up for the acceleration through gears 1 and 2. i was just looking for something to make up for my loss of back pressure. i plan on keeping this truck till a tacoma hybrid comes out

so if its gonna ruin the engine in the long run then might not be a good idea

1-3-2-4 · 10-02-2008, 04:45 AM

Like I said, there are no guarantees. But the info I provided on the dampers purpose is verifiable. Its a personal choice.

Shanes56 · 10-26-2008, 06:30 PM

Quote:

Originally Posted by tacoskim

does anyone know if a lighter (but same size) crank pulley is safe for a daily driver truck?? to me it sounds like since its the same size it will be a good investment, but i dont think in the long run if u want ur engine to last as long its not a good idea. am i wrong?

whats ur guys thoughts??

This is a very good question but one thing to keep in mind is the 4.0L V6 1gr is internally balanced, so the notion of a harmonic balancer to keep the vibration from hitting certain frequencies is inaccurate concerning this motor being that the OEM crank pulley does not have a harmonic balancer. So there would be no need for worry

Unless I completely misunderstood what 1-2-3-4 was referring to

1-3-2-4 · 10-27-2008, 05:56 AM

Every engine sold today is internally balanced. That phrase may have been important 50 years ago, but not today. That is like saying your new truck comes with tires - it better!

Concerning crank dampers, most if not all, engines today have them. I personally haven't looked at the V6's pulley, but my I4 has one...along with every other engine I've ever owned (except for my 83 GTI). If the crank pulley has a rubber layer impregnated between two masses, it is a harmonic balancer. Of course, if there really is no damper, you won't miss it by installing a lightweight pulley. It is possible you could aggravate cam chain wear, but I wouldn't bet money on it, especially in the short run. I'm betting it has one, though. V6 engines are harmonic nightmares.

10-01-2008, 02:42 PM	#1
tacoskim Tuned By Gadget Joined: Mar 2008, #5252 Location: Los Angeles, CA Age: 25 Gender: Male Posts: 1,321 06 black trd sport 2006 Double Cab Automatic 4.0 URD MAF Cal, JBA headers, URD TCAI, magnaflow cat-back, DT "PIPE-BOMB" Y-pipe, black headlight mod, T-Rex Eyelids, tinted taillights, yellow tinted fogs, LUND screenfront, TRD seat covers	Question on Lighter Crank Pulley does anyone know if a lighter (but same size) crank pulley is safe for a daily driver truck?? to me it sounds like since its the same size it will be a good investment, but i dont think in the long run if u want ur engine to last as long its not a good idea. am i wrong? whats ur guys thoughts?? __________________ URD MAF Cal (Tuned), JBA Headers, URD TCAI, Magnaflow Cat-Back, DT "PIPE-BOMB" Y-Pipe, Black Headlight Mod, T-Rex Eyelids, Yellow Tinted Fogs, TRD Seat Covers

10-01-2008, 07:25 PM	#3
tacoskim Tuned By Gadget Joined: Mar 2008, #5252 Location: Los Angeles, CA Age: 25 Gender: Male Posts: 1,321 06 black trd sport 2006 Double Cab Automatic 4.0 URD MAF Cal, JBA headers, URD TCAI, magnaflow cat-back, DT "PIPE-BOMB" Y-pipe, black headlight mod, T-Rex Eyelids, tinted taillights, yellow tinted fogs, LUND screenfront, TRD seat covers	thanks 1234, im guessing its more of a gain for the manual folks to make up for the acceleration through gears 1 and 2. i was just looking for something to make up for my loss of back pressure. i plan on keeping this truck till a tacoma hybrid comes out so if its gonna ruin the engine in the long run then might not be a good idea __________________ URD MAF Cal (Tuned), JBA Headers, URD TCAI, Magnaflow Cat-Back, DT "PIPE-BOMB" Y-Pipe, Black Headlight Mod, T-Rex Eyelids, Yellow Tinted Fogs, TRD Seat Covers

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10-01-2008, 06:25 PM	#2
1-3-2-4 Squirrel Mincer Joined: Apr 2008, #5944 Location: Ithaca, NY Gender: Male Posts: 164 06 Titan King Cab 2006 Access Cab Automatic 5.6 A.R.E. tonneau cover	The size (diameter) of the crank damper will have a minimal effect on performance. The only real reason to make the pulley smaller is to underdrive the accessories (spin them slower) and to make it lighter. Will the new pulley adversely affect engine life? Could. I've used lightened crank pullies on two of my cars with good performance gains. However, I never owned the car long enough to see any real damage. There is one reason and one reason alone OEMs install crank dampers: crankshaft durability. If the engineers who designed that crankshaft weren't concerned with the life of the crank, they would have saved the money. Every crankshaft has a different resonant signature (I4's are different than V6, V8, H4, etc.). I can say that V6 engines are not an inherently smooth running engine. That being said, YMMV because it really depends on your drive cycle and expectations. If your driving doesn't involve running the engine at the crankshaft's natural frequency, you won't have much of a problem. Or, if you only plan on keeping the truck for a short amount of time, you probably won't have any issues. If you are concerned with either case, save your time and don't worry about the few ponies.

10-02-2008, 04:45 AM	#4
1-3-2-4 Squirrel Mincer Joined: Apr 2008, #5944 Location: Ithaca, NY Gender: Male Posts: 164 06 Titan King Cab 2006 Access Cab Automatic 5.6 A.R.E. tonneau cover	Like I said, there are no guarantees. But the info I provided on the dampers purpose is verifiable. Its a personal choice.

10-27-2008, 05:56 AM	#6
1-3-2-4 Squirrel Mincer Joined: Apr 2008, #5944 Location: Ithaca, NY Gender: Male Posts: 164 06 Titan King Cab 2006 Access Cab Automatic 5.6 A.R.E. tonneau cover	Every engine sold today is internally balanced. That phrase may have been important 50 years ago, but not today. That is like saying your new truck comes with tires - it better! Concerning crank dampers, most if not all, engines today have them. I personally haven't looked at the V6's pulley, but my I4 has one...along with every other engine I've ever owned (except for my 83 GTI). If the crank pulley has a rubber layer impregnated between two masses, it is a harmonic balancer. Of course, if there really is no damper, you won't miss it by installing a lightweight pulley. It is possible you could aggravate cam chain wear, but I wouldn't bet money on it, especially in the short run. I'm betting it has one, though. V6 engines are harmonic nightmares.