aftermarket crank pulley question

[w_hodel]

Hey I recently bought a 3SX Aluminum Crank Pulley and put it on my car, which is waiting on a rebuild, and I have been reading on the net that these pulleys that not have the rubber inserts can mess up your bearings. They were saying (I forget the technical term) the when combustion occurs the rods twist as they go down, and slam the crank, if you don't have the rubber dampener, this will cause excessive bearing wear. Is this a load of bull, or do they really make a valid point? I am rebuilding because I have a connecting rod knocking, so I dont want to have to do it again very soon.

Thanks guys,
Bigg Willy

[2old]

It's called a harmonic dampner which is used to deaden the ringing in the crackshaft because the engine is basically changing a up and down motion to a rotating one.

And no, the problem is not so much the from the rod being forced down but from the ringing it causes in the crank shaft (you would get the impact of the rods onto the crank shaft regardless of what "rubber thingy" is on the end of the crank shaft) which can cause metal fatigue in basically anything metal (the main 2 being the crankshaft and the bearings).

Whether you will encounter a problem in your engines serviceable life is another story. When the engineers (gawd I just realised engine is in the word engineer...) designed the engine they would have tried to design out catestrophic failure out of the mean time to failure for the entire lifecycle of the car (which would be 10 years times several thousands of cars) so it's unlikely this one change will significantly affect the lifespan of a re-build engine.

The lighter pulley with no rubber thingy will likely make your belts wear faster but that is pretty trivial.

[Igovert500]

Yeah, it's been a point of debate for years. Which my opinions have even changed sides a few times. Many, including Stealthee ( ) will tell you not to worry, it wont matter. I see valid arguments on both sides, but finding definitive proof that it leads to catostophic failure has yet to be shown...so I'd say if you already have it, use it and don't worry.

[Stealthee]

Originally Posted by Igovert500

Yeah, it's been a point of debate for years. Which my opinions have even changed sides a few times. Many, including Stealthee ( ) will tell you not to worry, it wont matter. I see valid arguments on both sides, but finding definitive proof that it leads to catostophic failure has yet to be shown...so I'd say if you already have it, use it and don't worry.

Did I hear my name?? There is absolutely zero facts proving a lightweight or underdrive pulley has caused an engine failure. There are several people with over 30k miles on one or the other with no abnormal damage. Spun bearings comes from low oil or contaminated oil. The accessory belts themselves act as a dampener. Plus the flywheel acts as a dampner. Even people running lightweight flywheels in combonation with a LW/UD pulley have yet to prove they will damage the engine. Another thing to consider is this. Consider how many cars LW/UD pulleys are made for. DOnt you think if they hurt the engine we would hear ALOT more about it?? Some 3s guy spins a bearing and the first thing he wants to do is blame the pulley.

That being said I intend on buying a 3sx one sometime soon. I may wait till I get my extra engine redone. No point in adding mods to a hurting enigne.

[w_hodel]

Thanks Guys you rock!!! I will keep my pulley on there then. Thanks for your advice, it really helps.

Bigg Willy