3SX or other non-OEM Custom Crank Pulley vibrations vs STOCK CRANK PULLEY smooth ???

[ProwlerGT]

I am a DOHC, 1995. Basically, the worst has happened to my crankshaft pulley... its separated away from the rubber inner wheel/pulley just as seen in the 3SX photo: 3SX Custom Crank Pulley STOCK Sized - 3000GT / Stealth*-*Mitsubishi 3000GT*/*Dodge Stealth Parts

I'm considering getting the stock size aluminum crank pulley that 3SX makes (no interest in the under-drive pulley), but my main concern is vibration. Am I going to notice any big vibration difference/addition using the aluminum one vs the stock one???

Certainly the 3SX one seems like it will last a lot longer, perhaps forever, but I don't wanna do damage to the other attached accessories and/or vibrate the whole car any more than it does when using the stock crank pulley. Anyone have the 3SX or non-OEM stock sized DOHC pulley and/or anyone else can comment on it?

The way I see it, if I got the 3SX or similar pulley I'd be removing the dampening effect that the stock pulley provides right? but it will last longer and yield more HP?

[mb3000]

You will not feel a solid pulley. Some people don't think the negative effects are substantial, while others wouldn't be caught dead without the OEM dampener.

I've yet to find indisputable evidence that proves solid pulleys will destroy cranks, so until I do I'm not going to bother swapping mine out.

[BaadVR4]

There are literally hundreds, if not thousands, of papers/treatises/etc/etc/etc addressing the issue of torsional vibration in crankshafts in internal combustion engines. Here is the simplistic, Wikipedia version:

Torsional vibration - Wikipedia, the free encyclopedia

I am probably not going to convert anyone to abandon their solid pulleys, but I feel honor bound to try.

Torsional vibration dampeners are used by every OEM automobile manufacturer. Every Nascar engine has one. All NHRA Pro Stock engines have one.

I promise you, if there were no reason to use a torsional vibration dampener instead of a solid pulley, none of these engines would have anything other than a solid pulley.

Mitsubishi (or Ford or Nissan or Toyota or Chevrolet or Dodge or any other OEM) would NEVER install a $30 dampener when a $2 pulley would do. NEVER.

And none of the world's race car engines would have a dampener unless it were absolutely required. Especially not when theirs go for $1000 plus each.

As for "indisputable" evidence, just read the papers. You could start with the failures of the ABC Motors Co. "Dragonfly" engine sold to the British military in 1917. Here's an excerpt:

"Crankshaft torsional vibration has been a problem with
aircraft engines since before World War I.
Crankshaft torsional vibration happens because each
power stroke tends to slightly twist the shaft. When
the power stroke subsides, the crankshaft untwists.
One would think that something as massive as a
crankshaft would not twist significantly, but any piece
of metal always deflects a bit when a force is applied,
and when large amounts of power are generated, the
forces can become huge indeed. The effects of
torsional vibration can be amplified by a phenomenon
called torsional resonance. Each crankshaft design
has a natural torsional frequency like the note of a
ringing bell or sound of a vibrating guitar string. If this
natural frequency coincides with the torsional
frequency of the crankshaft, the effects can be
devastating, resulting in broken crankshafts, lost
propeller blades, sheared accessories, and stripped
gear trains.
One of the first major scandals in British aviation
began in April of 1917 and involved torsional
vibration. Granville Bradshaw, chief designer of ABC
Motors, Ltd., secured a production contract from the
British Air Board for a new engine, the Dragonfly.
Bradshaw was a better salesman than engine
designer. The Dragonfly had not even run at the time
it was procured. When it did run, it was a miserable
failure because Bradshaw had managed to design its
crankshaft with a resonance exactly in the operating
range. By the time the contract was cancelled, 1147
of the engines had been built. This episode upset
British air-cooled engine development for years."

Just my 1.5 cents worth.

You will not feel a solid pulley. Some people don't think the negative effects are substantial, while others wouldn't be caught dead without the OEM dampener.

I've yet to find indisputable evidence that proves solid pulleys will destroy cranks, so until I do I'm not going to bother swapping mine out.

[VR-4 0wnz j00]

I would do it. I bought one for mine and no problems to report.

[DrGonzo]

Agreed with MB3000. I have heard the rumors about needing the dampener to save the crank. In a high rev'ing engine yes I could see wanting it to prevent High rev vibrations from entering into the crank, But I don't take my engine over 6500 rpms so I'm pretty confident that the solid will not do any harm. Plus I have yet to see proof so my thoughts are still just speculation. I'll be running a solid on my next motor.

[ProwlerGT]

I'll be running a solid on my next motor.

I love that vote of commitment there ... "THE NEXT MOTOR". lol. Its exactly how I feel too and I'm still just an NA.

Thanks a bunch for the rest of your comments. This reminds me of how helpful 3SI was in the early to mid parts of the 1st decade of the 2000's. Doesn't that sound OLD? lol. Here we are in 2012 talking about cars that stopped being made in 1999 and they are IMPORTS at that!! Just amazes me, and seeing a 3S on the road is becoming a lot less frequent too.

So basically, the consensus seems to be if I'm beefing up my setup to turbos and beyond stock turbo HP, then go with the stock crank pulley. RIGHT?

Anyone know where I can get the special tool to remove the pulley or is there some other method where I don't need a special tool?

Do ya'll think over-tightening the belt can cause the outer wheel pulley to separate from the inner wheel crank pulley? The whole reason I

[UTRacerX9]

I've had both a solid underdrive pulley from UR, and the stock sized solid one from 3SX. Neither one will increase vibrations that are noticeable, and I've run solids for over 40k now with no ill effects. There are other things that increase vibration far more, like going with solid motor mounts, or cam gears for a bit lumpier idle.

[green-lantern]

I've had one for years. I got it when I was NA and I liked it a lot. If you are NA then yes get it. IMO If you are TT get one also unless you are making 500+hp. Then you might want to buy a new stocker.

[ProwlerGT]

I know this may be a dumb question, but I can't recall what it looks like right now, but does the 3SX crank pulley come with the other belt pulley on the back side of it too?

I see the stock one has grooves on the other side of the pulley, but there isn't a double-sided pic of the 3SX pulley. Being lazy. I'm in bed and don't feel like going into the garage to look. lol

[mb3000]

oohnoo sells a special tool for it, or you can use a breker bar braced on the frame, disconnect fuel or spark, and "bump" crank the engine to get it loose