Lightweight crank pulley?

[Redstar]

The PO of my car managed to crack part of the lip on the crank pulley...

Since it's coming off soon, and I should probably replace it, I figured I'd upgrade a little bit. But I can't find any companies that still make lightened pulleys for the 5S.

Does anyone on here know of any companies that still make lightweight pulleys for the 5SFE?

Thanks!

[GENESIS]

i don't know a anyone that sells crank pulley your best bet would ebay but since light weight pulley don't have harmonic dampers like the oem it might put a strain on your oil pump, also oem fitment is the best.

[Redstar]

Generic ebay stuff scares me, but thanks for the help!

Unorthodox Racing used to make one, they haven't gotten back to me yet though.

I thought the rubber on the stock crank pulley was an isolator, not a damper/balancer. I think it's there more to suppress noise from the accessories, but I could be wrong.

[GENESIS]

Originally Posted by Redstar

Generic ebay stuff scares me, but thanks for the help!

Unorthodox Racing used to make one, they haven't gotten back to me yet though.

I thought the rubber on the stock crank pulley was an isolator, not a damper/balancer. I think it's there more to suppress noise from the accessories, but I could be wrong.

its an isolator too many way to call it but it keeps your oil pump alive especially when you increases hp,lets pretend unorthodox makes one and you bought it and install it it will stress the oil pump a bit you might get away with it maybe later down the road you turbo the car or increase hp by 20-30 that right there will start doing some damage plus it will stress the snout where the pulley bolts on to.unless you want it for look,there's no power to be had,my friend turboed his miata and forgot to take it off and cracked his oil pump the labor factor right there is too much .your probably better of getting pully for the alt and water pump but there's also consequences with that too.If you want to drop weight try getting some ebay headers stocks are heavy.

[Redstar]

Originally Posted by GENESIS

its an isolator too many way to call it but it keeps your oil pump alive especially when you increases hp,lets pretend unorthodox makes one and you bought it and install it it will stress the oil pump a bit you might get away with it maybe later down the road you turbo the car or increase hp by 20-30 that right there will start doing some damage plus it will stress the snout where the pulley bolts on to.unless you want it for look,there's no power to be had,my friend turboed his miata and forgot to take it off and cracked his oil pump the labor factor right there is too much .your probably better of getting pully for the alt and water pump but there's also consequences with that too.If you want to drop weight try getting some ebay headers stocks are heavy.

Thank you for your response.
I’m not looking for power, I would like to remove some rotating mass from the engine, and now happens to be a convenient time for me to do it. I don’t want to under drive anything, plus the alternator and water pump pulleys are already plenty light. I do have headers, I posted my dyno results in your header thread.

Forgive me, I’m going to play devil’s advocate here.

How will it destroy my oil pump? When your friend turbo’d his miata, did he run the same oil he was using when his engine was still NA? When power is doubled a poorly designed oil pump is more likely to fail even with a stock crank pulley. Was the pulley really the main cause of the failure? The Miata is known to have a some crank issues from the factory, I don’t think that’s a good example.

How is it going to stress the crank snout? It’s lighter, it’s making it easier for the crank to rotate and do it’s job. A harmonic dampers job is to reduce dangerous harmonics that are in tune with the natural frequency of the structure affected, think of the Tacoma Narrows bridge collapse.

The 5S crank is a stout piece, I haven’t actually seen mine so I’m not sure if it’s fully counterweighted or not, but look at how much abuse it takes in a high hp 3S stroker builds. Look at the size of the stock 5S pulley and then look at an ATI damper, there really isn’t much to the stock piece. It looks like it’s there more to cut NVH issues. Think of it this way, why did Toyota install balance shafts in some 5SFE’s and not others if they were worried about the effect of engine vibrations? These things are getting old too, the rubber is deteriorating – and we’re still not seeing people have issues with oil pumps and crank failure.


Now, I know there are holes in the above argument, and I know some of it is not quite accurate. I’m not trying to be an a$$, just trying to point out there are a lot of other issues at work and that there is quite a bit of hearsay that follows lightweight crank pulleys.

I have no idea what the actual resonate frequency of the 5S is. And I don’t have the time or data to figure it out right now. Even if I did it would be affected by damn near everything attached to the crank.


Cliff notes:
The 5S crank is strong, I don’t think a lightweight pulley is going to cause any damage.


So, does anybody reputable still make lightweight crank pulleys for the 5SFE?

[mrturrari]

Where did you hear that? The oil pump is driven by the timing belt and is not really effected by how much HP you make other then the oil may heat up more when you make more power. Now the stock pulley is a dampener to reduce vibrations in the engine but since our engine internals are bisemetrical they are really nothing compared to what you get in a V8. If your engine is semi-balanced, you really don't need it. I have been running an NST lightweight underdrive pulley for over 3 years now, ~20,000 miles and no problems whatsoever. I've even have my oil pump shimmed to give me 75psi and I rev to 7500rpms which does put more stress on the oil pump. The power increase is not noticable but if you combine it with other things like a lightweight flywheel it does improve the feel of the engine in my opinion. It much more quickly responds to rev matching up and down. Anyway some of these lighter pulleys are half the price of a new one from Toyota which makes it something to consider just for money you save.

[Redstar]

NST - The Leader In Toyota MR2 Pulleys

Looks like they might still be availible! Mrturrari, I see there is a lot of room for tension adjustment in the alternator, does the stock belt still fit or are you using something different?

[mrturrari]

I had to use a slightly smaller belt but they come in 1/2" increments at the auto parts store.

[TomsMR2]

the lip on my crank pully has been cracked for years, in multiple spots. no reason to replace it just for a cracked lip.

[Redstar]

^ Mine likes the taste of alternator belts. It's just nibbles at them right now, but since the pulley is off to replace the timing belt I figured I'd fix it before it becomes a bigger problem.

[RedStarr]

Hey Redstar...this is the other Redstarr chiming in...I just got in on a group buy of about 10 people on the MR2OC.com for a lightweight crank pulley for 3SGTE and 5SFE motors...I should be seeing my pulley next week Monday or so.

It's made by a company called Go Fast Bits in Australia. Allegedly, they're discontinued. I'd contact them anyway and maybe you'll get lucky.

[GENESIS]

I believed he used regular oil,also i forgot to mention that the oil pump was driven by the crankshaft it may be different for the 5sfe so I apologize for that,the miata oil pump is more direct to the crank pulley. pump sits right behind the pulley.the miata is know to have the snout failure from 89-90 1/2 nothing about oil pumps tho, my friend has a 95 miata was only doing 8 pounds of boost i got a call from him after while probably a month saying that something was grinding and he eventually lost oil pressure,he took of the oil pump and showed it to me and I could hear a bunch of parts loose in the inside and the back part was cracked,I have no clue how old it was but someone else in the forum had the same issue so he bought a new oil pump and put the stock pulley back and never had a problem again,that was almost a year ago and my friend with a turbo is now boosting 18pounds without problems.he ended up selling his lightweight pulley since it had an appetite for belts I don't know the brand of the pulley but il ask him tomorrow.

Originally Posted by Redstar

Thank you for your response.
I’m not looking for power, I would like to remove some rotating mass from the engine, and now happens to be a convenient time for me to do it. I don’t want to under drive anything, plus the alternator and water pump pulleys are already plenty light. I do have headers, I posted my dyno results in your header thread.

Forgive me, I’m going to play devil’s advocate here.

How will it destroy my oil pump? When your friend turbo’d his miata, did he run the same oil he was using when his engine was still NA? When power is doubled a poorly designed oil pump is more likely to fail even with a stock crank pulley. Was the pulley really the main cause of the failure? The Miata is known to have a some crank issues from the factory, I don’t think that’s a good example.

How is it going to stress the crank snout? It’s lighter, it’s making it easier for the crank to rotate and do it’s job. A harmonic dampers job is to reduce dangerous harmonics that are in tune with the natural frequency of the structure affected, think of the Tacoma Narrows bridge collapse.

The 5S crank is a stout piece, I haven’t actually seen mine so I’m not sure if it’s fully counterweighted or not, but look at how much abuse it takes in a high hp 3S stroker builds. Look at the size of the stock 5S pulley and then look at an ATI damper, there really isn’t much to the stock piece. It looks like it’s there more to cut NVH issues. Think of it this way, why did Toyota install balance shafts in some 5SFE’s and not others if they were worried about the effect of engine vibrations? These things are getting old too, the rubber is deteriorating – and we’re still not seeing people have issues with oil pumps and crank failure.


Now, I know there are holes in the above argument, and I know some of it is not quite accurate. I’m not trying to be an a$$, just trying to point out there are a lot of other issues at work and that there is quite a bit of hearsay that follows lightweight crank pulleys.

I have no idea what the actual resonate frequency of the 5S is. And I don’t have the time or data to figure it out right now. Even if I did it would be affected by damn near everything attached to the crank.


Cliff notes:
The 5S crank is strong, I don’t think a lightweight pulley is going to cause any damage.


So, does anybody reputable still make lightweight crank pulleys for the 5SFE?

[RedStarr]

I have my GFB pulley installed. 4lb 12oz vs. 13.6 oz...

Car revs somewhat faster. I'm happy.

[MR2enV]

Light weight pullysput stress on your crank/ rod bearings... The rubber in the stock pulley absorbs vibrations from the belts so it wont transfer to the crank......

[RedStarr]

I haven't found ANYTHING definitive about crank pulleys. Some horror stories (as with many things ie. Spec clutches, Rota wheels, airbags, you name it, there's a horror story somewhere) some guys who have run their car over 25-50K miles with lightweight crank pulleys and love it.

DSM guys take off their harmonic balancer as a way to get free horsepower. But then again, DSM guys...

Anyway, my point is that I understand why it can be bad, but I haven't found anything definitive, especially as it applies to our motors that says that lightweight crank pulleys cause engine failure. For as many guys that have said it's bad, I've heard as many guys say they've had it running on their cars for years since UR was making pulleys for Hondas and people were putting them on in the 90s.

One thing I WILL say is that my buddy has a built NA SE-R that revs up to 10,000rpm and he was advised to ditch his lightweight crank pulley for an ATI Super Damper pulley because of the increased vibrations that come with revving to 10,000rpm.

Will having a blueprinted and balanced motor eliminate the stress of not having a harmonic damper? How many miles are we talking before any POTENTIAL stress shows in a daily street driven motor?

[Redstar]

Originally Posted by MR2enV

Light weight pullysput stress on your crank/ rod bearings... The rubber in the stock pulley absorbs vibrations from the belts so it wont transfer to the crank......

No, not exactly. Think about it, your alternator wants to spin freely, it's your engine that's pulsing. Belts are made of rubber, why do you need another piece of rubber to dampen things?

Again, the crank in the 5S is strong. Couple that with a relativly low redline... If you have real evidence of a 5S failing because of a lightweight crank pulley please share.

Originally Posted by RedStarr

I have my GFB pulley installed. 4lb 12oz vs. 13.6 oz...

Car revs somewhat faster. I'm happy.

haven't found ANYTHING definitive about crank pulleys. Some horror stories (as with many things ie. Spec clutches, Rota wheels, airbags, you name it, there's a horror story somewhere) some guys who have run their car over 25-50K miles with lightweight crank pulleys and love it.

DSM guys take off their harmonic balancer as a way to get free horsepower. But then again, DSM guys...

Anyway, my point is that I understand why it can be bad, but I haven't found anything definitive, especially as it applies to our motors that says that lightweight crank pulleys cause engine failure. For as many guys that have said it's bad, I've heard as many guys say they've had it running on their cars for years since UR was making pulleys for Hondas and people were putting them on in the 90s.

One thing I WILL say is that my buddy has a built NA SE-R that revs up to 10,000rpm and he was advised to ditch his lightweight crank pulley for an ATI Super Damper pulley because of the increased vibrations that come with revving to 10,000rpm.

Will having a blueprinted and balanced motor eliminate the stress of not having a harmonic damper? How many miles are we talking before any POTENTIAL stress shows in a daily street driven motor?

Awesome! I'm ordering mine soon from NST.

I think the DSM guys remove balance shafts, same thing camary owners with a 5S do to free things up a bit.

Your buddy probably had issues because he was reaching the resonate frequency of the motor, which is what causes damage. Blue printing and balancing will help, but not eliminate the issue. I have no idea on mileage, but for what it's worth I don't think a lightweight pulley will damage a 5S.

[RedStarr]

As I'm reading up on info right now...cheap coolant vs. Toyota coolant, TRD thermostat vs. stock thermostat, etc...

I came across this on the Supraforums...
The Danger of Power Pulleys & Understanding the Harmonic Damper - Supraforums.com

And found this elsewhere...
.: MotoRex Performance Pte Ltd :.
Here's a quote:

4) "Is my crank pulley a harmonic/torsional/vibration damper or a harmonic balancer?"

People are getting their crank pulleys confused with the harmonic dampers found on some V6 / V8 engines. "Harmonic Balancer" is a term that is used loosely in the automotive industry. Technically, this type of device does not exist. The "balancer" part comes from engines that are externally balanced and have a counterweight cast into the damper, hence the merging of the two terms. None of the applications that we offer utilize a counterweight as part of the pulley as these engines are internally balanced.

The pulleys on most of the new import and smaller JDM engines have an elastomer (rubber ring) incorporated into the pulley that looks similar to a harmonic damper. The elastomer in the OEM pulley serves as an isolator, which is there to suppress natural vibration and noise from the engine itself, the A/C compressor, P/S pump, and alternator. This is what the manufacturers call NVH (Noise Vibration & Harshness) when referring to noticeable noise and vibration in the passenger compartment. It is important to note that in these applications, this elastomer is somewhat inadequate in size, as well as life span, to act as an effective torsional damper. If you look at the pulleys on some of the imports there is no rubber to be found at all. This is not to say that with our pulleys you will hear a ton of noise or feel more vibration from your engine compartment. Most who have installed and driven a vehicle with our pulleys will notice the engine actually feels smoother. This is a natural result of replacing the heavy steel crank pulley with a CNC-machined aerospace aluminum pulley. NVH is variable and unique to every car. NVH will increase with the installation of an aftermarket intake and/or exhaust, for example. Think of OEM intake systems in newer cars, they use baffles and resonators in the intake to quiet all the intake noise. Aftermarket intakes eliminate these resonators and create dramatic increases in engine noise from the throttle opening and closing. So to most tuners, certain types of NVH can make the driving experience more enjoyable.

The purpose of a traditional harmonic damper is to protect against crank failure from torsional movement. This is not necessary in most modern engines because of the many advances in engine design and materials. Factors such as stroke, displacement, inline, V configurations, power output, etc., do determine when and how these harmonics and torsional movements occur.

Again, there is a lot of internet hearsay about the pulleys. When engine problems occur, too often people are quick to blame the pulley first, rather than taking the time to look logically into why there was a problem. We hope that after reading this you will understand the crank pulleys better.

I'm waiting to hear word from Ken Blake. He's as tech about MKII motors as ANYONE I know so I'm curious to what he says.

I have the stock crankshaft pulley and belts still so one day I might just put it back on. Who knows...I'm still hearing BOTH sides of the argument and although there are warnings about this stuff, I think there are SO many people who've done this mod w/ no glaring ill effects. My accessories are working fine. I can shut off my car, leave it, and start it right back up, battery charged.

For now, it's lightweight crank pulley. I may change my mind later.

[Raptor13x]

^ that right there has me sold on picking up a lightweight crank pulley.

[328FTW]

I want a lightweight pulley. Then again I want a lot of things