www.gt4dc.co.uk
http://www.gt4dc.co.uk/forum/

Crank Pulley Question
http://www.gt4dc.co.uk/forum/viewtopic.php?f=13&t=6576
Page 1 of 2

Author:  Muddy Water [ Mon Jun 10, 2013 6:36 pm ]
Post subject:  Crank Pulley Question

Will a crank pulley from a Toyota MR2 SW20 3SGTE fit an ST185?
TIA

Author:  two_OH_five [ Mon Jun 10, 2013 7:01 pm ]
Post subject:  Re: Crank Pulley Question

I don't think so as the mr2 doesn't have a ps pump it uses a smaller belt

Author:  Muddy Water [ Mon Jun 10, 2013 7:11 pm ]
Post subject:  Re: Crank Pulley Question

two_OH_five wrote:
I don't think so as the mr2 doesn't have a ps pump it uses a smaller belt


Sorry, I'll clarify why I asked the question.
I'm looking to see if this http://www.garage7.com.au/home/index.php?option=com_virtuemart&page=shop.product_details&flypage=flypage.tpl&product_id=2884&Itemid=53 will fit my ST185.
Then I'll work out what belt size I'll need afterwards.

Author:  Nibbles [ Mon Jun 10, 2013 7:18 pm ]
Post subject:  Re: Crank Pulley Question

Is there any guarantee these are tuned specifically for the 3s crank resonance ?

The MR2 has 2 belt sections, but both are the larger diameter. I haven't counted whether they are the same number of ridges or measured offsets to know whether they'd fit.

On the MR2, the alternator is in the same place as our PS pump and driven from one belt, the aircon pump is inthe same place and driven from the other belt.

Author:  two_OH_five [ Mon Jun 10, 2013 7:18 pm ]
Post subject:  Re: Crank Pulley Question

Sorry, I'll clarify what I meant too :lol:

I think the number of ribs on the belts is different due to the reduced loading on the mr2 setup

I might be wrong but I'm sure this came up when removing an engine recently

Author:  two_OH_five [ Mon Jun 10, 2013 7:25 pm ]
Post subject:  Re: Crank Pulley Question

Ps
A thought struck me a while back

Currently the popular school of thought is that alloy pulley -> broken crank
Yet nobody bats an eyelid lopping off several kilos from the other end and I'm fairly sure that would have an effect on crank resonance

Author:  Muddy Water [ Mon Jun 10, 2013 7:43 pm ]
Post subject:  Re: Crank Pulley Question

Well the reason I'm looking into this pulley is because of Harmonic Resonance.

Pointers suggest that alloy pulleys = broken crank - because of Harmonic Resonance.
However, if the pulley was just installed without the engine crank being balanced then I would agree with the "pointers" above.

My situation is that, I currently have an Unorthodox Alloy Underdrive Pulley which was installed and part of the crank/engine balancing process.

So....
    1. Do I keep what I have?
    2. Get one of those super-duper pulleys (and get a rebalance)?
    3. Go back to a stock 185 pulley (and get a rebalance)?

Author:  Nibbles [ Mon Jun 10, 2013 7:53 pm ]
Post subject:  Re: Crank Pulley Question

If it is to be used mostly in 'race conditions' - i.e. constantly changing RPM then I wouldn't be bothered about resonannce.

Author:  Muddy Water [ Mon Jun 10, 2013 8:02 pm ]
Post subject:  Re: Crank Pulley Question

It'll be used for sprints and the occasional track day (i.e. not road legal).

BTW: Its for my engine which is using an HKS 2.2L Stroker kit (if that makes any difference)

Guess I'm trying to weigh up the risk.
Thinking that the super-duper pulley would alleviate any risk.
Just don't know if it fits on the crank and what the rib setup is.
(p.s. only need to run Power Steering and Alternator as I have an EWP)

Author:  Muddy Water [ Mon Jun 10, 2013 8:15 pm ]
Post subject:  Re: Crank Pulley Question

Seems Fensport do one:
http://www.fensport.co.uk/Parts/Model_18/Category_1/25

Author:  two_OH_five [ Mon Jun 10, 2013 9:00 pm ]
Post subject:  Re: Crank Pulley Question

I'd stick with the setup that was balanced

Author:  Sunny [ Mon Jun 10, 2013 9:47 pm ]
Post subject:  Re: Crank Pulley Question

Hi,

i'am pretty sure that you will not find any pulley that fit better then the oem one designed by toyota itself :)
pure mass is one of the best ways to be safe of resonance problems

greetz

Author:  TrackToyFour [ Mon Jun 10, 2013 10:10 pm ]
Post subject:  Re: Crank Pulley Question

two_OH_five wrote:
I'd stick with the setup that was balanced

+1 :mrgreen:

Author:  Muddy Water [ Mon Jun 10, 2013 10:24 pm ]
Post subject:  Re: Crank Pulley Question

OK thanks guys :D

Author:  Nibbles [ Tue Jun 11, 2013 6:29 pm ]
Post subject:  Re: Crank Pulley Question

two_OH_five wrote:
Ps
A thought struck me a while back

Currently the popular school of thought is that alloy pulley -> broken crank
Yet nobody bats an eyelid lopping off several kilos from the other end and I'm fairly sure that would have an effect on crank resonance


I was thinking about this today. If the flywheel has a much larger rotational mass than the crank (which I think it does thanks to diameter) then it will effectively be an 'immovable object' as far as resonance goes, therefore any mass change will only have a minimal effect on frequency. The resonant frequency will be down to mass of crank + pulley vs elasticity of crank.Will be a complex equation due to the distributed mass. Changing mass of a solid pulley will only change frequency of resonance and will not offer damping. The elastic effect of the rubber section in the stock pulley is what causes the damping

Page 1 of 2 All times are UTC + 1 hour
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/